箱形鋼管混凝土柱火害後之強度評估

STRENGTH EVALUATION OF POST-FIRE CONCRETE FILLED STEEL BOX COLUMNS

本研究經由試驗方式探討填充混凝土之箱形鋼管柱在不同高溫時程及防火被覆時段下，鋼管內部混凝土之溫度分佈狀況及延燒冷卻後鋼管混凝土柱（CFSC）之殘餘抗壓強度。試驗過程共製作10支鋼管混凝土柱試體及2支純混凝土柱試體，分別對以不同組合方式加溫冷卻後之鋼管混凝土柱試體進行壓力試驗，評估其殘餘強度。探討之主題包括鋼骨及混凝土間交互作用、不同耐火被覆時效及延燒時間對鋼管內混凝土強度之影響，藉此瞭解使用防火被覆之鋼管混凝土柱在火害後之強度變化，做為防火被覆設計之參考，文中並嘗試以環氧樹脂灌注技術進行鋼管混凝土柱火災後修復工作之可行性。

Experiments were conducted to study the post-fire residual strength of concrete filled steel box columns (CFSC) and the temperature profile of the filled concrete within steel box sections under different fireproofing treatments and exposures to fire. A total of 10 concrete filled steel box columns and 2 plain concrete columns were cast and tested to study the effect of the interaction between steel and concrete during fire and the different fireproofing and fire exposures on post-fire residual concrete strength. During the experiments, axial loading tests were conducted on the CFSC specimens after fire to evaluate their residual strength. The results of these tests were used to predict the strength of CFSC with certain fireproof treatment. Finally, epoxy injection was used to fill the gap between steel and concrete and cracks in the concrete, which may develop within the steel box section during fire. The result was then analyzed to study the feasibility of using this technique as post-fire rehabilitation work for concrete filled steel box columns.