Experitalment Study On The Ducility Of Prestressed Frame Beam End Release

New type of prestressed beam is athe tip of a prestressed concrete frame beam with prestressed PVC casing will be Liang Duan’s release, this technology is the industrial production in line with the requirements of building industry. With the advantages of high efficiency, fast constructionspeed, easy quality control, environmental protection, and the good social benefit.Due to the lower frame beam with prestressed steel strand, beam end plastic hinge sleeve of prestressed beam with the release, on the upper part of the commissure is also provided with a stack of prestressed steel strand through. Because the steel hinge line of poor plasticity, the elongation, even the Liang Duan length of prestress release, still frame beam end can be in the earthquake the formation of plastic hinges or ductility can meet the energy requirements of the overall framework. The connection between precast units(nodes) for the overall structure, load transfer, dissipation of seismic energy plays an important role Based on the above reasons, studied the full depth of the ductility of the structure system of the frame beam end. Put forward reasonable improvement measures and methods of side frame beam ductility, provides the measures and suggestions for the study of the value of the parameters and verify the seismic behavior of the joints.In this paper, the different degree of prestress, the prestress release of different, different anchorage length of steel strand, the ultimate bearing capacity of concrete in the compressive zone height of four precast beams under low reversed cyclic loading test.The experimental phenomena are analyzed, and the experimental data are processed. Analysis of the four different components of the hysteresis curve, skeleton curve, stiffness and strength degradation, energy dissipation capacity, the residual deformation, steel and steel wire strain. From the theoretical analysis of the length and the range of plastic hinge region of Liang Duan, the curvature ductility of beam end section, the relationship between the rotation ductility, and the displacement ductility and the measured data are compared and analyzed. The plastic hinge region of precast prestressed beam length, cross-section curvature ductility, ductility, ductility and displacement angle.The main conclusions are:the anchorage length of steel strand and anchorage of 30 cm can’t satisfy the need of engineering, will produce a slip after the failure of anchorage. Precast prestressed beam has a good recovery, smaller residual deformation, but poor energy dissipation capacity. After the end of the beam prestress release, just reduce the component of. In the prerelease condition, reduce the degree of prestress can improve the ductility of the beams.The stress in the same pre,the decrease of the height of ultimate bearing capacity of compressive zone can improve the ductility of the beam end. Combining with the precast prestressed pier Liang Zailiang and no slip.Through the above analysis shows that the ductility and seismic performance of precast prestressed beam has a general evaluation. Some preliminary conclusions, provide a basis for engineering application.