铁路UHPC梁的正截面抗弯承载力计算公式及应用  

Calculation Formula of Flexural Capacity of Normal Section of UHPC Railway Beams and Its Application

作　　者：蔺鹏臻[1] 赵鸿伟 马俊军 LIN Pengzhen;ZHAO Hongwei;MA Junjun(Lanzhou Jiaotong University,Lanzhou,Gansu 730070,China)

机构地区：[1]兰州交通大学,兰州730070

出　　处：《铁道工程学报》2022年第5期33-38,72,共7页Journal of Railway Engineering Society

基　　金：国家自然科学基金高铁联合项目(U1934205);国家自然科学基金重大项目(11790281);甘肃省建设科技攻关项目(JK2021-03)。

摘　　要：研究目的:为发挥UHPC抗拉强度高的优势,探索在铁路UHPC梁抗弯承载力设计中合理计入UHPC的抗拉强度,以现有铁路桥涵规范为基础,建立预应力UHPC矩形和T形截面梁考虑UHPC抗拉强度的正截面抗弯承载力计算公式。通过与27组试验梁的试验结果对比,验证抗弯承载力计算公式的可行性。结合24 m跨度的预应力UHPC铁路桥梁设计实例,对比分析考虑UHPC抗拉强度后梁体的抗弯承载力和安全系数。研究结论:(1)结合铁路桥梁设计规范体系,推导了考虑UHPC抗拉强度的铁路UHPC桥梁抗弯承载力计算公式;(2)对比27组试验梁的结果,本文抗弯承载力计算公式与试验结果吻合良好,可供工程设计使用;(3)与不考虑UHPC抗拉强度的承载力结果相比,考虑受拉区UHPC抗拉强度后的预应力UHPC梁的极限承载力可提高约6%,在进行铁路UHPC梁设计时考虑截面受拉区UHPC的贡献可进一步优化截面和节约材料;(4)本研究结果对铁路UHPC梁的设计具有理论指导意义。Research purposes: In order to give full play to the high tensile strength of UHPC and explore the reasonable inclusion of UHPC tensile strength in the design of railway UHPC beam flexural capacity, based on the existing railway bridge and culvert specifications, the calculation formulas of normal section flexural capacity of prestressed UHPC rectangular and T-section beams considering UHPC tensile strength are established. Compared with the test results of 27 groups of test beams, the feasibility of the calculation formula of flexural capacity is verified. Combined with the design example of 24 m span prestressed UHPC railway bridge, the flexural bearing capacity and safety factor of beam body considering UHPC tensile strength are compared and analyzed.Research conclusions:(1) Combined with the railway bridge design code system, the calculation formula of flexural capacity of railway UHPC bridge considering UHPC tensile strength is deduced.(2) Compared with the results of 27 groups of test beams, the calculation formula of flexural capacity in this paper is in good agreement with the test results, which can be used for engineering design.(3) Compared with the bearing capacity results without considering the tensile strength of UHPC, the ultimate bearing capacity of prestressed UHPC beams considering the tensile strength of UHPC in the tensile area can be increased by about 6%. When designing railway UHPC beams, considering the contribution of UHPC in the tensile area of the section can further optimize the section and save materials.(4) The research results have theoretical guiding significance for the design of railway UHPC beams.

关 键 词：铁路桥梁 UHPC 正截面抗弯承载力 配筋率 强度安全系数 

分 类 号：TU37[建筑科学—结构工程]