一、外文原文Analysis of Some Building Damage Phenomena in the WenchuanEarthquakeLi Min1) and Li Xiaojun2) Earthquake Research in China,1) China Earthquake Networks Center, Beijing 100045，China2) Institute of Geophysics, CEA, Beijing 100081, ChinaThe Ms 8.0 Wenchuan earthquake caused a great deal of damage and collapse to engineering structures. Survey of disaster and engineering damage was made in detail by the authors and other researchers in the extreme earthquake disaster area. The paper makes an overview of the earthquake disaster status and damage phenomena which include brick-concrete buildings, frame structures, brick-wood structures, and timber frame residential buildings. Furthermore, the causes of the disaster and building damage phenomena are briefly discussed. According to the phenomena mentioned above, some feasible seismic measures are suggested for the development of buildings in future.Key words: Wenchuan earthquake ；Earthquake damage survey；Rural housesINTRODUCTION：In August 2008, the authors made an investigation and analysis of the earthquake damage in Gaoyuan village, Longchi village, the urban area of Dujiangyan city, Bailu town, Xiaoyudong, Yingxiu, Hanwang and so on. Based on the house survey from the earthquake disaster area, by analyzing the degrees and patterns of the house damage, damage analysis was done to find out the causes of the damage and lessons learned, and provide reference for improving and perfecting the housing construction, especially seismic design to improve the seismic capacity of residential buildings.The Dujiangyan city, Pengzhou city, Mianzhu city and other related area, where a detailed survey of building damage was carried out in this study, were in the extreme earthquake disaster area. Viewing from the earthquake damages to urban housing，houses with frame structure of first storey and the brick-concrete of the upper stores were damaged more seriously，while the damage to houses with the reinforced concrete structure was lighter. Houses built before the late 1990s were damaged more seriously，while houses built later were damaged lightly (Ge Xueli etal., 2008). In addition，houses designed in strict accordance with the requirement of seismic design code for buildings and through the seismic reinforcement before the earthquake (such as adding structural columns，ring beams，etc.)，had good seismic performance. When earthquake occurs，the dislocation of the fault often occurs in hundreds of millimeters to several meters in horizontal or vertical direction，which directly causes serious damage to foundation and structure of the buildings across or adjacent to the fault. At the same time，strong ground motion near the fault caused by a sudden dislocation of the fault can also lead to serious damage to nearby buildings. One phenomenon in this earthquake was that most severely damaged areas were near the fault，which demonstrates the seriousness of damage on the earthquake fault and the area nearby once again. Therefore the engineering site should avoid active faults as far as possible.In this paper，we use seismic damage survey data of houses from seriously damaged areas to analyze the seismic damage of ordinary residential buildings in urban area and self-built housing and public buildings in rural area，and discussed the causes of the significant differences of damage patterns and degrees on the building structures.1 ANALYSIS OF FIELD SURVEY DATA OF SEISMICALLY DAMAGED BUILDINGS1.1 Urban Commercial and Residential BuildingsMost of houses along the streets in Dujiangyan downtown were 5 〜6 storey brick-concrete buildings. Usually the first storey was with the frame structure. Prefabricated panels were widely used for floors and roofs，and the wall thickness was usually 240mm. Many of these houses were moderately or severely damaged，or even partly collapsed in the earthquake. Generally，the first and second floors were most seriously damaged，and the degrees of damage decreased with the increase of floor number. Patterns of housing destruction were：damage to the plastic hinges at the capitals or the end of columns on the first floor; X-shaped cracks，inclined cracks or horizontal cracks on spine wall of the first and second floors，serious cross-cracks on walls under windows (Sun Jingjiang，et al.,2008 ; Zhang Minzheng，2008).Most of houses in new residential areas in Dujiangyan city were 5 or 6-storey，brick-concrete or frame structures built after 2001. Most of these houses were largely intact or slightly damaged. Observed from the facade，little cracking phenomena were found on the outer vertical walls and gables. Horizontal cracks or peeling plaster layer were seen at a few entrancesof buildings. Cracks were commonly found on stairwell treads. This may be related with the retention of construction joints. Mostly slight cracks could be seen in inner longitudinal and transversal bearing walls on the first two floors while those on other floors remained largely intact.In the heavily damaged zone of Hanwang,Deyang city, brick-concrete residential building with ring beam and constructional columns near fault surface rupture zone collapsed completely . On the contrary, several 6-storey brick-concrete residential buildings located in an area of serious damage and collapse of houses suffered from significantly less damage with only X-shape cracks on walls under windows. These brick-concrete houses adopted more reasonable anti-seismic measures with proper setting of ring-beams, constructional columns and etc.1.2 Rural Residential BuildingsThe main source of income of Gaoyuan village was tourism，residential houses there were mostly built as holiday villages or rural households hotels. Some of them were built around 2006, some were renovated from old houses, and some were under the construction and remained self-finished invested. Overall, most of the houses in the village were seriously damaged by the earthquake. The structural types of the houses in the village can be divided into brick-concrete，frame, brick-wood and wood architecture. Most brick-concrete houses were two-storey ones. Most of floors were prefabricated panels. Most of houses of this type were seriously damaged, even partially or completely collapses, but there were also slightly damaged houses which were built in recent years. The frame structure houses were commonly built recently. However，compared with the semi-finished works under construction，the damage were relatively slighter，but difficult to repair and reinforce. However，a just-built frame structure tea-house in the village remained intact，even the window glass was not broken, and only the side wall was slightly damaged. Brick-wood houses were 1 〜2 storey ones, mainly hard purlin roofs, with roofs of small gray tiles or asbestos. Because of the low mortar strength, poor vertical and horizontal wall connection, usually lack of effective connection between the gable and purlin，seismic damages to this type of houses included damage to spindle tile and wall shear failure, and even the collapse of the walls (Wen Ruizhi, et al., 2008). Wood structure houses had sloping roof with small green tiles. These houses had acceptable seismic performance, and their overall structure remained intact except for the houses with shingle roofing.1.3 Public BuildingsIn the Dongqi technical school located in the seriously damaged area, Hanwang town, the single-story steel-structure workshop remained intact, but the frame structure of teaching building was completely destroyed, the brick-concrete structure of dormitory building with small column distance was slightly damaged (Fig. 10 〜Fig. 12). In the same small area, three buildings with different structures mentioned above suffered seismic damage of different forms. It was clear that the steel structure has the best anti-earthquake performance, but because its high cost, it has not been widely used in China for the general residential building.2 SEVERAL TYPICAL PHENOMENA OF EARTHQUAKE DAMAGEBased on the first-hand information collected from earthquake damaged areas, we analyzed the damage to house structures from aspects of brick-concrete, frame, brick-wood and wood structure residential buildings. Through the discussion on the characteristics of earthquake damage to houses，we summarized several typical earthquake damage phenomena of buildings.2. 1.Destruction at the Sites of Abrupt Change in StiffnessThe houses with high-low structure where the stiffness or strength changed abruptly were more susceptible to damage. The main structure (6-storey frame) of Dongqi Steam-cast Company along the street in Hanwang town was immediately adjacent to a 3-storey commercial and residential building (C&R building，with frame structure for the ground floor and brick-concrete for the upper two floors) . Observing from the side of Dongqi Company，the floors 4 〜6 of the building above the C&R building suffered significantly more serious damage than the lower three floors. This wa s due to “whiplash effect” generated by the earthquake. Locally prominent structures could be easily damaged as large ground motions occurred.2. 2 Destruction of Weak Transition LayerTourist shops along the street were mostly 2 〜3 story buildings，with brick or concrete columns on the ground floor, concrete beams and one brick thick walls above them (some load- bearing walls were only 120mm thick) . In the earthquake, often the bottom was severely damaged, spine wall presented severe cracking or even partial collapse. But in the seriously damaged area in Hanwang town, there was another situation. A single building, which had similar structure with the previous described one, but with half basements, was not damaged much on the bottom floor but its second floor was completely destroyed. In the seismic center Yingxiu town, an uncompleted six-story building with brick-concrete structure lost its entire second floor, the upperfloors 3 〜6 locating directly on the ground floor, and accompanied by reverse phenomenon . These earthquake damages showed that the first two floors of such structures were conversion floors, which were weak and could be broken as a breakthrough, while the construction with even stiffness could resist larger earthquake forces.2.3 Damage to Short ColumnIn the seriously damaged area in Hanwang town, the wall of the ground floor was not filled completely in consideration of ventilation, light and other factors, resulting in the short column effect of frame-column between two walls ( determined by whether the shear span ratio was small than or equal to 2 ) . As is known, the ductility of short columns was poor and prone to shear failure when suffered from earthquake of the seismic fortification. In this case the formation of the artificial short column inadvertently became seismic weak part of the whole structure. The short columns were crushed after the cut, causing severe structural damage.3 CONCLUSIONSBased on the field survey information in seriously damaged regions of Wenchuan earthquake，we showed typical earthquake damages to ordinary residential houses in cities,self-built houses in villages and towns, and public buildings. We also analyzed causes of various or even striking different patterns and degrees of damages to structure of buildings. For the purpose of tourism and economic development，large open rooms were needed for buildings along the urban streets for business. In some large communities，the bottom two floors were often used as gymnasium，restaurant and other public places. Therefore，such buildings usually adopted frame structure for the bottom part, while brick-concrete structure for the upper floors to meet the requirement for diversity and flexibility of room sizes. This kind of structural type change caused serious disaster in this earthquake. Thus, requirements for seismic resistance of such building structures should be emphasized, and reasonable solutions to the contradiction between the requirement for big space and the implementation of seismic measures (such as shear wall) are in need. For self-built housing by rural villagers, the main notion is that a house should not adopt the load-bearing structures of the combinational use of wooden, brick or reinforced concrete columns. In addition, integrity of houses should also be strengthened. It will have remarkable effect to set reinforced concrete ring beams and constructional columns in brick structure houses for the enhancement of anti-collapse performance.References：Ge Xueli, Huang Shimin, Xue Yantao, et al. Damage analysis and reconstruction suggestions on buildings in Dujiangyan of Wenchuan Ms8. 0 earthquake DO . Earthquake Resistant Engineering and Retrofitting, 2008, 30 (4) : 2 〜11 (in Chinese with English abstract).Sun Jingjiang, Ma Qiang, Shi Hongbin, et al. Building damage in cities and towns located in higher intensity areas during Wenchuan earthquake[ J] . Earthquake Engineering and Engineering Vibration, 2008, 28 (3): 7 〜15 (in Chinese with English abstract).Wen Ruizhi, Wei Jingzhi, Zhao Jisheng, et al. Damage analysis for the buildings in countryside at Wenchuan Ms 8. 0 earthquake and some recovering suggestions [J] . Technology for Earthquake Disaster Prevention, 2008 , 3 (4) : 391 〜397 (in Chinese with English abstract).Zhang Minzheng. Building damage in Dujiangyan during the Ms 8. 0 Wenchuan earthquake [J] . Earthquake Engineering and Engineering Vibration, 2008, 28 (3) : 1 〜6 (in Chinese with English abstract).二、翻译结果汶川地震建筑损坏的分析Li Min1) ，Li Xiaojun2)1) 中国地震台网中心, 北京100045，中国2) 地球物理研究所, CEA, 北京100081, 中国摘要：汶川8.0级地震造成了大量工程结构的破坏和倒塌。
