Dissertation
ANCHORAGE OF HEADED AND HOOKED STEEL REINFORCEMENT IN CONCRETE MASONRY
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004596
Handle:
https://hdl.handle.net/2376/125158
Abstract
The anchorage behavior of headed, 90° and 180° hooked, and straight reinforcement in concrete masonry was characterized through testing and analysis. An experimental study consisted of 132 reinforcement pull-out tests on beam ends, 12 transverse reinforcement pull-out tests, and eight direct tension lap splice tests. In the transverse reinforcement tests, longitudinal reinforcement crossed perpendicular to the test reinforcement and was loaded in tension. Test variables included bar size, bond length, cover dimension, reinforcement crossing perpendicular to test bar(s), and, for transverse reinforcement tests, strain demand on longitudinal reinforcement. Splitting of cover was the most common failure mode. Splitting did not always propagate through masonry block due to delamination between block and grout, making masonry block cover less effective in providing anchorage strength. Test results from this study were used in combination with results from previous studies to assess anchorage strength. Beam end tests had higher anchorage strength than equivalent splice tests by 1.7 on average. For #4 hooked and headed transverse reinforcement, bond length was not needed to reach rupture with longitudinal strain less than yield.The minimum required development length for straight and hooked reinforcement in the masonry building code, TMS 402-16, was determined to be overly conservative, and TMS 402-16 does not include provisions for headed bars. Results were used to develop proposed equations, which are proposed as changes to TMS 402-16, to determine the required development length for straight, hooked, and headed bars. The proposed equations for headed and hooked bars were modifications of the ACI 318-19 equations. The changes included modification of factors for bar location and confinement for hooked reinforcement and bar location and parallel ties for headed reinforcement. New factors were introduced for lap splices and shear lag for straight reinforcement and casting position for straight, headed, and hooked reinforcement. For development of #4 and smaller transverse reinforcement in elastic regions, it is recommended to discontinue use of the TMS 402-16 provision for required development length. At regions in structural members where longitudinal reinforcement is expected to reach plastic deformation, use of the TMS 402-16 provision was deemed adequate but not overly conservative.
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Details
- Title
- ANCHORAGE OF HEADED AND HOOKED STEEL REINFORCEMENT IN CONCRETE MASONRY
- Creators
- Majid Jarrah
- Contributors
- Christopher Motter (Advisor)James Daniel Dolan (Committee Member)Adam Phillips (Committee Member)Ji Yun Lee (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 216
- Identifiers
- 99900898939601842
- Language
- English
- Resource Type
- Dissertation