Steel structural members in different application areas may be subjected to localized flame impingement instead of flashover scenario due to several reasons. Though extensive research has been performed to study component level systems in conventional fires (ISO 834, ASTM E119, other parametric fire curve), the behavior of beam column rigid connection in localized fire is still not investigated in details. To understand the behavior of beam-column connection under localized fires, the present paper deals with a detailed numerical investigation of the behavior of a moment resisting frame (MRF) assembly with fully welded beam column connection in terms of connection rotation and forces under different positions of localized fire source underneath the exposed beam. For fire scenarios where the frame survived during the entire duration of fire, the post fire rotation of the connection located at far end from the fire source was found to be higher than the near end. Secondly, for cases where the frame failed, it was observed that for identical strength of weld and base material, failure is likely to initiate at the weld line connecting the bottom flange of the beam located at far end from the fire source. Finally parametric studies were performed with different weld sizes and it was concluded that size of weld has significant effect on increasing the joint survival time for MRF exposed to localized fire.

由于多种原因，不同应用领域的钢结构构件可能会遭受局部火焰冲击而不是闪络情况。尽管已经进行了广泛的研究来研究传统火灾中的组件级系统（ISO 834、ASTM E119、其他参数火灾曲线），但梁柱刚性连接在局部火灾中的行为仍然没有详细研究。为了了解局部火灾下梁柱连接的行为，本文对具有全焊接梁柱连接的抗弯矩框架（MRF）组件在不同位置下的连接旋转和力方面的行为进行了详细的数值研究暴露梁下方的局部火源。对于框架在整个火灾期间幸存的火灾场景，发现位于距火源远端的连接的火灾后旋转高于近端。其次，对于框架失效的情况，据观察，对于相同强度的焊缝和基材，失效很可能发生在连接位于远离火源的梁的底部翼缘的焊缝处。最后对不同的焊缝尺寸进行了参数研究，得出的结论是焊缝尺寸对于增加暴露于局部火灾的 MRF 的接头生存时间有显着影响。