摘要
为完善无筋钢纤维混凝土管片的设计方法,加速其在城市轨道交通中的应用,提出一种新的无筋钢纤维混凝土管片正截面结构设计方法。根据已有对钢纤维混凝土本构关系的研究成果,依据地铁管片的受力特点,分析了影响地铁管片正截面承载力的主要因素。依据无筋钢纤维混凝土管片极限拉应变与钢筋混凝土的极限拉应变不在一个数量级上的差异,结合现行混凝土规范,采用平面假设,把应力和应变作为无筋钢纤维混凝土管片设计的特征值;用钢纤维混凝土应变的取值范围对应不同的设计工况,将不同工况下的无筋钢纤维混凝土管片的设计验算结果归结到同一张应力应变图中。论述了采用轴力-弯矩包络图进行正截面设计验算的主要流程,并通过一个工程实例展示不同工况下无筋钢纤维混凝土轴力-弯矩包络图的相互关系。计算结果表明:在正常使用极限状态下,强度是影响承载能力的主要因素;而承载能力极限状态下,特别是偶然荷载作用下,无筋钢纤维混凝土的韧性是影响承载能力的主要因素。
In order to improve the design method of steel fiber reinforced concrete segment without rebars and accelerate its application in urban rail transit,a new design method of normal section structure of steel fiber reinforced concrete segment without rebars was proposed.According to the previous research results on the constitutive relationship of steel fiber concrete and the stress characteristics of subway segments,the main factors affecting the bearing capacity of the subway segmentsnormal section were analyzed.Based on the difference in order of magnitude between the ultimate tensile strain of the steel fiber reinforced concrete segment without rebars and the ultimate tensile strain of reinforced concrete,and combining with current concrete specifications and the assumption of plane deformation of the cross section,the stress and strain were taken as the characteristic values of the design of steel fiber reinforced concrete segments without rebars.The range of strain of the steel fiber reinforced concrete corresponds to different design conditions,the calculation results of steel fiber reinforced concrete segments without rebars under different working conditions were summarized into a same stress-strain diagram.The calculation flow of the axial cross section design using the axial force-bending moment envelope diagram was presented,and the relationship between the axial force-bending moment envelope diagrams of steel fiber reinforced concrete without rebars under different working conditions was shown through an engineering practice.The calculation results show that strength is the main factor that affects the bearing capacity under serviceability limit state,and toughness of the steel fiber reinforced concrete without rebars is the main factor that affects the bearing capacity under ultimate capacity state,especially under accidental loading.
作者
温书亿
阳卫卫
孔娟
王潘
邓一三
WEN Shu-yi;YANG Wei-wei;KONG Juan;WANG Pan;DENG Yi-san(Shenzhen Metro Group Co.,Ltd.,Shenzhen 518000,China;China Railway Academy Co.,Ltd.,Chengdu 610032,China)
出处
《科学技术与工程》
北大核心
2024年第13期5511-5515,共5页
Science Technology and Engineering
基金
深圳市地铁集团有限公司科研课题(SZDT-JSZX-ZC-2020-0022)。
关键词
无筋钢纤维混凝土
正截面结构设计
正常使用极限状态
承载能力极限状态
steel fiber reinforced concrete without rebars
normal section structural design
normal service limit state
ultimate state of bearing capacity
