矮塔斜拉桥斜拉索张拉工艺对桥梁结构性能的影响研究

为探讨矮塔斜拉桥斜拉索张拉工艺对桥梁结构性能的影响,文章以双塔双索江汉运河特大桥为研究对象,在具体论述斜拉索施工流程及张拉工艺的基础上,通过现场监测技术,综合评价了斜拉索张拉过程中桥梁结构关键构件的受力特点及施工效果。结果表明,合理的斜拉索施工及张拉工艺能有效避免索塔塔柱、混凝土主梁、索塔拉索锚固区出现不利受力状态,进而提升了斜拉桥的服役性能。

基于改进的有限马尔可夫链的桥梁性能退化预测系统

桥梁是交通系统的重要组成部分,对在役桥梁的结构性能进行有效评估和预测能促进桥梁的养护工作。根据实际项目应用情况,提出了一种符合国家行业标准,有效地进行桥梁结构性能评估与退化预测的模型。该模型建立了基于病害影响因素、病害、构件、桥梁与项目的自下向上五个层次的基于优化的有限马尔可夫链的桥梁结构性能退化预测方法,通过实际检测数据说明了该模型的适用性。最后对桥梁检测中得到的所有病害种类进行统计分析,结合病理分析知识库和改进的有限马尔可夫链,发现了现有桥梁的主要病害模式和主要病害因素,并预测桥梁未来的主要病害模式和主要病害因素。

部分斜拉桥静载试验分析

以桥梁设计理论、有限元法分析技术为理论基础,对国内一座部分斜拉桥的静载试验进行了研究。通过实测值与理论值比较分析,结果表明该桥在试验荷载作用下主梁实测最大挠度值、塔顶最大水平位移值、最大索力值和最大应变值均小于理论计算值,在各个工况荷载作用下,实测残余挠度值与残余应变值较小,表明结构具有良好的变形恢复能力,桥梁结构性能良好。本次试验可为同类桥梁结构的设计和检测评估提供有价值的参考。

Application of Non-destructive Testing to Evaluate the Performance of Bridges Structures

Bridges are important elements in road system and can influence the entire economy of cities and region. Usually, these structures have high financial investments for their constructions, in this way, maintenance and conservation become so important. Inspection is a technical activity that covers several operations, including performance analysis; examination; final performance report, other operations may be necessary, such as maintenance work, recovery, strengthening and rehabilitation. Technical examination together with some test methods allows a critical and parametric judgment of the bridge performance by minimizing the subjectivity of visual evaluations, and permits a more detailed diagnosis. This paper discusses the methodology to perform tests to complement the assessment recommended by DNIT （Brazilian National Department of Transport Infrastructure）, which consists only on a visual judgment. This approach provides technical basis to classify the bridges as its need and urgency of maintenance.

Study on the Mechanical Properties of Irregular Curved Steel Box Girder for City Viaduct

This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model of this bridge, calculation and analysis were made on the bridge of the strength, stiffness. It has certain reference value for guiding engineering design, have a good foundation for the mechanical properties and stability of linear and nonlinear further study of curved steel box girder.

Degradation process assessment of prestressed concrete continuous bridges in life-cycle

To accurately evaluate the degradation process of prestressed concrete continuous bridges exposed to aggressive environments in life-cycle,a finite element-based approach with respect to the lifetime performance assessment of concrete bridges was proposed.The existing assessment methods were firstly introduced and compared.Some essential mechanics problems involved in the degradation process,such as the deterioration of materials properties,the reduction of sectional areas and the variation of overall structural performance caused by the first two problems,were investigated and solved.A computer program named CBDAS(Concrete Bridge Durability Analysis System) was written to perform the above-metioned approach.Finally,the degradation process of a prestressed concrete continuous bridge under chloride penetration was discussed.The results show that the concrete normal stress for serviceability limit state exceeds the threshold value after 60 a,but the various performance indicators at ultimate limit state are consistently in the allowable level during service life.Therefore,in the case of prestressed concrete bridges,the serviceability limit state is more possible to have durability problems in life-cycle;however,the performance indicators at ultimate limit state can satisfy the requirements.