正弯矩区组合扁梁承载性能分析

Loading capacity of composite slim beam in the sagging moment region

钢-混凝土组合扁梁中的钢梁内嵌于混凝土楼板之中,最大限度地降低了结构的高度,增强了结构的防火能力.作为框架梁使用时,在竖向荷载作用下,跨中处于正弯矩区;水平荷载作用下,梁的一侧为正弯矩,另一侧为负弯矩.因此,明确正弯矩区组合扁梁的受力性能是进行结构分析的基础.对正弯矩区组合扁梁的抗弯刚度和承载力进行了理论分析,并通过简支梁的试验来验证理论分析结果的合理性.研究结果表明,组合扁梁抗弯承载力的理论值和试验值吻合良好,而刚度的理论值较为保守,主要原因是分析中没有考虑预制混凝土板对刚度的贡献.

For steel-concrete composite slim beams, the steel section is encased in concrete slabs, which provide a steel-concrete floor construction with minimum depth and high capability of fire resistance. Under vertical load, the moment at the midspan of framed beams is positive and under horizontal load, the sign of the moment depends on the position of the cross-section. The analysis of the bearing capacity of composite slim beam in the sagging moment region is the basis of structural analysis. The bending capability and flexural stiffness of the composite sections in sagging moment region are investigated theoretically. A simply supported beam is loaded in order to verify the theoretical result. The research shows that theoretical bending capability is well consistent with test results. The theoretical flexural stiffness is well relatively conservative, for ignoring the contribution of the pre-cast concrete slab in the analysis.