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1、ACI 313-97 was adopted as a standard of the American Concrete Institute on January 7, 1997, to supersede ACI 313-91, in accordance with the Institutes standardization procedures. Copyright 1998, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or
2、by any means, including the making of copies by any photo process, or by electronic or mechanical 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 pr
3、oprietors. This standard was submitted to letter ballot of the committee and was approved in accordance with Institute standardization procedures. 313-1 This ACI standard practice gives material, design, and construction requirements for concrete silos, stave silos, and stacking tubes for storing gr
4、anular materials. It includes design and construction recommendations for cast-in-place or precast and conventionally reinforced or post-tensioned silos. Silos and stacking tubes are special structures, posing special problems not encountered in normal building design. While this standard refers to
5、“Building Code Requirements for Structural Concrete (ACI 318)” for many requirements, it puts forth special requirements for the unique cases of static and dynamic loading from funnel flow, mass flow, concentric flow, and asym- metric flow in silos, and the special loadings on stacking tubes. The st
6、andard includes requirements for seismic design and hopper bottom design. Keywords: asymmetric flow; bins; circumferential bending; concrete; concrete construction; dead loads; dynamic loads: earthquake resistant structures; formwork (construction); funnel flow; granular materials; hop- pers; jumpfo
7、rms; lateral loads: loads (forces); lowering tubes; mass flow; overpressure; quality control; reinforced concrete; reinforcing steels; silos; slipform construction; stacking tubes; stave silos; stresses; structural analysis; structural design; thermal stresses; walls. CONTENTS Chapter 1General, p. 3
8、13-2 1.1Introduction 1.2Definitions 1.3Scope 1.4Drawings, specifications, and calculations Chapter 2Materials, p. 313-3 2.1General 2.2Cements 2.3Aggregates 2.4Water 2.5Admixtures 2.6Metal 2.7Precast concrete staves 2.8Tests of materials Chapter 3Construction requirements, p. 313-3 3.1General 3.2Conc
9、rete quality 3.3Sampling and testing concrete 3.4Details and placement of reinforcement 3.5Forms 3.6Concrete placing and finishing 3.7Concrete protection and curing 3.8Lining and coating 3.9Tolerances for slipformed and jumpformed structures Chapter 4Design, p. 313-4 4.1Notation Standard Practice fo
10、r Design and Construction of Concrete Silos and Stacking Tubes for Storing Granular Materials (ACI 313-97) An ACI Standard ACI 313-97 Mostafa H. Mahmoud Chairman Vahe A. AprahamianDonald Midgley William D. ArockiasamyGerman R. GurfinkelJack Moll Leon BialkowskiErnest C. HarrisLee A. Nash Alfred G. B
11、isharaDonald S. JackRodney M. Nohr William H. BokhovenRichard T. JenkynJ. Michael Rotter William L. ClarkMichael E. JohnsonJohn E. Sadler James M. EbmeierRobert D. JohnsonSargis S. Safarian Stephen G. FrankoskyF. Thomas JohnstonJoseph R. Tucker Reported by ACI Committee 313 313-2ACI STANDARD 4.2Gene
12、ral 4.3Details and placement of reinforcement 4.4Loads 4.5Wall design 4.6Hopper design 4.7Column design 4.8Foundation design Chapter 5Concrete stave industrial silos, p. 313-9 5.1Notation 5.2Scope 5.3Coatings 5.4Erection tolerances 5.5Wall design 5.6Hoops for stave silos 5.7Concrete stave testing Ch
13、apter 6Post-tensioned concrete silos, p. 313-12 6.1Notation 6.2Scope 6.3Post-tensioning systems 6.4Tendon systems 6.5Bonded tendons 6.6Unbonded tendons 6.7Post-tensioning ducts 6.8Wrapped systems 6.9Details and placement of non-prestressed reinforcement 6.10Wall openings 6.11Stressing records 6.12De
14、sign 6.13Vertical bending moment and shear due to post-tensioning 6.14Tolerances Chapter 7Stacking tubes, p. 313-15 7.1Scope 7.2General layout 7.3Loads 7.4Load combinations 7.5Tube wall design 7.6Foundation or reclaim tunnel Chapter 8Specified and recommended references, p. 313-17 Appendix ANotation
15、, p. 313-17 CHAPTER 1GENERAL 1.1Introduction This document, which covers design and construction of concrete silos and stacking tubes for storing granular mate- rials, replaced the 1968 ACI Committee 313 Report 65-37 and was adopted as an ACI Standard in March 1977 as ACI 313-77. It was subsequently
16、 revised in 1983 and 1991. The current revision reflects the most recent state-of-the-art in structural design, detail, and construction of concrete silos and stacking tubes. Static pressures are exerted by the stored material at rest and shall be computed by methods presented. Flow pressures that d
17、iffer from static pressures are exerted by the stored material during flow and also shall be computed by the methods presented. Design of the structures shall consider both static and flow loading. Applicable sections of ACI 318 shall apply. 1.2Definitions The term “silo,” as used herein, applies to
18、 any upright container for storing bulk granular material. Alternate names such as “bins” and “bunkers” are used in different localities, but for purposes of this Standard, all such structures are considered to be silos. “Stacking tubes” or “lowering tubes” are relatively slender, free-standing, tub
19、ular concrete structures used to stack conical piles of granular materials. See Commentary Section 7.2. “Slipformed” silos are constructed using a typically 4 ft. (1.2 m) high continuously moving form. “Jumpformed” silos are constructed using three typically 4 ft. (1.2 m) high fixed forms. The botto
20、m lift is jumped to the top position after the concrete hardens sufficiently. A “hopper” is the sloping, walled portion at the bottom of a silo. “Stave silos” are silos assembled from small precast concrete units called “staves,” usually tongued and grooved, and held together by exterior adjustable
21、steel hoops. Other special terms are defined in the Commentary. 1.3Scope This Standard covers the design and construction of concrete silos and stacking tubes for storing granular materials. Silos for storing of ensilage have different requirements and are not included. However, industrial stave sil
22、os for storage of granular materials are included. Coverage of precast concrete is limited to that for industrial stave silos. The Standard is based on the strength design method. Provisions for the effect of hot stored material are included. Explanations of requirements of the Standard, additional
23、design information, and typical details are found in the Commentary. 1.4Drawings, specifications, and calculations 1.4.1 Project drawings and project specifications for silos shall be prepared under the direct supervision of and bear the seal of the engineer. 1.4.2 Project drawings and project speci
24、fications shall show all features of the work, naming the stored materials assumed in the design and stating their properties, and including the size and position of all structural components, connections and reinforcing steel, the required concrete strength, and the required strength or grade of re
25、inforcing and structural steel. DESIGN AND CONSTRUCTION OF CONCRETE SILOS AND STACKING TUBES313-3 CHAPTER 2MATERIALS 2.1General All materials and tests of materials shall conform to ACI 301, except as otherwise specified. 2.2Cements Cement shall conform to ASTM C 150 (Types I, IA, II, IIAA, III and
26、IIIA), ASTM C 595 (excluding Types S, SA, IS and IS-A), or ASTM C 845. 2.3Aggregates The nominal maximum size of aggregate for slipformed concrete shall not be larger than one-eighth of the narrowest dimension between sides of wall forms, nor larger than three-eighths of the minimum clear spacing be
27、tween indi- vidual reinforcing bars or vertical bundles of bars. 2.4Water Water for concrete shall be potable, free from injurious amounts of substances that may be harmful to concrete or steel. Non-potable water may be used only if it produces mortar cubes, prepared according to ASTM C 109, having
28、7- and 28-day strengths equal to at least the strength of similar specimens made with potable water. 2.5Admixtures 2.5.1 Air-entraining, water reducing, retarding or acceler- ating admixtures that may be required for specific construc- tion conditions shall be submitted to the engineer for approval
29、prior to their use. 2.6Metal 2.6.1 Hoop post-tensioning rods shall be hot-dip galva- nized or otherwise protected from corrosion. Connectors, nuts and lugs shall either be hot-dip galvanized or made from corrosion-resistant castings or corrosion-resistant steel. Galvanizing shall conform to ASTM A 1
30、23. 2.6.2 Malleable iron castings shall conform to ASTM A 47. 2.7Precast concrete staves 2.7.1 Materials for staves manufactured by the dry-pack vibratory method shall conform to ASTM C 55. 2.7.2 Before a stave is used in a silo, drying shrinkage shall have caused the stave to come within 90 percent
31、 of its equilibrium weight and length as defined by ASTM C 426. 2.8Tests of materials 2.8.1 Tests of materials used in concrete construction shall be made as required by the applicable building codes and the engineer. All material tests shall be by an agency acceptable to the engineer. 2.8.2 Tests o
32、f materials shall be made in accordance with the applicable ASTM standards. The complete record of such tests shall be available for inspection during the progress of the work, and a complete set of these documents shall be preserved by the engineer or owner for at least 2 years after completion of
33、the construction. 2.8.3 Silo stave testsThe results of mechanical tests of silo staves and stave assemblies shall be used as criteria for structural design of stave silos. The application of the test results is given in Chapter 5. Example methods of performing the necessary tests are given in the Co
34、mmentary. CHAPTER 3CONSTRUCTION REQUIREMENTS 3.1General Concrete quality control, methods of determining concrete strength, field tests, concrete proportions and consistency, mixing and placing, formwork, details of reinforcement and structural members shall conform to ACI 301, except as specified o
35、therwise herein. 3.2Concrete quality 3.2.1 The compressive strength specified for cast-in-place concrete shall be not less than 4000 psi (28 MPa) at 28 days. The compressive strength specified for concrete used in precast units shall be not less than 4000 psi (28 MPa) at 28 days. The acceptance stre
36、ngth shall conform to ACI 301. 3.2.2 Exterior concrete in silo or stacking tube walls that will be exposed to cycles of freezing and thawing shall be air entrained. 3.3Sampling and testing concrete 3.3.1 For strength tests, at least one set of three specimens shall be made and tested of the concrete
37、 placed during each 8 hrs or fraction thereof. 3.3.2 Accelerated curing and testing of concrete cylinders shall conform to ASTM C 684. 3.4Details and placement of reinforcement 3.4.1 Horizontal tensile reinforcement in silo and hopper walls shall not be bundled. 3.4.2 Horizontal reinforcement shall
38、be accurately placed and adequately supported. It shall be physically secured to vertical reinforcement or other adequate supports to prevent displace- ment during movement of forms or placement of concrete. 3.4.3 Silo walls that are 9 in. (230 mm) or more in thick- ness shall have two layers of hor
39、izontal and vertical steel. 3.4.4 The minimum concrete cover provided for reinforce- ment shall conform to ACI 318 for cast-in-place concrete (non-prestressed), except as noted in Section 4.3.10. 3.5Forms 3.5.1 The design, fabrication, erection and operation of a slipform or jumpform system for a si
40、lo or stacking tube wall shall meet the appropriate requirements of ACI 347. 3.5.2 Forms shall be tight and rigid to maintain the finished concrete wall thickness within the specified dimen- sional tolerances given in Section 3.9. 3.5.3 Slipform systems shall include an approved means of determining
41、 and controlling level at each jack unit. 3.6Concrete placing and finishing 3.6.1 Construction joints in silos shall not be permitted unless shown on the project drawings or specifically approved by the engineer. 3.6.2 Concrete shall be deposited within 5 ft. (1.5 m) of its final position in a way t
42、hat will prevent segregation and shall 313-4ACI STANDARD not be worked or vibrated a distance of more than 5 ft. (1.5 m) from the point of initial deposit. 3.6.3 As soon as forms have been raised (or removed), vertical wall surfaces shall be finished by filling voids with mortar made from the same m
43、aterials (cement, sand and water) as used in the wall and by applying a “smooth rubbed finish” in accordance with Section 10.3.1 of ACI 301. 3.7Concrete protection and curing 3.7.1 Cold weather concreting may begin when tempera- ture is 24 F (4 C) and rising, provided that the protection method will
44、 allow 500 psi (4 MPa) compressive strength gain before the concrete temperature drops below 32 F (0 C). For cold weather concreting, ACI 306R recommendations shall be used where applicable. 3.7.2 In hot weather, measures shall be taken to prevent drying of the concrete before application of a curin
45、g compound. For hot weather concreting, ACI 305R recom- mendations shall be used where applicable. 3.7.3 Where the wall surfaces will remain moist naturally for 5 days, no curing measures are required. Otherwise, curing measures conforming to ACI 308 shall be used. 3.7.4 Where curing measures are re
46、quired, they shall be provided before the exposed exterior surfaces begin to dry, but after the patching and finishing have been completed. Wall surfaces shall be protected against damage from rain, running water or freezing. 3.7.5 Curing compounds shall not be used on the inside surfaces of silos u
47、nless required by the project drawings or project specifications, or unless specifically approved by the engineer. When curing of interior surfaces is required, non- toxic compounds and ventilation or other methods of assuring worker safety shall be used. 3.7.6 Curing compound shall be a non-stainin
48、g, resin base type complying with ASTM C 309, Type 2, and shall be applied in strict accordance with the manufacturers instruc- tions. Waxbase curing compounds shall not be permitted. If a curing compound is used on the interior surfaces of silos to be used for storing materials for food, the compou
49、nd shall be non-toxic, non-flaking and otherwise non-deleterious. 3.8Lining and coating 3.8.1 Linings or coatings used to protect the structure from wear and abrasion, or used to enhance flowability, shall be composed of materials that are non-contaminating to the stored material. 3.8.2 Lining materials installed in sheet form shall be fastened to the structure with top edges and side seams sealed to prevent entrance of stored material behind the lining. 3.8.3 Coatings used as barriers against moi
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