STUDY ON SAFETY APPRAISEMENT AND STRENGTHENING TECHNOLOGY OF MASONRY STRUCTURE BUILDINGS DAMAGED IN WENCHUAN EARTHQUAKEYing Ma , Yongsheng Yi,Shuchun Zhou ,Yuexing Zhu , and Qigang Jiang1) Graduate Student ,School of Architecture & Civil Engineering ,CUMT ,China2) General Manager , Xuzhou Architecture design & research institute CO ,LTD ,China3) Associate Professor ,School of Architecture & Civil Engineering ,CUMT , China4) Director ,Xuzhou Construction Engineering testing Center, China5) Chief Engineer ,Xuzhou Construction Engineering Testing Center, ChinaMaying410782163.com,sczhoucumt.edu.cn,yys7699163.com,xjcjqg163.comAbstract: Referring to the appraisement of masonry structure buildings in Mianzhu City, this paper studied the safety inspection methods, seismic capability appraisement process based on summarizing and analyzing of its earthquake damages; also, the strengthening technology was discussed. Most earthquake damages of masonry structure building were cracks on walls: the most common damages were X-shaped cracks on walls under or between windows(outer longitudinal) and incline cracks along corners of opening for doors and windows, then X-shaped, incline cracks on load bearing cross and inner longitudinal walls, also few horizontal and vertical cracks can be found. Considering the demand of seismic capability and reliability appraisement ,inspections were primarily carried out on structural measures of the mass structure. Compound seismic capability and reliability of building was appraised according to the results of first level appraisement, its performance in earthquake and values of strengthening .Strengthening of buildings damaged in earthquake must separate members to be repaired or strengthened according to their available bearing capacity; and also economic conditions and beauty appearance should be taken into consideration. All we do could be used as a reference to seismic and reliability appraisement or strengthening design of buildings damaged in earthquake or ordinary ones.Keywords: Wenchuan Earthquake, Masonry structure building, Seismic appraisement, Appraiser of reliability, Seismic strengthening of building1. INTRODUCTIONAt 14:28pm on May 12 2008, a devastating earthquake (M8.0) stuck Sichuan, a province in southwest of China. mianzhu city, 35km to the epicenter (wenchuan country), is one of the regions which were most severely hit I the disaster. Most severely damaged or collapsed buildings are of masonry structure. After the earthquake, we have appraised the seismic capability and reliability of buildings in Mianzhu, most of which are of masonry structure. In our paper, with a case study we appraised, studies were carried out on the methods and items of seismic capability appraisement, based on the investigation and analysis on earthquake damages of masonry structure buildings.Safety appraisement of buildings damaged in the disaster mainly include: earthquake damages inspection and analysis, safety inspection, seismic appraisement and reliability appraisement. In our paper, referring to appraisement of a commercial-residential with typical earthquake damages, studies were carried out on the of safety inspection method, seismic appraisement process of masonry structure buildings based on the investigation and analysis of its earthquake damages; also, the strengthening technology was discussed.Commercial-Residential Building (No.2-C) of Knitting Mill in Jiannan town, Mianzhu city, a primer-frame masonry structure with 5 storeys (6 storeys partially) designed in 1999, was appraised into degrade C (moderate damaged) in Emergency Appraisement. Figturel shows the structural Plan of this building.2. INSPECTION AND ANALYSIS ON EARTHQUAKE DAMAGESDifferent from the appraisement of normal buildings, appraisement of damage buildings in earthquake-stricken areas must take earthquake damages and their effects on seismic capability and reliability into consideration. So, the buildings earthquake damages were inspected and analyzed before appraisement, and damage of the mass structure was classified into four levels: severe, moderate, slight damage and basically sound.Earthquake damages of foundation can be reflected by cracks on walls caused by uneven settlement, variation of the surrounding floor, incline of upper structure and their variation tendency. So, appraise foundations damage grades can be appraised by inspecting on items mentioned above.Fig.1 Ground plan of Commercial-Residential Building (NO.2-C) of Knitting Mill in Jiannan town, Mianzhu city(a) Ground Plan, and (b) Standard PlanDamage inspection of masonry structure building should focus on the following locations: four corners of the building, walls on the ground floor, walls of big room, load bearing walls, ring beams, structural columns, connection of walls, and so on.For example, we detected earthquake damages of Commercial-Residential Building (NO.2-C) of Knitting Mill in Jiannan town, Mianzhu city, and summarized