FRP约束SRHC压弯构件正截面承载力计算

综合考虑钢骨混凝土柱的受力特性,提出一种在不增加构件截面尺寸的情况下,既提高其承载能力,又增加其抗剪能力和抗震延性的一种新型柱模式——FRP(纤维增强复合材料)与SRHC(钢骨高强混凝土)组合柱.在混凝土内部埋设型钢,形成SRHC柱,在进行施工的同时或待结构主体施工至一定高度后,再用FRP布横向包裹及纵向粘贴SRHC柱,形成FRP-SRHC组合柱.考虑到FRP钢骨混凝土柱多数是处于偏心受压状态,因此,分析环向FRP布对核心混凝土的约束作用及纵向FRP布对钢骨混凝土柱正截面承载力的贡献,确定FRP约束SRHC组合柱的界限相对受压区高度,分别给出FRP约束SRHC柱大(小)偏心受压柱的承载力计算公式.

Experiment on Qinghai-Tibet railroad subgrade temperature monitoring based on FBG sensors

Qinghai-Tibet Railway is the longest and highest plateau railway in the world. A long term monitoring system of the stability of the subgrade in the permafrost regions should be put forward immediately to prevent damage to the railway. As it's very difficult to set up the long-distance automatic monitoring system which contains a lot of measure points along the 550 kilometers railway in the permafrost area, we present a subgrade temperature monitor system based on fiber Bragg grating (FBG). In this paper the principles of the FBG was presented, and the feasibility of the FBG sensors in the permafrost area of Qinghai-Tibet plateau was analysized. We embedded fifteen FBG temperature sensors and thermal resistance temperature sensors. A contrast experiment is made while the two kinds of sensors are arranged in the same position. The result of the experiment shows that the accuracy of the FBG temperature sensors is less than 0.1 degrees C. and the FBG sensors can do well in the measurement of pattern which the temperature varies with the depth of the permafrost soil. The result also shows the stability of the FBG sensors in the bad environmental condition of Qinghai-Tibet plateau, which proves the feasibility of the application of FBG sensors and our monitoring system on the Qinghai-Tibet railway.