地铁车站型钢混凝土承台转换梁受剪性能研究

Research on the Shear Behaviors of Cap Transfer Beams with Steel Reinforced Concrete in the Subway Stations

研究目的:地铁车站与城市桥梁形成的合建体结构受力复杂,为提高其力学性能,本文提出一种双槽钢型钢混凝土承台转换梁结构形式。为探究该类转换梁的受剪性能,对3根钢筋混凝土及5根双槽钢型钢混凝土的承台转换梁试件进行受剪性能试验研究,观察试件受剪破坏过程及破坏形态,获取转换梁抗剪性能指标,分析剪跨比及配钢率对转换梁受剪性能的影响规律。研究结论:(1)在集中荷载作用下,承台转换梁支座与加载点处连线附近形成主斜裂缝,发生典型的剪切斜压破坏;(2)减小剪跨比可以有效提高承台转换梁的承载力,但试件的脆性破坏则越来越严重;与钢筋混凝土相比,在配钢率及剪跨比相同的情况下,设置双槽钢型钢试件承载力最大增幅约为111.8%;(3)增加配钢率在一定程度上可提高试件的承载力和变形能力,其中承载力最大增幅约为6.87%;(4)地铁车站与城市桥梁合建体结构中采用双槽钢型钢混凝土承台转换梁具有明显的力学性能优势,本研究结论可为类似结构设计提供借鉴与参考。

Research purposes: The mechanical properties of composite structure formed by subway stations and urban bridges are complex. In order to improve its mechanical properties, structural form of a double-channel steel reinforced concrete cap transfer beam is proposed. In order to explore the shear performance of this type of transfer beam, the author conducted shear performance tests on three reinforced concrete and five double-channel steel reinforced concrete cap transfer beam specimens. In the research, the shear failure process and failure form of the specimen were observed, the shear performance index of the transfer beam was obtained, and the influence of the shear-span ratio and the steel distribution ratio on the shear performance of the transfer beam was analyzed. Research conclusions:(1) Under the action of concentrated load, the main oblique crack is formed near the connecting line between the support of the cap transfer beam and the loading point, and a typical shear oblique compression failure occurs.(2) Decreasing the shear-span ratio can effectively improve the bearing capacity of transfer beam, but the brittle failure of corresponding specimens is more serious. Under the condition of the same reinforcement ratio and shear-span ratio, the maximum increase on the bearing capacity of specimen with double-channel steel is about 111.8%.(3) Increasing the steel distribution ratio can improve the bearing capacity and deformation capacity of the specimen to a certain extent, and the maximum increase in the bearing capacity is about 6.87%.(4) The use of double channel steel reinforced concrete cap transfer beam in the composite structure of subway station and urban bridge has obvious advantages in mechanical properties. The research conclusion can provide reference for similar structure design.