RTK技术在水下地形测量中的应用--以杭州湾跨海大桥的水下地形为例

以杭州湾跨海大桥的水下地形测量为例，简要介绍了水下地形测量主流技术的基本原理和工作流程以及影响测量精度的两大关键技术：测深和定位同步以及坐标转换，并结合实际的测量数据，重点阐述了如何通过保证测深和定位同步以及坐标转换精度来保证水下地形测量的精度．     

万州长江大桥车桥耦合振动的研究

结合万州长江大桥铁路桥梁的特点．分别建立了车辆的三维离散自由度模型和桥梁的模态模型．通过轮轨作用关系建立了车桥耦合振动的动力模型．并对万州长江大桥的车桥耦合振动进行了研究．分析表明：主梁较柔的大跨度钢桁架桥梁，车辆高速行驶对其动力响应特别是横向动力响应影响显著．     

Reliability-based optimal design using sample average approximations

An algorithm for reliability-based optimal design is developed using sampling techniques for estimating the failure probability. The algorithm applies a new method for sensitivity calculations of the failure probability. Initially, the estimates of the failure probability are coarse. As the algorithm progresses towards an optimal design, the number of sample points is increased in an adaptive way leading to better estimates of the failure probability. The algorithm is proven to converge to an optimal design. The applicability of the algorithm is shown in an example from the area of highway bridge design.     

Fatigue and Strength Performance of Concrete-Filled Steel-Grid Bridge Deck

The present paper reports on the results from a series of full-scale experimental tests carried out on concrete-filled steel-grid bridge deck assemblies. The testing focused on assessing the fatigue performance and ultimate strength response of a full-depth-overfilled concrete-filled steel-grid deck configuration. The results from the experimental testing program described herein are compared with the predicted deck responses as per the current AASHTO provisions contained in the LRFD and 16th edition specifications.     

Replacement of Pontesei Bridge, Italy

Pontesei Dam is a major concrete dam built after World War II across the canyon of Maè Creek (Valle di Zoldo) in the Italian Eastern Alps. Just upstream from the dam, a gully discharges water from steep mountains. The only road serving the dam and the entire valley upstream of the dam runs along the mountainside and crosses the gully. In 1959, an exceptionally rainy season caused a flood, which destroyed the bridge. A temporary Bailey bridge was subsequently built by the army, but in 1990 it was decided to design a new bridge. The main challenges posed to the designer included building the new deck and the abutments underneath the Bailey bridge without disrupting traffic, hoisting the deck just to the bottom of the Bailey bridge, and finally substituting the new deck for the Bailey bridge in one day. Other problems included the instability of the rock mass at the abutments and the gravitative convergence of the two sides of the gully. This paper describes the design, construction, and testing of the bridge replacement and the bridge abutments.     

Performance Comparison of Four Fiber-Reinforced Polymer Deck Panels

In an effort to assess the constructability and performance of bridges with fiber-reinforced polymer (FRP) composite decks, the short-term and long-term responses of a 207 m, five-span bridge retrofitted with four different FRP panel systems were monitored. The overall aspects of the panel systems, connection details, and construction techniques are presented prior to presentation of the observed and measured responses. Key design parameters (impact factors, girder distribution factors, and level of composite action) for FRP and reinforced concrete decks are evaluated. This paper demonstrates that FRP replacement decks are a viable alternative to reinforced concrete decks and identifies the differences in performances of various FRP deck systems. Two of the FRP panel systems were found to perform considerably better than the other deck systems. Issues that may reduce the service life of FRP deck systems are presented and discussed.     

逆磁致伸缩扭矩传感器温度漂移特性研究

温度漂移是影响逆磁致伸缩扭矩传感器灵敏度和测量精度的主要因素之一，为消除温度漂移的影响，设计了一种桥式电路并分析了输出信号的特性。实验表明：当受温度影响时，其输出信号由扭矩分量和温度影响分量组成，每个分量都具有稳定的相位角，通过相位差关系从输出信号中除去温度分量，就可以消除温度的影响。结果表明：传感器的温度漂移得到了很好地控制，在全刻度范围内小于1％／50℃，能够满足扭矩工程测量的要求。     

Fatigue crack sizing in steel bridge decks using ultrasonic guided waves

A baseline-free quantitative sizing methodology utilizing ultrasonic guided waves for fatigue cracks under welded stiffeners in steel bridge decks has been developed. An inverse wavefield extrapolation-based formulation for obtaining the crack reflectivity and depth profile has been presented in the kernel of which, the presence of welded orthogonal stiffeners has been accounted for. Having conducted experiments on a test bridge deck subject to fatigue loading, it has been demonstrated that the crack profile can be estimated from the reflection coefficients obtained. In comparison with the reference measurements, the maximum crack depth estimation error turned out to be about 20%.     

安平桥公园建设策略研究

笔者对安平桥的历史文化和周边环境等现状情况调查摸底,并通过专家咨询、部门座谈会等形式获取有关安平桥公园建设的建议和意见。运用SWOT法和AHP法综合分析影响安平桥公园建设的文物保护、生态质量、文化内涵、景观构造、景观效果、管理机构等不同指标重要性的差异,并根据差异结论总结出安平桥公园建设应以文物和生态保护为主的一系列措施,这些措施可作为安平桥公园建设的参考依据。     

Analysis of a bridge collapsed by an accidental blast loads

Analysis of the structural failure of a bridge caused by an accidental fireworks explosion is presented in this paper. The equivalent mass of TNT due to the fireworks explosion and the structural response of the bridge due to the dynamic load imposed by the explosion are modeled by engineering algorithms and numerical simulations. Analysis confirmed that bridge failure occurred due to the blast load and there was no inherent design defect. The results of this investigation are relevant towards understanding future events wherein a dynamic load might be accidentally applied to fixed structures.