小矢跨比上承式混凝土连拱拱桥设计方案优化  

Design Optimization of Deck-Type Concrete Multiple Arch Bridge with Small Rise to Span Ratio

作　　者：雷体生 钱永久[1] LEI Ti-sheng;QIAN Yong-jiu(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;CCDI(Suzhou)Exploration&Design Consultant Co.Ltd.,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都市610031 [2]悉地(苏州)勘察设计顾问有限公司,成都市610031

出　　处：《公路》2021年第11期149-154,共6页Highway

摘　　要：井田大桥为74m+128m+74m小矢跨比上承式钢筋混凝土三孔连拱拱桥,采用Midas/Civil软件建立全桥三维有限元模型分析结构在全施工过程中的受力状态,探寻小矢跨比连拱拱桥的合理成拱方案,优化主拱拱圈的拱轴系数与局部构造。结果表明,缆索拼接方案的拼接界面不能满足小矢跨比拱桥的弯矩需求,挂篮悬浇方案则可以保证结构的整体性、安全性及美观性;增加拱轴系数能减小拱脚负弯矩,增加拱顶正弯矩,对L/4截面的弯矩影响不显著,综合平衡全拱圈正负弯矩,井田大桥主拱圈拱轴系数取2.6;优化拱圈截面形式后,主拱圈最大压应力处于相对均衡水平,且拱顶负弯矩大幅降低,使全桥内力分布更为合理。Jingtian Bridge is a deck-type reinforced concrete multiple arch bridge with small rise to ratio,and the span layout being 30+120+30 m.A three-dimensional finite element model is built by Midas/Civil to analyze the stress state in the whole construction process.The reasonable arch forming scheme of small rise to span ratio multiple arch bridge is explored and the arch axis coefficient as well as local detail design is optimized.The results show that the splicing interface of the cable splicing scheme cannot meet the bending moment requirements of the arch bridge with small rise to span ratio,while the hanging basket casting scheme can ensure the integrity,safety and aesthetics of the structure.Increasing the arch axis coefficient can reduce the negative bending moment of arch foot and increase the positive bending moment of arch top,which has no significant influence on the bending moment of L/4 section.By comprehensively balancing the positive and negative bending moment of full arch ring,the arch axis coefficient of the main arch ring of Jingtian Bridge is decided as 2.6.After optimizing the arch ring section form,the maximum compressive stress of the whole bridge rib is at a relatively balanced level,and the negative bending moment of the arch roof can be greatly reduced,which results in a more reasonable internal force distribution of the whole bridge.

关 键 词：桥梁工程 钢筋混凝土拱桥 有限元分析 小矢跨比 成拱方案 拱轴系数 

分 类 号：U442.52[建筑科学—桥梁与隧道工程]