| 引用本文: | 郑文忠,侯晓萌,陈伟宏.火灾后预应力混凝土简支板力学性能试验[J].哈尔滨工业大学学报,2011,43(2):8.DOI:10.11918/j.issn.0367-6234.2011.02.002 |
| ZHENG Wen-zhong,HOU Xiao-meng,CHEN Wei-hong.Experiment and analysis on mechanical performance of prestressed concrete simply-supported slab after elevated temperature[J].Journal of Harbin Institute of Technology,2011,43(2):8.DOI:10.11918/j.issn.0367-6234.2011.02.002 |
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| 摘要: |
| 为了研究火灾后预应力混凝土板的承载力、变形和板中预应力筋有效应力的退化规律,进行了13块无粘结和1块有粘结预应力混凝土单向简支板火灾后力学性能试验.根据火灾下温度场分布沿板厚方向将截面分条带,引入火灾后钢筋、混凝土本构关系,基于截面轴力、弯矩平衡,获得了火灾下预应力混凝土板任意截面的弯矩-曲率关系全曲线,进而对截面曲率积分可求得简支板的变形.试验结果表明:初始有效应力越高、受火时间越长,火灾后预应力损失越大;保护层厚度越小、受火时间越长、荷载水平越大,火灾后板承载力降低幅度越大;相同条件下,火灾后有粘结板预应力混凝土板承载力降低幅度较无粘结预应力混凝土板大.根据试验结果拟合出火灾后无粘结预应力混凝土简支板中无粘结筋剩余应力、极限应力的计算公式,提出了火灾后预应力混凝土板正截面承载力计算公式. |
| 关键词: 预应力混凝土简支板 火灾后 钢丝应力 承载力 变形 |
| DOI：10.11918/j.issn.0367-6234.2011.02.002 |
| 分类号:TU378.5 |
| 基金项目:长江学者特聘教授奖励计划(2009-37);黑龙江自然科学基金资助项目(E201037) |
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| Experiment and analysis on mechanical performance of prestressed concrete simply-supported slab after elevated temperature |
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ZHENG Wen-zhong, HOU Xiao-meng, CHEN Wei-hong
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School of Civil Engineering,Harbin Institute of Technology,150090 Harbin,China
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| Abstract: |
| To research the load-bearing capacity,deflection and effective prestress in steel wire of prestressed concrete(PC) slabs after elevated temperature,experiments on mechanical performance of thirteen unbonded and one bonded PC simply-supported slab after elevated temperature were completed.The section of the slab was divided into strips along its depth according to the distribution of temperature field,and the strain-stress relationship of concrete and steel after elevated temperature were introduced,and then the moment-curve of the PC slab was obtained based on equilibrium equations of force and moment on slab section,therefore,the deflection of slab could be obtained by curve integral of section.The experimental results show that: the prestress losses in stress wire in the PC slab after elevated temperature increases with the rise of the effective prestress at ambient temperature and the heating time.The rate of load-bearing capacity degradation of the PC slab increases with the rise of heating time and load level and the decrease of concrete cover.The rate of load-bearing capacity degradation of bonded PC slab after elevated temperature is larger than that of the unbonded PC slab in the same condition.The residual stress and ultimate stress in unbonded stress wire in the PC slab were obtained by fitting curve of experimental data,and the calculation method for normal section load-bearing capacity of the PC slab was established. |
| Key words: prestressed concrete simply-supported slab after elevated temperature stress in steel wire load-bearing capacity deflection |
