EARTHQUAKE-INDUCED COLLAPSE PREVENTION CAPACITY OF BRICK MASONRY STRUCTURES CONFINED WITH TIE COLUMNS AND TIE BEAMS

Lessons learned from the Wenchuan Earthquake on May 12,2008 indicate that in addition to possessing sufficient collapse prevention capacity,the brick masonry structures should be able to collapse in such a reasonable pattern that the collapses of different structural components can follow expected sequence and the structural components enclosing particular spaces of the structure can be restrained from collapse for the maximum protection of human lives and properties when the collapse is unavoidable under the attack of a mega earthquake that largely exceeds the local seismic fortification intensity specified the code.The equivalent diagonal strut model is introduced to establish the load transfer path and the interaction between tie columns and brick walls.There seismic collapse patterns as well as the corresponding calculation methods are discussed.A confinement coefficient and a collapse prevention index are defined to reflect the confining capacity of the tie columns and tie beams and the collapse prevention capacity of brick walls.Finally,several fundamental measures for the improvement of seismic collapse prevention capacity of the brick masonry buildings confined by tie columns and tie beams are suggested.