南京长江公铁大桥三维扰动对混凝土力学性能的影响
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摘要
南京长江公铁大桥封闭修缮前,在铁路线运营时对混凝土浇筑部位的扰动信息进行了采集与分析,获取了不同方位的振幅与频率。利用振筛试验机模拟浇筑部位的三维扰动,设计并研究了不同扰动制度对混凝土力学性能的影响。结果表明,初凝后1 h起振及持续振动的混凝土试块受扰动后损伤最为严重,抗压强度最大降低幅度为25%左右,抗折强度几乎降为零;初凝前1 h起振的混凝土受扰动之后,试块表面剥落严重,均匀性降低导致强度下降15%左右。
Before the closure and repair of Nanjing Chang Jiang Railway Bridge,the vibration information at concrete placement under railway operating is gathered and analyzed,then amplitude and frequency in different directions are obtained. Tthe influence of different 3D vibration systems on the strength of concrete is studied, based on the shaker tester.Results show that the damage of concrete at 3D vibration systems, start vibrating one hour after initial set and continuous vibrating, are the most serious. The reduction of compressive strength is about 25%, while the flexural strength is almost zero. The reductions of strength of concretes at 3D vibration systems which start vibrating at and before initial set are about 15%,while the surface of the test concretes are seriously peeled off.
Before the closure and repair of Nanjing Chang Jiang Railway Bridge,the vibration information at concrete placement under railway operating is gathered and analyzed,then amplitude and frequency in different directions are obtained. Tthe influence of different 3D vibration systems on the strength of concrete is studied, based on the shaker tester.Results show that the damage of concrete at 3D vibration systems, start vibrating one hour after initial set and continuous vibrating, are the most serious. The reduction of compressive strength is about 25%, while the flexural strength is almost zero. The reductions of strength of concretes at 3D vibration systems which start vibrating at and before initial set are about 15%,while the surface of the test concretes are seriously peeled off.
引文
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[5]蔡燕娟.灌浆法在桥梁修复加固中的应用与案例分析[J].城市道桥与防洪,2016(4):32-134,14.
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