上拔水平力组合荷载作用下混凝土扩展基础承载性能试验

Experiments on Bearing Behavior Concrete Spread Foundation under a Combination Action of Uplift and Lateral Loads

介绍了2个相同尺寸混凝土扩展基础分别在上拔、上拔与水平力组合荷载作用下的室内足尺试验概况,并根据加载过程中的基顶荷载位移、基础主柱纵筋应变、扩大端钢筋和混凝土应变等试验数据,分析了2种荷载工况下混凝土扩展基础的承载变形特性及混凝土裂缝发展规律。结果表明:①上拔和水平力组合荷载作用下,基础上拔荷载位移曲线呈现出两阶段特性,而水平位移曲线随水平力增加近似呈线性增加,水平荷载降低了扩展基础的抗拔承载性能;②上拔和水平力组合荷载作用下,基础主柱横截面部分受拉、部分承压,在基础立柱与底板连接处的拉应力最大,混凝土裂缝未贯穿全截面,而在上拔荷载作用下,混凝土扩展基础主柱全断面受拉,裂缝贯穿全断面。

The full-scale indoor test of two spread foundation with same dimensions was carried out separately under uplift alone and uplift combined with horizontal loads in order to observe their bearing capacity and crack expansion regularity. The load displacement of foundation top plane, strain of reinforcing bars and concrete were measured and analyzed. The results show that the uplift load-displacement performance of foundations almost followed the same two-phase pattern in two kinds of load cases. However, under a combination of uplift and lateral load, the lateral displacement linearly increased with the horizontal load. And the lateral load reduces the uplift bearing capacity. The cross-section of the foundation is partially in tensile and partially in compressive stress state respectively. The crack do not break through the whole section. And the maximum tension stress is in the intersection of the foundation pillar and slab. The crack break through the whole section when the foundation is subjected to uplift load only.