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Development of Performance Based Fire Resistant Design the Prestressed Concrete Members

预应力混凝土构件性能化防火设计的发展

基本信息

批准号：
18560547
负责人：
NISHIYAMA Minehiro
金额：
$ 2.53万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560547/
关键词：
Fire Resistant Design Prestressed Concrete Prestressing Steel Green under High Temperature Concrete Beam ストランド高強度コンクリート

项目摘要

The objective of this study is to collect fundamental experimental data for developing a performance-based fire resistant design of prestressed concrete members.Tensile tests on 7-wire strands of 12.7mm in nominal diameter at elevated temperature were carried out and stress-strain relationships were obtained. The specified temperatures were room temperature of 20 degrees Celsius, and every 100 degrees till 600 degrees Celsius. Observed tensile strength reduction ratios which are defined as a ratio of tensile strength at a certain temperature to that at the room temperature was compared with those for prestressing bars, experimentally obtained in the previous year The comparison revealed that the reduction ratio of the strands was 20% larger than that of the prestressing bars. The difference can be attributed to the composites which were generated during their productions: strands have marlin and prestressing bars have martensite.In the second year of the project creep strain of prestre … More ssing bars at elevated temperature was investigated. SBPR1080/1230 prestressing bars of 13mm in diameter were used for the knowing two tests. After they were heated to a specified temperature the bars were subjected to a constant tensile stress. In the other tests after they were loaded to a specified stress, which was kept constant during the tests the bars were heated to a specified temperature. The temperature was up to 300 degree Celsius. Creep strain-time relationships were idealized in terms of the temperature.Three prestressed concrete beams were constructed and tested under service load and high temperature. The beams were heated following the temperature time relation specified in ISO834. The heat duration which was assigned to each beam was 30, 60 minutes or to failure which was defined by the deflection and deflection velocity at the center of the beam. The failure occurred at 209 minutes. The beams were found to have fire resistant capacity according to the concrete cover thickness. The beams which were heated 30 and 60 minutes were loaded to failure a few months after fire resistant tests. The residual load carrying capacities and stiffness were investigated. Less

为建立基于性能的预应力混凝土构件抗火设计提供基础试验数据，进行了公称直径为12.7 mm的7股钢绞线的高温拉伸试验，得到了应力-应变关系。规定的温度是室温20摄氏度，每100摄氏度到600摄氏度。将观测到的抗拉强度折减率(某一温度下的抗拉强度与室温下的抗拉强度之比)与前一年试验获得的预应力钢筋的抗拉强度折减率进行了比较，结果表明，钢绞线的折减率比预应力钢筋的折减率大20%。这种差异可以归因于在生产过程中产生的复合材料：钢绞线有马林氏组织，预应力钢筋有马氏体。在项目的第二年，Prestre…蠕变应变对更多的高温钢筋进行了研究。试验采用直径为13 mm的SBPR1080/1230预应力筋。在它们被加热到指定的温度后，这些棒材受到恒定的拉应力。在其他测试中，在加载到指定的应力后，棒材被加热到指定的温度，该应力在测试期间保持不变。气温高达300摄氏度。将徐变应变-时间关系理想化为温度，并进行了3根预应力混凝土梁在使用荷载和高温下的试验。按照ISO834中规定的温度时间关系对梁进行加热。分配给每根梁的热持续时间为30到60分钟，或者是由梁中心的挠度和挠曲速度定义的失效。故障发生在209分钟。根据混凝土保护层的厚度，发现梁具有耐火能力。这些梁被加热30分钟和60分钟，在耐火测试几个月后加载到失效。对其剩余承载能力和刚度进行了研究。较少