基于力流分析的铁路承台三维拉压杆模型研究

Research on 3D Strut-and-Tie Model of Railway Pile Cap Based on Stress Flow Analysis

由于铁路桥墩和承台尺寸较大,承台连接桥墩和桩基受力十分复杂。承台设计中套用"受弯理论"和公路规范的"撑杆-系杆理论"缺乏依据。在调研国内外相关厚承台研究成果的基础上,以石济高铁承台通用图为研究对象,对8个典型承台进行受载后力学分析,得到承台内部的受力特点。基于力流分析,并通过不断优化所建立的三维拉压杆尺寸和节点位置,得到可替代实体分析的三维拉压杆简化模型。以得到的各拉杆内力为依据,计算出承台底主筋数量,通过配置钢筋的三维实体模型验证了配筋的合理性。研究表明:通过三维拉压杆简化模型计算得到的承台钢筋数量满足承台受力要求,配筋数量比传统配筋方式节约20%。

Due to the large dimensions of railway piers and pile caps, the stress of the pile cap connecting pier and pile foundation is very complex. In pile cap design, simply applying the "bending theory" and the"stay bartie bar theory" from highway specification is lack of basis. Based on the research results of relevant thick pile caps at home and abroad, this paper makes a mechanical analysis on 8 typical load-bearing pile caps with the typical drawings of pile caps of Shijiazhuang-Jinan High-speed Railway as the research object, and obtains the stress characteristics inside the pile caps. Based on the stress flow analysis and by continuously optimizing the dimensions and node positions of the established 3D strut-and-tie, a simplified 3D strut-and-tie model is obtained to replace the physical analysis. Based on the obtained internal stress of each tie bar, the number of main reinforcement at the bottom of pile cap is calculated, and the rationality of reinforcement is verified by a 3D solid model of reinforcement layout. The study shows that the number of pile cap reinforcement calculated through the simplified 3D strut-and-tie model meets the stress requirements of the pile cap, and the number of reinforcement is 20% less than that of the conventional reinforcement layout mode.