3D Push-over Analysis Of R.C. Frame Structure

The static elastic-plastic Push-over analysis abroad was studied earlier than China. Great importance has been attached to this method after introduction, and it has been introduced into our country's new seismic code. Studies of Push-over on plane frame structures are tending mature, while on 3D frame structures especially the irregular 3D frame structures, many problems remain to be solved. The main work of this paper has been listed as follows:(1)Proper reinforced concrete beam-column element model and structure model were established to perform 3D Push-over analysis. The beam-column element adopted three-segment model which both ends are elastic-plastic fiber bars and the middle part maintains elastic. This fiber model is able to display the interaction between axial force and biaxial bending moments excellently. Layer-rod model was applied to structure. In the paper, rigid floor slab assumption was adopted and the P-Δeffect was also considered by applying additional load directly.(2)A corresponding program with GUI(Graphical User Interface) was developed by Matlab. This program can not only perform 3D Push-over analysis but also 2D Push-over by obtaining data of some plane frame from the structure. With Matlab's powerful capability, the program realized many functions expediently, such as plotting structure performance curves, as well as the distribution of plastic-hinges, structure internal force diagrams and deformation diagrams, nephograms for strain of sections, all of these is unachievable with Fortran language.(3)To testify the correctness of program, comparations with Seismostruct by the analysis of an instance were carried out.(4)In the paper, a ten-floor irregular 3D frame structures was analyzed with the Push-over program. First this paper compared the results of 2D Push-over analysis and 3D Push-over analysis in the positive direction of y axis. Then similarities and differences among several lateral load patterns of the 3D Push-over analysis results were studied. With those research achievements, some valuable reference suggestions on 3D Push-over for reinforced concrete frame structure were put forward.