约束PEC柱(强轴)抗火性能试验研究

为了研究轴向约束对部分包裹型钢混凝土组合柱(PEC柱)抗火性能的影响，开展了轴向约束PEC柱的抗火性能试验研究和有限元分析.考虑轴压和绕强轴压弯两种受力形式，进行了两根ISO-834标准火灾作用下四面受火轴向约束PEC柱的抗火性能试验.测试了试件截面温度场分布、轴向及侧向变形和耐火极限，观察了试件的破坏过程.试验结果表明：施加柱端弯矩的约束PEC柱侧向变形速率大，其破坏形态与轴压约束柱明显不同，为绕强轴的弯曲破坏；相同荷载比下有柱端弯矩的约束PEC柱耐火极限比轴压约束柱略长，总体而言两者的耐火极限均较短.有限元分析结果与试验结果吻合较好，具有较高的精度，可用于进一步的参数分析.
To study the axial constraint effect on fire resistance of partially encased concrete column (PEC column), an experimental study and a numerical simulation were carried out. Two unprotected PEC columns were tested under ISO-834 standard fire. The two columns were bent in strong axis subjected to axial load and eccentrically compression load, respectively. The distribution of temperature field on the cross-sections, axial and lateral deformations, fire resistance, and failure modes of the specimens were recorded and presented. The test results show that the restrained column applied end moment exhibits higher lateral deformation rate than that of the axially loaded column, and the failure modes are obviously different. The fire resistance of the restrained column applied with end column is higher than that of the axially loaded column under the same load ratio. Generally, fire resistance limits of the two PEC columns are all short. Moreover, a comparison between numerical analysis and test results shows good agreement. Therefore, the numerical model provides sufficient accuracy to predict the fire resistance of the restrained PEC columns, which could be used for further parametric analysis.