用ANSYS对连续刚构桥进行优化研究

深入研究了 ANSYS 软件的优化功能模块,并以某大跨连续刚构桥为研究对象,提出了通过分节段优化进而达到全桥沿纵向优化的思路。在保证刚度和强度的条件下,通过对双肢薄壁墩壁厚的优化,使桥梁总重量减少了5.7%;通过对箱梁各部分厚度的优化,使得桥梁的总重量减少了2.5%。说明桥梁设计时优选腹板顶、底板的合理比例是必要的,适当减小双薄壁墩的壁厚是切实可行的,可提高结构性能,减少工程造价。     

Required and available moment redistribution of continuous steel-concrete composite beams

Based on the ultimate limit state analysis, the required moment redistribution to enable full plastic mechanism for continuous composite beams is derived. The composite beams studied are continuous over the internal support and with a uniform section along the beams which are one of the conventional steel structural forms in Chinese construction practice for buildings and medium span bridges. It is illustrated that the required moment redistribution for the beam increases as the ratio of negative to positive moment resistance reduces, but decreases as the span difference, or the difference of load in the two spans increases. A method to assess the available moment redistribution based on the rotation capacity at the notional plastic hinges of a composite beam is developed. The potential moment redistribution in a continuous composite beam is also assessed when the available rotation capacity at the notional hinge fails to satisfy the required capacity capable of a plastic design. For a continuous composite beam to develop full plastic design, the available moment redistribution for the beam should be greater than or at least equal to the moment redistribution required, hence the full moment redistribution from the hogging region to the sagging region in the beam is capable. The derived available moment redistributions agree with the test results and computer simulations, but in a general lower bound of the strength capacity. An example is given and the results are compared with that based on the moment redistribution proposed in the present Chinese design code for steel-concrete composite beams. The present study provide a design approach to assess the load carrying capacity for a continuous composite beam based on the available moment redistribution capable depending on the rotation capacity or the force ratio etc rather than a fixed value of moment redistribution proposed, so that in most cases, an economic design is capable.     

双层矮斜拉空腹连续箱梁结构研究

本文以双层矮斜拉连续箱梁桥为研究对象,进行桥型的拟实用设计。利用大型通用有限元软件ANSYS建立结构分析空间模型,分析得到其在恒载作用下各控制截面的应力分布规律。对所设计的桥梁结构型式进行缩尺有机玻璃模型试验,验证了理论分析的可靠性。研究结果为进一步的结构分析和工程设计提供分析方法与理论依据。     

观音沙大桥桩基等效模拟计算

通过对带桩基础连续刚构桥的整体分析,基于m法并考虑桩土共同作用,介绍了三种桩基模拟方法,并运用到观音沙大桥实际设计工程中,取得了良好的效果。     

10 kV 变配电所高压系统设计中 MOA 避雷器的选型

分析民用10 kV 变配电系统中的过电压保护,对无间隙氧化锌避雷器的保护原理、设置原则、参数选择进行阐述。以10 kV 小电阻接地系统与经消弧线圈接地系统的避雷器选择为例,阐述避雷器参数的选型。     

煤油气相干燥设备在工程设计中的技术要求及其在变压器制造业中的应用

通过对煤油气相干燥设备原理的介绍,阐述了其在工程设计中的技术要求及其在变压器制造业中的应用。     

箱梁大吨位预应力的锚端应力分析

本文以三滩黄河连续刚构件大桥为例 ,比较系统地进行了张拉力为 371 0 7kN锚固区的应力分析。通过对 0 # 、1 1 # 块在纵向预应力 ( 1 91 5j1 5 2 4mm)作用下的大量三维有限元分析 ,研究了混凝土表面与纵向的应力变化规律、局部承压强度及抗裂性能     

福建泉州“生态连绵带”项目实施的 评估及优化策略

泉州“生态连绵带”规划建设作为一种新的生态网 络空间形式出现，虽然已经在生态空间连续、居民日常可达、 功能构成复合、景观形式优美、经济效益显著等方面取得一定 的成效，但仍然存在较多可以优化提升的空间。为更好地开展 “生态连绵带”项目实施，通过深入调查研究，并运用AHP 分析法和李克特量表双重科学的评估体系，对已完成的若干泉 州“生态连绵带”示范项目加以评估，确定出示范项目中规划 建设效果最佳的项目，再从其生态保护修复、园林景观营造、 可持续发展理念及历史文化展示等方面的关键技术和难点重点 进行研究分析，为泉州“生态连绵带”后续规划建设提供理论 依据与技术支撑。     

Ultimate strength of continuous composite box-girder bridges with precast decks

In order to apply precast decks to continuous composite bridges, several experiments and analytical studies were performed. From many previous studies, design criteria for crack controls in transverse joints of prefabricated slabs were confirmed. These considerations were needed for serviceability. The bridges which satisfy service limit states, also, should be evaluated for ultimate strengths to define limit states. In this paper, experimental and analytical studies of two-span continuous composite bridges with open box girder section were conducted. Cracking, yielding and ultimate loads were evaluated and compared with the test results for design of continuous composite bridges with precast decks. To evaluate yielding loads of continuous bridges, an uncracked section method considering moment redistribution which is defined in EUROCODE 4, was considered. In calculation of ultimate strengths, full or partial shear connection and sectional classes which were defined in EUROCODE or AASHTO LRFD specifications were considered. Also, through numerical analysis considering material nonlinearities, moment-curvature relationship and moment redistributions were estimated.     

无梁板桥的结构分析及尺寸优化

介绍了无梁板桥的特点以及其结构分析中的数值方法与优化方法。在一定跨度范围内,与梁桥的相比,无梁板桥具有更多的优点。着重对无梁板桥设计中的主要结构尺寸采用正交试验优化法进行了探讨并得出设计中各结构尺寸间合理的相互关系。