Design Criteria for Concrete Foundations & Structures 2

Spec RG -1700 -01 -Rev 5 Page 1 of 24

JOB SPECIFICATIONJob Number-Unit Discipline Serial Rev.

RG 17 00 01 5

QATAR PETROCHEMICAL COMPANY LTD

DESIGN CRITERIA FOR CONCRETE FOUNDATIONS AND STRUCTURES Page1 of 24

9

8

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4 16/11/93

3 05/05/93

2 26/03/03

1 21/01/93

0 08/01/93

Rev. DateWritten By

(Name, Initials)Checked By

(Name, Initials)Approved By

(Name, Initials)Status

DOCUMENT REVISIONS :Revisions indicated by <>with Rev Number inside

Spec RG -1700 -.01-Rev.5Page 2 of 24

C O N T E N T S

1. GENERAL

1.1. Scope

1.2. Reference documents

1.2.1. Local code, QNBS and BS codes and standards1.2.2. Uniform Building Code1.2.3. Other applicable specifications

2. CLIMATIC CONDITIONS

2.1. Rainfall

2.2. Snowfall

2.3. Wind

2.4. Earthquake

2.5. Temperature variations

3. LOADS ON STRUCTURES

3.1. Permanent loads

3.1.1. Dead loads of structures3.1.2. Dead loads of equipment & machinery

3.2. Climatic loads

3.3. Live loads

3.3.1. General3.3.2. Loads produced by persons3.3.3. Piping loads

3.3.3.1. Vertical loads3.3.3.2. Horizontal loads3.3.3.3. Tie girders for elevated pipe racks3.3.3.4. Friction factors

3.3.4. Vessels loads

3.3.5. Bridge crane & lifting appliances


3.4. Special loads

3.5. Thermal loads

3.5.1. Thermal expansion3.5.2. Thermal loads

3.6. Trench covers loads

4. LOAD COMBINATIONS

4.1. Structures and foundations

4.2. Tall vessels

5. STRUCTURAL CONCRETE

5.1. General

5.2. Design principles

5.3. Concrete grades

5.4. Concrete protection

5.4.1. Concrete paving5.4.2. All other concrete works

5.5. Concrete cover

5.6. Construction joints

5.7. Concrete paving

5.7.1. Paving thickness5.7.2. Expansion joints and slab protection

5.8. Reinforcement grades

5.9. Anchor bolts and base plates

5.9.1. Design5.9.2. Clearance5.9.3. Tolerance

5.10. Grouting


6. STRUCTURAL STEEL

6.1. General

6.2. Design conditions

6.2.1. Plastic design6.2.2. Structural elements exposed to heat6.2.3. Structural elements exposed to severe corrosion6.2.4. Shipment subject to water filling6.2.5. Special design conditions6.2.6. Allowable deflections

6.3. Connections

6.3.1. Shop connections6.3.2. Field connections6.3.3. Minor connections6.3.4. Black bolts6.3.5. High strength friction grip bolts6.3.6. Minimum bracing connection6.3.7. Single bolt prohibited

6.4. Corrosion protection

7. SOIL CHARACTERISTICS

7.1. Ground water level7.2. Soil bearing capacity and foundation level

8. FOUNDATIONS

8.1. Design principles8.2. Stability ratios8.3. Settlement8.4. Foundation types8.5. Foundation details

9. FIRE PROOFING

10. DESIGN AND CALCULATIONS


1. GENERAL

1.1. Scope

The purpose of this document is to define the design criteria for the concrete foundations andstructure applicable to the various projects of QAPCO in their Petrochemical Complexlocated in UMM SAID, State of QATAR.

These design criteria shall apply to all concrete foundations, concrete and steel structuresand concrete paving for equipments and buildings, pipe supports and platforms at the abovesite.

This specification is supplemented by other documents listed below and shall prevail overthe listed documents.

1.2. Reference documents

The following specifications, codes and standards, in their last revisions, shall be read inconjunction with and shall be part of this specification.

1.2.1. Local code, QNBS and BS codes and standards

Local code, Q.N.B.S. and the British Standards to which it refers,- BS 4 : Part 1 : (1980) : Specification for hot-rolled section.

- BS 12 : (1991) : Specification for Portland cements.

- BS 449 : Part 2 : (1969) : Metric units : specification for theuse of structural steel in building.

- BS 639 : (1986) : Specification for covered carbon and carbon manganese steel electrodes for manual metal arc welding.

- BS 648 : (1964) : Schedule of weights of building materials.(68-69)

- BS 3648 : (1968) : ISO metric screw threads.(67-85)

- BS 3692 : (1967) : Specification for ISO metric precisionhexagon bolts, screws and nuts, Metric units.

- BS 4027 : (1991) : Specification for sulphate resisting Portlandcement.

- BS 4165 : (1984) : Specification for electrode wires and fluxes for the submerged arc welding of carbon steel and medium tensile steel.

- BS 4190 : (1967) : Specification for ISO metric black hexagon(75-78) bolts, screws and nuts.

- BS 4320 : (1968) : Specification for metal washers for general engineering purposes.

- BS 4360 : (1990) : Specification for weldable structural steels.


- BS 4395 : : Specification for high strength friction grip bolts and associated nutsand washers for structural engineering.

- BS 4449 : (1988) : Specification for carbon steel bars for the reinforcement of concrete.

- BS 4466 : (1989) : Specification for bending, dimension and scheduling of reinforcementfor concrete.

- BS 4482 : (1985) : Specification for cold reduced steel wire for the reinforcement forconcrete.

- BS 4604 : (1970) : Part 1 : Specification for the use of high(71-72-82) strength friction grip bolts in structural steelwork(metric series) - general grade

- BS 5135 : (1984) : Specification for arc welding of carbon and carbon manganese steels.

- BS 6399 : part 1 : (1984) : Loading for building - Code of practice for dead and imposedloads.

- BS 7295 : (1990) : Fusion bonded epoxy coated carbon steel bars for the reinforcement ofconcrete.

- BS 8004 (1986) : Code of practice for foundations.

- BS 8007 : (1987) : Code of practice for design of concrete structures for retainingaqueous liquids.

- BS 8110 : Part 1 : (1985) Structural use of concrete code of practice for design andconstruction.

- CP3 : chapter V : part 2 : (1972) : Basic data for design of buildings - Wind loads.

- CP 2012 : part 1 : (1974) : Code of practice for foundations for machinery - Foundationsfor reciprocatingmachines).

- BS EN 10025 (1990) : Hot-rolled products in non-alloy structural steels. Technical deliveryconditions.

1.2.2. Uniform Building Code

To be used for earthquake calculation only.

1.2.3. Other applicable specifications

- RG 1400.01 - Site preparation and earthworks.

- RG 1700.02 - Concrete works.


2. CLIMATIC CONDITIONS

2.1. Rainfall

<5> Rainfall load should be at maximum 0.7 kN/m2 for the design.

2.2. Snowfall

Snowfall is not to be considered.

2.3. Wind

Wind loads shall be calculated in accordance with, CP 3 : ch. V - Part 2 : 1972 "Code ofbasic data for the design of buildings".

The following wind speed factors shall be used :

a) Topography factor S1 = 1.0.

b) Ground roughness shall be category 1.

Factor S2 as per CP 3, Table 3.

c) Statistical factor S3 = 1.0.

The wind is generally from the North, North West with occasional periods of southerly winds.

Structure and equipment which extend to more than 15 meters above grade will be designedfor a wind of 45 m/s.

Structure and equipment which extend less than 15 meters above grade will be designed fora wind of 38m/s.

2.4. Earthquake

Zone I of UBC shall be considered.

2.5. Temperature variations

Refer to section 1.1.1. of General Specification RG 00-90-01

3. LOADS ON STRUCTURES

The design of foundations and structures will take into account the following loads.3.1. Permanent loads

3.1.1. Dead loads of structures

All structural materials, floors, stairs, covering, fire proofing and all permanent materialsforming part of the structures shall be considered as dead loads.

3.1.2. Dead loads of equipment & machinery (except bridge cranes and lifting appliances)

Equipment and machinery loads without the liquid contained inside or without removableparts shall be considered as dead loads.


Erection loads

a) Temporary large point loads shall be considered on structural frames during theinstallation of equipment, such as gin pole loads on structures or foundations.

b) Vertical vessel foundations shall be designed for maximum overturning loads consideringvessels are at minimum vertically loaded condition.

c) Large rotary equipment part loads shall be investigated on framing members (e.g. rotorsduring maintenance or installation).

3.2. Climatic loads

Wind (refer to section 2.3).

3.3. Live loads

3.3.1. General

The following loads shall be considered as live loads :

- loads produced by persons,

- live loads of equipment (vessels, pipe racks, etc...),

- weight of liquid contained in equipment and piping during normal operation,

- loads (horizontal and vertical) caused by expansion and anchor of pipes,

- temporary loads such as bundle pulling loads, (for checking of ultimate load only),

- loads produced by movable equipment (with dynamic effect),

3.3.2. Loads produced by persons

The design live loads for floors, platforms, walkways and stairs shall be as follows :

- roofs (substation) 1.20 kN/m² ) for roofs not intended as ) walkways or working areas

+ 1.00 kN/m² ) for sand

1.8 kN/m2 for canteens roof

- stairs 2.40 kN/m² or (+ 1.5 kN concentrated at centre of thread)

- walkways 2.40 kN/m²

- access platforms 2.40 kN/m²

- operating platforms 2.40 kN/m² + equipment or concentrated load of 2.4 kN

- handrails 1.00 kN point load in any direction per metre.


3.3.3. Piping loads

Piping loads include all thrusts or moments due to thermal expansion or contraction of pipingand the blow-out forces of expansion joints, bell and spigot pipes, safety relief valves, etc.

Piping loads in general shall be considered as equipment loads.

Vertical loads shall consider :

- pipes empty (erection conditions),- pipes in operating conditions,- pipes in test conditions.

Horizontal loads caused by pipe expansion and anchor shall be considered as operatingloads.

3.3.3.1. Vertical loads

a) Vertical loads shall be computed according to size distribution and service conditions ofpipes which are supported.

For pipeways, use 1450 N/m² as a minimum pipe load. This approximates 6 inch pipesfilled with water (spacing between pipes : 12 inches).

b) Pipes larger than 12 inches diameter shall be considered as concentrated loads in theiractual locations.

c) Live load include :

. live load in operating conditions,

. live load due to water while testing.

3.3.3.2. Horizontal loads

a) Main supporting girders shall be calculated to withstand horizontally, in the directionof the pipes, the greater of following thermal (friction) loads :

- 10 % of the sum of all operating pipe loads acting longitudinally for pipes less or equal to 12" diameter,

and- 30 % for pipes larger than 12" diameter.or- Every main supporting girder (girder which supports all diameter pipes) shall be

calculated to withstand horizontally, in the direction of the pipes, friction forcesas mentioned above or an arbitrary anchor force minimum 5 kN located at themost unfavourable position, whichever results in a greater member size.

During refinement of the design, when location of anchors is defined the properloads shall be considered.

b) Pipe rack frames shall be calculated taking into account following horizontal thermalforces, at right angle with pipes, as a minimum :

5 % of the operating pipe loads at each concerned level.


c) Horizontal loads on the anchor bays of pipe racks shall be taken as the greatest of :(per longitudinal file)

- anchor forces from pipe stress calculation, or- 10 % of piping vertical loads from 4 bays length, or- 40 kN applied uniformly.

3.3.3.3. Tie girders for elevated pipe racks

They shall be calculated, (in addition to the above), for the following :

- vertical load 10 kN at mid span.

3.3.3.4. Friction factors

Friction factors to be used (for local effect) :

- steel/steel 0.33- PTFE/stainless steel 0.05 *) or PTFE/PTFE

*) contact pressure between PTFE and PTFE or stainless steel15-25 N/mm².

3.3.4. Vessel loads

Live loads include :

- live loads due to content in operating condition,- live loads due to water while vessel is being tested :

. when hydrostatic pressure testing of equipment is required at site, the weight of thisequipment completely filled with water shall be incorporated in the design of the supportingstructure.

. when more than one vessel, etc.. is supported by one structure, the structure and therelevant foundation need to be designed on the basis that one vessel will be tested at anyone time and that the others will either be empty or still in operation.

3.3.5. Bridge cranes and lifting appliances

a) Bridge crane

Loads applied from bridge cranes must be calculated in accordance with applicable codesand standards but should not be less than the following :

Electric Handoperation operation

- vertical loads : increase 25 % 10 %static wheel loads by

- horizontal force transverse 10 % 5 %to rails taken as percentageof loads + crab weight


- horizontal force along the 5 % 5 %rails taken as percentageof loads + crab weight

b) Monorails hoisting

When hoisting by means of chain hoist, air or electric hoist, increase loads on supportingmembers by 50 % for impact.

3.4. Special loads

Exchanger tube bundle pulling force

Provision shall be made for the pulling force required when removing (or installing) a tube bundlefrom a shell. The minimum horizontal force applied at the center of the bundle shall be equal to 50% of the weight of the bundle with a 5 kN minimum.

Horizontal pulling force shall be assumed to act at the centre line of the exchanger and resisted bythe fixed support only. When exchangers are stocked, the force shall be taken as acting at theupper exchanger centre line, with the lower exchanger bundle having been removed.

3.5. Thermal loads

3.5.1. Thermal expansion

Due to the wide range of temperature occurring throughout the year expansion joints are to beprovided at convenient locations.

The following data is to be used in thermal loading calculation :

- maximum temperature difference t = 40°C

- concrete linear expansion factor Ctc = 1.1 10-5

- steel linear expansion factor Cts = 1.2 10-5

Such data can be neglected for concrete structures and for steel structure with expansion jointsprovided at 30 meters maximum distance. Data shall be used to determine size of expansion jointwith a minimum joint width of 25 mm.

3.5.2. Thermal loads

Piping, vessels, fire equipment, ducts and heat exchangers on structural supports shall beanalyzed for thermal forces to be resisted by the structures and provision shall be made to relieveforces too large for the equipment or the supporting structure.

For thermal loads due to piping see also para. 3.3.3.

3.6. Trench covers loads

Trench covers in areas with vehicular access shall be designed for 50 kN wheel load. Contactarea of wheel on covers which has been considered is : 250 x 200 mm.


4. LOAD COMBINATIONS

4.1 . Structures and foundations

The following combination of loads shall be investigated in the design of structural members and foundations

LOAD COMBINATION ERECTION TEST (4) OPERATION EARTHQUAKEwith wind (1) without wind

(1)

Dead loads :

Structures

Weight of equipment

Live loads:

Persons

Operating vessels piping andequipment

Test load

Crane loads(dynamic load)

Dynamic loads (machinery)

Wind loads

Thermal loads

X

X

-

-

-

X

X

X

-

X

X (3)

X

X

X

X

-

X (2)

X

X

X

X

X

X

X

-

X (2)

X

-

X

X

X

X (5)

X

-

-

-

-

X

(1) The most unfavourable load combinations shall be taken into account.

(2) Crane loads with 50 % of wind pressure shall be applied on open structures and/or opensided buildings. Crane loads with full wind shall be applied on closed buildings.

(3) 50 % of wind pressure shall be applied in test condition.

(4) For structures supporting equipment subject to water filling, in which 90 % or more of the liveload is water, applied for 72 hours or less, the basic allowable unit stresses for all loadsduring the filled period may be increased by 20 %.

(5) Only 50 % of loads shall be taken into account.


4.2. Tall vessels

The following load combinations shall be used in assessing the design stability of tall vesselssubject to overturning.

a) Erection condition

. Dead load

Vessel without internals and attachments.

. Live load

Wind.b) Test condition

. Dead load

Vessel including test fluid, internals, platforms and ladders, piping.

. Live load

50 % of wind dynamic pressure.

c) Operating condition

. Dead load

Vessel including operating fluids at maximum level, internals, catalyst, insulation, platformsand ladders, piping.

. Live load

Wind, platforms, thermal, impact, vibrations.d) Shut-down condition

. Dead load

Vessels without operating fluids, with removable internals, platforms and ladders,insulation and piping.

. Live loadWind, platforms.

5. STRUCTURAL CONCRETE

5.1. General

The design and details of structural concrete shall be read in conjunction with relevant Britishcodes (refer to paragraph 1.2).



The allowable stress in concrete and reinforcing steel shall be in accordance with BS 8110 andBS 8007.The allowable stresses for members subjected to short time overload conditions may beincreased by 20 % where short time overload is defined as follows :Short-time overload

The structural and equipment operating and the piping dead loads, the design live load, liftingpoints load, appropriate equipment and piping contents loads resulting from short-timeoperational upsets (such as may occur during starting-up, shutting down, or an interruption inoperation of the process).

The magnitude and application of loads for the purpose of designing concrete structures andfoundations subject to hydrostatic test loading shall be as follows :

Case A : For small vessels where the hydrostatic test load will not be applied for more than 4days, wind loading shall be ignored.

Case B : For large vessels and small vessels where the hydrostatic test load will be applied for5 or more days, 50 % of wind load shall be considered to act simultaneously with thehydrostatic test load.

The allowable stress for members subject to hydrostatic test loads may be increased by 20 %for case A and by 25 % for case B.

For the design of foundations, refer to section 8.

5.3. Concrete grades

Type I : . For plain blinding concrete . Minimum strength 15 MPa at 28 days (ref. OPC 15).. 250 kg/m3 ordinary Portland cement minimum.

Type II : . For plain mass concrete.. Minimum strength 25 MPa at 28 days (ref. OPC 25).. 350 kg/m3 ordinary Portland cement minimum.

Type III : . For the reinforced concrete of :

- the paving slab,- the foundation slab and columns under steel structures or equipment (such asexchangers, columns, drums), - the foundations of concrete structures,

- all concrete structures and buildings above the ground level, - concrete trenches.

. Minimum strength 30 MPa at 28 days (ref. OPC 30).

. 400 kg/m3 ordinary Portland cement minimum (10-15 % of cement to be replacedby micro silica).

All underground concrete surfaces to be coated with Hempel "Hempadur 1513 of DFT 125microns, then covered with gage 1000 P.E. sheet, overlaid with 4 mm hard-board suitably fixedto retain its position.

All aboveground concrete surfaced (including the internal surface of manholes) to be coatedwith Hempel "Sealant O 597" as a primer and Hempel "Hempadur 4523" of DFT 100 microns asa top coating.


5.4. Concrete protection

5.4.1. Concrete paving

Concrete paving shall be separated from the foundations piers with flexible material about 20mm thick covered with heavy duty mastic 20 mm x 20 mm. The mastic must resist for water,weather and chemical.

A damp-proof membrane of polythene sheet (1000 gauge) shall be provided between thesubgrade and paving slab.

5.4.2. All other concrete works

The arrangements of above clause 5.3 shall be applied and for paving slab as above mentioned(clause 5.4.1.).

5.5. Concrete cover

Minimum thickness of concrete cover to principal reinforcementunless noted otherwise on the drawings is as follows :

Concrete poured against ground 75 mm³

Formed concrete against ground 50 mm³

Formed concrete exposed to weather 50 mm³

Formed concrete columns, girders and beams not againstground or not exposed to weather

40 mm³

Formed concrete slabs and walls not against ground or notexposed to weather

20 mm³

The bottom of excavations for reinforced concrete bases and footings shall be blinded with a 50mm thick layer of concrete prior to the reinforcement being fixed.

5.6. Construction joints

Construction joints in columns shall be positioned at the soffit of girders, beams, haunches orcolumn capitals and also at an appropriate 'kicker' height above slabs or bases.

Construction joints in girders, beams and slabs shall be positioned at approximately a third of thespan from a support.

Construction joints shall be arranged to minimise the effect of shrinkage of the concrete.Generally, the distance between joints shall not exceed 10 meters.

Where watertight construction is required, all construction joints shall have a continuous PVCWater bar of approved type.


5.7. Concrete paving

5.7.1. Paving thickness

Where required, a 100 mm thick reinforced concrete slab shall be used in process unit areas notsubject to regular maintenance loads or other heavy loads.

A 150 mm thick reinforced concrete slab shall be used in areas regularly subject to maintenanceloads.Paving areas which sustain constant concentrated equipment loadings (piping assemblysupport, etc.) shall be properly thickened and reinforced in the loaded area to insure proper loadtransfer to the subgrade.

5.7.2. Expansion joints and slab protection

In the paving slab, the expansion joints shall be spaced every 6.0 m in two directions.

An horizontal dowel will be inserted in the joint every 400 mm (as per sketch below) to preventthe vertical movements but not the horizontal expansion.

The joint will be filled with a 2.0 cm thick flexible material, which will be covered at the top withheavy duty mastic 20 mm x 20 mm, water, weather and chemical resistant.

The dowel shall be coated as per section 5.9. It will be cast on one side in the concrete. Theother half will be inserted in a closed p.v.c. pipe which will prevent the bonding of the dowel withthe concrete.

The dowel shall be O 16 mm and 600 mm long.

heavy duty mastic 20 mmm*20 mm

flexible joint material

dowal bar

closed PVC pipe


Typical expansion joint

5.8 Reinforcement grades

<5> Reinforcement (re-bars) shall be coated steel

- Reinforcing steel shall be high yield deformed bars with a specified strength of 460 N/mm²according to BS 4449. For design purpose the steel characteristic strength shall be limited to425 N/mm².

- Mild steel bars may be used for links and binders. Characteristic strength shall be 250N/mm² according to BS 4449.

- Wire characteristic strength shall be 485 N/mm² according to BS 4482.

The bending of bar reinforcement shall be carried out in accordance with BS 4466.

5.9. Anchor bolts and base plates

Anchor bolts shall be in accordance with the relevant British Standards.

5.9.1 Design

Anchor bolts shall be designed to cater for initial tension, induced loads and horizontal shear.

The maximum allowable stresses for anchor bolts shall be based on the root area of the thread.

When anchor bolts are set in concrete and are subjected to combined shear and tensile loads,the shear load shall be transmitted to the concrete by the anchor bolts and keys (if required).

When anchor bolts are to be set in sleeves, the sleeves shall be filled with grout. When requiredto allow the equipment expansion due to temperature, sliding plates shall be provided ; anchorbolts at sliding plates shall be hand tight only.

The maximum concrete stress beneath base-plates shall be limited to 5 N/mm². A 25 %increase for stress shall be permitted for wind loading.

Bolt capacities embedments and plate sizes will be based on a concrete having a strength of 28MPa at 28 days.

5.9.2 Clearance

Minimum clearance between anchor bolts axis and the face of the foundation shall be as follows: - diameter < or equal to 30 mm : 150 mm,

- 30 mm < diameter < or equal to 56 mm : 200 mm,- 56 mm < diameter < or equal to 80 mm : 300 mm.

Anchor bolts shall always be located inside the reinforcement frame.


5.9.3 Tolerance

Refer to section 16.2 of specification RG 1700.02 - Concrete works.

5.10. Grouting

Machinery shall be bedded on concrete foundations with a suitable non-shrink grout. For details,refer to Specification RG 1700.02 - Concrete works.

Sand/cement grouts for use under stanchion base plates etc... shall consist in one part ofPortland cement to three parts of sharp sand by volume mixed with the minimum water forworkability.

The minimum thickness of grout shall be 25 mm unless specified otherwise on the designdrawings.

All grout shall have a compressive strength at least equal to the foundation concrete.

6. STRUCTURAL STEEL

6.1. General

Structural steel shall be designed in accordance with the local Code, Q.N.B.S. and the BritishStandards to which it refers (in particular, BS449 Part 2).For loads, refer to section 3 and 4 of this specification.All structural steel shall be grade 43B to BS EN 10025 or equivalent.

6.2. Design conditions

Design shall be in accordance with the above standards with the following modifications :

6.2.1. Plastic design shall not be used for structures

6.2.2. For structural elements continuously exposed to heat above 260°C (500°F), allowable designstresses shall be reduced in proportion to reductions in yield strength of the steel at the designtemperatures.

6.2.3. Special materials protection or material thickness allowance shall be employed for structuralelements subjected to severe corrosion or wear conditions.

6.2.4. For structures supporting equipment subject to water filling, in which 90% or more of the live loadis water, applied for 72 hours or less, the basic allowable unit stresses for all loads during thefilled period may be increased of 20%.


6.2.5. Where special design conditions require higher strength materials, they may be used but shallbe submitted to Engineering Contractor or to QAPCO for approval and must be designed,designated and detailed accordingly.

6.2.6. Allowable deflections

- Design vertical deflections on structural steel members under the effect of dead loads,equipment loads, live loads, crane loads and wind loads shall not exceed the following values:

. purlins and girders L/200

. floor beams- without equipments L/300- with equipments L/500

. runway and monorail beams L/750

. cantilever beams(L equals the span of beams) L/400

- Design horizontal deflections on structural steel frames under the effect of equipment loads,live loads, crane loads and wind loads shall not exceed the following values :

. frames without equipment H/200

. frames with equipment or crane(s)- without wind allowance H/300- with wind allowance H/200

(H equals the height of frames)


- In case of pipe racks design deflection under the effect of dead loads and imposed loads shallnot exceed the following values :

. main supporting beams L/400(L equals the span of beams)

. combined deflections of intermediatebeams and longitudinal tie beams L/200(L equals the span of theintermediate beams)

6.3. Connections

6.3.1. Shop connections may be welded or bolted with high strength friction grip type bolts.

6.3.2. Field connections are to be bolted with high strength friction type bolts, conforming to BS 4604.No field welding shall be permitted for structural steelwork unless approved by the EngineeringContractor. The welding procedure specification and welders qualification test certificates willhave to be submitted to the Engineering Contractor for approval. If approved, field welding maybe used if facilities are available and if so, field welding shall be designed, detailed and specified.

6.3.3. Minor connections such as handrail, floor plate, etc..., may be bolted with common black bolts ofgrade 4.6, conforming to BS 4190 or welded if required on drawings.

Minimum diameter to be used :

- Walkway structures, joints, grits, etc... : 16 mm- Handrails and ladders : 12 mm

6.3.4. Black bolts connecting members supporting vibrating equipment shall have lock-washer or otherequivalent system.

6.3.5. High strength bolts friction type shall be tightened in accordance with the minimum tensionspecified in BS 4604.

6.3.6. The minimum bracing connection shall be made using two 20 mm (3/4 inch) diameter highstrength bolts or be capable of resisting to 59 kN if welded.

6.3.7. Connections by a single bolt is prohibited in all cases.

6.4. Corrosion protection

Structural steel shall be painted as per applicable painting specification.


7. SOIL CHARACTERISTICS

7.1. Ground water level

For design purposes, the maximum height of the ground water shall be taken as follows :

- Ethylene Plant area : 0.700 m above QNHD (Reference level 97.450),- Other areas : 1.000 m above QNHD (Reference level 97.750).

7.2. Soil bearing capacity and foundation level

- For ethylene plant area, design will be performed with 0,3 MPa at 2 meters depth on soilsubstitution for foundations not less than 1 m wide. For foundations less than 1 m wide, thebearing pressure will be reduced prorata.

- For new plants like LDPE Unit N° 2 and utility generation facilities extension, a specific soilsurvey will be made.

8. FOUNDATIONS


8.1.1. Foundations subject to static loads only, shall be designed generally in accordance with theBritish Code of Practice for foundations BS 8004.

8.1.2. Foundations subject to overturning moments, shear or uplift forces, shall be proportioned so thatunder any condition of loading the Factor of Safety against overturning and shear, shall not beless than described in section 8.2. The weight of earth superimposed over foundations may beused in computing the resisting moment or load.

8.1.3. Foundations and structures for reciprocating machinery subject to vibration shall be designedgenerally in accordance with the British Code of Practice for foundations for machinery, CP 2012: Part 1 : 1974 or equivalent.

8.1.4. Foundations and structures for rotating machines.

Rotating machinery may be supported either directly on a rigid foundation or on an elevatedstructure.


The horizontal eccentricity in any direction, between the centroid of mass of themachine-foundation system and centroid of the base contact area, shall not exceed 5 % of therespective dimension.

The center of gravity of the machine-foundation system should be as close as possible to thelines of action of the unbalanced forces.

Elevated structures for rotating machinery shall be as follows :

a) machinery loads shall be directly over vertical supports, where possible,

b) beams and slabs shall have a span as short as possible,

c) within the weight requirements of the foundation, the upper table and the foundation slab shallbe as rigid as possible in the horizontal plane.

Dynamic design shall show that the natural frequencies of foundation-soil system are either lessthan 80 % or greater than 120 % of the operating frequency of the machine.

In case such a provision is impracticable, it shall be shown that the amplitudes are within theallowable values indicated in fig. 1. A reasonable amount of damping shall be estimated.

8.1.5. Pump foundation block shall be reinforced only on exposed faces, however appendages to suchfoundations shall be reinforced to ensure integral action.

8.1.6. Masonry walls shall be supported on either grade beams or continuous strip footings.

8.1.7. Allowance must be made for buoyancy where any foundations are submerged by ground water.

8.2. Stability ratios

Foundations and structures shall be checked for resistance to overturning and sliding. Theminimum factors of safety shall be as follows :

a) 1.5 times the overturning moment for erection condition or test condition.

b) 2.0 times the overturning moment for operating condition or shut-down condition.

c) Sliding resistance to be 1.5 times maximum sliding force.

8.3. Settlement

Except for vibrating machinery a maximum settlement of any one foundation should be 25 mmwith maximum differential settlement of 12 mm from one foundation to another after hydrostatictests.

8.4. Foundation types

In general, foundations for equipment, structures, buildings etc...shall be shallow type (refer tosection 7.2. here above).

8.5. Foundation details


Foundation plinths for structural columns and equipment leg supports shall extend not less than50 mm from the edges of base-plates 0.2 m sq. and less in area, and 75 mm for base-platesover 0.2 m sq in area.

Foundations for equipment such as pumps and compressors shall extend not less than 75 mmfrom the edge of base-plates except when otherwise specified on the manufacturer's drawings.

Foundations, for vessels supported on skirts, shall have the area within the skirt sloped fordrainage to a 50 mm pipe drain, cast in the foundation and directed to the paving or ground.

Unless otherwise specified, exposed edges of concrete above grade shall have a 25 mmchamfer.

All reinforced concrete foundations shall be constructed on mass concrete blinding. Thethickness of blinding shall be 50 mm.

9. FIREPROOFING

<5> See specification Rg 1700-03 Rev210. DESIGN AND CALCULATIONS

Detail of design and calculations shall be shown on sketches showing structure arrangements,loads, member sizes, etc... Computer printout shall supplement sketches whenever computersare utilised.All calculations shall be in English language, using S.I. units.

Units to be used shall be :

. Length m, mm

. Area m², mm²

. Volume m3, mm3

. Force N, kN

. Distributed loads kN/m²

. Stress N/mm² (MPa)


Documents

Design Criteria for Concrete Foundations & Structures 2