低矮型鋼筋混凝土住宅結構耐震快速評估法之開發與驗證

Abstract

歷年的地震勘災經驗顯示，臺灣既有低矮型鋼筋混凝土(RC)建築物容易遭受嚴重損壞，例如街屋即為損壞最嚴重的類型之一。現有的初步評估工具偏保守，應用在校舍的篩選率約近五成。然而街屋數量龐大，若篩選出大量的街屋後送進行詳細評估及補強，並非現今社會經濟所能負擔。因此有必要發展一套適用於街屋的快速評估方法。 首先本研究以校舍耐震詳細評估資料庫為基礎，利用統計分析找出柱量比對應建築物之耐震性能的關係，再將磚牆及RC牆轉換為等值柱量，即可利用此迴歸關係式快速評估出建築物的耐震能力。由典型街屋結構資料庫統計分析得知，磚牆是此類建築物耐震能力的關鍵構件。因此，有效掌握磚牆的行為，才能改善快速評估方法的篩選性。 本研究進行了RC構架內含填充磚牆實驗。實驗結果顯示，填充磚牆的面內側向強度與磚牆的破壞路徑有關。現行四面圍束磚牆評估模型的強度計算方式，有適度考慮磚牆的破壞路徑，因此評估的強度與實驗的強度相近。本研究再利用成大柱含磚翼牆實驗的觀察，提出改善既有三面圍束磚牆評估模型的修正建議。本研究磚牆評估模型的驗證與修正，亦可供詳細評估使用。 本快速評估方法經過59棟低矮型RC建築物震損資料庫驗證，證實其耐震能力快速評估之結果，與其震損程度趨勢相符。又本方法對145棟台灣典型街屋進行快速評估，篩選結果顯示約有三成八的街屋須後送進行專業之詳細評估，以確認耐震能力。因此本方法可做為民眾住家自主檢查之工具，協助其篩選出耐震能力可能有疑慮之街屋，再尋求專業之詳細評估與補強設計，為一個經濟可行的做法。

The experience of seismic reconnaissance showed that the low rise reinforced concrete (RC) buildings in Taiwan were severely damaged, e.g., street house. The existing seismic preliminary evaluating methods are quite conservative. For instance, the screening rate of the seismic preliminary evaluation for the public school buildings in Taiwan is almost 50%. However, if a huge number of street houses needs to be carried out the seismic detailing evaluation by professionals, the community cannot sustain it nowadays. Therefore, to develop a seismic rapid evaluating method is significant. Based on the seismic evaluation data of the school buildings of the database collected by the National Center for Research on Earthquake Engineering, an empirical formula of the performance ground acceleration and the column-to-floor area ratio was established. The cross sectional areas of brick infill and RC wall can be transformed into the equivalent area of column according to their seismic capacities. Consequently, the performance ground acceleration of a low-rise street house can be rapidly evaluated by the ratio of column sectional area to floor area of building. Statistic on the structural database of the typical street house in Taiwan indicated that brick walls were the significant structural members of the street house. Thus, to study on the behavior of brick wall can improve the accuracy of the rapid evaluation method. Tests of RC frames with brick infill were carried out. The test results indicated that the lateral strength of brick infill related to the major fracture path. The existing evaluation model of the brick infill was verified that the model well predicted the lateral strength of the tests because of considering the major fracture path of the brick infill. Moreover, the study proposed to improve the evaluation model of brick wing wall in accordance with the observation of the tests on the brick wing wall by NCKU. The verification and improvement on the evaluation models of brick infill and wing walls can be applied for the seismic detailing evaluation. The seismic rapid evaluation method has been verified by 59 damaged buildings of database collected through earthquake reconnaissance. The seismic capacities obtained from the rapid evaluation method correlate well with the damaged status of low-rise buildings. 145 buildings of the database of typical street house were rapidly evaluated. About 38% of the buildings need to be carried out the seismic detailing evaluation by professionals. In general, the rapid evaluation method is conservative but still possesses a screening capacity.