SABP-Q-004.PDF

Best Practice SABP-Q-004 Heat Exchanger and Horizontal Vessel Foundation Design Document Responsibility: Onshore Structures

31 August, 2002

Heat Exchanger and Horizontal Vessel Foundati on Design 37' - 0"

" 6 ' 6

" 0 ' 8

" 0 ' 4

22' - 0"

Developed by: Hisham Abu-Adas Developed: July, 2002 Civil Engineering Unit/M&CED Consulting Services Department

Previous Issue: New

Next Planned Update: 1 September, 2007 Page 1 of 35

Primary contact: Abu-Adas, Hisham on phone 874-6908

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Document Responsibility: Onshore Structures Issue Date: 31 August, 2002 Next Update: 1 September, 2007 2007

SABP-Q-004 SABP-Q-004 Heat Exchanger and Horizontal Vessel Foun dation Design

HEAT EXCHANGER AND HORIZONTAL VESSEL FOUNDATION DESIGN GUIDE

Table of Contents Page

1.

2

Introduction ...................... ................................. ...................... ...................... ...................... ...................... ...................... ................. ...... 2 1.1

Purpose ...................... ................................. ...................... ...................... ...................... ...................... ......................3 ...........3

1.2

Scope ...................... ................................. ...................... ...................... ...................... ...................... ....................... .............. .. 3

1.3

Disclaimer............................ Disclaimer....................................... ...................... ...................... ...................... ...................... ............. .. 3

1.4

Conflicts with Mandatory Standards.................. Standards.............................. ....................... ............... .... 3

References ....................... .................................. ...................... ...................... ...................... ....................... ....................... ............... .... 4 2.1

Saudi Aramco References ...................... ................................. ....................... ....................... .............. ... 4

2.2

Industry Codes and Standards................... Standards............................... ....................... ...................... ...........4 4

3

General ...................... .................................. ....................... ...................... ....................... ....................... ....................... ..................... .........5 5

4

Design Procedure ...................... ................................. ...................... ...................... ...................... ...................... .................. ....... 5 4.1

Design Considerations ...................... .................................. ....................... ....................... .................... ........ 5

4.2

Vertical Loads.............................. Loads......................................... ....................... ....................... ...................... ............... .... 6

4.3

Horizontal Loads ....................... .................................. ...................... ...................... ....................... .................. ...... 6

4.4

Load Combinations ....................... .................................. ...................... ...................... .......................11 ............11

4.5

Anchor Bolts ....................... .................................. ...................... ...................... ....................... .......................13 ...........13

4.6

Slide Plates.................. Plates............................. ...................... ...................... ...................... ....................... ................... .......13 13

4.7

Pier Design ....................... .................................. ...................... ...................... ....................... ....................... ............. .. 14

4.8

Column Design ..................... ................................ ...................... ...................... ...................... ..................... ..........15 15

4.9

Footing Design ..................... ................................ ...................... ...................... ...................... ..................... ..........16 16

ATTACHMENTS:

Attachment 1 – Exchanger and Tube Bundle Weights Weights ....................... ..................................21 ...........21 Attachment 2 – Thermal Expansion Data ....................... .................................. ...................... .................... .........23 23 Attachment 3 – Soil Pressure for Biaxial Loaded Footings........... Footings ....................... ................. ..... 25 Attachment 4 – Sample Design 1: Horizontal Horizontal Vessel Foundation ................. ................. 26
















1.


Introduction 1.1

Purpose

The purpose of this Practice is to establish guidelines and recommended procedures for the analysis and design of heat exchanger and and horizontal vessel foundations for use by engineers working on Saudi Aramco projects and Saudi Aramco engineers. It shall be used where applicable unless otherwise specified. specified. 1.2

Scope

This design guide defines the minimum requirements for the a nalysis and design of heat exchanger and and horizontal vessel foundations foundations in process industry facilities at Saudi Aramco Aramco sites. In the ensuing sections, pertinent references are given, and design loadings and general design consideration are presented and discussed. This Practice addresses isolated foundations supported directly on soil. Pile supported footings are not included in this practice. Process Industry Practice STE03360 forms the basis for the de velopment of this design guide. 1.3

Disclaimer

The material in this Best Practices document provides the most correct and accurate design guidelines available to Saudi Aramco which comply with international industry practices. This material is being provided for the general guidance and benefit of the Designer. Use of the Best Practices in designing de signing projects for Saudi Aramco, however, does not relieve the Designer from his responsibility to verify the accuracy of any information presented or from his contractual liability to provide safe and sound designs that conform to Mandatory Saudi Aramco Engineering Requirements. Use of the information or material contained herein is no guarantee that the resulting product will satisfy the applicable requirements of any project. Saudi Aramco assumes no responsibility or liability whatsoever for any reliance on the information presented herein or for designs prepared by Designers in accordance with the Best Practices. Use of the Best Practices by Designers is intended intended solely for, and shall be strictly limited to, Saudi Aramco projects. Saudi Aramco® is a registered trademark of the Saudi Arabian Arabian Oil Company. Copyright, Saudi Aramco, 2002. 1.4

Conflicts with Mandatory Standards
















2


References This Best Practice is based on the latest edition of the references below, unless otherwise noted. Short titles will be used herein when appropriate. 2.1

Saudi Aramco References

Saudi Aramco Engineering Standards (SAES) SAES-A-112

Meteorological and Seismic Design Data

SAES-A-113

Geotechnical Engineering Requirements

SAES-A-114

Excavation and Backfill

SASES-A-204

Preparation of Structural Calculations

SAES-M-001

Structural Design Criteria for Non-Building Structures

SAES-Q-001

Criteria for Design and Construction of Concrete Structures

SAES-Q-005

Concrete Foundations

Saudi Aramco Best Practices

2.2

SABP-001

Anchor Bolt Design and Installation

SABP-002

Spread Footings Design

SABP-007

Wind Loads on Piperacks and Open Frame Structures

Industry Codes and Standards

American Concrete Institute (ACI) ACI 318

Building Code Requirements for Reinforced Concrete

American Society of Civil Engineers (ASCE) ASCE 7

Minimum Design Loads for Buildings and Other Structures

Wind Load and Anchor Bolt Design for Buildings and Other Structures
















3

4


General 3.1

The design and specifications for construction of heat exchanger and horizontal vessel foundation shall be adequate for the structure intended use, in accordance with commonly accepted engineering practice, Saudi Aramco Standard SAESQ-005 and this guideline.

3.2

A geotechnical investigation is required for all new structures and foundations as described in SAES-A-113. (Ref. SAES-Q-005, Para. 4.1.1)

3.3

The allowable soil bearing pressure shall be based on the results of the geotechnical investigation, and a consideration of permissible total and differential settlements. settlements. Soil pressures shall be calculated under the action of vertical and lateral loads using load combinations that result in the maximum soil pressures. The maximum soil pressure pressure shall not exceed the applicable allowable value. (Ref. SAES-Q-005, Para. 4.1.2

3.4

Foundations shall be founded on either undisturbed soil or compact fill and at least 600 mm below the existing or finished grade surface, unless a detailed soils investigation indicated otherwise. otherwise. In the case of foundations supported on compacted fill, the geotechnical investigation and/or SAES-A-114 shall govern the type of fill material and degree of compaction required. (Ref. SAES-Q-005, Para. 4.1.3)

3.5

The design and construction of all concrete foundations shall comply with the requirements of SAES-Q-001, SAES-Q-005 and ACI-318. (Ref. SAES-Q-005, para. 4.3.1)

3.6

The design concrete compressive strength of concrete shall be 27.6 MPa (4000 psi ) at 28 days. (Ref. SAES-Q-005, Para. 4.3.2.b)

3.7

The structural calculations shall be prepared in accordance with the requirements of SAES-A-204.

Design Procedure 4.1

Design Considerations

4.1.1

Heat exchanger and horizontal vessel wind and seismic loads shall shall be in accordance with Saudi Aramco Standard SAES-A112.
















4.2

4.3


Vertical Loads

4.2.1

Erection Weight (P f ) - Fabricated weight of heat exchanger or horizontal vessel, generally taken from equipment drawing

4.2.2

Empty Weight (Pe) - Fabricated weight of vessel plus weight of internals, piping, insulation, fireproofing, and platforms, generally taken from equipment drawing.

4.2.3

Operating Weight (Po) - Empty weight plus weight of operating liquid; generally taken from equipment drawing.

4.2.4

Test Weight (Pt) – Empty weight plus weight of water required for hydrostatic test, generally taken from the equipment drawing.

4.2.5

Eccentric Load (Pc) – Unless more exact information regarding piping supported on the foundation is available, a load of 10% of the applicable vessel weight should be applied to each pedestal and footing at a inches from the longitudinal centerline of the distance of D/2 plus 18 inches vessel, where “D” is the basic diameter (basic diameter = exchanger I.D. + 2 times the wall thickness + 2 times the insulation thickness).

4.2.6

Dead Load (D) – Vessel’s foundation weight that is defined as the combined weight of footing, pedestal, and overburden soil.

4.2.7

Load Distribution Distribution (Exchangers) – For most common shell shell and tube tube heat exchangers, vertical loads should normally be distributed with 60% to the channel end (slotted end ) support and 40% to the shell end ( fixed end ) support. However, the actual exchanger shape and support configuration should be reviewed when determining weight distribution, since in many cases load distribution may vary.

4.2.8

The above loads shall be considered as dead loads (e.g., 1.4 load factor) when applying load factors.

Horizontal Loads

4.3.1

Wind Loading (W) 4.3.1.1

Wind loads shall be calculated in accordance with the requirements of SAES-A-112, SAES-M-001 “Structural Design Criteria for Non-Bulding Structures”, Saudi Aramco


















4.3.1.2


Transverse Wind - The wind pressure on the projected area of the side of the vessel should be applied as a horizontal shear at the center of the vessel. The saddle-to-pier connection should be considered fixed for for transverse transverse loads. The saddle design is a function of either the vessel supplier or the De signer’s Mechanical/Vessel Group.

Longitudinal Wind 4.3.1.3 Longitudinal - The wind pressure on the end of the vessel should be applied as a horizontal shear at the center of the vessel. Also include the flat surface wind wind pressure on the exposed area of both piers or columns, applied as a horizontal shear at the centroid of the exposed area. The saddle-to-pier connection will be considered pinned for for longitudinal loads unless there is more than one row of anchor bolts.

4.3.1.4

Shielding - Make no allowance for shielding from wind by nearby equipment or structures except under unusual conditions.

4.3.1.5

The following guidelines of ASCE “Wind Load and Anchor Bolt Design for Buildings and Other Structures” may be used to calculate wind loads on horizontal vessels: a)

No check for dynamic properties is required.

b)

For the projected diameter, add 1.5 ft (0.46 m) to the insulated diameter to account for ladders, nozzles and pipe 8 in. (0.2 m) (incluidng insulation) or smaller.

c)

For wind perpendicular to the long axis of the vessel (transverse wind), the force coefficient (Cf ) should be

































For handrails use the values for area a rea and froce coefficients from Table 4.1below. Use the projected area of each ea ch railing system. TABLE 4.1 Force Coefficients for Wind Loads on Components Item Handrail Ladder without cage Ladder with cage Solid Rectangles & Flat Plates Stair w/handrail Side Elevation End elevation Round or Square Shapes

Cf 2.0 2.0 2.0 2.0 2.0 2.0

Projected Area 0.80 sq. ft./ft. 0.50 sq. ft./ft. 0.75 sq. ft./ft. Handrail area plus channel depth 50% gross area

See ASCE 7 Table 6-7

(Adapted from ASCE - “Wind Loads and Anchor Bolt Design for Petrochemical Facilities”)

4.3.2

Seismic (E) 4.3.2.1

Seismic forces shall be calculated in accordance with SAES-A112 and the requirements of SAES-M-001 “Structural Design Criteria for Non-Bulding Structures”.

4.3.2.2

Seismic loads calculated by the Vessel Vendor shall be independently verified as appropriate by the Engineer prior to performing foundation design to ensure compliance with the project specifications and the applicable Saudi Aramco Standards.

4.3.2.3

For low friction slide plates (µ ≤ 0.2), apply all of the seismic

















between the piers. For stacked exchangers, the load should be applied at the center of the top bundle. The portion of the bundle pull force at the sliding end support will equal the lesser of the friction force or ½ the bundle pull force. The remainder of the bundle pull force will be resisted at the fixed end support. 4.3.4

Thermal Force (TL) 4.3.4.1

Calculate thermal growth using maximum design temperature. Thermal expansion data can be found in Attachment 2. Thermal force is defined as the force due growth of the horizontal vessel or exchanger between supports.

4.3.4.2

The thermal force used for design should be the smaller value resulting from the following two calculations: •

The force required to overcome static friction between the vessel support and the slide plate: Ff = µ (Pop)

(Eq. 1)

where, Ff = static friction force µ

= coefficient of friction, refer to the table under 4.6 Slide Plates or values

Pop = operating vertical load on slide plate •

The force required to deflect the pier or column an amount equal to 1/2 of the thermal growth between supports:
















4.3.5

4.4


Load Distribution

4.3.5.1

Divide the load equally between piers except where otherwise specified.

4.3.5.2

When the longitudinal loads, such as seismic and bundle pull, govern the pier/foundation design, a strut between the piers has been found to be economical. The savings in concrete commonly exceeds the added cost of a strut. strut. A strut could consist of two nested pipes field welded to each other and to embedded plates on the inside of each pier. pier. If the vessel vessel or exchanger has a central pipe that interferes with at strut on the centerline, two struts can be used, which straddle the pipe.

Load Combinations

4.4.1

Piping thermal loads should be included included in combinations when deemed advisable and should be considered as dead loads when applying load factors.

4.4.2

Wind forces and seismic forces shall not be considered to act simultaneously.

4.4.3

In combinations involving Test Load (Pt) or Erection Load (P (Pf ), ), and Wind Load (W) or Seismic Load (E), only one-third of the load need be considered. For wind load, this is justified because hydrotests are not conducted during high winds and, for earthquake load; the probability of shocks occurring during hydrotest is low.

4.4.4

The loads used for for footing footing design shall be service service load reactions obtained form certified vendor drawings. drawings. In computing footing soil pressures pressures the reactions are used. The weight of the footing and soil



















Load Comb. 2 (Po + D + Pc + W or E) (Operating + Transverse Wind or Seismic + Eccentric) Load Comb. 3 (Po + D + Pc + W or E) (Operating + Longitudinal Wind or Seismic + Ecce ntric)

(Pe + D + Pc + W or E) Load Comb. 4 (Empty + Transverse Wind or Seismic + Eccentric) Load Comb.5 (Pe + D + Pc + W or E) (Empty + Longitudinal Wind or Seismic + Eccentric)

(Pf + + D + 1/4 W) (Pt + Pc + D)

(Pt + Pc + D + 1/4 W)

Load Comb. 6 (Erection Weight + 1/4 Wind) Load Comb. 7 (Test + Eccentric) For Horizontal Vessel Only Load Comb. 8 (Test Weight + Eccentric + (1/4 Wind) For Horizontal Vessel Only

















Load Comb. 2 0.75 (1.4 Po +1.4 D +1.4 Pc +1.7 W or 1.9 E) 0.75 (Operating + Transverse Wind or Seismic S eismic + Eccentric) Load Comb. 3 0.75 (1.4 Po +1.4 D +1.4 Pc +1.7 W or 1.9 E) 0.75 (Operating + Longitudinal Wind or Seismic + Eccentric)

0.75 (1.4 Pe +1.4 D +1.4 Pc +1.7 W or 1.9 E) Load Comb. 4 0.75 (Empty + Transverse Wind or Seismic + Eccentric) Load Comb.5 0.75 (1.4 Pe +1.4 D +1.4 Pc + 1. WL or 1.9 E) 0.75 (Empty + Longitudinal Wind or Seismic Se ismic + Eccentric)

0.9Pf + + 0.9 D + 1.3 (1/4 W ) 0.80 (1.4 Pt + 1.4 Pc + 1.4 D)

Load Comb. 6 (Erection Weight + 1/4 Wind) Load Comb. 7 0.80 (Test + Eccentric) For Horizontal Vessel Only

0.75 (1.4 Pt + 1.4 Pc + 1.4 D + 0.40 W ) Load Comb. 8 0.75 (Test Weight + Eccentric + (Partial Wind) For Horizontal Vessel Only

















Exceptions to this should be as follows: •

When the deflection force F d equal to or less than the sliding force F f f for d is low friction bearing.

•

When it is more economical to distribute a large load more evenly between the two piers by increasing the friction force on the sliding end.

Typical coefficients of friction are as follows: • No slide plate (steel support on concrete)

0.50

•

Steel Slide Plate

0.30

•

Teflon Slide Plate*

•

- Bearing Pressure 100 psi and below

0.10

- Bearing Pressure Above 100 psi

0.06

Lubrite Slide Plate*

0.10

* Values should be verified against aga inst Vendor’s data. 4.6.3

Use the the following following criteria criteria for sizing low temperature temperature (less (less than 500°F) slide plate elements. elements. For higher temperatures, refer to manufacturer’s manufacturer’s literature.

















4.7.2

Anchorage Considerations – It is normally desirable to make the pedestal deep enough to contain the anchor bolts and keep them out of the footing. Consideration must be given to anchor bolt development and foundation depth requirements.

4.7.3

Reinforcing 4.7.3.1

Piers should be designed as cantilever beams with two layers of reinforcement. When the required reinforcing approaches ρmax, investigate the pier as a column. Size and reinforcement for for each pier should normally normally be the same. same. Dowel splices are not required if the vertical pier reinforcing projection is less than 6 feet in height, or the rebar size in feet above the top of the footing. For cases that exceed this limit, use dowels with minimum projections required for a class B tension splice in accordance with ACI 318 (see Table 1).

4.7.3.2

Minimum reinforcing for piers is #5 at 12 inches on each face with #4 ties at 12 inches . Place double ties at top of piers to protect anchor bolts. All ties should encircle the vertical reinforcement. Pier ties are are not normally detailed detailed as column
















4.9


Footing Design

4.9.1 Sizing: The size of spread footing may be governed by stability requirements, sliding, soil bearing pressure, pressure, or settlement. settlement. Plan view footing dimensions should should be in 2-inch increments. The footing thickness shall be 12 inches minimum and thickened in 2-inch increments. Size for both footings should normally normally be the same. 4.9.2

The footing footing thickness adequate for embedment of pier or column reinforcement should be checked in accordance with ACI 318, Chapter 12 (see also Table 2 – Attach. 6).

4.9.3

If a footing has uplift, there will be a moment at the heel that will cause tension in the top of footing. Provide top steel to account for the moment resulting from the footing weight and soil ove rburden weight.

4.9.4

Footing shall be designed so that under sustained loads loads (operating loads) the total settlement and the differential settlement between footings d o not exceed the established established limits. The maximum allowable amount amount of total settlement and differential settlement is typically set by the Project Structural Engineer based on the sensitivity of the equipment or structure being supported.



















where L = dimension of footing in the direction of the overturning moment, ft. e = eccentricity = overturning moment at the base of the footing divided by the total vertical load, ft. Eccentricity e = ΣMO.T./Σ ./ΣP MR = Resisting Moment 4.9.7

Foundation Sliding

The minimum safety factor against sliding shall be 1.5 The coefficient

































4.9.9.2

Top Reinforcing Reinforcing – If If a footing has uplift, there will be a moment at the heel that will cause tension in the top of footing. Provide top steel to account for the moment resulting from the footing weight and soil overburden weight. Development length of top steel shall be checked. The bars may be hooked o 90 downward to achieve the required development length if straight embedment is is not adequate. If top reinforcing is required, minimum reinforcing shall shall be #4 at 12 inches on center, each way.

4.9.9.3

Minimum Bottom Reinforcement - To ensure that a footing failure is ductile, the minimum amount of bottom steel (grade
















Shear Strength of Concrete in Footings

SABP-Q-004 SABP-Q-004 Heat Exchanger and Horizontal Vessel Found atio n Des ign

















Attachment 1 – Exchanger and Tube Bundle Weights 20 19 18 17 16 15

s s l a C d n o u P 0 5 4 0 0 3

0 5 1



















Attachment 1 – Appropriate Exchanger and Tube Bundle Weights (Cont'd)

















Attachment 2 – Thermal Expansion Data

















Attachment 2 – Thermal Expansion Data (Cont'd)

















Attachment 3 – Soil Pressure for Biaxial Loaded Footings

















Attachment 4 – Sample Design 1: Horizontal Vessel Foundation

















































































































SABP-Q-004.PDF

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