Study On Shear Behavior Of Reinforced Concrete Deep Beams Based On OpenSEES

At present, reinforced concrete deep beams had been widely applied to transfer beam of high rise building, the bottom girders of shear wall structure, basement walls and wall foundation beams, etc. Because of the shear mechanism of reinforced concrete deep beams is complex, and there are many influence factors, the shear theory is still imperfection even some researches had been conducted. Most of the current standards are half theory and experience or empirical formula, so the shear model is unclear and its applicability is poor. Therefore, it is necessary to conduct further research on the shear behavior of reinforced concrete deep beams.Firstly, this paper states several shear theories of reinforced concrete and discusses the advantages as well as disadvantages of each model. The strut-and-tie model is more suitable for the analysis of shear bearing capacity of reinforced concrete deep beams. Besides, the basic principle of strut-and-tie model and its design method has been introduced.Secondly, the ETABS software is used to build the model of reinforced concrete deep beams which had been tested. Then the modified code can be put in OpenSEES after the model had been set in the ETO pre-processing program. The results shows that using the finite element software OpenSEES is feasible and accurate to simulate the shear bearing capacity of reinforced concrete deep beams by comparing Load-deflection relationship and Load-strain of longitudinal tensile steel bar with the experiment.Then, the influence factors of shear bearing capacity of deep beams which are under the concentrated load have been studied by changing concrete strength, the diameter of longitudinal tensile reinforcement, the span and load position based on the OpenSEES software. The main results are as follows: The shear capacity of deep beam increases with concrete strength, but the increase is small; The shear capacity of deep beam increases with longitudinal steel ratio, but the improvement is limited; The span-depth ratio has little effect on the shear capacity of deep beam; The shear capacity of deep beam decreases with the increase of shear span ratio. Especially, it will rapidly reduce when shear span ratio is between 0.1 and 0.5, and the effect will become weaker when shear span ratio is between 0.6 and 1.0.Finally, the shear capacity calculation formula of reinforced concrete deep beams has been modified based on the simulation datum. Its accuracy and rationality has been verified by comparing an example with Chinese standard and American standard. A reasonable calculation method which is available for reference in design had been provided for reinforced concrete deep beams in our country.