Evaluation of Welded Deformed Wire Fabric Reinforcement in Machine-Made Concrete Pipe FRANK J. HEGER and RICHARD E. CHAMBERS, Simpson Gumpertz and Heger, Inc., Cambridge, Massachusetts; and WALTER PODOLNY, JR., and LAWRENCE L. BALLARD, United States Steel Corp., Pittsburgh, Pennsylvania A research project was undertaken to evaluate the structural behavior of machine-made concrete pipe reinforced with welded deform'ed wire fabric and to determine the validity of previously developed design methods for this type of pipe. Test results indicate significantly greater variability of both 0.01-in. crack strength and ultimate strength for machine-made pipe compared to the previously tested cast pipe. As long as this possibility of greater strength variability is recognized, the design formulas previously developed for 0.01-in. crack strength and ultimate flexural strength of cast pipe also apply to machine-made pipe. The design formula for ulti- mate diagonal tension strength may also be applied to machine-made pipe, but only with a larger safety factor and with certain modifications of pro- visions tentatively suggested in earlier work. Comparison of test results on companion pipe indicates that deformed wire fabric offers higher 0.01- in. crack strength than smooth wire fabric. For pipe made by the Packer- head process, the degree of improvement is even greater than was pre- viously found for cast pipe. •SEMI-EMPIRICAL DESIGN METHODS have been developed for concrete pipe with welded deformed wire fabric reinforcements made by the cast process and were pre- viously reported by Heger and Gillespie (4). The general formulation of the equations used in that method, as derived by Heger ll, 2), are based on theoretical reasoning that describes the behavior of the concrete -and the steel reinforcement for pipe tested with the three-edge bearing method (ASTM Method C 497). Equations were presented for 0.01-in. crack strength, ultimate flexural strength, and ultimate diagonal tension strength. Automated machine processes for pipe manufacture are becoming increasingly im- portant in the economical production of larger sizes of pipe. Because the existing design method was derived for cast pipe, the primary goal of this research program was to determine the validity of the theory for these machine-made pipes. A second- ary objective of this program was to determine if there is an advantage in using de- formed fabric in machine-made pipe beyond that already demonstrated for cast pipe. TEST PROGRAM The test program was undertaken to evaluate U.S. Steel welded deformed wire fabric reinforcing in two types of machine-made pipe. This program covers 65 full- size tests on ASTM Specification C 76 pipe ranging in diameter from 48-in. to 96-in. for dry-pack-vibration pipe and 48-in. to 72-in. for Packerhead pipe. Strength classes range from Class II to Class V, with Class V restricted to the 48-in. diameter size. This range of size and strength provides a reasonable spread of the important vari- ables whereby the validity of the design method may be evaluated. Paper sponsored by Committee on Culverts and Culvert Pipe and presented at the 49th Annual Meeting. 41
Evaluation of Welded Deformed Wire Fabric Reinforcement in Machine-Made Concrete Pipe
May 10, 2023
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