In the present paper, a behavioral model is proposed for study of the individual contributions to shear capacity in shearcritical reinforced concrete members. On the basis of the relationship between shear and bending moment (V = dM/dx) in beams subjected to combined shear and moment loads, the shear resistant mechanism is explicitly decoupled into the base componentsbeam action and arch action. Then the overall behavior of a beam is explained in terms of the combination of these two base components. The gross compatibility condition between the deformations associated with the two actions is formulated utilizing the truss idealization together with some approximations. From this compatibility condition, the ratio of the shear contribution by the tied arch action is determined. The performance of the model is examined by a comparison with the experimental data in literatures. The results show that the proposed model can explain beam shear behavior in consistent way with clear physical significance.

The composited structural member in which two or more materials having different stress-strain relationships (steel & concrete) has increased greatly in recent years. This paper presents the experimental results of flexural capacity of the composited H-Pile subjected to bending moment. Eight composited beams were tested under direct loading condition using the frame tester. Based on the experimental results it is noted that flexural capacity of composited H-Pile increased about 20~30% and ductility ratio significantly increased. Limit state analysis of the specimens was conducted and the result shows that flexural strength by limit state analysis is conservative.

An enhanced truss model is presented in the present study. The model is theoretically based on the well-known relationship between shear and the rate of change of bending moment in a reinforced concrete beam subjected to combined shear and moment loads. The new model shows that a new perspective on the shear resistance can be gained by considering the variation of the internal arm length along the span. And the shear resistance mechanism is resolved into three independent base components; arch action, truss action and membrane action. The compatibility of deformation associated to the two actions is indirectly taken into account by employing an empirical factor. Then the base equation of V=dM/dx is numerically formulated so as to clarify the physical basis of the behavior related to beams under combined action of flexure and shear.

Hsu recently conducted a shear test on nine reinforced concrete panel elements subjected to applying pure shear using a shear testing device. Modern truss models (i.e. modified compression field theory and a rotating angle softened truss model) are used to perform a complex nonlinear analysis through a trial and error method based on a double loop. This analysis is conducted by employing equilibrium conditions, compatibility conditions, and a ductile stress-strain relationship of a reinforced concrete membrane panel in a biaxial state. In this study, an effective algorithm that uses a revised Mohr compatibility method based on the failure criteria of struts and ties is proposed. This algorithm is used to improve the convergence rate in the analysis of shear history, which was performed in the experiment of Hsu. The result of the analysis indicates that the shear strain energy in a state of extended shear strain is influenced by the relationship between principal compressive stress and strain (crushing failure).

There has been a great increase in the number of structural members composed of two or more materials with different stress–strain distributions. This study investigated the bending performance of composite H-shaped piles subjected to bending moments. Load–displacement hysteresis curves were analyzed using limit state analysis, and eight specimens—six composite H-shaped piles made of reinforced concrete and H-shaped steel beams (i.e., composite H-shaped piles) and two conventional H-shaped steel piles—were tested using a loading apparatus. The test results show that the ductility capacity of the composite H-shaped pile is 138 % more than that of the conventional H-shaped steel pile.