摘要
针对现有规范的徐变控制标准不适用于超过128 m的大跨度预应力混凝土主梁,且经验控制标准存在指标严、结构经济性差等问题,提出128 m以上大跨度预应力混凝土主梁的徐变控制标准。通过调研分析徐变对行车影响、徐变控制成功经验、规范控制标准演变、挠跨比与曲率关系、曲率控制下徐变限值、工程应用效果等综合因素,指出大跨度连续梁具有变形异于简支梁的规则不平顺、运营荷载富裕大、主梁刚度富裕大、主梁活载变形预拱效应和大跨度索辅结构变形可调等徐变控制有利因素,研究提出大跨度预应力混凝土主梁取消20 mm限值,按L/5000标准控制工后徐变变形的建议,并选取京沪高铁、合福高铁和广深港城际4个连续梁拱桥案例佐证建议的可行性和安全性。最后对影响徐变变形的原因进行探讨分析,建议结合案例开展调研和徐变理论研究,为无砟轨道桥梁进一步向大跨度发展提供理论支撑。
In view of the fact that current creep control standards are not applicable to prestressed concrete main beams with spans exceeding 128 meters,and that empirical control standards often involve overly stringent indicators and poor structural economic efficiency,this study proposed creep control standards specifically for such long-span prestressed concrete main beams.Through a comprehensive analysis of factors such as the effect of creep on train operation,successful creep control practices,the evolution of control standards,the relationship between deflection-to-span ratio and curvature,creep limits under curvature control,and engineering performance,it was pointed out that the long-span continuous beams possessed favorable conditions for creep control.These included irregular deformation patterns unlike those of simply supported beams,large reserve capacity for operating load,large stiffness of main beam,pre-camber effects due to live load deformation of the main beam,and adjustable deformation in cable-assisted systems.This study proposed cancelling the 20 mm limit for long-span prestressed concrete main beams and recommended controlling post-construction creep deformation according to the L/5000 standard.The feasibility and safety of this recommendation were validated through four case studies of continuous beam-arch bridges along the Beijing-Shanghai high-speed railway,Hefei-Fuzhou high-speed railway,and Guangzhou-Shenzhen-Hong Kong intercity railway.Finally,the factors influencing creep deformation were discussed and analyzed,and it was suggested to carry out investigations and theoretical studies on creep in combination with cases,so as to provide theoretical support for the further development of ballastless track bridges with long spans.
作者
柏华军
BAI Huajun(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)
出处
《铁道标准设计》
北大核心
2025年第7期94-100,共7页
Railway Standard Design
基金
国家重点研发计划项目(2021YFB2600400)
中铁第四勘察设计院科技研发计划项目(KY2023014S)。
关键词
高速铁路
预应力混凝土主梁
无砟轨道
徐变变形
曲率
挠跨比
连续梁拱
high-speed railway
prestressed concrete main beam
ballastless track
creep deformation
curvature
deflection-to-span ratio
continuous beam-arch
