Research On Seismic Behavior Of Latticed System Column With RC Bracings

In2008WEN Chuan earthquake, reinforced concrete frame structures weredamaged seriously, plastic hinges may occur at the ends of columns rather than beams,which is significantly different to the failure mode expected in the seismic design ofStrong Column Weak Beam. The main reasons are the effects of Cast-in-site floor,the bigger limit value of the axial compressive ratio and the influence of rigidconnected fill walls constraints and so on."Strong Column Weak Beam" is theimportant principle which should be followed in the seismic design of frame structure,and it is the important tectonic measures to achieve the beam hinge mechanism.In the actual engineering, it costs much through increasing the size of column toachieve the target of strong column weak beam. In order to explore and realize framestructure "Strong Column Weak Beam" design principle, supported by the NationalNatural Science Foundation of China, this thesis researched the lattice system columnwith RC braces, its characteristic is made up of common beams and columns and RCbraces, had simple structure, reliable connect and well integrity, use whole system torealize the frame structure "Strong Column". The frame structure using this systemcolumn not only costs less but also makes full use of space, it is helpful to promotethe use of this structure in engineering.Based on two latticed system columns with different brace forms and one latticesystem column without brace, this thesis conduct low-cyclic reverse lateral loadingpseudo static test. Through the collection and analyses of the experimental data, Themain research objective was to establish the cyclic behavior of the w alls includingfailure pattern, ultimate capacity, stiffness degradation, strength degradation, anddeformation capacity. And through contrasting the RC braces lattice system columnwith the unbrace lattice system column, which get the RC braces lattice systemcolumn in the strength, stiffness，energy dissipation and redundancy had certainadvantages, and the lattice system columns with RC braces realized the "StrongColumn Weak Beam" seismic design principles from a certain extent.A finite element model was developed by SAP2000to simulate the wholeprocess of the experimentation. The analysis results show that, the lattice systemcolumns with RC braces can successfully accomplish the transfer of plastic hinges,which made it a "Strong Column Weak Beam" model of the structure. Compared with the results of the tests, a suitable numerical model for the latticed system column wasdeveloped for the lateral simulation studies, which laid foundation for further finiteelement analysis.This thesis presents a new type of structure system. Its research results haveenriched the research on reinforced concrete frame structure, and provided referencedata for the future research on this kind of latticed system column.