Pounding and deck unseating may occur at the main span and the side span of the tied arch bridge during the ground motion.A simplified tied arch bridge model with to degrees of freedom is employed.

• 摘要地震作用下，作为主跨的系杆拱桥与连接跨处容易发生碰撞和落梁现象，本文以双自由度简化分析模型为研究对象，考虑梁间伸缩缝处的碰撞。