方志禾  王众毅  杜自力
    （北京市市政专业设计院 100037）

[提要] 介绍了路口人行天桥采用的正交预应力系杆空间刚架的特征、静动力分析和结构设计。用系杆对整个刚架施加预应力，用支座使空间刚架实现完全对称、减震、消能，经体系转换，将分段预制的构件组成空间刚架。采用空间梁单元建模，进行了自振频率核算及地震力计算，并进行了截面、岔口区域及刚架角隅的设计，可供同类设计时参考。
[关键词] 人行天桥 预应力系杆 刚架 结构分析

The two dimensional orthogonal steel rigid frame with a ring box beam, four curved box beams and four straight stepped beams,and a pair of cross prestressed tie bars at the lower end of its columns, is very suitable for pedestrian bridge at the crossing of two urban truck roads.Two bridges have been designed in Beijing for the crossing of truck roads with the width of 49.0m. The diagonal spans of the rigid frames are 69. 30m. Authors introduce the structural characteristics and details, i.e: the prestressed ties, the bearings, the knees, the intersecting areas between the curved box beam and the ring box beam, and that between the curved box beam and the straight box beam.The methods of static and dynamic analysis for the rigid frame are also introduced.
Keywords: pedestrian bridge; rigid frame; prestressed tie bar; structural analysis