Design Criteria of Civil Work Portion

1. General

a. Site location and condition

The project locations Genyem HPP 2X10 MW utilize the Sermo river flow run-off and the head of the elevation between river up-stream and down-stream. Therefore the Power-house will be allocated on the down stream area and the water flow back to down-stream of Sermo river through tail-race of its Power-station.

General Description of the Project Feature

Weir structure

River diversion and temporary coffer-dam

Water Intake structure

De-sedimentation structure

Head-race Box-culvert

Head-race tunnel

Adit-tunnel

Surge Shaft

Guard valve house

Penstock Tunnel

Open-face Penstock

Bifurcation

Hydro Gate

Power-house

Civil works design for Switch-yard and 70 KV Transmission-line

Infra-structures, such as: access-road, bridge, slope protection and etc.

Prior to perform the detailed design engineering site investigations shall be carried out, accordingly it consists of the followings.

Hydrology and hydraulic site investigation comprise of catchments area, river water flow and run-off, water discharge, water quality, hydraulic condition and etc.

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Topographical survey comprise of sites detailed survey are focus to main structures and infra structures, which are required to allocate Plant component of HPP.

Geological site-survey and investigation cover geotechnical investigation are consisting of boring-hole investigation, laboratory test and DCPT ( Dutch Cone Penetration Test). Many points number of boring-hole investigation are determined by several depth requirements, event laboratory-test include soil and rock physical - mechanic test to find the geological and geotechnical parameter as detailed design requirements

b. Code and standard

In principle the latest edition of codes and standards as listed below shall be applied.

ASTM American Society for Testing and Materials (2005)

JIS Japanese Industrial Standards (2004)

AASHTO American Association of States Highway and Transportation Officials (1997)

ACI American Concrete Institute (2005)

AISC Architecture Institute of JapanRecommendation for design of building form (2001)Design Standard for steel structure (2002)

JSCE Japan Society of Civil Engineering (2002

ASCE American Standards for Civil Engineering (2002))

AWS American Welding Society (2002)

UBC Uniform Building Code (1997)

SNI Standard Nasional Indonesia

2. Hydrology and Hydraulic Condition

Various hydrologic data such as daily rainfall, river discharge, catchments area shall be compiled and shall be added by the result data of Hydrology and Hydraulic site investigation; and then all data will be evaluated, interpretive and analyze for detailed design engineering.

a. Catchments area

b. Discharge.

On the basis of the calculation on the detailed design, the following discharges shall be determined.

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Average Annual Discharge

Average Monthly Discharge

Firm Discharge

Flood Discharge

c. Hydraulic calculation

d. Water Management

e. Water quality and sedimentation

3. Topographical Condition

a. Detailed Topography of Main Structure

b. Detailed Topography of Infra Structure, include civil-work for supporting to main –structure, such as access road, permanent road, slope protection and etc.

c. Plant Grade include Setting out for allocation the elevation and coordinate of main civil structure, hydro-gate, route-line of Head-race tunnel and penstock, main Generating Equipment and Power-house based on the analyze and interpretation of result of site Topography survey.

4. Geological condition

a. Prior to perform the Detailed Design, the geological fields Investigations shall be carried out consist primarily of the followings.

Lugeon tests

In-situ rock tests

Vertical logging

Grouting tests

Unconfined compression tests

Triaxial compression tests

Permeability tests

Underground water table measurement tests

Soil resistivity test

b. Interpretation & Analyze against to Geological condition for Hydraulic Structure and Main Structure will be described by Parameters and formulas

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as input design data for detailed Design are used by Civil & structure Engineer for hydraulic structure, Main- structure, and all foundations.

c. Interpretation & Analyze against to Geological Condition for Tunnel in particularly for rock mechanic tests and the field geological investigations is intended to secure approximate solutions to such problems as:

Determine to depth of bed-rock

Determine depth of rock weathering

Determine major layering conditions in soil material

Locate boundary of different materials

d. Interpretation & Analyze against to Geologic Condition for depth of excavation requirement for the several main structure during construction as in the followings

River Diversion

Hydraulic structure as Weir and rive-intake area

Head-race Box Culvert area

Penstock route line area

Power House area

5. Civil Design

a. River Diversion and temporary Coffer Dam/temporary Dyke

Allocation of temporary Coffer Dam based on topography condition

Topography map is performed by the result of site Topography survey at the area from the up-stream area up to down-stream area of Weir location to allocate up-stream and down-stream of temporary Coffer-dam. In related to location of temporary Coffer-dam, Topography map are performed to provide the route line of temporary river diversion during construction stage for Weir and water-intake area.

Hydrological Requirement

Hydrological analyze and interpretation against to the investigation result and secondary data for sufficient design of temporary Coffer-dam and river diversion are consisting of the following figures.

River water flow.

River discharge,

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10 years periodical flood discharge

daily/yearly rain-fall

Geological condition and interpretation.

Geological analyze and interpretation against to the investigation result and laboratory test result for sufficient design of temporary Coffer-dam and river diversion are consisting of the following figures.

Geo-technical data for excavation of river diversion

Geo-technical data for used embankment material

Geo-technical data for design temporary Coffer-dam foundation base.

Hydraulic calculation

Hydraulic calculation and analyze will be performed by the followings.

Stream water run-off for river diversion

Turbulence water-flow to temporary coffer-dam and river diversion

Hydraulic jump.

Stability of temporary Coffer-dam embankment

The embankment of temporary Coffer-dam will be designed by soil and rock coffering; accordingly the embankment stability is considered by the followings.

Overturning Stability.

Shear stability

Stability of seepage

Stability of water pressure

b. Weir structure

The Weir structure will be designed by coble concrete and reinforced concrete cover for the Weir body and stilling – basin particularly.

Hydraulic requirement

Hydraulic calculation and analyze will be performed by the following requirements.

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Maximum water level in the weir elevation

Minimum water level in the weir elevation

Maximum water discharge

Hydraulic jump.

Water pressure

Periodical Flood water

Turbulence water-flow

Topographical requirement

To allocate the Weir require Topographical map and data resulted by site survey, where indicate the contour line and terrain interpretationAccordingly the position of Weir can be determined by several technical considerations are related to other structures and technical requirements during detailed-design. The main purpose of Topographical survey result is described by the followings.

To design the lay-out of Weir structures area from its up-stream up to down stream area, include stilling basin

To indicate the coordinate of these structures and its structures parts.

To indicate the elevations of these structures and its structures parts.

To determine the proper structures positions.

To determine the structure level.

To determine water level

Geological condition and interpretation

Geological analyze and interpretation against to the investigation result and laboratory test result for sufficient design of Weir structure are consisting of the following figures.

Geo-technical data for excavation

Geo-technical data for Weir foundation

Geo-technical data against seepage

Geo-technical data against to foundation treatment

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Structural design calculation and analyze

Structural design calculation and analyze will be performed by the following condition.

Structure analyze of Periodical-flood discharge of 500 years condition

Structure analyze of Periodical-flood discharge of 100 years condition

Maximum water level condition

Minimum water level condition

Normal condition.

Water-turbulence condition

Structural design calculation and analyze will be applied by the following loading and pressure.

Water pressure of all kind conditions.

Live load

Dead load

Earth pressure

Allowable stress

Structure stability analyze

The Weir structure will be and calculated by the following stability.

Overturning Stability.

Shear stability

Stability of seepage

Stability of water pressure

Stability of horizontal force

Stability of both side of abutment

Up lift pressure

Up lift pressure will be analyzed by the several conditions, such as: minimum and maximum water level condition, flood condition and etc.

Stress Calculation

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In case to design and calculate the structure which related by soil, coble concrete and reinforced concrete, there are consideration of stress and strength parameter as follows:

Allowable soil bearing capacity

Allowable settlement

Concrete strength

Allowable shear strength

Allowable tensile strength

Treatment against Seepage

If the analyze of soil investigation result indicate seepage under Weir-foundation will be occurred, therefore treatment against seepage will be applied; such as: curtain grouting.

Foundation treatment requirement

If the analyze of soil investigation result indicate that weak soil are found under Weir structure; therefore foundation treatment will be applied, such as:

Enlarge of dimension of foundation base. Wooden piles are driven to sustain Weir structure. Grouting for soil improvement

Stilling basin requirement

The length of Stilling basin will be determined by hydraulic analyze against to the height of water overflow above the Weir due to the following conditions.

Periodical Flood discharge of 500 years condition

Periodical Flood discharge of 100 years condition

Maximum water level condition

c. Water Intake and De-Sedimentation structure

Hydrological and hydraulic requirement.

Hydraulic calculation and analyze will be performed by the following requirements.

Maximum water level in the weir elevation

Minimum water level in the weir elevation

Maximum discharge

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Hydraulic jump.

Water pressure

Periodical Flood water flow

Turbulence water-flow

Sedimentation

Topographical requirement

To allocate the Water Intake and De-Sedimentation structure require Topographical map and data resulted by site survey, where indicate the contour line and terrain interpretationAccordingly its position can be determined by several technical considerations are related to other structures and technical parameter requirements during detailed-design. The main purpose of Topographical survey result is described by the followings.

To design the lay-out of Water-intake and De-sedimentation structures area from its up-stream up to down stream area.

To indicate the coordinate of these structures and its structures parts.

To indicate the elevations of these structures and its structures parts.

To determine the proper structures positions

To determine water level

Geological condition and interpretation

Geological analyze and interpretation against to the investigation result and laboratory test result for sufficient design of Water-intake and De-sedimentation are consisting of the following figures.

Geo-technical data for structure excavation

Geo-technical data for structure foundations

Geo-technical data for foundation treatment

Structural design calculation formula

Structural design calculation and analyze for Water-intake and De-sedimentation will be performed by the following condition.

Periodical Flood discharge of 500 years condition

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Periodical Flood discharge of 100 years condition

Maximum water level condition

Minimum water level condition

Normal condition.

Water-turbulence condition

The closing of Hydro Gate condition

Structural design calculation and analyze will be applied by the following loading and pressure.

Water pressure of all kind conditions.

Live load

Dead load

Earth pressure

Allowable stress

Stability formula

Water Intake and De-Sedimentation structure will be and calculated by the following stability.

Overturning Stability.

Shear stability

Stability of seepage

Stability of water pressure

Stability of horizontal force

Stability of both side of abutment

Up lift pressure

Up lift pressure against to Water Intake and De-Sedimentation structure will be analyzed by the several conditions, such as: minimum and maximum water level condition, flood condition and etc.

Stress Calculation

In case to design and calculate for the Water Intake and De-Sedimentation structure which related by soil, coble concrete and reinforced concrete, there are consideration of stress and strength parameter as follows:

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Allowable soil bearing capacity

Allowable settlement

Concrete strength

Allowable shear strength

Allowable tensile strength

Foundation requirement

If the analyze of soil investigation result indicate that weak soil are found under the Water Intake and De-Sedimentation structure ; therefore foundation treatment will be applied, such as:

Enlarge of dimension of foundation base.

Grouting for soil improvement

d. Headrace Box Culvert

The Headrace Box Culvert is the underground water way structure due to achieve the elevation requirement at the lower level than original ground level; therefore it will be constructed by excavation, const ruction of Box Culvert and soil embankment for backfill up to original level. In related to this specification requirement Headrace Box Culvert is designed by reinforced concrete structure; accordingly all technical aspect shall be considered by detailed design engineering.

Hydraulic design

The Head Race Box Culvert is designed for a flow of 19 cubic meter and this flow corresponds to the maximum discharge for two Turbines occurring at a minimum water operating level

Hydraulic calculation and analyze will be performed by the following requirements.

Hydraulic analyze

Water pressure

Periodical Flood water analyze

Turbulence water-flow

The main parameter used in the hydraulic design includes:

Maximum water level in the weir elevation

Minimum water level in the weir elevation

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Maximum discharge

Head race Box Culvert length

Headrace Box Culvert (Dimension and Cross Section)

Water velocity in Headrace Box Culvert

Frictional resistance in Headrace Box Culvert

Hydraulic losses

Geological and geo-technical condition

Geological analyze and interpretation against to the investigation result and laboratory test result for sufficient design of the Headrace Box Culvert are consisting of the following figures.

Geological analyze for structure excavation Geo-technical analyze for structure foundations

Geo-technical analyze for foundation treatment

Geo-technical analyze for embankment

Geo-technical data for structural calculation, such as: earth pressure coefficient, consolidation, bearing capacity and etc.

Excavation requirement

Deep excavation as the level requirement shall be analyzed and calculated by the following considerations.

Circle sliding

Slope stabilization

Open cut excavation

Structural calculation.

Structural calculation of Headrace Box Culvert shall be analyzed by the followings.

All loadings analyze, such as: live loads and dead loads, including of soil embankment.

All Pressures calculation

Foundation structure calculation

Box culvert structure calculation

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Box culvert structure stability

Reinforced concrete calculation

Embankment requirement

Embankment requirement shall be considered by the followings.

Embankment material

Embankment shall be specified by layer per layer

Embankment material shall be compacted by layer per layer

e. Head Race Tunnel

The Head Race Tunnel is connected from the Headrace Box Culvert at the upstream profile, even to achieve the purposed elevation at under ground level are too depth from the original ground level. At its downstream end, its connected to the Penstock Tunnel which is steel lined Tunnel.The Tunnel-adit is situated near and up-stream of the Surge-tank and its main purpose is to provide on access for the construction of the Surge-tank and the up-stream portions of the headrace Tunnel.

Hydraulic design and Dimension

The Head Race Tunnel is designed for a flow of 19 cubic meter and this Tunnel flow corresponds to the maximum discharge for two Turbines occurring at a minimum water operating level

The main parameter used in the hydraulic design includes:

Maximum water level in the weir elevation

Minimum water level in the weir elevation

Maximum discharge

Head race tunnel length

Headrace Tunnel (Diameter and Cross Section)

Water velocity in headrace tunnel

Frictional resistance in tunnel

Hydraulic losses

Geological condition and interpretation

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Geological analyze and interpretation against to the investigation result and laboratory test result for sufficient design of the Headrace Tunnels are consisting of the following figures.

Geological analyze and condition for tunnel route, such as rock fault, rock crack and other rock condition

Geo-technical analyze for earth and rock opening

Geo-technical analyze for tunnel treatment analyze

Geo-technical analyze for rock support

Geo-technical data for structural calculation, such as: rock-mechanic coefficient, bearing capacity and etc.

Structure of tunnel portal

Rock support design

Depending on the rock characteristics along the tunnel four typical tunnel sections are developed for which rock support measure. The rock support measures used in the tunnel are consisting of the followings.

Rock bolts

Shotcrete and wire mesh

Steel rib support, for use in portions of the tunnel with extremely difficult ground conditions.

Grouting Pressure.

Contact and consolidation grouting along the tunnel is to be performed along the tunnel as required according the rock condition.

Contact grouting along the entire length of the tunnel.Consolidation grouting will apply in portion of the tunnel only, where the rock conditions require grouting. Determination of where the consolidation grouting will be required by the examination on field in situ rock condition.

Tunnel concrete lining

In generally concrete structure lining consist of two kind orientation is as follows:

To determine the thickness of reinforced concrete structure, include reinforcement requirements

To determine the elasticity modulus of rock mass

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The concrete lining is designed for internal and external water loads as applicable.

Internal PressuresThe lining is designed for full internal hydrodynamic pressures and will be investigated for cases where concrete will be considered un-cracked and cracked.

External Pressure.When the tunnel is dewatered for inspection or repair, the lining will be subjected to external hydrostatic loads.

Stress due to Internal Hydrodynamic Pressure.However, for the design of the lining, the maximum internal hydrodynamic pressures due to water hammer are reduced due to the presence of external water pressure

Stress due to external Hydrodynamic Pressure When the tunnel is dewatered for inspection or repair, the lining will be subjected to external hydrodynamic pressure

Pressures due to grouting are also considered.

f. Surge Tank

Allocation of Surge-tank will be determined by Detailed Topography Map

Geological condition and interpretation

Hydraulic consideration

Hydraulic Transient analyze

Design philosophy

The hydraulic transient analyzed included: 1. Hydraulic stability of the system composed of a

headrace tunnel, surge tank, penstock tunnel, and penstock, through different levels of plant regulation.

2. Determination of limiting sizes of various features of the power waterways by computing maximum and minimum of surge heights and pressure rises.

3. Water hammer and speed regulation studies.

Stability analyze

In order to reduce the problem to a practical level so that the mass oscillations in the surge tank and the

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assorted pressure variations could be investigated and compared, it was required that certain simplifying assumptions be made.

The following criteria for surge stability analysis were adopted:

1. In order to severely test the damping characteristics, assume small load changes at a low level of plant load and low conduit friction in the headrace tunnel.

2. If a differential or a restricted orifice surge tank is contemplated, the surge tank should be treated as a simple tank for small oscillations.

3. The velocity head effects in the headrace tunnel should be included in the analysis.

4. When a load change is imposed on the turbine, the water level in the surge tank begins to oscillate. The governors will act to maintain a constant speed by closing the turbine wicket gates as the surges act to increase the head, or by opening them as the surges decrease the head. The above means that, in practice, the governor or the turbine do not ensure constant discharge but a constant speed.

5. Since the wicket gates movements are very small, the water hammer effects are small and do not significantly affect the stability problem.

6. The efficiency of the units will be assumed to the

constant.

Surge calculation

Water-hammer calculation

Hydraulic calculation includes:

Design parameter

The main parameters used in the hydraulic design of the differential type surge tank were as follows:

- Maximum water level in the weir elevation- Minimum water level in the weir elevation- Maximum discharge- Head race tunnel length- Headrace Tunnel (Diameter and Cross Section)- Velocity in headrace tunnel- Horizontal cross section of main surge tank, riser

and port- Bottom of surge tank, elevation- Top or riser, elevation

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- Frictional resistance in tunnel (Load acceptance & Load rejection)

- Hydraulic losses (Load acceptance & Load rejection)

- Discharge coefficient at bottom side.- Coefficient in overflow weir formula

Hydraulic losses in terms of velocity head were computed for entrance curves, trash racks, transition upstream of gates, transition downstream of gate, reducers, stop log and gate slots, all of these located in the intake structure.

For the headrace tunnels, the hydraulic losses consisted of friction losses, and losses due to bends, transitions and reducers.

Stability analyze

Stability condition will be calculated.

Surge calculation

Hydraulic design of the differential surge tank was based on the following basic differential equation:

= ……………………………………. (1)

= ………………….(2)

= …………………..……………….(3)

Where: Qp = ± CpFp Zr > Zt : +

Zr < Zt : -Qrs = CB (Zr – Hr)3/2 when Zr<Hr; Qrs = 0

when Zr > HrV : velocity in headrace tunnelZr : water level in riserά : loss coefficient in headrace tunnelL : length of headrace tunnelg : acceleration of gravityQt : discharge for water turbineQp : discharge passing through portQrs : overflowing discharge from riserZt : water level in main tankFt : sectional area of main tankFr : sectional area of riserCp : resistance coefficient of portFp : sectional area of potC : coefficient of overflowB : length of overflow portion

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Hr : height of riser

Structure Design

The reinforced concrete design of the surge tank structure was based on the provisions of the Japanese Civil Engineering Association Guideline.

A concrete having a compressive strength of 250 kilograms per square centimeter at 28 days was specified.

The main structural features of the surge tank are the main tank concrete lining and the riser. Although these two features are physically connected, for structural analysis they were considered to act independently. The riser being a circular reinforced concrete structure was analyzed as a free standing elastic arch rigidly attached to the main tank concrete lining. The riser was assumed to be assisted by the main tank lining in resisting lateral forces, such as earthquake effects.

The lining was considered to comprise an elastic ring embedded in the surrounding rock. To improve on the quality of the rock, consolidation grouting was used around the tank opening and throughout its entire height. The tank lining was assumed to be assisted by the rock in resisting the internal and external water pressure. The effect of the bottom slab on the load distribution was also considered.

The pressures analyses are as follows:

Internal pressures

Case I : Water level in the tank at maximum elevation is corresponding to the maximum flood level in the water-intake.

Case II : Water level in the tank is corresponding to the maximum surge rise (full load rejection,). External water pressures disregarded.

Case III : Water level in the tank is corresponding to the steady state flood level in the water-intake. No water pressure on the outside. Lining subjected to internal water pressure.

Case IV :Water level in the tank is corresponding to the maximum surge rise with no water pressure on the outside. Lining subjected to internal water pressure.

External pressures

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For external water pressures, the tank was assumed to be empty on the ground water table surface

For structural analysis the riser was considered to be a circular arch fixed at its two ends in the lining of the main tank. The riser was analyzed for the following condition:

Water level in the main tank at minimum water level corresponding to the maximum drawdown

The tunnel lining below the surge tank was analyzed as an inverted circular arch with two vertical legs fixed into the bottom slab of the tank. The arch was assumed to be assisted by the surrounding rock in resisting the internal and external loads.

For the external water pressure effects, the tunnels were assumed to be empty and the ground water table around the surge tanks at maximum elevation. This level was based on actual field measurements at this location.

The allowable stresses used in the analysis of all the structural members of the surge tank mentioned above:

1. Tensile stresses in reinforcementб sa = 1,800 kg/m2, normal loadingб sa = 2,700 kg/m2 , exceptional loading

2. Compressive stresses in concreteб ca = 70 kg/cm2, normal loadingб ca = 105 kg/cm2 , exceptional loading

3. Shearing stresses in concreteζ a = 8.5 kg/cm2, normal loadingζ a = 13.0 kg/cm2 , exceptional loading

The exceptional loading mentioned above includes the effects of water hammer and surge rises.

Stability and treatment

g. Penstock Open-face and Penstock Tunnel (Civil works)

Topography

Geotechnical analyze and interpretation.

Anchor block Foundation

The anchor blocks provided along the open penstock are of a reinforced concrete and they provide the necessary anchorage against unbalanced hydraulic forces at the horizontal and vertical bends of the penstock.

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The anchor blocks are reinforced and they resist the unbalanced loading by their own weight. In locating the anchor blocks, in addition to the geometry, an attempt was made to place them on the best available rock along the penstock route.

1. General

Penstock design loads can be accurately determined and reliable methods of structural analysis are used in designing these structures. These factors, coupled with good quality control of fabrication and installation, were considered in deciding the use of the following design conditions with the corresponding factors of safety.

Normal Condition

This condition includes maximum static head plus pressure rise due to normal operation. The FS (Factor of Safety) is 3.0 based on the specified minimum ultimate tensile strength, but in no case the allowable stress is allowed to exceed 2/3 the specified minimum yield point.

Intermittent Condition

This includes conditions during filling and draining the penstock and earthquake during normal operation. The factor of safety (FS) is 2.25 based on the specified minimum ultimate tensile strength, but in no case the allowable stress is permitted to exceed 0.8 of the specified minimum yield point.

Emergency Condition

This condition includes governor cushioning stroke inoperative and part case closure in 2 L/s seconds at maximum rate. (L = conduit length, in meters, a = pressure wave velocity, in meters per second). The FS is 1.5 based on the specified minimum ultimate tensile strength, but in no case the allowable stress is permitted to exceed the specified minimum yield point.

Exceptional Condition

This condition includes malfunctioning of control equipment in the most adverse manner and was not used as a basis of design. It the maximum stress does not exceed the specified minimum ultimate tensile strength; the structural integrity of the penstock is assured. Precautions must be taken to minimize the probability of occurrence and effects of the exceptional condition.

The design of the tunnel steel liners, free-standing (no embedded) penstocks, and the manifolds was generally based on the above loading conditions and as described in the following paragraphs. For the tunnel steel liners, however, in case of internal pressures, the minimum plate thickness was computed, using design head for

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normal condition, on the basis of the pr/t stress for a free (no embedded) shell equal to the specified allowable for normal condition of operation.

In addition, the minimum plate thickness was also checked as required for handling by using the following empirical formula:

t =

The liners were also checked for external loading due to pressures from contact grouting or percolating water.

The normal internal pressure is distributed between the steel liner, concrete and rock. The maximum normal steel stress is obtained by combining the stresses produced in closing the gap between the liner and the concrete with that produced by further increase in pressure.

2. Free-Standing (Non Embedded) Penstocks

The free-standing non embedded penstocks exposed to view are a continuous beam with a number of intermediate supports between anchors and an expansion joint installed between the anchors. The structural analysis of this type of installation involves determination of many longitudinal and circumferential stresses which, when appropriately combined, result in maximum stresses not permitted to exceed the allowable stresses.

The stresses considered under normal operating conditions were:

Between Supports Longitudinal stresses due to beam bending. Longitudinal stresses due to longitudinal movement under

temperature changes and internal pressure.

Circumferential (hoop) stress due to internal pressure.

At Supports

Circumferential stresses in supporting ring girder duetobending and direct stresses and tensile stress due to internal pressure.

Longitudinal stresses in the shell at support due to beam bending and stresses in the shell due to longitudinal movement of the shell under temperature changes and internal pressure.

Bending stresses imposed by the rigid ring girder.

The penstock shell between supports was designed as a continuous beam. Several combinations of span lengths were studied in arriving at the optimum span for the existing conditions. The span lengths between supports and length of cantilevered sections adjacent to the expansion joint were proportioned so that the longitudinal bending

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moment at the supports was equal to or approaches the moment for a fixed end beam, M = ±W 12/12

The moments, reactions at the supports, and bending stresses were readily computed. Combined with these stresses were the stresses due to longitudinal forces imposed on the shell in overcoming the forces of friction at the supports and expansion joints.

3. Anchor Blocks

Anchor blocks were provided at all vertical and horizontal bends to prevent shifts in the pipeline during installation and to resist the forces which tend to cause displacement in a bent pipe under pressure.

Displacement at bends could be caused by a variety of forces. They may be caused by temperature changes, or by gravitational, dynamic and hydrostatic forces. The anchor blocks are reinforced concrete structures. They were designed to resist the above forces by transferring them to the foundation in accordance with the physical properties of the rock.

The forces which were assumed to act on the anchors, the anchors were designed to resist the above forces through their own weight. The resultant of all forces was required to intersect the base within its middle third. The weight of the pipe and contained water and the weight of the concrete in the anchor itself were included in the combination of forces. The size of the anchor blocks were influenced by the sliding coefficient or friction between concrete and foundation rock. In order to increase stability, an effort was made to place the anchors on good rock.

Penstock Tunnel

Design of the steel liners in the tunnels for internal pressure is normally based on the theory of equating the deflections of steel, concrete and rock. For this purpose, the physical properties of the steel liners, concrete and surrounding rock must be determined. The modulus of elasticity of the rock used in the design is not the modulus determined by laboratory tests of small samples of rock, but the modulus of the rock mass in place determined by field tests.

A radial gap may exist between the steel liner and the concrete prior to introducing the internal pressure. Such a gap could be caused by water temperatures lower than the temperature of the surrounding concrete. The liner must carry internal pressure, unaided by the embedment, until the gap is closed and the liner comes into contact with the concrete. The remainder of the load from internal pressure will then be distributed between the liner, the concrete embedment and the surrounding rock, with the concrete and rock carrying most of the load.

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The stresses produced in the liner shell solely in closing the gap due to temperature differential are calculated using the followings:

St = Ee ∆T

in which St = tensile stress in kilogram per square centimeter, E = modulus of elasticity in kilogram per square centimeter, e = coefficient of expansion equal to 6.5 x 10-6, and ∆T = differential temperature in degree Fahrenheit.

Distribution of the internal pressure between the steel liner, concrete and rock, after closure of the gap, is computed

For external water pressure, the basic approach was used which has been shown to produce results which are in good achievement with test values. Provisions were made to assure stability of the steel liner against external pressures after dewatering. The above permitted grouting around the penstock and provided adequate safety against higher-than-anticipated pore water or seepage pressures.

h. Power House

Building design of Power-house is semi underground means a part of building arrangement in under-ground and another part on over ground; therefore deep open excavation is required

Allocation Topography

Geological and Geo-technical conditional

Foundation Structure

The substructure for the main powerhouse units consists of first and second stage concrete. The first stage concrete comprised of the bottom slab of the draft tube, the slab under the penstock valve at the proper elevation, the upstream and downstream main longitudinal walls of the powerhouse and the main transverse walls between the units. The portion of the transverse walls between the slab under the penstock valve and the main downstream powerhouse wall was over six meters thick. Structural analysis of the first stage concrete of the substructure was included in and became part of the main frame analysis for construction stages 1 and 2.

The second stage concrete consisted of second stage concrete around the draft tube, the spiral case, the turbine pit, the turbine and generator support, and the concrete around the generator. Most of the machine hall floor at was also part of the second stage concrete.

The design of the second stage concrete involved mainly the design of the turbine and generator support and the reinforcement around the spiral casing and the draft tube.

Building structure

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The power house structure is one continuous monolithic structure without transverse contraction or expansion joints. For construction purpose, transverse construction joints were provided as required for the adopted construction sequence with the steel reinforcement passing through these joints. The tailrace structure, incorporating also the most downstream portion of the draft tube, is separated from the rest of the powerhouse by a vertical longitudinal contraction joint. This enables the tailrace structure to perform structurally independently from the main powerhouse structure as required by its different size, geometry and loading. Despite the provision of the contraction joint, however, the tailrace structure was assumed to participate in resisting sliding and overturning tendencies of the main powerhouse structure, thus adding considerably to the overall stability and safety of the powerhouse.

The powerhouse also houses the machine (repair) shop which will be used for routine maintenance, and the service bay which will be used for service, maintenance, control, and operation of the plant. Most of the service bay area is located on the back side of the powerhouse, as said previously, is part of the main power house structure. The erection bay is at elevation properly, and is located at ± 0.00 FFL (Finished Floor Level)

Behind the powerhouse is a penstock manifold consisting of one bifurcations, for each penstock, through which one penstock is connected to two units. The bifurcation, portion of the penstock and the branch pipes are all embedded in a system of reinforced concrete anchor blocks designed to resist various loading conditions produced by the operation of the units. These anchor blocks are separated from the powerhouse by a contraction joint.

The powerhouse is constructed of reinforced concrete except for the roof which consists of steel girders with both sides rigidly connected to the reinforced concrete columns. The roof structure consists of a system of beams supported by steel girders and a deck. The powerhouse basically consists of a substructure and super-structure.

The turbines pedestal are embedded in mass concrete with longitudinal entrances over the top of the turbines at the proper elevation. To access to each spiral case is provided from an entrance on the floor at elevation of± 0.00 FFL . The accesses to the draft tubes are provided from an entrance on the floor at elevation of ± 0.00 FFL go through the down stair. The final entrance into the spiral case and the draft tube is affected through a standard type manhole normally used for this purpose.

Foundation design.

Based on the topography and geotechnical condition the foundation of Power-house is designed by spread foundation principally; even these foundations are consisting of Sub-structure, building foundation and equipment foundation.Prior to design of foundation, it shall design and consider to excavation. Due to the existing of ground elevation is too high to reach the lowest elevation for generating-equipment arrangement of draft-tube

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and tail-race; particularly, therefore the deep excavation of Power-house area is requiredIn order to deep excavation are required, accordingly soil condition shall be considered to determine the excavation design. Foundation design covers the followings,

Excavation designExcavation design shall be calculated by excavation slope stability during construction work for Sub-structure; accordingly open excavation shall be designed by many steps of open cut excavation

Sub-structure designSub-structure shall be designed by Reinforced concrete structure, even will be calculated against to the following load and pressure.

Dead load of both super structure and substructure

Live load

Earth pressures

Hydraulic pressure

Earthquake

Building foundation

Equipment foundation

Architecture of Power House

The exterior architectural treatment of the superstructure is of a contemporary design and void of any unnecessary ornamentation.

The alls of the machine hall of the powerhouse to the level above the crane girders have no windows. There is only one single line of small windows around the hall located above the crane girders and immediately below the ceiling. Windows are provided on the main wall of the powerhouse These windows are used for the offices, the main entrance hall, and other auxiliary rooms, such as conference room, reception room. The control room at is provided with windows.

Interior finishes consist mainly of exposed concrete and cement mortar. Exposed concrete finish has been used for the columns and the crane girders. The ceiling of the machine hall consists of steel girders and beams and a deck plate with oil paint finish.

The control room floor has a finish consisting of a vinyl – asbestos tile on cement mortar, a skirting of vinyl emulsion paint finish on cement mortar, and walls finished with cement mortar or asbestos cement sheets. Acoustic rock wool tiles with plywood were used for the ceiling.

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The floor at the main entrance was finished with ceramic tile. The main wall consists of a glass screen and a door. Aluminum panels were used for the ceiling. Ceramic tiles were also used on the floors of rooms such as offices, manager room, conference room, etc. The floors of the turbines and generator rooms received a cement mortar finish 30 millimeter thick.

i. Miscellaneous

Access road

Slope protection

Construction Material for civil work include concrete materials, such as: Quarry, borrow pit and spoil bank

6. Mechanical design

a Hydraulic analysis for Penstock

A penstock is a pressure conduit which conveys water from source (Surge-tank) to the hydraulic turbine. Scope of hydraulic analysis for penstock includes two (2) items:

a. Determine economical pipe diameterb. Determine maximum hydraulic pressure due to hydrostatic pressure

and the pressure rise due to water hammer and surging.

Economical Pipe Diameters

Diameter of the penstocks should be suitable decided in consideration of the construction cost, power loss (head loss) and other factors. The penstock construction cost will be minimum if the penstock diameter smaller, but the head loss will be minimum if the diameter is larger. There should be optimum diameter to be considered as economical diameter.

Head LossHead loss is important parameters to be calculated in

designing penstock. Head loss in hydro - power penstock includes:

Head Loss due to Friction

Whereas:hf = Water head loss due to frictionn = Kutter’s coefficient of roughnessL = Length of conduit

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V = Velocity of flowR = Hydraulic radius of conduit

In the case of circular section, when the conduit inner diameter is

The value of n for normal steel pipes ranges from 0.010 to 0.013. Another alternative the value f can be provided from Moody Diagram.

Head Loss due to Entrance

Equation :

= Head loss due to entrance

fe = Loss coefficient of entranceV = Flow velocity after entranceRemarks : Loss coefficient of entrance (fe)Circular bell mouth entrance 0.1Square bell mouth entrance 0.2Square entrance without bell mouth 0.5

Head Loss due to Valves

Table 1. Head loss due to valve

Equation :

hv : Head loss due to valvesfv : Loss coefficient for valvesV : Average flow velocity in the pipe, upper and Downstream of the Valve

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Figure 1. Head loss due to valves

Minor Head LossMinor head loss due to reduce or increaser of diameter, branch, bend etc. will be calculated according standards.

Maximum Hydraulic Pressure for Designing

The maximum hydraulic pressure to be used for designing, when it is filled with water, should be the maximum value foreseeable in consideration of the hydrostatic pressure and the pressure rise due to water hammer and surging.

The pressure rise due to water hammer depends on the efficiency of the surge tank, block instrument, pressure controller, etc. and also on the constant of the pipe. The maximum pressure rise takes place at the center of the block instrument (the guide vane in the case of Francis turbines, diminishes along pipe, and vanishes at the expanded part of the head tank (Surge-tank).

The diminishing rate of the water hammer pressure along the pipe can be considered to be proportional to the pipe length. Attention should be paid when the surge tank is comparatively slender or of restricted orifice type, because the water hammer pressure does not vanish at the surge tank bottom.

The maximum expected value at each point should be added to calculate the addition of the water hammer pressure and the pressure rise at the surge tank.

b. Mechanical Design of Penstock

After decided the pipe diameter and maximum pressure from hydraulic analysis, further step is mechanical design it’s include pipe thickness, material, construction, stress calculation and safety factor and other requirement of the penstock. Some item should be analysis in this scope include:

Materials of Penstock and Minimum Plate Thickness

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The minimum plate thickness of the main pressure linings, when no stiffeners are used, should be not less than the value calculated by the following equation. The minimum plate thickness should not fall below 6 mm even though the pipe diameter is small and stiffeners are used.

Whereas : t : Plate thickness including the allowance ( mm )

D : Inside diameter of pipe (mm)

Allowable due to Corrosion and Abrasion Factor

The pate wall thickness to be used for the construction of the main pressure linings should have an allowance in excess of 1.5 mm – 4 mm against the corrosion and abrasion. This allowance can be reduced when sufficient method have been paid regarding corrosion abrasion.

Thickness of the Lowest part ( area ) of the Penstock

The thickness of the lowest part of the penstock should be able to instant to the maximum hydraulic pressure due to the hydrostatic pressure and the pressure rise due to water hammer and surging with safety factor minimum 2.The permissible pressure for lowest part of the penstock can be decided from following formula:

Ha = Maximum head can be with should (m)

a = Permissible stress of the pipe (kg/cm2)t = Thickness of pipe (cm)η = Welding efficiency (90%)D = Pipe diameter (cm)ε = Corrosion factor (0.4 cm)

Thickness variation of Upper Part of the Penstock

The Thickness of upper part of the penstock can be reduced proportionally the working pressure due to the hydrostatic and water hammer with safety factor not less than safety factor of lowest part of the penstock. Practically the thickness of the penstock will be made in three or four graded.

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Loading consideration

a. Loading to be Consideration

The main pressure linings should be designed as to be safe against the internal pressure, self-weight of conduit, weight of water in the conduit, temperature change and external pressure.The principal factor in determining the plate thickness of the main pressure linings is the circumferential hoop tension caused by the internal pressure. In the cases of conduits with long span and ring supported type, such factors as the self-weight of conduit, weight of water in the conduit and temperature change play a large role is deciding the plate thickness.

b. Combinations of Loads

The loads mentioned in the previous article should be considered for the following combinations:

When the pipe is filled with water: internal pressure, self-weight of the pipe, weight of water in the pipe, temperature change.

When the pipe is being filled with water: weight of the water in the pipe.

When the pipe is empty: external pressure.

Design Conditions of Main Pressure Lining

The main pressure linings should be designed to be suitable for the following conditions with respect to the loads with in article 2.6.

When the pipe is filled with water :

The stressing acting circumferentially, longitudinally and perpendicularly to the longitudinal line and also the combined stress should respectively be less than the allowable stress of the materials to be used. The allowable unit stress may be increased by 1.35 when the shell bending stress has been considered.

The combined stress is to be calculated by the following equation :

Whereas: Page 30 of 56

σg : Combined stressσ1 : Circumferential stress (tension is considered

Positive)σ2 : Pipe axial direction stress (tension is Considered positive)τ : Shearing stress acting perpendicularly to the

Pipe axial

When the pipe is being filled with water :

The circumferential stress should be not more than 1.5 times of the allowable stress of the materials to be used.

When the pipe is empty

The pipe should not buckle against an external pressure which is 1.5 times of the acting external pressure.

Materials of Penstock

Materials to be used for the construction of penstock should be the kind listed in Table 1. After a through study ha been made, other materials than those listed in Table 1 maybe used for the construction of penstock.

Table 2: Kind of Materials

Rolled Steel for General Structure JIS G3101 (1966)Rolled Steel for Welded Structure JIS G3106 (1966)Hot rolled Atmospheric Corrosion Resisting Steel for Welded Structure

JIS G3114 (1968)

Rolled Steel for Boilers and Other Pressure Vessels

JIS G3103 (1966)

Rolled Steel for Rivets JIS G3104 (1965)Carbon Steel Castings JIS G5101 (1958)Carbon Steel Forgings JIS G3201 (1964)Grey Iron Castings JIS G5501 (1956)

Allowable Stress

The allowable stress to be used for design calculations should be below the value listed in Table 3. It is, however, necessary to consider the joints efficiency when materials are to be joint. When materials not specified in Table 3 are to be used, their allowable stress should be carefully decided in consideration of their quality and characteristics.

Table 3 : Allowable Stress of Materials

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Note: In the cases of field rivet joints, the allowable shearing stress of rivets and the allowable bearing stress of steel plates are 80% of the respective values in the above table.

Supporting and miscellaneous requirement

Bend Pipe

The radius of curvature of bend pipes should be more than 3 times of the inside diameter of the pipe and the swing angle at each pipe should be less than 7˚. However, under such inevitable cases as right angle bend pipes, bifurcating pipes, and the like, the radius of curvature may be more than 2 times of the inside diameter of the pipe.

Branch Pipe

Branch pipe are, in principle, to be of bifurcating type, and the bifurcating part should be suitably reinforced so that no substantial stress concentration or deformation takes place at the bifurcating points.

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Man Holes

Penstock should have manholes required for the proper maintenance in consideration of their length, diameter and inclination. Manholes should be ellipse in the form, and their standard dimensions are 450 mm minimum at their major axis and 350 mm minimum at their minor axis.

Expansion Joints

Expansion joints should be provided at parts where considerable stress or deformation would occur on the longitudinal direction, due to the temperature variations and other external forces.Expansion joints should have a sufficient strength and water-tightness and should be so constructed as to satisfactorily perform their function against the longitudinal expansion and contractionThe range of the temperature variations to be used for the calculation of the expended or contracted length of penstocks should be determined in consideration of the maximum and the minimum temperatures of the erection site.The sliding length of sleeve type expansion joints should have an allowance in excess of 5 cm for the designed value.

Air Pipes or Air Valves

Air pipes or air valves should be provided so that it may be possible to maintain the difference between the pressures of inside and outside of the penstock during transmitting water within 0.2 kg/cm2.In the event the air pipe or air valve may be frozen during severe winter days, or when they may be clogged by fallen leaves, effective measure should be taken so that their function will not be disturbed.

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Main pipe

Branch I

Figure 3 : Types of multi-branching pipes

Branch II

Anchor Bolts, Anchor Bands and Thrust collars

When the penstock top is exposed at the anchor block position, or when the covering concrete on the penstock is not thick and the tensile stress is working on the anchor block, such construction as anchor bolts, anchor bands, and the like should be provided against the external force to securely anchor the penstock to the anchor block.In parts penstocks are fixed within an anchor block, or buried in a tunnel, they should be fixed by anchor bolts, anchor bands, or other construction against the buoyancy of penstock at the concrete placement and also by thrust collars against the longitudinal external force.

Supporting Points of Piers

Supporting parts of piers of penstock should be so constructed as to permit safe and free sliding of penstock against its axial displacement.

Ring Girders and Their Piers

Ring supports should be so designed as to be safe against the inner pressure, self-weight of penstock, water weight within the penstock, temperature variations, earthquake, wind pressure.Earthquake, for the sake of designing is considered as a force working horizontally and its seismic coefficient in a horizontal plane is not less than 0.1.Wind pressure, for the sake of designing, is a pressure working horizontally on an area projected on a vertical plane of the penstock, and is not less than 0.2 ton/m2.Permissible stress for designing ring piers is the value shown in Table 2 , when temperature variations, earthquake or wind pressure are not considered. The permissible stress may be increased by 1.5 of the value shown in the above mentioned table when temperature variations, earthquake, wind pressure are considered.

c. Hydraulic Gate

Gate Types

Gates are made up of, generally, gate leaves, gate frames anchorages and hoist. The gate leaf consists of the parts on which direct water pressure is applied and the bearings through which the load applied on the gate leaf is transmitted to the gate frames and anchorages.Seal guides are the part embedded in the concrete and on which surface the sealing part of the gate leaf contacts to make the gate water-tight.Gate frames and anchorages are the part through which the load on the gate bearings is transmitted to the concrete. With the exception

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of the hinge type gates, the seal guide and the gate frames are commonly called as “Seal guide “.Hoists are the devices to open or close the gate leaves. For the Genyem hydro power stations, the types of gates have been proposed in the contract are:

Radial weir gate 1 unit

Roller intake gate 2 unit

Slide tail race gate 2 unit

Design Requirement

The gates should be so designed as to be in conformity with the following conditions:

a. The type and the dimensions should be suitable for the place to be installed and for the object to be used.

b. Gates should have sufficient safety against the expected load.

c. Gates should have ample water-tightness.

d. Gates should be capable of being easily and positively operated.

e. Gates should have good durability.

f. Gates should not have harmful vibration during operation.

g. Gates should be capable of being easily maintained.

Power Source for Operation

Gates should have a power source for operation. However, for simple gates manual operating devices may be used. Gates should generally have a power source for quick and positive operation. Electric motors are usually used as the power source.

Internal combustion engines may be used for Gates of such small capacity dam as torrent intake dams. In this instance, the type and the number of units of the power source should be decided in consideration of the positiveness of the control, frequency of flood, speed of gathering water, etc. No power source is required for automatic flash boards, of which operation is made by means of the buoyancy, and for small gates of which operation can be made manually.

Emergency Closing Device

Emergency closing device should be provided for Gates which require quick closing operation. It is necessary to provide an emergency closing device on the hoists of Gates at the inlets,

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outlets and water tanks which are required to shut off the passing water to minimize the damage when the head race, penstocks or turbine generator develops trouble.

The emergency closing device lowers the gate leaf by disengaging it from the power source by means of a clutch, and its lowering speed is 4 – 8 m/min. Brakes are used for controlling the lowering speed, which may be a hand brake, magnet brake, centrifugal brake, fan brake, hydraulic pump brake, electric brake, etc.

Materials of Gates

The materials to be used for making Gates should conform with the materials shown in Table 4 Through study should be made in the event materials other than those specified in Table 4 are to be used.

Table 4: Materials

1 Rolled steel for general structures JIS G 31012 Rolled steel for rivets JIS G 31043 Rolled steel for welded structures JIS G 31064 Hot rolled atmospheric corrosion resisting steel for

welded structuresJIS G 3114

5 Cold finished steel bars JIS G 31236 Carbon steel forgings JIS G 32017 Carbon steel tubes for general structural purpose JIS G 34448 Carbon steel pipes for ordinary piping JIS G 34529 Carbon steel pipes for pressure service JIS G 345410 Carbon steel pipes for high pressure service JIS G 345511 Austenitic stainless steel pipes JIS G 345912 Wire Ropes JIS G 352513 Uncoated stress relieved wires and strands for pre

stressed concreteJIS G 3536

14 Carbon steel for machine structural use JIS G 405115 Nickel chromium steel JIS G 410216 Nickel chromium molybdenum steel JIS G 410317 Chromium steel JIS G 410418 Chromium molybdenum steel JIS G 410519 Stainless steel bars JIS G 430320 Hot rolled stainless steel sheets and plates JIS G 430421 Cold rolled stainless steel sheets and plates JIS G 430522 Hot rolled stainless steel strip JIS G 430623 Cold rolled stainless steel strips JIS G 430724 Carbon steel castings JIS G 510125 Alloy steel castings for structural purposes JIS G 511126 Stainless steel castings JIS G 512127 Grey iron castings JIS G 550128 Spheroidal graphite castings JIS G 550229 Brass sheets and plates JIS H 320130 Bronze castings JIS H 511131 Phosphor bronze castings JIS H 511332 Leaded bronze castings JIS H 5115

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Allowable Stresses

Allowable stresses of materials to be used for the design calculation of the Gates should be as follows:

When Gates are in loaded condition during normal operating time :

Table 5. Loaded condition during normal operating time

No MaterialsSS41 SM 41Thickness≤40 mm

SM 50Thickness≤40 mm

1 Axial tensile stress ( per net section area )

1200 1600

2 Axial compressive stress ( per gross area section )Compressive members ( l = buckling length of member )r = radius of gyration of area of gross section area of members splice plates

0 < l/r ≤ 1101,100–0.048 (l/r)2

l/r > 1106,350,000 / (l/r)2

1,100

0 < l/r ≤ 901,500 – 0.09 (l/r)2

l/r > 906,350,000 / (l/r)2

1,500

3 Bending stressBending tensile stress ( per net section area )Bending compressive stress ( per gross section area )l = Flange supporting lengthb = Flange widthwhen compressive flanges are directly welded or riveted as in the case of skin plates

1,200

1,100 – 0.5 (l/b)2

However l/b ≤ 30

1,100

1,600

1,500 – 0.9 (l/b)2

However l/b ≤ 30

1,500

4 Shearing stress (per gross section area)

700 900

For SS 41 and SM 41 thicker than 40 mm, the stresses should be multiplied by 0.92.For SM 50 thicker than 40 mm, the stresses should be multiplied by 0.94.

Table 6. Steel Castings

Material SC 46Axial tensile stressAxial compressive stressBending stressShearing stressBearing stress

1,2001,2001,2007001,700

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In the cases of high pressure gates used during normal operating time and when the stress due to vibration need not be considered, the allowable stresses may be 80% of those mentioned in the foregoing table.

In the cases of Gates not in use during normal operating time, the allowable stresses may be increased by 15% of those mentioned in the foregoing table.

Allowable stresses of materials not listed in the foregoing table should be decided on the basis of the above table.

Increase of Allowable Stresses Stresses under seismic conditions should be increase by 50 % of

those stipulated in the preceding article.

Load to be considered

In designing the gate leaf, it is necessary to consider the self-weight, statically water pressure, mud pressure, wave pressure, buoyancy, hoisting force, ice pressure, seismic acceleration force, hydrodynamic pressure for seismic, variation of water pressure due to flowing water, and the increase of load resulting from the vibration caused by the variation of water pressure.The design standard on large dam should be referred to in order to obtain the values of statically water pressure, mud pressure, seismic acceleration force, hydrodynamic pressure for seismic. The static water pressure is the force that acts perpendicularly on the surface contacting the gate leaf, and should be calculated from the following equation:

P = w0HWhere:P : static water pressure at an optional point on the contacting

surface (ton/m2)w0 : weight of water ( ton/m2)H : head (m) to the optional point on the contacting surface

from the value obtained by adding the wave height to the water level directly upstream of the gate leaf.

The wave height for the purpose of the calculating the value H above, should be the “ wave height due to wind “ for the normal period, and should be the addition of “wave height due to wind” and “wave height due to seismic”.

Following equations may be used for obtaining the wave height :

Wave height due to wind :

hw = 0.0612 √UF + 0.762 – 0.274 √F (m)

where:hw : total wave height (m)U : wind velocity (m/sec)F : distance between the shores (km) when it is less

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than 72.5 km

Wave height due to seismic :

Where he : half of wave height (m)R : seismic coefficientr : seismic period (sec)Ho : head (m)

The wave pressure is the pressure that acts on the gate leaf when the wave hits the gate leaf, and is caused by superimposed waves and /or breakers.

Variation of water pressure due to flowing water is the variation of the water pressure distribution surrounding the gate leaf depending upon the shape of gate leaf and seal guides, when the gate leaf is operated in flowing water, so that the horizontal and the perpendicular loads on the gate leaf is different from those in static water. Accordingly, it is necessary to consider the effect of the variation of water pressure on the gate leaf strength and the operating load.

The increase of load due to vibration is, according to the actual results, about 15% of the design load in the worst conditions.7-11)

Combinations Of Load

The load dealt with in the preceding article should be considered in the following combinations:

During normal working periods :Self weight, static water pressure, mud pressure, wave pressure, buoyancy, variation of water pressure due to flowing water and increase due ti vibration resulting from the above variation, hoisting force, ice pressure.

During earthquake

Self weight, static water pressure, mud pressure, wave pressure, buoyancy, ice pressure, seismic acceleration force, hydrodynamic pressure for seismic.

Shape of Gate Leaf, Seal Guide and Embedded Part

The shape of gate leaf, seal guide and embedded part should be carefully selected so as to be a combination of optimum shapes for the intended application.For example in the case of long span gates, with overflow, the gate leaf top should be so curved as not to cause negative pressure by the overflow but to provide a sufficient means for supplying air to

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the back of the gate leaf. For instance, side plates as shown in the sketch on both sides of the gate leaf top may be provided to facilitate air supply. Another instance when the overflowing water depth is not deep

May be to provide a suitable numbers of spoiler at the downstream end of the gate leaf top. Generally speaking, it is best to minimize the horizontal part at the lower end of the gate leaf.

Margin Skin Plates

Steel plates to be used as the skin plate should have more than 1 mm margin in the thickness against the corrosion and abrasion. This article may be waived when special materials are used for making the skin plate or special surface treatment is provided on the skin plate surface.It is advisable to give a margin of 2-4 mm thickness for the plates to which access is difficult or which cannot be repainted or cleaned after erection work is completed.t is also advisable to provide certain margin, as in the case of skin plates, to those parts where water is in constant contact during operation of the gate.

Minimum thickness and slenderness ratio

The minimum thickness of the steel materials to be used as the main strength members of gates, including the corrosion allowance, should be more than 6mm for steel plates, and more than 5mm for steel sections.The slenderness ratio of the main compressive members of gates should be not more than 120 and that of the secondary members not more than 150.When calculating the slenderness ratio, the buckling length of a compressive member in the Rahmen structure is considerably longer than the distance between the panel joints so that due attention should be paid to the buckling length.The buckling length of a compressive member is the result if multiplication of buckling coefficient according to the structure if

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the member and the supporting condition at the member end, with the member length.

Deflection due to bending of gate leaf

The deflection of gate leaf due to bending should be not more than 1/800 of the span, except in the special cases.In the cases of metal touch sealing gates, it is advisable that the deflection be 1/1000-1/2000 so as to ensure good water tightness. In the cases of long span gates, of which span ranges between 30 and 50 meters, and when due consideration has been paid for the water-tightness, stability of structure, vibration, and other points, it may be permissible to increase the deflection to a maximum of 1/600. In the cases of stop logs, of which water tightness can be lower than the normal gates, it is possible to reduce the deflection requirement to 1/600.It is, however, not permissible at all to allow for the reduction in the deflection requirements as far as such members as radial gate supports, which may buckle or collapse due to excessive deflection, are concerned.

Bearing Part

The bearing part and the fitting members of rollers and pins of the gate leaf should be so constructed as to safely and positively transmit the load acting on the gate leaf to the gate frame or embedded part, and to smoothly operate the gate leaf and to permit easy maintenance.

It is advisable that the bearing pressure on the roller shaft or radial gate bearing shaft be less than 150 kg/cm2 against the projected area of the shaft. It Is however, permissible to increase the value up to 250 kg/cm2 when special consideration is paid to the quality of material of shaft and bearing and also to the method of lubrication.

The surface pressure of metal sliding surface of slide gates should be 50 kg/cm2 under normal conditions and 150 kg/cm2 under static conditions.

Gate Frame and Embedded Part

The gate frame and embedded part should be so constructed as to transmit safely and positively the load on the gate leaf bearing part to the concrete, and also to have an optimum shape for the intended.

Regarding the roller rail supporting beams of large size roller gates, the rolling tire rail supporting beams of rolling gates, and the similar parts, it is advisable to calculate them as elastic support beams. The embedded part of radial gates receives concentrated the total water pressure load from the bearing part, and it is necessary to have anchoring members to transmit the concentrated load to as large an area as possible of the concrete pier or to the dam.

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Protection of Part contacting with the gate leaf bottom

The part contacting with the gate leaf bottom should be capable of safely supporting the perpendicular load transmitted from the gate leaf and should be suitably protected with steel plate or other materials so as to ensure good water –tightness.

Generally, the part contacting with the gate leaf bottom is protected with steel section with a sufficient rigidity. When sand and gravel are mixed with the flowing water, it is advisable to cover the concrete surface adjacent to the gate leaf bottom contacting part with steel plates or anti abrasive steel.

Hoisting load

The hoisting load of gate leaves should consider the self weight of the gate leaf, self weight of the ballast, friction at the bearing part and sealing part and other necessary loads.

The self weight of the gate leaf and the ballast may be reduced, when they submerge in water, by the weight of water with the volume corresponding to the part submerged in water.

In calculation the friction force, the friction coefficient stipulated in Table 7 should be used as a standard value.

Table 7. Friction Coefficients

Classification of Friction CoefficientRolling friction of bearing part roller 0.1Sliding friction of shaft at the bearing part 0.2Sliding friction of metals at the water tight part 0.3 – 0.6Sliding friction of metal and rubber at the water tight part

0.5 – 0.7

Friction when roller bearings are used on the bearing part shaft ( value for the shaft )

0.01 – 0.02

Other than the above mentioned load, it is necessary to consider various water pressure caused by the flowing water around the gate leaf.Special attention should also be paid to the load working on the upper and bottom faces of the gate leaf due to water pressure, because the value of such load may become considerable.

Hoisting Speed

The hoisting speed of gate leaves should be suitable for the application. In consideration of the effect of hoisting speed of gate leaves to the up-down streams by the discharge of water, the hoisting speed is generally set as 0.3 – 0.5 meter/minute. In the cases of automatic control or other purpose where slow hoisting speed is desired, the speed may be decreased to 0.1 m/min. The hoisting speed may also be increased to 1 m/min. depending upon the circumstances. For emergency closure, a speed ranging from 4 to 8 m/min. is often adopted.

Lift

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The lift of gate leaves should be so determined that the water flows unobstructed when they are lifted to the fullest stroke. The flood discharge gates should be so designed to have a clearance under their highest position to the flowing water surface so as to permit free passage of various kinds of goods that may be carried with flooding water, and the clearance is generally given 1.5 meters or more to the designed flood water level. This is also applicable to the bearing shaft position of radial gates.

Motor Capacity

The motor capacity should be more than 120% of the calculated hoisting force and the motor starting torque should be more than 200% of the rated torque. For the operation of ordinary gates, three phase squirrel cage induction motors are used. Because unsolved matters are often left in calculating the hoisting load, and allowance of more than 20% is usually given to the calculated value.Chances are that the gates are often left unused for a long period of time, and are affected by silting or rusting. Voltage may drop in the feeding cables due to the starting current. For these reasons, the motor starting torque is specified to have more than 200% allowance.In cases of using wound rotor induction motors for the purpose of limiting the starting current, the motor maximum torque may be more than 200%.

Capacity of Emergency Power Source

The capacity of emergency power source should be such that it is capable of operating the gate leaf positively.In the event of using internal combustion engines, their capacity should be more than 120% of the calculated operating force.In the event of adopting generators, their capacity should be determined in consideration of the motor starting load, voltage drop up to the motor terminal, and the magnet brake power when a magnet brake is provided for the hoist.

Diameters of Drum, Sheaves and Wire Rope

The diameter of the drum should be not less than 400 times of the wire diameter of the wire rope, and that of the sheaves should be not less than 350 times of the wire diameter of the wire rope. The safety factor of the wire rope of Gates under load should be not less than 8.

7. Structural design

a. Design method

b. Concrete design

The specified minimum compressive strength of concrete by cylinder test at 28 days age shall be as follows :

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For lean concrete : 15 N/mm2 (Grade 15)For General Structure : 25 N/mm2 (Grade 25)For Important Structure* / Marine Structure : 30 N/mm2 (Grade 30)

*Turbine foundation, turbine building, central control building.

Table 8. For grading of aggregate

Grading RequirementGrading Requirements – ASTM C33

Nominal Size (Sieves)

Size Number

All concrete 300mm or less in thickness, unless otherwise indicated

19mm to No.4 64

All other concrete work, unless otherwise indicated

38mm to No.4 467

c. Reinforced concrete design

ASTM A615 Grade 60 for a deformed barASTM A615 Grade 40 for a round barMinimum Yield strength : 280 N/mm2 for Grade 40

420 N/mm2 for Grade 60

Table 9. Sizes and Dimensions for Deformed Bar

Bar Designation Number

Nominal Diameter (mm)

Cross Sectional Area (mm2)

Perimeter (cm)

10 9.53 78 2.9913 12.70 132 4.0016 15.88 200 5.0019 19.05 284 5.9822 22.23 380 6.9825 25.40 490 8.00

Table 10. Sizes and Dimensions for Round Bar

Bar Designation Number

Nominal Diameter (mm)

Cross Sectional Area (mm2)

Perimeter (cm)

8 8.00 50 2.5110 10.00 79 3.1412 12.00 113 3.77

d. Loading

Loading shall be comply with in the Owner’s specification.

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The design loads for buildings and other structures shall be as specified in ASCE 7-05 except as specified.

1) Dead Load (DL)

Main material unit weights are as follows and for other materials not described below the C1 and C2 in ASCE7-98 shall be referred.

Steel : 77.0 kN/m3

Aluminum : 26.5 kN/m3

Reinforced Concrete : 24.0 kN/m3

Plain concrete : 24.0 kN/m3

Cement Mortar : 22.6 kN/m3

Wood : 7.8 kN/m3

Asphalt : 22.6 kN/m3

Soil : 17.7 kN/m3

Soil (submerged) : 7.8 kN/m3

Gravel : 19.2 kN/m3

Brick : 19.6 kN/m3

2) Live Load (LL)

a) Live load shall be based on the Owner’s specification as indicated below, for another occupancy or use the values shown in the table 4-1 in ASCE 7-05

b) Live load shall comprise assumed unit loading deemed sufficient to provide moving loads, portable equipment, fixtures and parts and also thermal shrinkage and creep load and other necessary load.

c) Live load shall not be superimposed over the area occupied by the equipment unless there is space for possible storage or traffic under the equipment. The floors shall be designed for the removal of equipment as required per the equipment removal arrangement.

d) Floor live load

The floor live load are determined by indicated in the Owner’s specification.

3) Machine Load (ML)

Equipment loads shall be defined as the loads of equipments, its accessories and content and divided into the following three categories.

a) Empty weight (ML1)

b) Operation load (ML2)

c) Full water test load (ML3)

ML1 shall be used only for the stability check, ML2 and ML3 shall be combined with other loads as specified hereinafter. Loads by piping and cable shall be included in this machine load (ML).

4) Thermal Load (TL)

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Thermal loads due to equipment or piping acting on the fixed or sliding points thereof shall be considered according to the mechanical engineer’s information in the structural design.

5) Construction Load (CL)

Construction load shall include significant temporary loads of false work, construction plant and equipment, etc., including any loading from these as determined by the manufacturer or erector.

6) Crane/Hoist Load

The vertical and horizontal load from electric overhead traveling cranes shall be as per manufacturer’s loading data. In the absence of specific information the following impact loads will be considered as minimum.

Table 11.

Direction Impact Loading Applied toVertical Force 20% of Max.

wheel loadsElectric overhead crane

Lateral Force 10% of Max.wheel loads

Electric overhead crane

Longitudinal Force

15% of Max.wheel loads

Electric overhead crane

Crane dead loads (CDL) shall comprise weight of trolley and bridge under a non-operating condition. Crane operating loads (COL) shall comprise lift load, weight of trolley and bridge and their impact under operating condition.Crane testing loads (CTL) shall comprise 125% of lift load, weight of trolley and bridge and their impact under test operating condition.

7) Wind Loads (WL)

Wind load shall be calculated by multiplying velocity pressure from wind velocity on meteorological observation data by wind force coefficient from shape of structure types. The design wind pressure shall be calculated by the following equation.

WL = A * P (kN)P = C * q * Ce * Iw (kN/m2)

Where : WL : Wind Load (kN)A : Effective Area (m2)P : Wind Pressure (kN/m2)C : Wind Force Coefficient q : Wind Velocity Pressure (kN/m2)

q = V2/16 (kg/m2)V = 33.3 m/sec (120 km/h)Q = 693.3 kg/m2 0.7 kN/m2

Iw : Importance Factor = 1.15 Ce : Distribution Factor

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Table 12.

Height (m) Ce Interpolated0 – 5 1.41

6 1.458 1.519 1.54

12 1.6118 1.7225 1.8230 1.8737 1.9350 2.03

8).Allowable soil bearing capacity

Soil

1 ) Allowable soil bearing capacity Qa = 1/F ( ά * C * Nc + β * γ1 * B * Nγ + γ2 * Df * Nq ) sQa = 1/F ( ά * C * Nc + β * γ1 * B * Nγ + ½ * γ2 * Df * Nq ) where : Qa : Allowable soil bearing capacity of long term (kN/m2)

sQa : Allowable soil bearing capacity of short term (kN/m2)C : Cohesion of soil below foundation (kN/m2)γ1 : Unit weight of soil below foundation bottom (kN/m2)γ2 : Unit weight of soil above foundation bottom (kN/m2)(Use submerged unit weight for the soil below groundwater level)ά, β : Shape factor of foundation as given belowDf : Dept of foundation in ground (m)B : Shorter side length of foundation (m)(Use diameter for octagonal and round foundation)L : Longer side length of foundation (m)F : Factor of Safety (Long term F= 3,Short Term F=1.5)

Table 13. Table of ά and β

Shape of Foundation

Continuous

Square Rectangular Round

ά 1.0 1.3 1 + 0.3B/L 1.3β 0.5 0.4 0.5 – 0.1B/L 0.3

Table 14. Table of φ, Nc, Nγ , Nq

Φ Nc Nγ Nq0° 5.3 0 3.05° 5.3 0 3.4

10° 5.3 0 3.915° 6.5 1.2 4.720° 7.9 2.0 5.925° 9.9 3.3 7.628° 11.4 4.4 9.132° 20.9 10.6 16.136° 42.2 30.5 33.6

40° or 95.7 114.0 83.2

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moreNc, Nγ , Nq : Bearing capacity factor in connection with ΦΦ : Internal friction of soil

2) Allowable SettlementFor important structures and foundations, unless otherwise required by the Specification from Equipment manufacturer, the total Settlement shall not exceed 25 mm. The important Structures and Foundations mean the will have an effect on Plant operation

9).Earthquake (Seismic Load)

The site falls into zone-4 of seismic zone of the “Tata Cara Perencanaan Ketahanan Gempa Untuk Bangunan Gedung” SNI 03-1726-2002 (Earthquake Design Regulation for Building) published by “Direktorat Penyelidikan Masalah Bangunan” Ministry of Public Work.

Regular structures shall be designed against nominal earthquake loading due to effect of design Earthquake in the direction of each main axis of the structure, in form of equivalent static normal earthquake load in accordance with Article 6 of the SNI 03-1726-2002

i) For Superstructure such as Buildings/Structures/Pipe racks above ground parts(According to SNI 03-1726-2002)

- Horizontal Forces

The total horizontal earthquake base shear force in a given direction shall be (SNI 03-1726-2002, Clause 6.1.2) determined from the following equation.

V = (C1 * I / R) Wt

Where : V :Total design lateral force or shear (kN)C1 : Earthquake respond factor obtained from earthquake

response spectrum for T1 < Tc C1 = Am for T1 > Tc C1 = Ar / T1

Tc : 1.0 sec (Assume the area is categorize “Soft Land”)I : Importance factor I = I1 * 12 = 1.4R : Earthquake reduction factorWt :Total weight of the building including suitable live load

(kN)

For T1 T1 < ξ * nξ : 0.17 (Natural tremble time of building structure)n : StoryHowever, T1 shall be confirm with result of detail computing

Table 15. Design Earthquake Response Spectrum

Earthquake Area

Hard LandTc = 0.5 sec

Mid-Hard LandTc = 0.6 sec

Soft LandTc = 1.0 sec

Am Ar Am Ar Am Ar

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1 0.10 0.05 0.13 0.08 0.20 0.202 0.30 0.15 0.38 0.23 0.50 0.503 0.45 0.23 0.55 0.33 0.75 0.754 0.60 0.30 0.70 0.42 0.85 0.855 0.70 0.35 0.83 0.50 0.90 0.906 0.83 0.42 0.90 0.54 0.95 0.95

Table 16. Importance Factor for Various Building and Structure

Building CategoryImportance Factor11 12 I

Monument and monumental structures 1.0 1.6 1.6Important post-earthquakes buildings such as hospitals, fresh water installation, power plant, emergency and rescue centers, radio facility and TV stations

1.4 1.0 1.4

Table 17. Seismic Coefficient

Name of Building / Structure C1 I RC1 * I/R

Turbine hall Moment resisting steel frame

0.82 1.4 5.5 0.22

Ordinary braced steel frame 0.85 1.4 5.6 0.21Reinforced Concrete Structural of Auxiliary Building / Shed

Moment resisting concrete frame

0.85 1.4 5.5 0.22

Steel structure of Auxiliary Building, Shed and Plant Structure

Moment resisting steel frame

0.85 1.4 5.5 0.22

Ordinary braced steel frame 0.85 1.4 5.6 0.21

- Vertical Forces

Building structures that have high sensitivity to gravitational load sauce as balcony, canopy and long span cantilever beam, transfer beam at high raise building structure supporting gravitational load from two or more levels about it and long span pre-stressed concrete beam must be calculated against vertical movement of soils surface due to effect of Design Earthquake, in form of equivalent static nominal vertical earthquake load to be examined whether it works upward or downward which value must be calculated as multiplication Cv Vertical Earthquake Response Factor and gravitational load, including the corresponding live load.

Cv = ψ * A0 * I = 0.29Fv = Cv * W = 0.29Wt

Where : ψ : coefficient depends on the Seismic zone where the building

structure is located, ψ = 0.6A0 : Peak ground of soil surface, A0 = 0.34I : Important factor, I – 1.4Fv : Vertical Earthquake ForceWt : Total Weight of the building including suitable live load (kN)

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- Vertical Distribution of Horizontal Earthquake Force

Nominal basic shear load V according to Section 8.2 shall be distributed along the height of the building structure to be equivalent static nominal Fi working at the center of gravity at the ith level in according with the following equation:

Fi = (Wi * Zi / ΣWi * Zi) * V

Where: Fi : Design seismic force applied to level I respectively (kN)Wi: That portion of W located at or assigned to level I Respectively (kN)Zi : Heigh above the base to level I respectively (m)

ii) For Structural Components of Equipment Support

VE = Cd * Wt

Where : VE : Shear lateral force (kN)Cd : Above ground seismic coefficient

Stack Foundation Cd = 0.25 Other FoundationCd = 0.20

Wt : Above ground weight (kN)

iii) For Non-Structural (Architectural, Mechanical & Electrical) Components

1) In the absence of detailed supporting structure analysis

In the absence of detailed supporting structure analysis, the horizontal earthquake force for non-structural (architectural, mechanical and electrical) components and their attachments shall be calculated according to Article 10.5 of SNI 03-1726-2002.

Each of the non-structural (architectural, mechanical and electrical) components shall be designed against an equivalent static nominal earthquake load Fp working in the most severe direction which the value can be determined according to equation.

Fp = (C1/R)*Kp * P * Wp

Where : C1 :The earthquake Response Factor from the Design

Earthquake Response Spectrum according to Figure 2 of SNI 03-1726-2002 for fundamental

natural frequency period of the building structure bearing the non-structural (architectural, mechanical and electrical) components

Wp :Weight of non-structural componentR :The earthquake reduction factor of the bearing

structureP :The performance factor of the componentKp :The response amplification coefficient

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Kp = 1 + (Zp/Zn)

Where : Zp : The elevation of the componentZn : The elevation of top floor

Fp is intended to make sure that the non-structural component can perfectly transmit the horizontal force due to earthquake to the structural component.

2) In the presence of detailed supporting structure analysis

When the supporting structure data is available in advance, equivalent static nominal earthquake load Fp will be derived from structural analysis of the supporting structure.

iv) For Below Ground Parts both Superstructure and Equipment Support

VF = k * WF k = 0.1 * (1.0 – H1 / 40) * Z

Where : VF : Below ground shear lateral force (kN)WF : Below ground weight (kN)k : Seismic coefficient of below groundH1 : Below ground height (m)Z : Seismic zone factor (Z = 1.0)

10). Pressure (Soil, wind, hydraulic)

The following equation shall be applied for calculating soil pressure

i) For sand or sandy clay

Ka = tan2 (45 - φ/2)Kp = tan2 (45 + φ/2)K = 1 - sin φΦ = angle of internal friction

ii) For clay (φ = 0)

Active soil pressurePa = Kaγh – 2C (Ka)0,5

Active soil pressurePa = Kaγh – 2C (Ka)0,5

Where : γ = Density of Soil (kN/m3)C = Coefficient of CohesionH = Depth between ground level and level concerned (m)

For all underground wall design a surcharge of 12.5 kN/m2 shall be applied unless otherwise any other conditions required in the Project site.

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11). Structural design

Design Method

1) The following design methods are applied in this structural design

Concrete : Limit Strength Design (ACI 2005)Steel : Allowable Stress Design (AISC 2005)

2) D > Fy/26000 . LD : depth of fully stressed beams and girdersFy : Steel yield stress in kg/cm2L : Beam or girder span

For A36 steel, for simple supported memberL/D < 22and in any caseL/D < 30

3) In any case for Cantilevered beamL/D < 5

4) In any case for Strut beam L/D < 22

5) For Flexural members supporting reciprocating or rotating machineryL/D < 12

6) Deflection (δ) of beams, girders under normal loadδ = L/300 or 40 mm, whichever is less

7) All connection shall be shop welded and field bolted and shall conform as a minimum to AISC Manual Table II, III and IV unless otherwise noted.

8) Slenderness ratio (λc) of steel column λc < 200

9) a. Horizontal deflection of girder due to wind load (∆WL)∆WL girder < 180

b.For girder supporting windows, horizontal and vertical deflections be consistent with manufacturer requirements c.Vertical deflection of carrier beam (δcarrier beam)

δcarrier beam < L/300 or 25 mm, wherever lesser

12). Steel Structure design.

ASTM A36

Tension strength (Fu) : 400 N/mm2

Minimum Yield strength (Fy) : 245 N/mm2

Allowable stress for tension (Ft)Fracture in net section : 0.5Fu = 200 N/mm2

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Allowable stress for tension (Ft)Yielding in gross section : 0.6Fy = 145 N/mm2

Allowable stress for tension (Ft)For compact section : 0.66Fy = 160N/mm2

Allowable stress for shear (Fv)Shear in beam web For fasteners &welds: 0.4Fy = 95 N/mm2

Allowable stress for Compression (Fa)For KL / r < Cc : Fa = A / B

Where : KL/r : Slenderness ratioCc = (2π2 E / fy)0.5

A = (1 – ( KL / r)2 / 2Cc2 ) * FvB = 5/3 + 3( KL/r) / 8Cc – (KL/r)3 / 8Cc3

For KL / r > Cc : Fa = 12π2E / 23 (KL/r)2

Allowable stress for bending (Fb)Major axis bendingFor Lb < Lc : Fb = 0.66Fy (N/mm2)

Where : Lb : Maximum unbraced length of the compression flange at wich allowable bending stress may be taken at 0.66Fy, or as determined by AISC Specification Ea. (F1-3) or (F2-3), when applicable (cm)

In case of Fy = 25 kN/cm2

Lc = 63.3bf / Fy0.5 (cm) and 13,888/((d/Af) * Fy) (cm) or Lc = 12.66bf (cm) and 555.6/ (d/Af) (cm)

For Non-compact member and Lb < Lc :

Fb = (0.79 – 0.005*bf/tf)*Fy<0.60Fy or

For Non-compact member and Lb < 12.66bf (cm) :

Fb = 0.60 Fy (N/mm2)

For Compact and Non-compact member and Lb > Lc

Fb is the larger value of Fb1 or Fb2

Fb1 = 8274 * Cb / Ld / Af (kN / cm2)

Fb2

For L < rT < (354,000Cb/Fy)0.5 or L/rT < (14,160Cb)0.5

Fb2 = (2/3 – 36(L/rT)2 / (1,530,000 * Cb)) * Fy (kN/cm2)

For L > rT < (354,000Cb/Fy)0.5 or L/rT < (14,160Cb)0.5

Fb2 = 117.,212 * Cb / (L/rT)2 (kN/cm2)

Where :

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L : Unsupported length of compression flange (cm)rT : Radius of gyration of a section comprising the compression

flange plus 1/3 of compression web area, taken about an axis in the plane of the web (cm)

Af : Area of compression flange (cm2)Cb : Bending coefficient depending on moment gradient

1.75 + 1.05(M1/M2) + 0.3(M1/M2)2 < 2.3

Minor axis bending :Fb = 0.75Fy (N/mm2)

Allowable stress for Bearing (Fp)On the contact surface surface and pins : Fp = 0.9Fv = 220 kN/mm2

on the contact area of expansions : Fp = { (Fy – 90 ) / 138 } * 1.67drollers and rockers Where : d = the diameter of roller or rocker (cm)

High strength bolts

ASTM A325 or equivalentAllowable stress for tension :300 N/mm2

Allowable stress for shear Threads in shear plane :117 N/mm2 for Slip Critical Connection)

145 N/mm2(for Bearing TypeConnection)Threads excluded in shear plane :117 N/mm2(for Slip Critical Connection)

207N/mm2(for Bearing TypeConnection)

Common bolts

ASTM A307 or equivalentAllowable stress for tension : 135 N/mm2

Allowable stress for shear : 65 N/mm2

Welds

Base metal ASTM A36 Welding electrode AWS A5.1 E70XX or equivalentAllowable stress for Complete -Penetration Groove weld : Same as of the Base MetalAllowable stress for Fillet Weld : Same as of the allowable shear stress

of the Base Metal

Embedded Steel PlateASTM A36 or equivalentMinimum Yield Strength : 245 N/mm2

ASTM A3108 or equivalentMinimum Yield Strength : 245 N/mm2

Anchor BoltsASTM A36 or equivalentMinimum Yield Strength : 245 N/mm2

Allowable stress for tension : 132 N/mm2

Allowable stress for shear : 65 N/mm2

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j. Structural Stability

8. Interfacing between Civil Work Portion(C-W P) and Generating Equipment Plant (G-E Plant)

a. Hydrology & Hydraulic Analyze include Water-quality, hydro-losses. b. Topography Map of Power House area & 70 KV Tran’s Line, include

Coordinate & Elevation for allocation general Plant and route-line.

c. Geology condition, in particular for soil resistivity

c. Interfacing between Generating Equipment Plants lay out (G-E P) and building lay-out (C-W P).

d. Interfacing between Penstock – line(C-W P). to Power House Equipment (G-E P), include interfacing between Inlet Penstock and Inlet Valve.

d. Interfacing among Hydro turbine, include Draft tube & Spiral Casing(G-E P) and foundation structure (CWP).

e. Interfacing between Power-house foundations(C-W P). and grounding & lightning system (G-E P)

f. Interfacing between Power-house building structure (C-W P) and Mechanical Building-facilities (G-E P), such as Over Head Crane, lighting, plumbing and etc.

g. Interfacing between Power-house building structure (C-W P) and Electrical Building-facilities (G-E P), such as inside and outside lighting, cabling and electrical panel system.

h. Interfacing design input between both parties Civil Works Portion (C-W P).and Generating Equipment Plant (G-E P)

i. Interfacing between Switchyard Electrical system (G-E P) and Switchyard Civil Works (C-W P).

j. Interfacing between 70 KV Transmission Line Electrical system (G-E P) and 70 KV Transmission Line Civil Works (C-W P).

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Table 18. Interfacing design input data

DescriptionDesign Input

From Civil Works Portion

From Generating Equipment

Hydrology & Hydraulic data, include water quality

√

Topography Map for Power-house and Transmission-line route.

√

Generating Equipment Plants lay out

√

Soil Resistivity data √

Power-house lay-out √ √Penstock – line √

Hydraulic Pressure √ √Water Hammer √ √Inlet Valve √Guard Valve √Equipment dimension √Detail Turbine arrangement, include Spiral-casing and Draft-tube

√

Equipment loading data √Equipment positioning √Electrical building facilities of Power-house data

√

Mechanical building facilities of Power-house data

√

Building structure √Building Architecture √Over-head crane data √Control room requirement data √Turbine hall requirement data √Emergency Diesel requirement data

√

Switchyard Electrical detail and lay out

√

Electrical of Transmission line data

√

Tail-race structure √Tail-race Gate √

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