Research On Earthquake Intensity Evaluation Based On Earthquake Damage Of Typical Lifeline Engineering

At present, Evaluation of seismic intensity in China Seismic Intensity Scale(2008) mainly rely on people’s feelings, housing destruction, and other seismic phenomenon and horizontal earthquake acceleration and velocity peak value. Along with the progress o f society and further research on lifeline seismic engineering, there are some unreasonable factors when evaluating seismic intensity after an earthquake in a certain area according to the existing Seismic Intensity Scale. Under these circumstances, Some typical lifeline engineering index are introduced into Seismic Intensity Scale to assist evaluation of seismic intensity to meet the demand of the society. The study focuses on lifeline engineering seismic intensity as a penetration point, and selects some typical structures or equipments to evaluate seismic intensity. The main contents and achievements are as follows:1. An extensive and careful survey and analysis of earthquake damage bridges in the domestic destructive earthquakes are conducted, and classification and summary are made based on the construction type, seismic intensity, damaged parts, numbers o f damaged parts, damage degree of bridges, and whether indirect seismic damage occurred. Based on their shares in bridge structure types, beam bridges and arch bridges are chosen as the research objects, the relation between two types of bridge macro damage and seismic intensity basically classified by level of seismic intensity are studied, through statistic analysis some probability rate acquired, including the probability rate of various seismic damge of bridges at the different level of seismic intensity; probability rate of bridges being undamaged, minor damaged, medium damaged, severely damaged and collapse at the different level of seismic intensity; the probability rate of different parts of two types of bridges at different level seismic damage; the probability rate of damaged part classification at different level seismic damge. To simplify the probability rates from statistic analysis, the indefinite quantity such as“several, minor, major, most” are used to depict various seismic damage and damage levels. Through the study, two types of suggested intengsity evaluation index based on bridge damage by bridge damage level and damaged parts are gieven.2. An extensive and careful survey and analysis of earthquake damage electrical equipments in transformer substation are conducted, and a summary of structure and features of materials of electrical equipments are made. Through comparison, comprehensive summary and statistic analysis, select the macro damagessuch as transformer displacement, transformer bushing, disconnector, disconnecting switch. CT damage, PT damage and arrester damage to study, the classified statistic analysis is conducted according to different seismic intensity. The probability rates of damage of various electric equipments at different level of seismic intensity are acquired. The probability rates of transformer substation being undamaged, minor damaged, medium damaged, severely damaged and collapse at different level of seismic intensity are obtained by judging the damage level of transformers. Through statistic analysis some probability rate acquired, including the probability rate of various equipments damage at different level of seismic intensity; probability rate of damaged equipment classification at different level of seismic intensity. To simplify the probability rates from statistic analysis, the indefinite quantity such asfctseveral, minor, major, most” are used to depict various seismic damage and damage levels. Through the study, two types of suggested intengsity evaluation index based on electric equipments damage by transformer substation damage level and damaged electric equipment are gieven.3. An extensive and careful survey and analysis of earthquake damagewater-supply pipeline in destructive earthquakes are conducted, through the analysis of water-supply pipeline damage, the features and regulations of seismic destruction are concluded. The pipeline is fragile and easy to be damaged during earthquakes, such as, courtyard pipelines could be damaged at the level of intensity VI, and the damage to the pipeline could be more severe as the seismic intensity increase. It is very hard to give accurate statistic relation due to various factors such as earthquake parameter,site condition, pipe features,the design of pipes,durable years and construction quality et al. Chosing the area-based average damage rate and systemic functional condition as penetration points, macro survey and statistic analysis of domestic water-supply pipelines damage are conducted, and the seismic damage regulations are obtained. Based on the statistics of damaged places per unit length pipe, the water-supply pipeline damage level at different level of seismic intensity are acquired, and evaluate pipe damage level in a wide range by summary of water pressure of pipeline after earthquake, leak rate, misfunction and difficulty level of systemic function recovery. With reference to the description of Seismic Intensity Scale in Japan and ex-Soviet, the suggestive seismic intensity evaluation index based on water-supply pipeline damage by pipeline damage level and misfunction mode.4. The QCA method is used to study the relationships between bridges, electric equipments damage and the seismic intensity and the corresponding probability rates, the results are more reseanable than conventional statistic approaches. This is first time the QCA method appling in earthquake engineering study, and this study willbuild a foundation for the wide application of QCA in the domain.Through the study o f this paper, the suggestive seismic intensity evaluation index based on bridges damage, electric equipments damage, water-supply pipeline damageare give. The modes are close to that of China Seismic Intensity Scale and the indefinite quantity is the same, so that the suggestive seismic intensity evaluation index can be used as a reference in the further modification of China Seismic Intensity Scale.