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利用预应力次梁等效荷载对边主梁的有利影响,降低非预应力边主梁扭矩,并对多段预应力布筋形式产生的多段等效荷载进行了改进,利用实用等效荷载方法把多段均布荷载转化为满跨均布荷载,从而方便了楼盖结构的设计。 相似文献
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单跨预应力次梁结构的边主梁扭矩实用计算研究 总被引:1,自引:0,他引:1
利用预应力次梁等效荷载对边主梁的有利影响,降低非预应力边主梁扭矩,并对多段预应力布筋形式产生的多段等效荷载进行了改进,利用实用等效荷载方法,把多段均布荷载转化为满跨均布荷载,从而方便了预应力混凝土的设计. 相似文献
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大跨度预应力次梁对主梁产生的扭矩与结构施工顺序有关。对武汉国际会展中心主楼32.0m×17.0m跨构成的双向正交部分预应力混凝土梁进行各个施工阶段的内力计算,表明主梁的抗扭设计不能简单地对主梁的扭矩乘以扭矩折减系数后进行配筋,而应先计算次梁在每个施工阶段对主梁产生的扭矩,然后进行叠加。同时也提出主梁所施加的预压力Np0对主梁抗扭是有利的,在设计中可考虑这一有利因素。 相似文献
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1 现 象现浇钢筋砼单向板肋梁楼盖 ,有时在板面出现裂缝。裂缝位置在主、次梁附近 ,方向与主、次梁平行 ,尤以边跨板面裂缝更为突出 (见图 )。2 原因分析现浇钢筋砼单向板肋梁楼盖板面出现图示裂缝 ,与主要梁肋处板面附加钢筋的配置、次梁处板面负筋的保护层厚度和有效高度有关 ,分析如下 :( 1 )主梁附近板面裂缝的产生原因单向板工作时承受竖向荷载 ,靠近主梁肋附近的板面荷载将直接传递给主梁而引起负弯矩 ,这样将引起板与主梁相接的板面产生裂缝。在单向板计算中 ,沿板长方向的荷载 (即传递给主梁的荷载 )是略去不计的。为防止出现上… 相似文献
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本文通过工程实例,分析了次梁作用于主梁上的扭矩引起主梁抗剪扭箍超筋的问题;并提出了对此类问题的处理方法。 相似文献
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《结构工程师》2021,(3)
针对预应力混凝土曲线梁桥空间受力问题,基于曲线梁预应力等效荷载理论,采用Visual C++编写了相应的预应力混凝土曲线梁桥等效荷载计算程序。采用该程序进行了简支曲线梁预应力等效荷载效应计算,并将计算结果与实体力筋模拟结果进行了比较;以某三跨预应力混凝土曲线连续梁桥为例进行了曲线连续梁桥预应力效应分析与优化研究。结果表明:基于预应力等效荷载理论编写的曲线梁桥预应力等效荷载计算程序可准确分析曲线梁预应力效应;预应力混凝土曲线梁桥关键截面内力及位移响应绝对值总体上随曲率半径的增加而减小,当曲率半径超过200 m时,变化趋势趋缓。采用预应力钢束合力重心线布置预应力钢束可有效改善曲线梁主梁扭转角及扭矩沿跨径方向分布;设置中支座预偏心距对承载能力极限状态作用下曲线梁主梁扭转角及扭矩沿跨径方向的分布具有一定的改善作用,而对预应力作用下主梁扭转角和扭转沿跨向分布改善不明显。 相似文献
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M. L. Bullen 《Fire Technology》1977,13(1):21-34
A study has been made of the effect of sprinkler sprays on hot buoyant smoke layers with particular reference to covered shopping
malls. 相似文献
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简要介绍了某酒店综合楼加固改造的抗震评价,通过相应的加固措施,使得加固后的结构能满足规范的抗震要求,提出在做改造方案时,应预先估算,以免给结构带来安全隐患,为同类结构的改造加固提供了参考. 相似文献
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ABSTRACTThis paper explores the dynamics between social innovations and socio-spatial transformations using practice theory as linking pin. Social innovations, such as the case study of a meal sharing platform here presented, are considered as proposals. Using social practice theory as a theoretical lens enables us to explain how the principles of the proposal’s design are moderated and appropriated by its users. Consequently, familiar routinized practices expand, becoming more complex and hybrid. It is in the performance of the practice that this complexity is revealed. Specific focus is on the socio-spatial transformations that social innovations propose. This paper shows how tactics of appropriation can result in trespassing the boundaries between private and public, and between domestic and communitarian space. This way, we connect social innovations to DIY-urbanism, showing how citizens appropriate urban space. 相似文献
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The National Institute for Occupational Safety and Health (NIOSH) Division of Surveillance, Hazard Evaluations and Field Studies (DSHEFS) conducts investigations of health hazards in the workplace under the NIOSH Health Hazard Evaluation (HHE) program. In September 1990, the International Association of Fire Fighters (IAFF) requested that NIOSH assess the health and safety practices used by fire personnel during a brush fire on September 6, 1990, in Sedgwick County, Kansas. A 25-year-old fire fighter died of heat stroke at the scene.The NIOSH site visit to Sedgwick County, Kansas included a tour of the fire scene, personal interviews with 25 fire fighters and support personnel, and a review of incident reports, incident command procedures and other documents. NIOSH investigators concluded that a preventable series of events preceded the fire fighter's death. Recommendations were made for incident command and safety procedures, as well as medical monitoring, rehabilitation of fire fighters at fire scenes, and rehydration schedules. 相似文献