城市建筑物震害预测方法的改进

Improvement of Seismic Damage Prediction Method for Urban Buildings

目前基于地震烈度的建筑物震害预测方法,通常按整烈度给出预测结果,造成在设定地震影响下烈度分界线两侧相邻的、抗震能力相同的建筑物震害预测结果有很大的差异,而同一烈度圈内靠近高烈度分界线与靠近低烈度分界线的建筑物震害预测结果却完全相同,这与实际震害情况严重不符。为了解决这个问题,将地震烈度按0.2度间隔进行分档,同时将震害指数和破坏等级也进一步细化出5个分档。按地震烈度与震害指数的关系,通过拟合方法和等分方法得到5个烈度分档的震害指数调整系数和分档震害指数,拟合方法获得的调整系数适用于群体房屋震害预测,等分方法获得的震害指数适用于单体房屋震害预测,通过改进方法获得的设定地震影响下震害预测结果,可以体现同一烈度不同烈度分档内建筑物震害差异,并使烈度线两侧,抗震能力相同的建筑物的震害预测结果不再出现跃变。

The present seismic damage prediction method of predicting damages of buildings is based on onedegree-interval intensity zone. This method results in quite different damages predicted for buildings with same seismic capacity but closely located in two sides of the intensity isocline, while the damages predicted for all buildings within the same intensity zone, no matter close to the higher intensity isocline or the lower intensity isocline, are identical under a certain scenario earthquake. This kind of results predicted is quite different from actual seismic damage.To solve this problem, the authors subdivide one-degree-interval intensity zone by 0.2degree interval, and break down the damage index and damage level into five smaller grades accordingly at the same time. Based on the relationship between seismic intensity and damage index, the authors use fitting and equal division methods respectively to get adjustment coefficient of damage index or graded damage index for five subdivided intensity grades. The adjustment coefficient of damage index obtained by fitting method is suitable for seismic damage prediction of building groups, and the damage index obtained by equal division method is applicable to single building. This improved method for damage prediction can not only reflect the discrepancy among buildings located in different subsections of the same intensity zone, but also make sure that the predicted damages of buildings with same seismic capacity and from two sides of anintensity isocline not fluctuate sharply.