跨中集中荷载下两跨UPC矩形截面连续梁塑性铰性能  

Performance of plastic hinge in a two-span continuous rectangular cross-section beam prestressed with unbonded tendons under concentrated load at mid span

作　　者：王英[1] 周威[1] 郑文忠[1] 

机构地区：[1]哈尔滨工业大学,黑龙江哈尔滨150090

出　　处：《土木工程学报》2008年第5期26-32,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(50178026);教育部新世纪优秀人才支持计划项目(教科司[2005]290号)

摘　　要：无黏结预应力混凝土(UPC)连续梁在肋梁楼盖中得到了较为广泛的应用,目前国内外对无黏结预应力混凝土连续梁内力重分布的研究相对较少。为此,以两跨连续梁内支座控制截面综合配筋指标、张拉控制系数、内支座控制截面预应力度、跨高比及跨中与内支座控制截面综合配筋指标比为主要参数,开展了16根两跨无黏结预应力混凝土矩形截面连续梁试验。介绍了试验梁设计、试验方案、试验现象及试验梁达到正截面承载能力极限状态标志的选取。集中报道了两跨无黏结预应力混凝土矩形截面连续梁内支座塑性铰形成与发展情况,提出了与加载形式相对应的内支座等效塑性铰区长度及塑性铰的塑性转角计算公式,为以相对塑性转角为自变量的弯矩调幅系数提供了基础性素材。It is common to use continuous unbonded prestressed concrete（UPC）beams for the one-way concrete floors systems. Fewer studies have been made on the redistribution of internal forces in unbonded prestressed concrete continuous beams. Experiments on sixteen two-span rectangular cross-section concrete beams prestressed with unbonded tendons are reported here, in which the global reinforcement index in critical section above inner support, tensioning control coefficient, prestressing degree in critical section, the span to section depth ratio, and the ratios of global reinforcement indices at critical sections of mid-span and over inner support locations are the main testing parameters. Design of testing beams, test scheme, phenomena and determination of normal section load-bearing capacity are presented. The emphasis is placed on the appearance and development of plastic hinges above inner support in continuous rectangular cross-section concrete beams prestressed with unbonded tendons. Formula is proposed for calculating the equivalent length of plastic zone above inner support in correspondence with load type. The results may serve as a basis for moment modulation coefficient with relative plastic rotation as the independent variable.

关 键 词：无黏结 预应力混凝土 连续梁 等效塑性铰区长度 塑性转角 

分 类 号：TU378.1[建筑科学—结构工程]