Calculation Of Shear Bearing Capacity Of Freely-suppoted Reinforced Concrete Beams Under Biaxial Bending

Calculation of shear bearing capacity on oblique section of reinforced concrete member in compound bending is one of the remaining problems till now. At present, the relevant researches mainly focus on the experiment in want of the systematic theoretical analysis. The present applicable codes and standards have described the calculation of bearing capacity on head-on cross section of member in compound bending while they don't clearly state the calculation of shear bearing capacity on oblique section. Therefore, deeply researching the shear bearing capacity on oblique section of reinforced concrete member in compound bending is of the important practical application value and theory meaning.Firstly, on the basis of the experimental beam in compound bending, this thesis analyzes the resisting shear of beam in compound bending under distributed load in analog form with ANSYS software, discusses the development regularity of the oblique crack of beam in compound bending, analyzes the six factors affecting the shear bearing capacity on oblique section, including the span-depth ratio L/h, the concrete strength grades f_cu, longitudinal ratio of reinforcementρ_s, ratio of stirrupρ_sv, slanting bend angleβand the section depth-width ratio h/b.Then, using the equivalent mechanical translation principal and equivalent shuttle sectional methodology, the problem is transformed from compound bending to unidirectional bending. Adopting discretization method and model of girder-arch, the thesis deduces the theoretical formula of anti-shear bearing capacity on oblique section of freely-supported reinforced concrete member in compound bending under concentrated load according to the present specification of reinforced concrete in our country and the testing data of experimental beam. On this basis, by introducing the conception of equivalent shear-span, this thesis presents the unitized theoretical formula of resisting shear bearing capacity on oblique section of reinforced concrete member in compound bending under both concentrated load and distributed load.Secondly, in view of the inconvenience of the theory formula in practical application, this thesis illuminates respectively the simplified regression formula as per the 4 separate situations of reinforced and plain concrete beams in compound bending under concentrated load and distributed load along with the made testing data.( i.e. reinforced concrete beams with concentrated load, reinforced concrete beams with distributed load, plain concrete beams with concentrated load and plain concrete beams with distributed load, along with the made testing data).Last, taking the example of theoretical formula of anti-shear bearing capacity on oblique section of freely-supported reinforced concrete beam in compound bending under concentrated load, this thesis performs the calculation of the index of the formula reliability through calibration method.