框架效应对预应力混凝土箱梁桥顶板横向预应力储备的影响分析

Analysis of Linfluuence of Frame Effect on Transverse Prestress Reserve of Prestressed Concrete Box Girder Bridge Roof

基于数值模拟研究了预应力混凝土箱梁桥三种不同横向预应力筋布置方式的预应力框架效应影响、横隔板设置、箱梁参数对顶板横向有效预应力的影响,并与现场测试结果进行了对比,表明了数值模拟方法的有效性,选取预应力混凝土箱梁桥高跨比、宽跨比、腹板与底板厚度之比等关键参数,进行实桥参数敏感性分析.表明预应力混凝土箱梁桥墩顶外由于横隔梁刚度大,在其5 m左右范围内横向框架效应影响显著,应按非预应力混凝土设计预防顶板纵向裂缝产生,在跨中设计的横隔板附近应增加纵向抗裂钢筋;增加宽跨比、底板与腹板厚度之比、腹板与顶板宽度之比以及减少高跨比有利于保证预应力混凝土顶板横向有效预应力.

Based on numerical simulation,the influence of prestressed frame effect,the arrangement of diaphragm and the influence of box girder parameters on the lateral effective prestress of the roof are studied.The test results are compared to show the effectiveness of the numerical simulation method.The key parameters such as the high-span ratio,the wide-span ratio,the ratio of the web to the thickness of the prestressed concrete box girder bridge are selected,and the sensitivity analysis of the real bridge parameters is carried out.It shows that the transverse beam of the prestressed concrete box girder has a large stiffness,and the transverse frame effect is significant in the range of about 5 meters.The non-prestressed concrete design should be used to prevent the longitudinal cracks in the roof.Longitudinal crack-resistant steel bars should be added nearby;increasing the width-to-span ratio,the ratio of the thickness of the floor to the web,the ratio of the web to the width of the roof,and reducing the high-span ratio are beneficial to ensure the transverse effective prestressing of the prestressed concrete roof.