预应力UHPC-NC组合梁结合面徐变剪应力分析  

Creep shear stress on the interface of prestressed UHPC-NC composite beam

作　　者：邓继华[1,2] 李冬亮 周亚栋 田仲初 刘新华[4] DENG Jihua;LI Dongliang;ZHOU Yadong;TIAN Zhongchu;LIU Xinhua(School of Civil Engineering,Changsha University of Science&Technology,410114 Changsha,China;State Key Laboratory of Health and Safety for Bridge Structure,430034 Wuhan,China;China Railway Bridge Science Research Institute,Ltd.,430034 Wuhan,China;CCCC Second Highway Consultants Co.,Ltd.,430056 Wuhan,China)

机构地区：[1]长沙理工大学土木工程学院,长沙410114 [2]桥梁结构健康与安全国家重点实验室,武汉430034 [3]中铁大桥科学研究院有限公司,武汉430034 [4]中交第二公路勘察设计研究院有限公司,武汉430056

出　　处：《应用力学学报》2024年第5期1075-1082,共8页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金资助项目(No.51478049);湖南省教育厅资助项目(No.21A0187);桥梁结构健康与安全国家重点实验室开放基金资助项目(No.BHSKL21-06-GF);长沙理工大学研究生“实践创新与创业能力提升计划”项目(No.SJCX202014);云南省交通运输厅科技项目(云交科教[2017]17号)。

摘　　要：在恒载应力作用下,预应力UHPC-NC组合梁因两种材料不同的徐变特性及加载龄期的差异导致结合面产生徐变剪应力,分别采用解析法和有限元法对结合面徐变剪应力进行分析。在解析法中,用三角级数表示UHPC-NC结合面的应力分布,基于结合面上的变形协调,利用最小余能原理推导出结合面徐变剪应力计算公式。在有限元法中,将组合梁UHPC层与NC层均划分成四边形平面应力单元,对结合面则采用等效杆单元模拟。以T形截面预应力UHPC-NC组合梁为例进行计算方法的验证,两种方法的计算结果吻合良好,且研究发现徐变剪应力最大值位于梁端;在此基础上对影响结合面徐变剪应力分布的UHPC层压应力、梁高、计算龄期、环境年平均相对湿度等参数进行分析,结果表明:结合面徐变剪应力最大值随着UHPC层压应力、计算龄期、环境年平均相对湿度的增大而增大,但基本不随梁高变化;结合面徐变剪应力最大值的位置随着梁高的增大而逐步向跨中靠近,其他因素不影响应力最大值的位置。研究结果可为UHPC-NC组合梁结合面的抗剪设计提供参考。Under dead load stress,the creep characteristics and loading age difference of UHPC and NC materials lead to the creep shear stress on the UHPC-NC interface.In this paper,the creep shear stress of UHPC-NC interface is analyzed by analytical method and finite element method,respectively.In the analytical method,the stress distribution of the interface is represented by trigonometric series.Based on the deformation coordination of the interface,the stress calculation formula is derived by using the principle of minimum complementary energy.In the finite element method,both UHPC and NC layers are divided into quadrilateral plane stress elements,and the interface is simulated by equivalent beam element.Taking the prestressed UHPC-NC composite beam with T-section as an example,the calculation results of the two methods are in good agreement,and the maximum creep shear stress is found to be located at the beam end.On this basis,parameters including the UHPC laminated stress,beam height,calculated age,and the annual average relative humidity affecting the distribution of creep shear stress on the interface are analyzed.The results show that the maximum creep shear stress of the interface increases with the increase of UHPC laminated stress,calculation age and the annual average relative humidity of the environment,but it basically does not change with the beam height.The position of the maximum creep shear stress on the interface gradually approaches the midspan with the increase of beam height,and the other factors do not affect the position of the maximum stress.The results can provide some reference for the shear capacity design of the interface of UHPC-NC composite beam.

关 键 词：UHPC-NC组合梁 结合面剪应力 徐变 最小余能原理 有限元法 

分 类 号：TU378.2[建筑科学—结构工程]