Journal of Earthquake and Tsunami, Vol. 3, No. 4 (2009) 249–259 c  World Scientific Publishing Company FAILURE MECHANISM AND ITS CONTROL OF BUILDING STRUCTURES UNDER EARTHQUAKES BASED ON STRUCTURAL SYSTEM CONCEPT YE LIEPING and QU ZHE Department of Civil Engineering, Tsinghua University Beijing 100084, China Accepted 3 November 2008 By taking building structures as systems, the difference between the safety margins of a structure and that of its element is clarified and the robustness of the structure to resist unexpected disasters is discussed. The system concept is further used to intro- duce the concepts of importance levels and functionality levels in structural systems, the designability of structural systems is then pointed out. The local and global failure mechanisms of building structures under earthquake are summarized, and the failure mechanism control method is discussed based on the concepts of system and designabil- ity. For global failure mechanism, the desirable seismic performance is put forward, and at last some practical methods to control the seismic failure mechanism and the failure procedures are proposed based on the hierarchy concept of the structural system. Keywords : Failure mechanism; structural system concept. 1. Definition of the Structural System and Its Function In “Unified design standard for reliability of engineering structures GB 50153-2006” (draft for approval) [2006], a structure is defined as a system that is composed by a set of elements, can resist certain loads or effects and has appropriate stiffness. This new definition of structures is a great development in the structure engineering and will encourage new theories and methodologies in the study on the structural performance, safety margin, and disaster resistance. Based on the system concept, this paper is to provide some new approaches on controlling the failure mechanisms and procedures of building structures under earthquake. In this paper, a structure is defined as a well-organized load-bearing system composed by a set of properly connected elements. This system has adequate load- bearing capacity, stiffness, deformability, and energy-dissipating capacity. It has proper serviceability, adequate safety under design loads, as well as adequate anti- collapse capacity under unexpected loads. This definition can be further explained as follows: (1) A structural system should have certain capacities, including load-bearing capacity, stiffness, deformability, and energy-dissipating capacity. 249 J. Earthquake and Tsunami 2009.03:249-259. Downloaded from www.worldscientific.com by UNIVERSITY OF AUCKLAND LIBRARY - SERIALS UNIT on 05/07/15. For personal use only.