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1、ACI 351.2R-94 Foundations for Static Equipment (Reapproved 1999) Reported by ACI Committee 351 Erick N. Larson* Chairman Hamid Abdoveis* William Babcock J. Randolph Becker* William L. Bounds* Marvin A. Cones Dale H. Curtis* Shraddhakar Harsh* C. Raymond Hays* A. Harry Karabinis* John C. King Joseph
2、P. Morawski* Navin Pandya* Ira W. Pearce* Mark Porat* James P. Lee* Chairman, Subcommittee 351.3 John A. Richards* Robert W. Ross* Philip A. Smith Robert C. Vallance* Alfonzo L. Wilson Matthew W. Wrona* * Members of Subcommittee 351.3 which prepared this report. The Committee also wishes to extend i
3、ts appreciation and acknowledgement of two Associate Members who contributed to this report: D. Keith McLean and Alan Porush. The committee has developed a discussion document representing the state- of-the-art of static equipment foundation engineering and construction. It presents the various desi
4、gn criteria, and methods and procedures of analy- sis. design, and construction currently being applied to static equipment foundations by industry practitioners The purpose of the report is to pre- sent the various methods. It is not intended to be a recommended practice, but rather a document whic
5、h encourages discussion and comparison of ideas. Keywords: anchorage (structural); anchor bolts: concrete; equipment; forms; formwork (construction): foundation loading; foundations; grout; grouting: pedestals; pile loads; reinforcement; soil pressure: subsurface preparation; tolerances (mechanics).
6、 CONTENTS Chapter l-Introduction, p. 351.2R-2 l.l-Background 1.2-Purpose 1.3-Scope ACI Committee Reports, Guides, Standard Practices and Com- mentaries are intended for guidance in designing, planning, executing, or inspecting construction and in preparing specifica- tions. References to these docum
7、ents shall not be made in the Project Documents. If items found in these documents are de- sired to be part of the Project Documents, they should be phrased in mandatory language and incorporated into the Pro- ject Documents. The American Concrete Institute takes no position respecting the validity
8、of any patent rights asserted in connection with any item mentioned in this report. Users of this report are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. Chapter 2-Foundation types,
9、 p. 351.2R-2 2.1-General considerations 2.2-Typical foundations Chapter 3-Design criteria, p. 351.2R-4 3.1-Loading 3.2-Design strength/stresses 3.3-Stiffnes/deflections 3.4-Stability Chapter 4-Design methods, p. 351.2R-19 4.1-Available methods 4.2-Anchor bolts and shear devices 4.3-Bearing stress 4.
10、4-Pedestals 4.5-Sail pressures 4.6-Pile loads 4.7-Foundation design procedures Chapter 5-Construction considerations, p. 351.2R-24 5.1-Subsurface preparation and improvement 5.2-Foundation placement tolerances 5.3-Forms and shores 5.4-Sequence of construction and construction joints 5.5-Equipment in
11、stallation and setting 5.6-Grouting ACI 351.2R-94 became effective Feb. 1, 1994. Copyright EI 1994, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any mans, including the making of copies by any photo process, or by any elec- tronic or mec
12、hanical device. printed, written, or oral or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. 351.2R-1 351.2R-2 ACI COMMlTTEE REPORT 5.7-Materials 5.8-Quality control Chapter
13、 6-References, p. 351.2R-28 6.1-Recommended references 6.2-Cited references Glossary, p. 351.2R-30 Metric (SI) conversion factors, p. 351.2R-30 CHAPTER l-INTRODUCTION l.l-Background Foundations for static equipment are used throughout the world in industrial processing and manufacturing fa- cilities
14、. Many engineers with varying backgrounds are engaged in the analysis, design, and construction of these foundations. Quite often they perform their work with very little guidance from building codes, national stan- dards, owner s specifications, or other published infor- mation. Because of this lac
15、k of consensus standards, most engineers rely on engineering judgment and experience. However, some engineering firms and individuals have developed their own standards and specifications as a result of research and development activities, field studies, or many years of successful engineering or co
16、nstruction practice. Firms with such standards usually feel that their information is somewhat unique and, therefore, are quite reluctant to distribute it outside their organization, let alone publish it. Thus, without open distribution, review, and discussion, these standards represent only isolate
17、d practices. Only by sharing openly and discussing this information can a truly meaningful consensus on engineering and construction requirements for static equipment foundations be developed. For this reason, the committee has developed a discussion docu- ment representing the state-of-the-art of s
18、tatic equipment foundation engineering and construction. As used in this document, state-of-the-art refers to state-of-the-practice and encompasses the various engi- neering and construction methodology in current use. l.2-Purpose The Committee presents, usually without preference, various design cr
19、iteria, and methods and procedures of analysis, design, and construction currently being applied to static equipment foundations by industry practitioners. The purpose of this report is to present these various methods and thus elicit critical discussion from the indus- try. This report is not inten
20、ded to be a recommended practice, but rather a document that will encourage discussion and comparison of ideas. 1.3-Scope This report is limited in scope to the engineering and construction of static equipment foundations. The term “static equipment” as used herein refers to industrial equipment tha
21、t does not contain moving parts or whose operational characteristics are essentially static in nature. Outlined and discussed herein are the various aspects of the analysis, design, and construction of foundations for equipment such as vertical vessels, stacks, horizontal ves- sels, heat exchangers,
22、 spherical vessels, machine tools, and electrical equipment such as transformers. Excluded from this report are foundations for machinery such as turbine generators, pumps, blowers, compressors, and presses, which have operational charac- teristics that are essentially dynamic in nature. Also exclud
23、ed are foundations for vessels and tanks whose bases rest directly on soil, for example, clarifiers, concrete silos, and American Petroleum Institute (API) tanks. Foundations for buildings and other structures that contain static equipment are also excluded. The geotechnical engineering aspects of t
24、he analysis and design of static equipment foundations discussed herein are limited to general considerations. The report is essentially concerned with the structural analysis, design and construction of static equipment foundations. CHAPTER 2-FOUNDATION TYPES 2.1-General considerations The type and
25、 configuration of a foundation for equip- ment may be dependent on the following factors: 1. Equipment base configuration such as legs, saddles, solid base, grillage, or multiple supports locations. 2. Anticipated loads such as the equipment static weight, and loads developed during erection, operat
26、ion, and maintenance. 3. Operational and process requirements such as ac- cessibility, settlement constraints, temperature effects, and drainage. 4. Erection and maintenance requirements such as limitations or constraints imposed by construction or maintenance equipment, procedures, or techniques. 5
27、. Site conditions such as soil characteristics, topo- graphy, seismicity, climate, and other environmental effects. 6. Economic factors such as capital cost, useful or anticipated life, and replacement or repair costs. 7. Regulatory or building code provisions such as tied pile caps in seismic zones
28、. 8. Construction considerations. 9.Environmental requirements such as secondary con- tainment or special concrete coating requirements. 2.2-Typical foundations 2.2.1 Vertical vessel and stack foundations - For tall vertical vessels and stacks, the size of the foundation required to resist gravity l
29、oads and lateral wind or seis- mic forces is usually much larger than the support base of the vessel. Accordingly, the vessel is often anchored to FOUNDATIONS FOR STATIC EQUIPMENT 351.2R-3 a pedestal with dimensions sufficient to accommodate the anchor bolts and base ring. Operational, maintenance,
30、or other requirements may dictate a larger pedestal. The pedestal may then be supported on a larger spread footing, mat, or pile cap. For relatively short vertical vessels and guyed stacks with large bases, light vertical loads, and small over- turning moments, the foundation may consist solely of a
31、 soil-supported pedestal. Individual pedestals may be circular, square, hexa- gonal or octagonal. If the vessel has a circular base, a circular, square, or octagonal pedestal is generally pro- vided. Circular pedestals may create construction diffi- culties in forming unless standard prefabricated f
32、orms are available. Square pedestals facilitate ease in forming, but may contain much more material than is required by analysis. Octagonal pedestals are a compromise between square and circular; hence, this type of pedestal is widely used in supporting vertical vessels and stacks with circular base
33、s (see Fig. 2.2.1). 2.2.2 Horizontal vessel and heat exchanger foundations -Horizontal equipment such as heat exchangers and re- actors of various types are typically supported on pedes- tals that rest on spread footings, strap footings, pile caps, or drilled piers. Elevation requirements of piping
34、often dictate that these vessels be several feet above grade. Consequently, the pedestal is the logical means of sup- port. The configuration of pedestals varies with the type of saddles on the vessels, and with the magnitude and direc- tion of forces to be resisted. Slide plates are also used to re
35、duce the magnitude of thermal horizontal forces be- tween equipment pedestals. The most common pedestal is a prismatic wall type. However, T-shaped (buttressed) pedestals may be required if the horizontal forces are very high (see Fig. 2.2.2). 2.2.3 Spherical vessel foundations - Large spherical ves
36、sels are sometimes constructed with a skirt and base ring, but more often have leg-supports. For leg-supported spherical vessels, foundations typically consist of pedes- tals under the legs resting on individual spread footings, a continuous mat, or an octagonal, hexagonal or circular annular ring.
37、Concerns about differential settlement be- tween legs and large lateral earthquake loads usually dictate a continuous foundation system. To economize on foundation materials, an annular ring-type foundation is often utilized (see Fig. 2.2.3). 2.2.4 Machine tool foundations - Machine tool equip- ment
38、 is typically supported on at-grade mat foundations. These may be soil-bearing or pile-supported depending upon the bearing capacity of the soil and the settlement limitations for the machinery (see Fig. 2.2.4). Where a machine tool produces impact type loads, it is generally isolated from the neigh
39、boring mat to minimize transmis- sion of vibration to other equipment. 2.2.5 Electrical equipment and support structure founda- tions - Electrical equipment typically consists of trans- formers, power circuit breakers, switchgear, motor con- FOOTING PLAN ANCHOR BOLTS TYP , Fig. 2.2.l-Octagonal pedes
40、tal and footing for vertical vessel trol centers. Support structures consist of buses, line traps, switches, and lightning arrestors. Foundations for electrical equipment, such as trans- formers, power circuit breakers, and other more massive energized equipment, are typically designed for (1) dead
41、loads, (2) seismic loads, (3) erection loads (i.e., jacking), and (4) operating loads. These foundations are typically slabs on grade, or slabs on piles. Anchorage is provided by anchor bolts or by welding the equipment base to em- bedded plates. Foundations of support structures for stiff electrica
42、l buses, switch stands, line traps, and lightning arrestors are designed to accommodate operating loads, wind loads, short circuit loads, and seismic loads. These loads are usually smaller than those of transmission line sup- port structures; therefore, the supporting foundations commonly used are d
43、rilled piers. If soil bearing condi- tions are unfavorable, however, spread footings or pile supported footings are generally used. Support structures for overhead electrical conductors, such as transmission towers, poles, dead-end structures, and flexible bus supports, are designed for tension load
44、s from the conductors along with ice and wind loads. 351.2R-4 ACI COMMlTTEE REPORT _._._ -.- -. -.-.-.-a- ./ i HORIZONTAL VESSEL I SIDE ELEVATION FOOTING PLAN 1% REINFDRcEMENT WWN ow THIS FIGURE I S INTENDED T O BE ILLUST- RATIVE ONLY. TIE SPACING SPLICES AND OTHER SPECIFIC LAP DETAILS A R E THE RES
45、PONSIBILITY OF THE DESIGN ENGINEER AS NEED- ED FOR SPECIFIC LOADING REQUIR- EMENTS AND SOIL CONDITIONS Fig. 2.2.2-Footingswith strap for horizontal vessels Drilled piers are commonly used to support such struc- tures. Spread footings or pile supported footings are also used when required by soil con
46、ditions. CHAPTER 3-DESIGN CRITERIA Criteria used for the design of static equipment foun- dations vary considerably among engineering practition- ers. There may be several reasons for this variability. Most heavy equipment foundations are designed by or for large organizations, which may include uti
47、lities and government agencies. Many of these organizations, with their in-house expertise, have developed their own engi- neering practices, including design criteria. Many organi- zations, after investing considerable resources in devel- opment, consider such information proprietary. They find no
48、incentive to share their experience and research with others. For these reasons, there is limited published in- formation on the criteria used for the design of the types of static equipment foundations covered by this report. 3.1-Foundation loading Most practitioners first attempt to use the common
49、 PEDESTALS ARE LOCATED REINFORCEMENT-T ,: . .- A- -_. - -._- 2 - - E / PEDESTAL REINFORCEMENT FOOTING PLAN Fig. 2.2.4-Combined footing for horizontal vessel Live loads, as described above, normally will not occur during operation of the equipment. Typically, such loads will be present only during maintenance and shutdown periods. Most practitioners do not consider operating loads, such as the weight of the contents during normal operation, to be live loads. 3.1.1.3 Operating loads - Operating loads include the weight of the equipment contents during normal op- erating co