Low Cycle Reverse Experimental Research On Prestressed Concrete Truss Transfer Structure

As a form of structure to take a full advantage of prestressed and transfer turss,prestressed concrete truss transfer structure can meet the requirements of thearchitecture on the bottom large space and the plumbing crossing. Consequently, itfinds the application on an increasing number of engineering. However, the bearingcapacity still need be further investigated.Firstly, a1/4scale prestressed concrete open-web truss transfer structrue modelthat is ingle span three layers and3.3m×3.3m is tested by the low cyclic loading, andthe test focus on basic design principles, failure mode, lateral stiffness ratio, prestressedaction, etc. Then, comparative analysis of the two form prestressed transfer structure(open-web truss and mixed-truss) on the seismic performance and the bearing capacity.The main conclusions are as follows:①Prestressed concrete open-web truss transfer structure should follow the designprinciples “transfer floor and the lower floor to be enhanced, the structure of the upperpart of transfer floor to be weakened” and should meet the seismic requirements of theexisting codes, such as “strong column-weak beam”,“strong shear-weak bending”,“strong node”, in which “strong column-weak beam” is allowed not to be taken intoconsideration in vertical web member of truss. It can be seen in the experimentalphenomena and the analysis that the prestressed concrete open-web truss possesstransfer structure following this principles possess good seismic performance, couldmeet the fortification requirements in design seismic, and have considerable safetystock.②The test process and the ultimate failure mode of specimen indicate：prestressed concrete open-web truss transfer structure in reasonable design, whichfollow above principles, can not be avoided the formation of plastic hinges on transferfloor and the lower floor, even form the plastic hinges in advance, but the rotation ofplastic hinges are very limited until the structrue failure stage. The reason of theultimate failure of the specimen is that after the full development of beam hinges ofupper structure, the upper structure ultimate is failed.The whole specimens of theframework is a structural system with good energy dissipation capacity.③Mixed-truss transfer floor with oblique web member has better forcetransmission path, Compared to open-web truss transfer structure in the vertical and horizontal loads, its internal force distribution is more uniform and reasonable, deformsmore effectively control, performs better deformation capacity too.