Probability Analysis Of Ductility Collapse Mechanism Of Multiple Shear Wall

The favorable lateral resistant ability of multiple shear wall makes it widely usedin high-rise building; Ductility design goals of the shear-wall structure-“weak beamstrong wall”,“strong shear weak bending”, is important to the life and property in theseismic design. It is by the method of amplitude modulation coefficient that thecurrent code can realize the ductility design goals of the shear-wall structure, butamplitude modulation coefficient was less proved to be entirely reasonable by relatedtheory and experiments, and the reliability level of ductility collapse mechanism ofmultiple shear wall is still not clear.This paper analyses the reliability level of ductility collapse mechanism of thetypical three-shear wall(α=8.51) with the structural reliability theory. The primarycontents are summarized as follows.(1) The paper comprehensively describes the basic design method of multipleshear wall and ductile designing principle with the method of amplitude modulationcoefficient in current code. Whether can multiple shear wall with the empiricalcoefficient design satisfy ductility design goals or not needs to be proved by thereliability theory.(2) According to structural mechanics principle, the plastic hinge is transformedinto the specific mechanical model; the reliability analysis model of ductility collapsemechanism of multiple shear wall is set up with the ductile demand “weak beamstrong wall”. The fundamental method of probability analysis is using ANSYS finiteelement software to calculate the moment at the wall limb’s bottom of the plastichinge formed before and after; then get the resistance R and action effect Siso asto establish the performance function and calculate the reliability index. (3) When the value ρ of the ratio of live load to dead load changes, thereliability index of ductility collapse mechanism of multiple shear wall is inverselyproportional to the value ρ; the value ρ increases in the range of10%~50%, thereliability index decreases from2.0753to2.1596. When the coupling beam yields toform plastic hinges in different position, the reliability index of structural ductilitycollapse mechanism changes within the range of1.9499～2.1596; the upper beams ofthe structure yield significantly, and corresponding to the reliability index of ductilitycollapse mechanism is the largest. As the above two factors change, the reliabilitylevel of structural ductility collapse mechanism is higher than the reliability level ofserviceability limit states.Along with the change of value ρ and the different positions of plastic hinges, thechange law of the reliability index of ductility collapse mechanism of multiple shearwall indicates that the method of amplitude modulation coefficient can effectivelysatisfy ductile designing goals of multiple shear wall-“weak beam strong wall”,“strong shear weak bending”; and the result powerfully demonstrates that the methodof amplitude modulation coefficient designs ductile multiple shear wall is reasonableon the specific reliable measurements; the paper could deepen the understanding ofstandard specifications and guide practical engineering design work better. Thisdesign method of reliability analysis model has universal applicability, and can checkthe reliability of other types of structure.