3550-8310-SP-0007 Rev D2 - Revision Marked - Thanh Thao

FOUNDATIONS AND STRUCTURES SUPPORTING MACHINERY

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FOSTER WHEELER ENERGY LTD

PROJECT SPECIFICATION CIVIL

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5.1 Common Foundations ........................................................................................................ 9 5.2 Pulsation Bottles ................................................................................................................. 9 5.3 Eccentricities ...................................................................................................................... 9 5.4 Unbalanced Forces and Moments .................................................................................... 10 5.5 Group A - Reciprocating Machinery Foundations ............................................................. 10 5.6 Group B - Reciprocating Machinery Foundations ............................................................. 10

5.6.1 Design Codes ............................................................................................................ 10 5.6.2 Primary Forces .......................................................................................................... 10 5.6.3 Secondary Forces ..................................................................................................... 10 5.6.4 Amplitudes ................................................................................................................. 10 5.6.5 Dynamic Amplitudes .................................................................................................. 10 5.6.6 Frequencies ............................................................................................................... 11

6. DESIGN OF ROTATING MACHINERY FOUNDATION .......................................................... 11 6.1 Rotating Machinery Foundations ...................................................................................... 11

6.1.1 General ...................................................................................................................... 11 6.1.2 Amplitudes ................................................................................................................. 11

6.2 Group C - Rotating Machinery Foundation ....................................................................... 12 6.2.1 Group C - Foundation Not Requiring Dynamic Analysis ........................................... 12 6.2.2 Group C - Foundation Requiring Dynamic Analysis .................................................. 12

6.3 Group D - Rotating Equipment Foundation ...................................................................... 12 6.4 Group E - Rotating Equipment Foundations ..................................................................... 12

6.4.1 Design ....................................................................................................................... 12 6.4.2 Machine Shafts .......................................................................................................... 12 6.4.3 Beams and Slabs ...................................................................................................... 12 6.4.4 Rigidity ....................................................................................................................... 13 6.4.5 Weight of Foundation Base Slab ............................................................................... 13 6.4.6 Frequencies ............................................................................................................... 13 6.4.7 Differential Temperature ............................................................................................ 13 6.4.8 Minimum Applied Loading ......................................................................................... 13

7. SOILS DATA ............................................................................................................................ 13 7.1 Soil Bearing Foundations ................................................................................................. 13 7.2 Piled Foundations ............................................................................................................. 14

8. PERMISSIBLE FOUNDATION SETTLEMENT ....................................................................... 14 9. ANTI-VIBRATION MOUNTINGS ............................................................................................. 14 10. ENVIRONMENTAL REQUIREMENTS ................................................................................ 14


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1. SCOPE

This Specification defines the basis for the design of foundations and structures supporting reciprocating and rotating machinery. Foundations at grade and tabletop structures are both considered. Static and dynamic methods of analysis are recommended where appropriate.

2. REFERENCES

2.1 General

Design shall conform to the latest revision of the following Specifications, Standards and Codes of Practice current at the time of contract award.

It shall be executed and completed with full compliance to all National and local laws and bye laws and regulations.

The order of precedence shall be as follows and design shall be based on the most stringent of them:

1) Mandatory Vietnamese Standards

2) Project Specifications

3) International or Vietnamese Applicable Codes

In the event of a conflict between specifications and/or standards and/or national or local laws or bye laws, the Employer’s decision shall be sought and govern.

The CONTRACTOR shall obtain all of the Employer’s specification and standards.

2.2 Project Specification

This specification must be read in conjunction with the following:

3550-8820-SP-0001 Basic Engineering Design Data (BEDD)

3550-8310-SP-0001 Design Loading

3550-8310-SP-0004 Specification for Concrete Fire Protection

3550-8310-SP-0005 Specification for Concrete Works

3550-8310-SP-0006 Specification for the Foundations of Storage Tanks

3550-8310-SP-0008 Design of Concrete Foundations, Structures, Asphalt Roads and Paving

3550-8310-SP-0009 Earthwork Specification


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2.3 Project Civil Standard Drawings

3550-8310-39-0001 General Notes, Legends and Abbreviations

3550-8310-39-0002 Holding Down Bolts

3550-8310-39-0003 Underground – General Notes, Legends and Abbreviations

3550-8310-39-0004 Typical Paving Details

3550-8310-39-0005 Typical Concrete Foundation & Plinths for Ladders & Stairs

3550-8310-39-0006 Typical Asphalt Road Details

3550-8310-39-0007 Typical Ditches, Channels & Misc. Paving Details

3550-8310-39-0008 Typical Manholes & Pipe Penetration Details

3550-8310-39-0009 Firemain Details

3550-8310-39-0010 Typical Weir Box, Drainage Valve Pit, Lift Station and Culvert Protection Details

3550-8310-39-0011 Typical Sand Fire/Trap Details

3550-8310-39-0012 Electrical and Instrument Cable Trenches & Duct Banks

3550-8310-39-0013 Fencing & Gates

3550-8310-39-0014 Catch Basin, Miscellaneous Drainage Structures and Crash Barrier Details

3550-8310-39-0015 Typical Foundation Detail for Vertical and Atmospheric Storage Tanks

2.4 Soil Investigation Report

28030/4 Geotechnical Report from Soil Mechanics

2.5 British Standards

The Work shall be performed to the following specifications and standards or its equivalent.

BS 8004 Code of Practice for Foundations

BSCP 2012 Code of Practice for Foundations for Machinery

: Part 1 Foundations for Reciprocating Machines


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2.6 Eurocodes

Design to Eurocodes shall be in conjunction with the corresponding British National Annex

BS EN 1997 Eurocode 7: Geotechnical Design

: Part 1 General rules

2.7 German Standards

DIN 4024 - Machine Foundations

: Part 1 - Flexible Structures that Support Machines with Rotating Elements : Part 2 - Rigid Foundations for Machinery Subject to Periodic Vibration

2.8 Vietnamese National Standards

TCVN 4453 Concrete Structure and Reinforced Concrete Technical Requirements.

Vietnamese Building Code, Vol I General Provisions & Construction Planning

Vietnamese Building Code, Vol II -

Vietnamese Building Code, Vol III -

2.9 Statutory Legislation

Local Vietnamese Health and Safety at Work Act.

3. DEFINITIONS

3.1 Reciprocating Machinery

Machinery with reciprocating masses as major moving parts. This machinery should be supported as close to grade elevation as possible directly on a rigid block.

Dynamic loading from a reciprocating compressor comprises primary and secondary loads which are principally:

- a horizontal force - a moment about the vertical axis.

Note: secondary forces are at a frequency of twice the machine speed.

3.2 Rotating Machinery

Machinery with rotating masses as major moving parts. This machinery may be supported on a rigid block or on an elevated structure.


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Dynamic loading from rotating machines takes the form of an out of balance force, applied radially from the rotor centre. Values can be initially assessed from rotor weight and machine speed; subject to confirmation by vendors. Vertical and horizontal directions are usually the critical applications.

3.3 Foundation Grouping

For the purpose of this specification, machine foundations shall be grouped as shown in Table 1.

GROUP

FOUNDATION

TYPE

MACHINE TYPE

MACHINE WEIGHT

(KG)

DYNAMIC ANALYSIS

RECOMMENDA B C D E

Rigid Block Rigid Block Rigid Block Elevated Struct. Elevated Struct.

Reciprocating Reciprocating Rotating Rotating Rotating

<2500 ≥2500 --- <2500 ≥2500

No Yes See Note 1 See Note 2 Yes

NOTE 1: The analysis performed for rotating machinery supported on a rigid block foundation shall be at the discretion of the Employer, who shall take into consideration the operating speed of the machine and the loading imposed by the machine on the foundation.

NOTE 2: The analysis performed for rotating machinery weighing less than

2500kg and supported on an elevated structure, shall be at the discretion of the Employer, who shall take into consideration the nature of the supporting structure, the location and speed of the machine, and the loading imposed by the machine on the structure.

TABLE 1

FOUNDATION GROUPING

Where reciprocating and rotating machines are fixed to a common foundation the loads shall be determined from the relevant sections of this specification for each machine and the foundation designed for the reciprocating machine.

4. DESIGN OF ALL MACHINERY FOUNDATIONS

Reciprocating or rotating machinery foundations shall be designed in accordance with the following general criteria:-

4.1 Health and Safety at Work Act

Designs shall comply with the duties imposed on engineers, suppliers, manufacturers and importers etc. by the Local Vietnamese Health and Safety at Work Act.


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4.2 Shape of Foundation

Clean, simple outlines shall be used for foundations. Beams and columns shall be of a uniform rectangular shape. Block foundations should be rectangular.

4.3 Pockets

Pockets where vapour could accumulate shall be avoided.

4.4 Elevation

The elevation of the machine support above grade shall be the minimum to accommodate suction and discharge piping arrangements, oil drainage requirements or when condensing turbines are used, by the condenser dimensions and the condensate pump.

4.5 Adjacent Structures

All parts of the foundation and superstructure shall be kept independent of adjacent foundations, structures and buildings, Concrete floor slabs adjacent to the machinery foundation shall be spaced a minimum of 15mm from the foundation and the space between the two filled with a flexible joint filler and sealant.

4.6 Thickness of Foundation

Thickness of the rigid block or foundation base slab for machinery shall be not less than:-

0.60 + L Where L (in metres) is the greater of the length or breadth. 30

Where two or more machines are on a common foundation, L = the greater of:

a) the breadth of the common foundation, or b) the length of the longest segment assigned to any one machine.

4.7 Fatigue

To prevent fatigue failures, all sections shall be proportioned to resist the sum of the static dead and live loads, plus an equivalent static force equal to three times the dynamic force determined from analysis.

4.8 Reinforcement

Minimum Reinforcement

The effects of shrinkage and thermal expansion shall be taken into account to prevent cracking. The minimum quantity of reinforcement in concrete shall be 50 kg/m3, except for base slabs and rigid blocks which shall contain at least 30 kg/m3.


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Reinforcement shall be provided on all faces of members whether required in the design calculations or not.

Maximum Bar spacing shall be 300mm for side faces.

Symmetrical reinforcement shall be provided in all columns.

The maximum spacing of stirrups in columns shall be 350 mm and in beams 250 mm or 0.75 x effective depth for both columns and beams whichever is less

Foundation Slab

In slabs up to 1.0 m deep, vertical reinforcement should extend to the full depth of the base, linking top and bottom reinforcement.

Double reinforcement shall be provided.

Starter bars for the column reinforcement should extend to the base of the foundation slab if up to 1.0 m deep. For deeper bases half the reinforcement may end in the middle provided adequate bond is provided. When there are haunches, the reinforcement along the inclined plan should be fastened with stirrups.

4.9 Concreting

The concreting of the foundation shall be carried out in horizontal lifts and in one continuous operation. If this is not possible any interruption should occur where the columns join the base slab.

The concreting of the superstructure should be carried out in one continuous operation.

4.10 Dynamic Modulus of Elasticity

The dynamic modulus of elasticity for concrete shall be based on the specified 28 day strength test results, (standard cylinder strength).

4.11 Soil Bearing Pressure

For spread foundations, soil bearing pressures shall not exceed 50% of the net allowable value. For piled foundations no reduction in the allowable pile capacity is required. Earthquake loading shall be included if applicable.

4.12 Static Design

Static design shall include the weight of the machinery, auxiliary equipment, piping and pipe thrusts, vacuum forces (in the case of condensing operations).

Other applied loads shall include the following:-


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4.12.1 Vertical Impact

Vertical impact of 50% of the dead weight of the machine and base plate.

4.12.2 Lateral Force

A lateral force of 25% of the weight of each machine including its base plate applied normal to its shaft at a point midway between its end bearing.

4.12.3 Longitudinal Force

A longitudinal force of 25% of the weight of each machine and its base plate applied along the shaft axis.

4.12.4 Combined Lateral and Longitudinal Forces

Lateral and longitudinal forces shall not be considered to act concurrently.

4.12.5 Damping

Damping shall be considered in amplitude calculations if the ratio of foundation natural frequencies to disturbing frequencies in the range 0.7 to 1.3 cannot be avoided in the modes being excited.

5. DESIGN OF RECIPROCATING MACHINERY FOUNDATION

Foundations for all reciprocating machinery shall be designed in accordance with the following:-

5.1 Common Foundations

Where two or more reciprocating machines are located adjacent to each other they may be anchored to a common foundation when the net result is reduced amplitudes.

5.2 Pulsation Bottles

Pulsation bottles shall have their supports integral with the compressor foundation.

5.3 Eccentricities

The foundation shall be designed so that the horizontal eccentricity, in either direction, between the centroid of mass of the machine foundation system and the centroid of the base contact area or pile group, shall not exceed 5% of the respective base dimension. The centroid of mass of the machine/foundation shall, whenever possible, lie below the top of the foundation block.


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5.4 Unbalanced Forces and Moments

Design shall include unbalanced forces and moments. In addition, unbalanced moments obtained by multiplying the unbalanced forces by their eccentricities, shall be considered.

5.5 Group A - Reciprocating Machinery Foundations

Group A reciprocating machinery foundations are defined as rigid block foundations for reciprocating machinery weighing less than 2500 kg. Such foundations are not subject to dynamic analysis but the weight of foundation shall be at least five times the total weight of machinery including base plate.

5.6 Group B - Reciprocating Machinery Foundations

Group B reciprocating machinery foundations are defined as foundations for machinery weighing 2500kg or more. Such foundation shall be subject to dynamic analysis as follows:-

5.6.1 Design Codes

A dynamic analysis including the calculation of natural frequencies and amplitudes shall be carried out in accordance with the recommendations of BSCP 2012: Part 1. or equivalent whichever is more onerous.

5.6.2 Primary Forces

Primary forces, couples and moments shall be applied at the machine speed, over the full range of specified operating speeds, for the calculation of primary amplitudes.

5.6.3 Secondary Forces

Secondary forces, couples and moments shall be applied at twice the machine speed, over the full range of specified operating speeds, for the calculation of secondary amplitudes.

5.6.4 Amplitudes

Total amplitudes shall be calculated by combining, in phase, primary and secondary amplitudes, Maximum permissible single amplitudes shall be in accordance with the recommendations of BSCP 2012: Part 1 or equivalent.

5.6.5 Dynamic Amplitudes

The dynamic amplitudes of any part of the foundation including any reciprocating compressor shall be limited to a peak to peak amplitude as otherwise specified by the Principal Manufacturer/Supplier of the rotating equipment.


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5.6.6 Frequencies

All natural frequencies below 2 times the operating frequency for reciprocating equipment shall be calculated.

It shall be demonstrated that the natural frequencies are outside the range of 0.7 and 1.3 times the operating frequencies of the machinery. In case this is impossible resonance shall be considered. A reasonable estimate for damping will then be required.

It shall be further demonstrated that the amplitudes of the natural frequencies between 0.35 to 0.7 and 1.3 to 1.5 times the operating frequency are within the allowable values taking into consideration differences between the actual structure and assumed model and that resonance does not occur. In this case a reasonable amount of damping shall be estimated.

The natural frequency of the supporting structure shall not coincide with any resonant frequency of the equipment.

6. DESIGN OF ROTATING MACHINERY FOUNDATION

Foundations for all rotating machinery shall be designed in accordance with the following:-

6.1 Rotating Machinery Foundations

6.1.1 General

Dynamic analysis shall be carried out in accordance with the recommendations of this Standard.

6.1.2 Amplitudes

Amplitudes shall be determined using dynamic forces from each rotor, calculated as follows in the absence of more accurate information:-

Dynamic force (kN) =(rotor weight, kN) x (rotor speed, r.p.m.) 6000

With more than one rotor, amplitudes shall be computed with the rotor forces assumed in phase and 180˚ out of phase to obtain, respectively, the maximum translational and torsional amplitudes. Permissible amplitudes shall not exceed machine manufacturer's requirements or the following whichever is more stringent:-

The amplitude (single amplitude) which causes the effective velocity of vibration to exceed:

a) 1.8mm/sec at the location of the machine bearing housing b) 2.3mm/sec at any location on the foundation


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6.2 Group C - Rotating Machinery Foundation

Group C rotating equipment foundations are defined as rigid block foundations to which dynamic analysis may or may not be required at the discretion of the Employer (Refer Note Table 1).

6.2.1 Group C - Foundation Not Requiring Dynamic Analysis

When the Employer decides that dynamic analysis is not required then the weight of foundation shall be at least three times the total weight of machinery including base plate.

6.2.2 Group C - Foundation Requiring Dynamic Analysis

When the Employer decides that dynamic analysis is required then a rigid block foundation shall be designed in accordance with Para 5.6 of this Specification.

6.3 Group D - Rotating Equipment Foundation

Group D rotating equipment foundations are defined as elevated structure foundation for rotating equipment weighing less than 2,500kg.

Where the Employer decides that dynamic analysis is required such design shall be in accordance with section 6.4 of this Specification.

6.4 Group E - Rotating Equipment Foundations

Group E rotating equipment foundations are defined as elevated structure foundations for rotating equipment weighing 2,500kg or more. Such foundations shall be subject to dynamic analysis as follows:-

6.4.1 Design

Elevated structures supporting rotating machinery shall generally be designed in accordance with DIN 4024.

Analysis may be by 3 dimensional finite element method.

Short circuit couples, vacuum tension, oil whirl frequency, rotor critical speeds and background vibration shall also be considered.

6.4.2 Machine Shafts

Machine shaft bearings shall, whenever possible be located directly over transverse supports.

6.4.3 Beams and Slabs

Beams and slabs shall not be of excessive span and corner rigidity shall be taken into account.


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6.4.4 Rigidity

The upper table and foundation base slab shall be rigid in the horizontal plane.

6.4.5 Weight of Foundation Base Slab

The foundation base slab shall not weigh less than the combined supported weight of the upper table, columns, walls and machines (including base plates).

6.4.6 Frequencies

Refer Section 5.6.6

6.4.7 Differential Temperature

In the absence of more exact information for reinforced concrete a temperature increase of 20˚C shall be assumed for uniform heating of the table top compared with the base slab.

For shrinkage of the table top, a temperature drop of 10˚C compared with the base slab shall be assumed.

Local temperature gradients across structural members shall be considered whenever applicable.

6.4.8 Minimum Applied Loading

Structural members not subject to external loading shall be designed for a static equivalent force equal to 50% of their dead load vertically or horizontally, provided setting up loads do not govern.

7. SOILS DATA

The sub-soil design parameters necessary to carry out the design shall be as stated in the Geotechnical Report. For all parameters/issues related to soil/foundation, reference shall be made to the latest Soil Investigation Report.

7.1 Soil Bearing Foundations

The following soil parameters are generally used for soil bearing foundations:-

E - Dynamic Modulus of Elasticity of the soil

ν - Poissons Ratio

Cu - The coefficient of elastic uniform compression of the soil

Cφ - The coefficient of elastic non-uniform compression of the soil

Cτ - The coefficient of elastic uniform shear


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Cψ - The coefficient of elastic non-uniform shear

When values for Cφ, Cτ and CΨ are not available the following assumptions shall be made:

Cφ - 2 Cu

Cτ - 0.5 Cu

CΨ - 0.75 Cu

7.2 Piled Foundations

The following soil parameters are generally used for piled foundations:-

- The horizontal and vertical dynamic stiffness of a single pile

- The horizontal and vertical dynamic stiffness of pile groups

- An assessment of soil mass participation

8. PERMISSIBLE FOUNDATION SETTLEMENT

The total and differential post-construction settlements for individual concrete foundations shall not exceed the values noted in the Design of Concrete Foundations, Structures, Asphalt Roads and Paving 3550-8310-SP-0008.

9. ANTI-VIBRATION MOUNTINGS

When it is considered that an economically acceptable foundation design cannot be achieved, the Contractor shall submit to the Employer for approval, recommendation to improve the dynamic characteristics by introducing anti-vibration mountings.

10. ENVIRONMENTAL REQUIREMENTS

Considerations shall be given to the effect of noise and vibration generated by the machine/foundation system on both people in the vicinity and any nearby sensitive equipment to which reference shall be made to the Local Vietnamese Health and Safety at Work Act.

Documents

3550-8310-SP-0007 Rev D2 - Revision Marked - Thanh Thao