UHPC-砖砌体组合托换梁正截面受弯承载力计算方法研究  

Research on calculation method of normal section flexural bearing capacity of UHPC-brick masonry composite underpinning beams

作　　者：朱燕竹 王琨[1,2] 朱智宇 帅华国 戴长明 陈再现 Zhu Yanzhu;Wang Kun;Zhu Zhiyu;Shuai Huaguo;Dai Changming;Chen Zaixian(College of Civil Science and Engineering,Yangzhou University,Yangzhou 225127,China;Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education,Harbin Institute of Technology,Harbin 150090,China;Yangzhou University Engineering Design and Research Institute Co.Ltd,Yangzhou 225009,China;Shandong Provincial University Civil Engineering Structure and disaster Prevention Laboratory,Harbin Institute of Technology at Weihai,Weihai 264209,China)

机构地区：[1]扬州大学建筑科学与工程学院,江苏扬州225127 [2]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,黑龙江哈尔滨150090 [3]扬州大学工程设计研究院有限公司,江苏扬州225009 [4]山东省高等学校土木工程结构与防灾实验室,哈尔滨工业大学(威海),山东威海264209

出　　处：《建筑科学》2024年第9期72-81,共10页Building Science

基　　金：扬州大学研究生科研与实践创新计划资助项目(KYCX23-3541);国家自然科学基金(51878589);哈尔滨工业大学结构工程灾变与控制教育部重点实验室开放基金课题(HITCE202105)。

摘　　要：本文提出了一种采用UHPC对砖砌体墙进行托换改造的方法,此法可有效减少托换组合梁截面宽度。采用有限元软件ABAQUS,在合理选用UHPC、砖砌体及钢筋的材料本构关系的基础上,建立了UHPC-砖砌体组合托换简支梁的精细化有限元模型,并用相关文献对比验证。随后,考察了受拉钢筋配筋率、UHPC层厚度、UHPC强度等级等主要因素对UHPC-砖砌体组合梁荷载-跨中挠度曲线的影响,并进行竖向荷载下梁的受弯性能全过程分析。依据前述有限元分析结果,提出了UHPC-砖砌体组合托换梁正截面受弯承载力计算公式。研究结果表明,UHPC-砖砌体组合托换梁的纵向受拉钢筋首先屈服,然后UHPC和砖砌体受压区被压碎,整体表现为受弯破坏;随着纵筋配筋率和UHPC层厚度的增加,托换梁屈服荷载和峰值荷载均有较高程度的提高;相对于纵筋配筋率,UHPC层厚度的提高,能明显提高托换梁的开裂荷载;UHPC-砖砌体组合梁的开裂荷载远高于NC-砖砌体组合梁,但当UHPC强度等级达到150MPa~180MPa时,托换梁的承载力变化不大。本文提出的UHPC-砖砌体组合托换梁正截面承载力计算方法与有限元计算结果吻合较好,为此类托换梁的设计分析提供了理论依据。In this paper,a method is proposed to use UHPC to transform brick masonry walls,which can effectively reduce the section width of the composite underpinning beam.Using finite element software ABAQUS,a refined finite element model of UHPC-brick masonry composite simply supported beam is established based on the reasonable selection of material constitutive relationships for UHPC,brick masonry,and steel reinforcement,and is compared and verified with relevant literature.Subsequently,the effects of main factors such as tensile steel reinforcement ratio,UHPC layer thickness,and UHPC strength grade on the load deflection curve of UHPC brick masonry composite beams are investigated,and a full process analysis of bending performance under vertical loads is conducted.On the basis of the aforementioned finite element analysis results,a formula for calculating the flexural bearing capacity of the UHPC brick masonry composite support beam is proposed.The research results indicate that the longitudinal tensile steel bars of the UHPC brick masonry composite support beam first yield,and then the compression zone of the UHPC and brick masonry is crushed,resulting in overall flexural failure;With the increase of longitudinal reinforcement ratio and UHPC layer thickness,the yield load and peak load of the supported beam both increase to a higher extent;Compared with the longitudinal reinforcement ratio,the increase in UHPC layer thickness can significantly increase the cracking load of the supported beam;The cracking load of UHPC-brick masonry composite beams is much higher than that of NC-brick masonry composite beams,but when the strength level of UHPC at 150MPa to 180MPa,the bearing capacity of the support beams do not change much.The calculation method for the normal section bearing capacity of UHPC-brick masonry composite support beams proposed in this article is in good agreement with the finite element calculation results,providing a theoretical basis for the design and analysis of such support beams.

关 键 词：结构改造 正截面受弯承载力 非线性分析 UHPC(超高性能混凝土) 砌体 托换梁 

分 类 号：TU398[建筑科学—结构工程]