Test Study on the Resisting Shear Strengthening Effect with External Pre-Stressed Wire Rope

Abstract

The resisting shear strengthening technology of existing reinforced concrete bridges as an important research topic in the field of old bridges, play an important significance to improve the mechanical properties of old bridges and reduce security incidents. Based on comparative test analysis on two basic beams and twelve reinforced concrete beams strengthened with external pre-stressed wire rope, the influence of the shear strengthening effect was studied systematically caused by the original beam design parameters and the spacing of wire rope, in the meantime the strengthening mechanism was analyzed. Research results showed that the shear capacity of the strengthened beams was improved, because the development of cracks was not only effectively limited, but also stirrup strain was reduced, and yield load was put off. Along with the increasing of the ratio of original beams longitudinal reinforcement and the ratio of stirrup ,and the concrete grade, as well as the decreasing of spacing of external wire rope, the stirrups strain were decreasing and the shear capacity of strengthened beams increased. With the spacing of external wire rope decreasing, the diagonal crack resistance of the strengthened beams increased. The research results can provide reference for the design and research on shear strengthening of bridges.

The Ultimate Shear Bearing Capacity of RC Beam Strengthened with SWR External Prestressing under Dead Load Level when Strengthening

“…After strengthening, the loading went ahead with grading, and encrypted the load grading when approaching cracking load and ultimate load [5] . B13 B15 B10 are three beams when the preload is finished then unload to 0 [6] , the load level was divided into three stages: presplit stage, strengthened beams stage after dead the preload and experiment on strengthened beams stage. All these experimental beams' load level are divided refer to reference [7], and when the experimental load is getting the cracking load and the yield load then encrypt the load level in order to get the cracking load and yield load accurately.…”