Experimental Study On Shear Strength Of Super High-strength Concrete Unconstrained Beams Under Point Load

Concrete is the most popular manmade structural material on this planet, and as a result of the progress of structural and material technique, concrete's developing to higher strength and higher performance becomes an irreversible trend. High-strength and high-performance concrete is relatively full developed now, but the research on super high-strength concrete marked higher than C100 is far from accomplishment, it should go deeper into.This article summarizes the advantage and disadvantage of HSC and HPC in the first instance, then retrospects the past research and application in this field, and brings forward the theme - experimental research on shear strength of super high-strength concrete unconstrained beams under point load. On the basic of former research men's experience, 18 experimental members (including 9 simple beams and 9 restrained beams) are designed and tested. In the experiment, phenomena are observed and record by taking photos in the whole process from the first crack appears to test members crash completely, experimental data is attained including load values of crack-appear load, critical load and terminal load, stress values of reinforcing steel bar stress, compressed concrete stress and beam flank stress and values of deflection etc. By analyzing the crack's appearing and developing form and stress values of concrete and steel bars, the crash modes of test beams are defined; shearing force-deflection curves are contrasted and analyzed; the effects on shear strength of the three factors as shear span ratio, concrete strength and restraining moment are also analyzed. By contrasting the experimental values with values which are calculated by the codes of GB50010-2002, GBJ10-89, HSCC93-1 and ACI, this article evaluates the safety and applicability of applying these codes to calculate the shear strength of super high-strength concrete members. Finally, according to regression analysis of the experimental data, the shear strength formula of super high-strength concrete unconstrained beams under point load is achieved.