型钢混凝土组合结构承台受力机理分析

Analysis on Stress Mechanism of Steel Reinforced Concrete Composite Structure Base Slab

摘要:

为实现承台轻量化和提升承载能力，提出了一种新型型钢混凝土组合二桩承台。为研究其受力机理，建立了传统钢筋混凝土承台与新型承台的三维非线性有限元模型，比较了两种承台的破坏过程，揭示了新型承台中型钢下弦杆、斜撑杆截面积、承台高度、混凝土强度等对承台初始刚度、极限承载力的影响，并基于拉压杆模型提出了新型承台极限承载力计算方法。结果表明：新型承台破坏模态为剪切破坏；相比于传统承台，相同尺寸的新型承台承载力可提高2.7倍；增加下弦杆截面积与承台高度可显著提升承台的极限承载力，而对刚度影响较小；提出的计算方法与数值模拟结果具有较高的吻合度。

Abstract:

To achieve the lightweight of base slab and enhance its load-bearing capacity, a new type of steel reinforced concrete composite two-pile base slab is proposed. To study its stress mechanism, a three-dimensional nonlinear finite element models are established for both the traditional reinforced concrete base slab and the new base slab to compare the failure process of the two base slabs, and reveal the effects of lower steel chord of new base slab, diagonal member sectional area, base slab height and concrete strength on initial stiffness and ultimate bearing capacity of the base slab. Based on the strut-and-tie model, a new calculation method for the ultimate bearing capacity of base slab is proposed. Results show that the failure mode of the new base slab is shear failure. Compared with the traditional base slab, the bearing capacity of the new base slab with the same size can be increased by 2.7 times. Increasing the lower chord section and base slab height can significantly improve the ultimate bearing capacity of base slab with minor impact on stiffness. The proposed calculation method has a high degree of agreement with the numerical simulation results.