The concrete-filled steel tube ( CFST ) arch-bridge has widely engineering application .But cracks will occur be-tween steel tube wall and concrete as time goes on ,which can result in the decrease of bearing capacity of reinforced concrete member.According to the above problem ,this paper developed a optical fiber grating sensor that suitable for concrete -filled steel tube cracks monitoring .Its main structure consists of crack sensitive grating ,temperature compensation grating and elastomer .The experimental data show that the sensitivity of this sensor is 0.5329 nm/mm,while the linear correlation coefficient is up to 0.999, the temperature sensitive coefficient of crack sensitive grating and temperature compensation grating are 0.011nm/℃,hysteresis is 0.725%and repeatability is 1.61%.The sensor performance is good and has highly practical value .%钢管混凝土拱桥得到了较多的应用,但是随着桥梁运营时间增长,钢管混凝土之间会产生裂缝,导致结构的承载能力严重下降.针对上述问题,开发了适用于桥梁钢管混凝土裂缝监测的光纤光栅传感器,其主体结构由裂缝敏感光栅、温补光栅与弹性体组成.实验数据表明:该传感器的裂缝灵敏系数为0.5329 nm/mm,线性拟合系数大于0.999;裂缝敏感光栅与温补光栅的温度灵敏系数均为0.011 nm/℃;该传感器迟滞为0.725%,重复性为1.61%.该传感器性能良好,具有较强的推广应用价值.
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