摘要
强度不足是高温下宽窄接缝损伤的主要原因之一,通过建立基于混凝土塑性损伤理论的宽窄接缝有限元模型,分别研究宽接缝与窄接缝强度一致、窄接缝强度高于宽接缝强度和宽接缝强度高于窄接缝强度等工况下3种典型损伤模式与强度分布的关系。计算表明:温升作用下,窄接缝的破损是由窄接缝处强度低导致的受压损伤,受宽接缝强度影响小;宽接缝破损是由于宽接缝强度低所导致的拉压复合损伤并受窄接缝强度影响;宽接缝与窄接缝交界处断裂属于突变的受拉损伤;窄接缝强度越高于宽接缝强度,宽接缝越易损伤,但会提高宽接缝与窄接缝交界处断裂所需温升。损伤模式与强度分布相关,为避免接缝破坏,建议保证窄接缝混凝土强度等级至少为C55,宽接缝混凝土强度等级至少为C45,但低于窄接缝混凝土强度等级。
Insufficient strength is one of the main causes for slab joints damage under temperature rise.By establishing a finite element model of slab joints based on the theory of plastic damage of concrete,the relationships between three typical damage patterns and strengths are studied respectively under such conditions as the same strength of both broad joints and narrow joints,the higher strength of narrow joints than that of broad joints,and higher strength of broad joints than that of narrow joints.Study results show that,subject to temperature rise,the breakage of narrow joints is a type of compressive damage caused by low strength at narrow joints and is less affected by the strength of broad joints;the breakage of broad joints is a type of mixed failure compressive damage and tensile damage caused by low strength of broad joints and is affected by the strength of broad joints;the fracture at the junction between broad joints and narrow joints is a sudden tensile damage;the higher the strength of the narrow joint than the that of the broad joint,the more likely the broad joint is damaged,but it will increase the temperature rise required for the fracture at the junction between broad joints and narrow joints.Damage patterns are related to the distribution of strength.To prevent joints damage,it is recommended that the concrete grade of narrow joints should be at least C55,and that of broad joints at least C45 but lower than that of narrow joints.
作者
张雯皓
刘学毅
郭恒
肖杰灵
刘笑凯
董佳佳
ZHANG Wenhao;LIU Xueyi;GUO Heng;XIAO Jieling;LIU Xiaokai;DONG Jiajia(MOE Key Laboratory of High-speed Railway Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of Science,North University of China,Taiyuan 038507,China;Xuzhou Engineering Construction Headquarters of China Railway Shanghai Bureau Group Co.,Ltd.,Xuzhou 221000,China)
出处
《铁道标准设计》
北大核心
2021年第2期54-59,66,共7页
Railway Standard Design
基金
国家自然科学基金面上项目(51978584,51778543,51678506)。
