- 學位論文
利用能量耗散觀念評估鋼筋混凝土柱之韌性強度
Evaluation of Ductility of Reinforced Concrete Columns Based on Energy Dissipation
摘要
現今鋼筋混凝土柱的極限強度一般是指利用反覆載重試驗(cyclic loading test)所獲得之遲滯迴圈中，其最大側向力的80％，此方法為一個約定俗成的方法並無任何的理論背景。因此本論文將利用能量耗散觀念對鋼筋混凝土柱之韌性強度研擬出新的評估方法。此評估方法為計算反覆載重試驗所獲得之每一個遲滯迴圈的面積，此面積即為鋼筋混凝土柱在該循環(cycle)所能消耗的能量，將各個循環所能消耗的能量依序繪成能量消散容量圖。另一方面，如將各循環的能量除以該循環所對應之反覆載重的總位移，即可得到各循環之單位位移所能消散的能量，在本文中將簡稱為單位位移消散能量容量，而當此單位位移消散能量容量達最大值時，此時之試體將視為已達破壞。因而此循環之最大側向力與最大位移即為極限強度與極限位移。至於降伏位移的決定則由以下的方式來決定，利用試體達極限強度時，其所能消散的能量的某一百分比，而此一百分比能消散的能量即定義為鋼筋混凝土柱降伏時所能消散的能量，因而降伏時所能消散的能量所對應之循環的最大位移即為降伏位移。在求得極限位移及降伏位移之後，即可計算韌性強度。為了驗證本論文所研擬評估方法的正確性，將利用搜集的反覆載重實驗資料，分別以先前慣用的方法以及本研究所提出的方法來分別求得其極限強度，隨後再進行比較以得知其差異性，本研究係以能量消散的觀念來研擬出一套有系統計算韌性強度的方法。
並列摘要
It is accepted that the ultimate lateral force of reinforced concrete columns is the 80% maximum lateral force of hysteresis loops evaluated by the cyclic loading test. However, this method is not theoretically supported. Thus, this study aimed to create a new method to evaluate ductility of reinforced concrete columns by applying the concept of cycle energy dissipation. Our method was to count the area of each hysteresis loop derived from the cyclic loading test, and the area represented the energy of reinforced concrete columns dissipated in that cycle. Then, the figures of cycle energy dissipation capacity were made orderly according to the energy dissipated in each cycle. Besides, the term "unit displacement dissipation cycle energy capacity" in this study was the energy dissipated in unit displacement of each cycle. When the unit displacement dissipation cycle energy capacity became maximal, the specimen was regarded destroyed. Therefore, the homologous maximum lateral force and maximum displacement individually represented ultimate lateral force and ultimate displacement. Moreover, when the specimen bore ultimate lateral force, a certain percentage of the dissipating energy was defined as the energy that reinforced concrete columns could dissipate when yielding. As a result, the displacement of the cycle homologizing the dissipating energy when yielding became yield displacement. After getting ultimate displacement and yield displacement, were attained the ductility could be evaluated. In order to test the validity of the new method, the data of cyclic loading test were collected and analyzed to get the ultimate lateral force. The accepted method and our method were both applied and then the comparison of two methods was made to get the differences. This study intended to create a systematic method to evaluate ductility strength.