全尺寸鋼筋輕質混凝土梁之偏心載重行為

Eccentric load behaviors of full-size reinforced lightweight concrete column

簡志軒(Jhih-Sian Jian)

指導教授 ： 干裕成

朝陽科技大學/理工學院/營建工程系/碩士(2010年)

摘要

本文以水庫淤泥燒製之輕質粒料，製作全尺寸輕質粒料混凝土RC 柱，探討實尺寸輕質粒料混凝土柱構件之承重行為與尺寸效應，進行偏心載重試驗。製作柱試體之混凝土強度包括245 kgf/cm2及350 kgf/cm2兩種。各組柱之補強鋼筋均依ACI規範之最小鋼筋比設計。研究中進行試驗、分析並比較各種強度輕質粒料混凝土與常重混凝土柱構件，在承重行為上的差異性。
試驗結果顯示，輕質粒料混凝土柱的破壞模式，與常重混凝土柱相當近似，有二種典型破壞產生，大多數的柱試體都是先撓曲後撓壓破壞，另一種則是橫向撓曲裂縫隨加載發展至一定程度即停止，於柱端擴大區破壞。ACI 規範計算之理論值較為保守，較適用於中強度，輕質和常重混凝土柱當混凝土強度越高時實驗值會越接近理論值。無論輕質或常重混凝土柱，試體尺寸越大其延展性越差，可顯見其尺寸效應之存在，造成延展性降低。

關鍵字

混凝土 ； 柱 ； 偏心載重

並列摘要

This research aims at investigating the full-size lightweight concrete column of the size effect subjected to eccentric load. Two concrete mixes of compressive strengths of 245 kgf/cm2 and 350 kgf/cm2 were used. The reinforcement used to strengthen column specimens in each group are designed in accordance with ACI code for the minimum reinforcing steel ratio. In the experiment, the distinction of mechanical behavior between the lightweight concrete columns and normal concrete columns with different strength were analyzed and compared.
The result reveals that the failure process of lightweight concrete column is similar to that of normal one. Two typical failure types were observed in this research. Most column specimens turn out flexural failure first, followed by crushing on compressive side. Another is that lateral flexural cracks take place on the tension side first and propagating to certain extent, then followed by a longitudinal crack near the tapered joint section of the column. Besides, the load capacity of column evaluated based on ACI code appear more conservative for both lightweight concrete column and normal concrete column in middle strength. The load capacities obtained from the test for both higher strength concrete columns turn out closer to those evaluated by the code. For all columns, it seems that the ductility becomes lower as the specimen size is getting larger, which implies the existence of size effect in column.

並列關鍵字

concrete ； column ； eccentric load

參考文獻

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