Fatigue Behavior and Retrofit Investigation of Distortion-Induced Web Gap Cracking

This paper studies a Kansas Department of Transportation welded plate girder bridge that developed fatigue cracks at small web gaps close to the girder top flange. Repair had been previously performed by softening the connection plate end with a slot retrofit, but cracks were recently found to have reinitiated at some of the repaired details and are again propagating. A comprehensive finite-element method study was performed to investigate the cracking behavior observed in the bridge and to recommend appropriate measures for future bridge retrofit. The analytical results show that stresses developed at the top flange web gaps could exceed yielding under the loading of an HS15 fatigue truck. The current slot repair used in the bridge was found to have introduced higher magnitude fatigue stresses in the web gap. To achieve a permanent repair of the bridge, it is recommended that a welded connection plate to flange attachment be used during future bridge retrofit. The web gap details should be able to withstand unlimited number of load cycles once this additional repair is performed.     

Issues in nonlinear stochastic grey box identification

Grey box identification refers to the practice of identifying dynamical systems in model structures exploiting partial prior information. This contribution reviews a method for stochastic grey box identification and surveys experiences and lessons of applying it to a number of industrial processes. Issues to be addressed include advantages and costs of introducing stochastics into the model, the question of what contribution must be expected from the model designer as opposed to what can be formalized in computer algorithms, and an outlook on future plans to resolve present shortcomings.     

具多件内装物的瓦楞纸箱尺寸优化设计

跳出传统的设计思路，提出装多件内装物的瓦楞纸箱尺寸优化设计方法，建立优化设计模型，编写程序用于生产，节省纸用量，降低成本。     

百万吨级乙烯冷箱的设计

分析了百万吨级乙烯冷箱的设计难点和采取的对策，介绍杭氧设计、制造的乙烯冷箱的技术参数和设计方案，与国外公司设计方案的比较，说明杭氧乙烯冷箱的设计、制造技术与世界先进水平的差距大大缩小。     

加氢反应器内构件—急冷箱的试验研究

急冷箱是加氢反应器的重要内件。洛阳石化工程公司设备研究所在认真分析UOP急冷箱的基础上,对其结构进行了改进,开发出了新型急冷箱(已获专利)。经过流体力学、传质、传热性能对比试验、分析,新型急冷箱结构性能优良。     

VOD在有线电视网的实现

从视频点播系统的结构及组成和在有线电视网络中VOD系统的结构模式与应用两个方面，详细地阐述了如何利用有线电视网络实现视频点播，主要从以下3个方面介绍关于视频点播系统VOD技术：①视频点播VOD的技术原理；②视频点播系统的结构及组成；③有线电视视频点播系统的结构模式与应用。     

预应力混凝土箱梁主要裂缝成因和防治措施的探讨

预应力混凝土连续箱梁的裂缝问题一直以来倍受桥梁界专家及技术人员的关注。本文通过对预应力混凝土连续箱梁主要裂缝产生的原因进行了浅析，并提出了相应的防治的措施。     

加氢裂化反应器新型冷氢箱的研究与工程设计

报道了加氢加化反应器新型旋流式冷氢箱的研究设计及实用效果，催化剂床层径向温差不大于5℃。     

钢筋混凝土连续曲线箱梁设计探索

以上海市沪闵路高架道路二期工程SW匝道曲线箱梁设计为例 ,对曲线梁的内力特点及调整方法作了初步探索。     

Bridge design with reserve and residual reliability constraints

System reliability is evolving as an important design method for selecting components and topology. It should be used to investigate the original intact structure behavior as well as providing sufficient reserve capacity under likely accident and damage scenarios. Highway bridges are an area of special concern since effort to optimize the cost of construction may not provide adequate redundant capacity. The paper describes an example in which a typical girder bridge structure is optimized (both size and girder spacing) to achieve target system performance. System reliability constraints are imposed on the behavior of the intact structure under highway loads. Also, residual system reliability constraints are imposed to control safety under specified accident scenarios corresponding to damage and “lost” members due to corrosion, fatigue, fire or accidental collisions. An optimal design framework for controlling safety under all these life cycle situations is thus provided.