密集横隔板UHPC箱梁桥面板双向受力性能试验研究

发布时间：2018-06-11 20:55

本文选题：桥梁工程 + 双向受力性能　；参考：《湖南大学》2015年硕士论文

【摘要】：超大跨径UHPC(Ultra High Performance Concrete,简称UHPC)连续箱梁桥是一种将超高性能混凝土材料、具有密集横隔板的薄壁箱梁和体外预应力有机结合起来的纵向单向预应力新型连续梁桥。该体系梁桥所具有的优异结构性能,有望解决传统预应力混凝土箱梁桥所面临的梁体开裂和主跨下挠两大病害,并实现预应力混凝土连续梁桥的经济跨径突破400m。密集横隔板的设置有利于解决UHPC箱梁薄壁化所面临的整体稳定性、截面畸变及腹板抗剪等问题,同时也改变了箱梁桥桥面板在汽车局部轮载作用下的受力模式:传统混凝土箱梁桥多在墩顶及跨中处设置横隔板,桥面轮载单向地由顶板传递至腹板;而在UHPC箱梁桥中,横隔板沿纵桥向密集设置,横隔板与箱梁腹板共同支承顶板承受桥面轮载,桥面轮载沿纵横双向传递,较传统构造混凝土箱梁桥面板,UHPC箱梁桥面板的受力性能与传力机理均发生改变。本文研究即从具有密集横隔板构造UHPC箱梁桥面板的受力性能和传力机理两方面展开:(1)通过静力模型试验和有限元数值模拟,定性地分析了UHPC箱梁桥面板受力性能和内力分布特征,获取UHPC箱梁桥面板受力性能改善的依据,同时对双向受力模式下桥面板跨中截面荷载有效分布宽度的变化规律进行研究,形成进一步理论分析的参考。结果表明:密集横隔板UHPC薄壁箱梁通过高性能材料的应用和对桥面支承体系的改变,扩展了桥面板的线弹性工作区间,5.5倍设计车轮局部荷载作用下,试验工况桥面板仍处于线弹性受力阶段;与传统无密隔板构造箱梁桥面板对比,密集横隔板构造箱梁桥面板属双向传力构件,单向承载比重降低,且主受力方向由传统箱梁桥面板的横桥向变为纵桥向;横隔板沿纵桥向密集设置,对横桥向受力板带荷载有效分布宽度具有一定约束作用。(2)以试验及有限元分析为基础,基于等代简支跨原理,对双向传力模式下模型桥面板的荷载纵、横向分配问题进行了理论分析,对控制截面内力进行了初步计算。结果表明:等代简支跨原理对荷载分配进行计算的思路较合理;线弹性受力阶段,最不利正弯矩工况下桥面板轮载纵、横向分配比,疏隔板侧约为1:0.64,密隔板侧约为1:0.53,轮载双向分配趋于均匀,桥面板受力效率提高;桥面板负弯矩控制值为横隔板支承处顶部纵桥向弯矩,采用现行规范内力算法对桥面板正、负弯矩的计算结果与实测内力相接近,但限于其理论来源,计算结果尚存在偏差。
[Abstract]:UHPC-Ultra High performance Concrete (UHPC) continuous box girder bridge is a new type of longitudinal unidirectional prestressed continuous girder bridge, which combines ultra-high performance concrete material, thin-walled box girder with dense transverse diaphragm and external prestressing force. The excellent structural performance of the system is expected to solve the two major diseases of the traditional prestressed concrete box girder bridge, such as cracking of the beam body and deflection of the main span, and the economic span of the prestressed concrete continuous beam bridge exceeds 400m. The installation of dense transverse diaphragm is helpful to solve the problems of overall stability, cross-section distortion and web shear resistance of UHPC box girder, which are faced with thin-walled UHPC box girder. At the same time, it also changed the stress mode of deck slab of box girder bridge under the action of vehicle partial wheel load: the traditional concrete box girder bridge installed transverse partition at the top of pier and the middle of span, and the wheel load of deck was transferred from top plate to web plate in one direction, while in UHPC box girder bridge, The transverse partition plate is arranged intensively along the longitudinal bridge, the roof plate supported by the transverse partition board and the box girder web plate is subjected to the bridge deck wheel load, and the bridge deck wheel load is transmitted in both longitudinal and horizontal directions. Compared with the traditional concrete box girder bridge, the mechanical behavior and force transfer mechanism of UHPC box girder bridge face slab have been changed. In this paper, through static model test and finite element numerical simulation, the stress behavior and force transfer mechanism of UHPC box girder bridge with dense transverse diaphragm are studied. This paper qualitatively analyzes the behavior and internal force distribution characteristics of UHPC box girder bridge face slab, obtains the basis for improving the bearing performance of UHPC box girder bridge face slab, and studies the variation law of effective load distribution width of bridge deck slab in the middle section of bridge deck under bidirectional loading mode. To form a reference for further theoretical analysis. The results show that through the application of high performance material and the change of bridge deck supporting system, UHPC thin-walled box girder with dense transverse diaphragm extends the linear elastic working interval of bridge deck under local load of 5.5 times of designed wheel. The bridge deck is still in the stage of linear elastic force under test conditions, and compared with the traditional non-dense diaphragm construction box girder bridge panel, the dense transverse partition plate construction box girder bridge face belongs to the two-way force transfer component, the unidirectional bearing specific gravity is reduced, The direction of the main force is changed from the transverse direction of the traditional box girder bridge slab to the longitudinal bridge direction, and the transverse partition plate is arranged intensively along the longitudinal bridge direction, which has a certain constraint on the effective distribution width of the load of the transverse bridge bearing slabs. 2) based on the test and finite element analysis, Based on the principle of equal-generation simply supported span, the longitudinal and transverse load distribution of the model bridge deck under the bidirectional force transfer mode is theoretically analyzed, and the internal forces of the control section are preliminarily calculated. The results show that it is reasonable to calculate the load distribution under the principle of equal-generation simply supported span, and the longitudinal and transverse load distribution ratio of bridge deck under the most unfavorable positive moment condition in linear elastic loading stage, The negative moment control value of bridge deck plate is about 1: 0.64 and 1: 0.53 respectively. The load distribution tends to be uniform, and the control value of negative bending moment of bridge deck plate is the longitudinal moment of the top of the bridge slab at the support of the transverse partition board. The current standard internal force algorithm is used to direct the bridge deck plate. The calculation result of negative moment is close to the measured internal force, but limited to its theoretical source, the calculation result still exists deviation.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446.1

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