Research On Indirectly Loaded Reinforced Concrete Deep Beams With Web Opengings

Reinforced concrete deep beams have been widely used in concrete structures because of excellent shear capacity.The idea that making an opening hole in the abdomen of deep beam makes the pipeline throught it in order to save more building using space becomes more and more popular.But in many cases,because of the influence of the unavoidable factors,deep beam with web openings resists load indirectly,rather than direct effect of the load.In the past few decades,a large number of scholars and experts at home and abroad had studied the deep beam with web openings and achieved fruitful results.Yet few studies have looked into the forced properties of deep beam with web openings under indirect load,and there is not relevant provision in the "code for design of concrete structures",resulting in lack of corresponding theoretical basis and reliability in actual construction,and a safety hazard.Therefore,at this stage the research about the bearing performancehole of the deep beams with web openings under indirect load has great social benefits and economic benefits.In this paper,we designed 14 deep beams,of which 8 ones have openings,and we tested 12 ones under indirect load and 2 ones under direct load.By observing the crack development,shear strength and failure pattern of the specimens,on the basis of experimental data,and in comparison with deep beams without openings under indirect and direct load,we analyzed the effects on shear strength and mechanical properties of the deep beams with openings of three factors: position of openings,cross section form and the form of reinforcement under the indirect load.Next by nonlinear finite elements analysis and contrastive analysis of the test results,we found they were close,in turn,to verify the applicability of the finite elements analysis for the deep beams with openings.Combining strut-and-tie theory we analyzed the transfer mode of the hole positions not at the same time,and obtaine calculation formula about the shear bearing capacity of deep beams with openings under the indirect load.More importantly,the results from the formula conformed with the test results very well,so it can be used as a reference for engineering design.Finally,we summarized the main results of this paper,then posed some questions for further study.