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1、ACI 548.7-04 became effective October 27, 2004. Copyright 2004, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral
2、, or recording for sound or visual reproduc- tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. 548.7-1 It is the responsibility of the user of this document to establish health and safety practices appropriate to
3、the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws
4、and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Test Method for Load Capacity of Polymer Concrete Underground Utility Structures Reported by ACI Committee 548 ACI 548.7-04 Polymer concrete underground util
5、ity structures are used to house outside plant equipment such as electrical distribution line splices, natural gas dis- tribution vaults, water meters, and communication line splices. This test method provides procedures for full-scale testing of three loading conditions similar to vehicle loading t
6、hat may be experienced in field installations. Results obtained may be used to determine the load-carrying capacity of the structure being tested and provide data for direct comparison between struc- tures of various designs. While this method may be used for any underground structure, it is primari
7、ly for use on polymer concrete and polymer concrete/ composite structures up to 10 x 10 x 10 ft (3 x 3 x 3 m) in size. Ke ywords: handholes; polymer concrete; testing; underground structure; utility structure. CONTENTS Section 1Introduction, p. 548.7-1 Section 2Scope, p. 548.7-2 Section 3Referenced
8、documents, p. 548.7-2 Section 4Terminology, p. 548.7-2 Section 5Significance and use, p. 548.7-2 Section 6Apparatus, p. 548.7-3 Section 7Sampling, test specimens, and test units, p. 548.7-3 Section 8Measurements, p. 548.7-3 Section 9Conditioning, p. 548.7-3 Section 10Procedures, p. 548.7-3 Section 1
9、1Calculation or interpretation of results, p. 548.7-5 Section 12Report, p. 548.7-5 Appendix, p. 548.7-5 SECTION 1INTRODUCTION 1.1 Testing polymer concrete (PC) underground utility struc- tures as described herein began during the 1970s and the method was included in the Western Underground Guide 3.6
10、, Nonconcrete Enclosures, last printed in 1988.* Guide 3.6 was developed by a group of utilities in the western United States to specify underground utility structures made from materials other than portland-cement concrete for their use. The guide includes complete product specifications and Milton
11、 D. AndersonRobert W. GaulDonald A. SchmidtCumaraswamy Vipulanandan J. Christopher BallMohammad S. KhanQizhong ShengRonald W. Vogt John J. BartholomewStella L. MarusinW. Glenn SmoakWafeek S. Wahby Constantin BodeaJoseph A. McElroyJoe SolomonD. Gerry Walters James T. DikeouPeter MendisAriel SorianoHa
12、rold H. Weber, Jr. Floyd E. Dimmick, Sr.John R. MillironGeorge L. SouthworthDavid White Harold R. EdwardsBrad NemunaitisMichael M. SprinkelDavid P. Whitney Garth J. FallisRichard C. PrusinskiMichael S. StenkoTom Wickett Larry J. FarrellMahmoud M. Reda TahaBing TianPhillip Y. Yang David W. FowlerSure
13、sh SawantDonald P. TragianeseStefan Zmigrodzki Albert O. Kaeding Chair James Maass Secretary *Western Underground Committee Guide, Nonconcrete Enclosures, WUC 3.6/02/ 0588, Western Underground Committee. 548.7-2 ACI STANDARD addresses four specific enclosure sizes. Its use has spread across the coun
14、try and the Guide has become a de facto standard. Preparation of this ACI 548.7 document as a stan- dardized, separate test method permits users to specify performance criteria and incorporate testing procedures by reference. It can be used for all underground utility structure sizes currently in us
15、e. This document is to be provided to ASTM for consideration as an ASTM test method. SECTION 2SCOPE 2.1 This test method provides data to be used in evaluating the load-carrying capacity of polymer concrete (PC) under- ground utility structures, frequently called handholes, by full-scale testing of
16、the structure. A PC underground struc- ture includes a box, typically without a bottom, and a matching cover (Fig. 1). It may include an extension and, if so, testing shall be of the box and extension together. These test methods are primarily for PC and PC/fiber-reinforced polymer composite enclosu
17、res. They may also be used to test underground enclosures of portland-cement concrete or other materials. 2.2 Four procedures are provided: 2.2.1 Vertical load capacity evaluation for the enclosure coverA concentrated load is applied to the cover to approximate a vehicle wheel load. 2.2.2 Vertical l
18、oad capacity evaluation for enclosure wallsA concentrated load is applied to the box along its edge to approximate a vehicle wheel as it passes onto or off of the assembly. 2.2.3 Lateral load capacity evaluation for enclosure wallsA uniformly distributed load is applied to the largest box wall to ap
19、proximate the pressures resulting from earth backfill and the surcharge of a nearby vehicle. 2.2.4 Determination of failure loads for the three defined load conditions as detailed in Section 10.4. 2.3 Each of three specimens shall be tested to the design load and cycled for each procedure. Test the
20、three specimens to failure using Procedure 4 as given in 10.4 for each. 2.4 The design load shall be determined for testing purposes, and all safety factors related to the design load shall be reported. 2.5 Ambient service temperatures affect the performance of the enclosures. These tests shall be c
21、onducted at 75 10 F (24 5 C) unless another temperature is specified in the request for testing. 2.6 The paired values stated in inch-pound and SI units are usually not exact equivalents. Therefore, each system is to be used independently of the other. Combining values from the two systems may resul
22、t in nonconformance with this test method. SECTION 3REFERENCED DOCUMENTS 3.1ASTM standards C 857 Standard Practice for Minimum Structural Design Loading for Underground Precast Concrete Utility Structures SECTION 4TERMINOLOGY 4.1Definitions 4.1.1 boxmain section of handhole containing a recess to re
23、ceive the cover. 4.1.2 covertop surface section of the handhole for closing the top access opening of the box section. 4.1.3 design loadThe actual, expected load or loads that an underground utility structure supports in service calcu- lated using ASTM C 857 or other rational design method. 4.1.4 ex
24、tensionAn add-on section that fits to the bottom or to the top of a box and extends its height. 4.1.5 handholeA complete assembly that is not large enough for a person to enter and providing an access to an underground utility or fixture. The assembly includes a box, a cover, and, if needed, an exte
25、nsion. 4.1.6 underground utility structureAn enclosure for use underground that may be either a handhole or manhole. SECTION 5SIGNIFICANCE AND USE 5.1 The results from these test methods provide users with information about the maximum load capacity and deflection characteristics of the enclosure un
26、der three static loading conditions. The loading conditions approximate the three most severe conditions of loading encountered in actual installations and allow users to compare alternative materials and constructions to determine relative structural performance in service. 5.2 Actual loads and loa
27、d footprints vary in service. 5.3 This test method provides information under repetitive static load conditions and does not provide any determina- tion of resistance to impact, creep, or fatigue. Fig. 1Typical cover, box, and extension assembly. LOAD CAPACITY OF POLYMER CONCRETE UNDERGROUND UTILITY
28、 STRUCTURES 548.7-3 SECTION 6APPARATUS 6.1 A hydraulically powered testing machine capable of applying at least 50,000 lb (220 kN) force to a full-size enclosure in the various positions described. Figure 2 shows an example of a suitable machine with a 30 x 48 x 36 in. (750 x 1200 x 900 mm) specimen
29、 installed for edge load testing. Gauges on the hydraulic system shall be capable of displaying the hydraulic pressure to the nearest 25 psi (0.2 MPa) or displaying the actual load applied to the nearest 250 lb (1000 N). 6.2 Dial or digital indicators capable of accurately displaying deflections of
30、0.01 in. 0.001 in. (0.25 mm 0.025 mm). 6.3 A loading pad consisting of a 10 x 10 x 1 in. (254 x 254 x 25 mm) steel plate with a 10 x 10 x 0.5 in. (254 x 254 x 13 mm) piece of 60 durometer neoprene placed between the steel plate and the enclosure to be loaded. 6.4 A pneumatic device, such as a pressu
31、rized air bag, capable of uniformly distributing forces over the entire sidewall of the enclosure (such as inflatable dunnage bags for freight that have a minimum rated capacity of 10 psi 0.069 MPa). 6.5 Gauges capable of displaying the air pressure applied to the nearest 0.05 psi (3.4 104 MPa) or w
32、ater-filled manometer capable of displaying up to 120 in. (3000 mm) of water column. 6.6 A strong-back reaction frame assembly capable of containing the pressure exerted by the air bag between the specimen wall and the strong back with less than 0.1 in. (2.5 mm) deflection in the reaction assembly.
33、SECTION 7SAMPLING, TEST SPECIMENS, AND TEST UNITS 7.1 At least three nominally identical enclosure assemblies are required to complete the tests specified. The enclosure assemblies are to be complete, full size, and equipped according to project specifications or manufacturers proposed configuration
34、. Test each of the three assemblies using Procedures 1, 2, and 3. Determine failure load using one assembly for each condition using Procedure 4. 7.2 Mount the cover in the box during the tests. Secure attach- ment hardware if so equipped. Test assemblies shall be supported by the base of the reacti
35、on frame for each of the tests. SECTION 8MEASUREMENTS 8.1 Measure the cover length and width; the box length, width, and depth; and all other pertinent dimensions shown on the enclosure drawing from the manufacturer. Report any dimensional discrepancies. 8.2 Measure the actual contact area of the ai
36、r bag on the tested wall for the lateral load capacity evaluation. 8.3 Weigh the box and the cover. SECTION 9CONDITIONING 9.1 Condition enclosures at the planned test temperature for at least 24 h preceding the test. SECTION 10PROCEDURES 10.1Procedure 1: Vertical load evaluation for the enclosure co
37、ver 10.1.1 Position the enclosure being tested in the testing machine so that the test load is applied perpendicular within 5 degrees to the plane of the cover at the location that produces maximum cover deflection. Center the 10 x 10 in. (250 x 250 mm) loading pad on that position. Measure deflecti
38、ons perpendicular within 5 degrees to the cover at the point of maximum deflection. Support the gauges on a tripod fixture mounted on the cover supports to measure only the deflection of the cover. Use two gauges to measure cover movement on opposite sides of the load plate and average the readings.
39、 Alternatively, a remote-reading gauge mounted on a frame supported by the box walls inside of the box, directly under the load, shall be used. Refer to Fig. 3. 10.1.2 Preload the specimen cover in the test apparatus to 20% of the design load before test-loading to seat all Fig. 2Typical loading app
40、aratus with hydraulic ram and self-reacting frame. 548.7-4 ACI STANDARD components. Set deflection measuring gauges to zero after removing the preload. 10.1.3 The specimen shall be tested through ten loading cycles. For the first cycle, apply the load in ten increments, each equal to 1/10 of the des
41、ign load. Record load and deflection at each load increment until the design load is reached. Hold the design load for 1 min and then reduce the load to zero in equal increments of 10% of the covers design load. Allow the enclosure assembly to rest at zero load for 1 min before resuming loading. 10.
42、1.4 After the first cycle, and for the next nine cycles, reload the cover without increments to reach the design load within 1 min; hold at the design load for 1 min; unload without increments within 1 min; and rest at zero load for 1 min. 10.1.5 Within 1 min of completely removing the load followin
43、g the tenth cycle, permanent deflections shall be measured and recorded. 10.1.6 Repeat the loading process given in Sections 10.1.1 through 10.1.5 on the other two specimens. 10.2Procedure 2: Vertical load evaluations for walls 10.2.1 Position the enclosure in the testing machine so that the test lo
44、ad is applied to the center of the longest wall. Place the loading pad so that 1/2 of it overhangs the edge of the box wall, leaving a 5 x 10 in. (125 x 254 mm) portion over the box and cover edge. Measure deflections perpendicular to the center of the box wall below point of load. Figure 4 illustra
45、tes an enclosure setup for edge load testing. Preload the specimen enclosure in the test apparatus to 20% of the design load before test loading to fully seat all components. Set deflection measuring gauges to zero after removing the preload. 10.2.2 Apply the test load in 10 incremental steps equal
46、to 10% of the vertical design load. Record load and deflection at each load increment until the design load is reached. Hold the design load for 1 min and then reduce the load to zero in equal increments of 10% of the design load. Allow the enclosure assembly to rest at zero load for 1 min before re
47、suming loading. 10.2.3 After reaching the design load, unload and reload the enclosure nine more times at a uniform speed. Each cycle includes loading to the design load within 1 min, holding the design load for 1 min, unloading within 1 min, and resting the specimen with no load for 1 min. 10.2.4 P
48、ermanent deflections shall be measured within 1 min of load removal after the last repetition. 10.2.5 Repeat the loading process given in Sections 10.2.1 through 10.2.4 on the other two specimens. 10.3Procedure 3: Lateral load capacity evaluation for the walls 10.3.1 Position the enclosure in the te
49、sting machine so that a pneumatic bag installed between the enclosure specimen and a strong-back reaction frame loads the largest box wall from the outside (Fig. 5). The opposite sidewall shall be supported to achieve a uniform reaction, or it shall be supported on ribs or stiffeners so long as no local failure occurs. Ensure the pneumatic bag surface has a constant pressure and is in full contact with the test specimen before any load is applied. A deflection-measuring device shall be positioned to measure the deflection of the wall bei
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