梁侧锚固钢板加固火后混凝土梁受弯试验研究

Experimental Study on Flexural Performance of Fire damaged RC Beams Strengthened by Bolted Side plating

摘要:

按照ISO834国际标准升温曲线对6根钢筋混凝土梁进行受火试验, 并用梁侧锚固钢板法对其中5根受损梁进行加固, 然后进行四点弯曲试验. 分析了锚栓间距、角钢加劲肋、梁侧钢板的高度与厚度等因素对加固梁受弯承载力、刚度及延性的影响. 结果表明：火灾后受损梁采用梁侧锚固钢板加固后, 峰值荷载和刚度均得到显著提高, 但其延性变化各异; 受弯性能的加固效果随钢板厚度增大及锚栓间距减小而增强, 而角钢加劲肋可有效限制钢板屈曲. 通过限制钢板与混凝土连接界面上的相对滑移以及梁侧钢板的屈曲, 可显著提高钢板与混凝土梁之间协同工作的程度.

关键词:钢筋混凝土梁; 梁侧锚固钢板; 受弯性能; 延性; 火灾后

Abstract:

Six reinforced concrete (RC) beams were fabricated and exposed to fire in accordance with the international standards ISO834 temperature curve, and five of which were retrofitted employing the bolted sideplating (BSP) technique, then all the specimens were tested under fourpoint bending. The influence of the plate depth and thickness, the bolt spacing, and the arrangement of steelangle stiffeners on the strength, stiffness and ductility of the specimens was investigated. The results indicate that the flexural bearing capacity and the stiffness of all the firedamaged specimens were significantly improved by the BSP technique, but the variation of ductility was highly dependent on the arrangement of strengthening. The strengthening effect increased with the increase of plate thickness and the decrease of bolt spacing, and the local buckling of the bolted steel plates could be restrained effectively by the implementation of the steelangle stiffeners. The degree of partial interaction between the bolted steel plates and the RC beam could be enhanced considerably by limiting the relative slips on the steelconcrete interface and the local buckling of the bolted steel plates.

Key words:reinforced concrete (RC) beam; bolted sideplating; flexural performance; ductility; after fire