高性能预应力混凝土空心板梁系列优化设计研究

在前期实验室单板受力性能试验和2座试验桥工程建设成功经验基础上,进行了跨度13～25m、宽度1 2m、采用C80高强混凝土和1860级高强低松弛预应力钢绞线的新型双拱门式断面(空心率为45%～64%)预应力混凝土空心板梁系列优化设计。与普通强度等级预应力混凝土空心板梁进行的对比分析结果表明,高性能预应力混凝土空心板梁具有明显的技术经济效益,并可由原材料消耗的减少和路基高度的降低带来环境保护方面的社会效益,具有较好的工程推广应用价值。     

Numerical Simulation on Thermal Stress of Large-scale Bearing Roller during Heating Process of Final Heat Treatment

IntroductionThetemPeratUredifferencebforeentheinsideandoutsideofthelnye-scaleforgingworkPieceislmpewhenheatedbecauseofitsbigcross-seCtion.ThelereetCmPerforedffeencewillgeneratethermalstrCss.IfthethemalstressislargeenOugh,theforsingworkPiecewil1crack.Howtodesigntheheatingtechnology,controltheheatingProcess,avoidtheoverlargethemalstresscausingcrackisanimPortatPToblemfortheheattreWntofthelarge-scalefOrgingworkPiecel'].InthispaPeqthethermalstressevolvingProcessofthe70Cr3Mobearingrollerdur…     

高墩大跨连续刚构施工监控控制技术分析

文章结合朝阳寺特大桥连续刚构工程施工监控实践,介绍了高墩大跨连续刚构桥箱梁施工监控控制技术的应用方法,并分析了该种监控技术的优势,为同类型桥梁施工监控提供参考。     

斜拉桥索塔施工过程的模拟分析

文章以神农溪斜拉桥索塔为研究对象,运用有限元分析软件Midas／civil建立索塔的空间模型,对索塔有临时支撑和无临时支撑两种施工方式进行模拟分析,结果表明：在索塔斜塔柱施工过程中添加临时支撑钢管减小了斜塔柱的应力,优化了索塔的应力状态。     

600t起重船结构强度有限元分析

本文建立了某起重船起重结构的有限元模型。通过有限元计算,在其建造和结构强度测试之前,初步核算其结构的强度能否满足作业的要求,为结构设计提供参考。本文介绍的计算,可供起重船设计人员在设计起重船结构时参考使用。     

堆载预压处理吹填砂软土地基的固结度分析

固结度是评价大面积吹填砂软土地基处理效果的一个重要指标。文章结合珠江某港口大面积吹砂与排水板堆载预压联合地基处理工程实践,从应变与应力两个方面分析了固结度的计算方法以及存在的问题,为类似工程中的固结度计算提供参考。     

Hoop stress approximation in offshore design codes

For a circular cylindrical vessel with an elastic material, Lame equations can accurately predict hoop stress variation within the vessel wall. However, because of the complexity involved in Lame formulations they are seldom used in design. In this paper, Lame equations are reproduced in terms of vessel outer and material cross-sectional areas and presented in a very simple format that enables hoop stress calculation without use of any approximation. Lame equations are also presented in terms of diameter-to-wall-thickness ratios in order to perform parametric studies. For a practical range of diameter-to-wall-thickness ratios the Lame hoop stress predictions are compared with approximate solutions of a selected design codes. For a range of loading conditions, comparison of results shows that a number of design codes overestimate the hoop stress. In contrast, a selection of offshore codes is shown to underestimate the hoop stress and, for a certain loading condition some codes ignore the hoop stress effect completely. The present paper also shows how the hoop stress approximation may lead to onerous results when the true wall axial stress is derived based on design code hoop stress formulations. It is concluded that what makes the present hoop stress formulations so important in design is their ability to interpret the mechanics of behavior that Lame equations strived to reveal.     

中央自动充放气铜管开裂失效分析

通过对中央充放气铜管宏观检查、化学成分分析、硬度测试、氨熏试验等结果分析,确定了其开裂原因是由于工件冷变形后未消除残余应力,加之装配后产生的应力,在露天放置又受到大气雨水等共同作用,形成了腐蚀环境,导致产生应力腐蚀裂纹。并提出了去应力退火预防中央充放气铜管开裂,效果良好。     

虚拟支撑力法数值模拟技术的应用

文章结合湖南雪峰山特长公路隧道的工程实践,根据隧道开挖过程中地应力随施工工序逐步释放的真实过程,基于有限元计算程序,运用“施加虚拟支撑力法”进行适当的开发,对隧道开挖过程进行数值模拟研究,获得了对隧道围岩应力形变场一种快捷准确的认识思路,不仅能更好的符合工程实际,也为隧道开挖过程的数值模拟研究提供了一种思路和方法。