Experimental Study On Flexural Behavior Of Simply Supported Concrete T Beam

Prestress on the project can be divided into two types:unbounded and bonded. External prestress, an unbounded prestressed structure, is one of the fundamental branches of post-tensioned prestressed structural system. Nowadays externally prestressed technology is widely used in bridges and large span structures. But it has comparatively few applications in the field of structural mechanism and its corresponding design in China, which causes the superiority of this kind of structural system far from being fully realized. Therefore, in an attempt to promote the application and development of externally prestressed technology in our country, theoretical and practical studies are desperately needed for further in-depth research.In this paper, based on science and technology plan projects of guangdong province (2010A040308005) and Guangdong province natural science foundation project (S2012010009615), ultimate flexural capacity of externally prestressed beam was studied systematically on the basis of predecessors’research results and the design experience. Details are listed as follows:1) According to a large number of experimental data and analysis of externally prestressed concrete beam and reasonable simplified calculation, basic calculation assumptions about the ultimate bearing capacity of externally prestressed concrete beam was provided. Stress increment formulas of linear externally prestressed simply supported concrete beam with no-steering block, unidirectional block dogleg, double deviators dogleg were proposed.2) Loading process, failure pattern, loading versus mid-span deflection curve were analyzed at length based on test results of eight specimens. The results indicated that beneficial effect of prestress had greatly improved the carrying capacity of T beam, especially its ultimate load capacity. The fact that the effect of mid-span with single steering block was no better than the effect of loading point with steering block delivered us a message that setting a steering block in the concentrated loading point should be superior to others, if construction condition allowed. The results also revealed that setting a steering block at two loading points for TYL-2linear concrete beam improved the cracking load of component most significant. Moreover, steering block of externally prestressed beam exerted little impact on the yield capacity of component. Besides, it increased the ultimate load capacity of beam remarkably by setting steering block in the position of two loading points for beam TYL-2.