含抗彎矩接頭鋼構造梁之耐火性能研究

Abstract

一、研究緣起 鋼構造建築物一般為梁柱抗彎矩構架，大梁以剛接與柱接合，小梁以鉸接與大梁接合。梁構件不論為大梁或小梁，遭受火害時，其高溫中後之結構行為，受其周圍結構構件的影響，與單一簡支梁受火害時不同。鋼梁構件於火害升溫時受熱膨脹，因其周圍結構構件之束制而將產生軸向壓力，於冷卻降溫時，由於收縮和鋼梁兩端的束制，將承受軸向拉力，可能會造成束制鋼梁兩端接合造成破壞，本研究擬透過火害實驗加以探討此一情形。 二、研究內容 1.進行含抗彎矩接頭束制鋼梁構件火害試驗：規劃進行二次實尺寸試體之定載加溫試驗。 2.探討束制鋼梁構件在高溫下之變形行為(變形與變形速率)與破壞模式。 3.進行分析驗證束制鋼梁構件之防火時效。

Special moment frames are generally used for steel building structures. Steel beam girders are joined to the column by a moment connection while small steel beams are connected to the steel beam girders by shear connection. Different from the isolated steel beams, the behavior of the steel beams in a moment frame subjected to elevated temperatures is affected by the surrounding members. The steel beams would be subjected to axial compression caused by the thermal elongation owing to increasing temperature while the beams expose to fire. However, the steel beams would be tensioned due to contraction and the restraint at both ends when the beams are in cooling phase. These phenomena may result in the failure at ends of the restrained steel beams. This study aims to investigate experimentally and numerically the fire behavior of the restrained steel beams.

The objectives of this study are as follows. 1. Complete the fire test and analysis of large-scale restrained steel beams with moment connection. 2. Establish fire resistance and failure mode of restrained steel beams. 3. Supplement current “Technical handbook of certification of fire resistance performance for building structures,” via the understanding of fire behaviors of restrained steel beams.