Investigation of collapse of teaching buildings during the Wenchuan Earthquake: third anniversary memorial of 5·12 Wenchuan Earthquake

Based on the on-the-spot investigation of the damages to teaching buildings of schools in rural areas during the Wenchuan Earthquake,the collapse phenomena was introduced and analyzed in depth.Research results indicate that the deficiency of the conceptual design of the structure,i.e.the insufficient whole structural robustness,is the fundamental cause.The dismantle of the structure is attributed to the deficient connection construction measures.The brittleness of the construction material and the uncontrollable construction quality leads to the inadequate overall resistance of structure.The collapses of structures were also due to the following reasons: the top-heavy structural system,uneven distribution of stiffness,inadequate load transfer path,lack of redundant constraint.Critical components of load path severely weakened,lack of horizontal load resistance,lack of ring beam-structural column restraint,precast slab without any connection measures,insufficient strength and ductility of materials such as concrete,masonry,and cold steel.Arbitrarily added stories,and etc.As a result of historic reasons,the poor management and violation of standards are human related factors.Consequently,it is important to strengthen management and the compliance with standards and codes.