高强钢管混凝土(HSCFST)抛物线拱的稳定性研究

With the development of technology of material manufacture and construction, it is an inevitable trend that high strength steel tube filled with concrete(HSCFST) to be applicated widely owning to its many advantages. But because of their large slenderness ratio and the major compressive action, instability becomes the most important factor for the design of HSCFST arches. However, comprehensive studies of the instability and strength design do not appear to be reported in public. In this project, a series of investigations on the instability and strength of HSCFST parabolic arches are carried out using the methods of theoretical derivation, finite element simulation and experimental investigations. (1) Since the in-focus distance of the parabola is a constant and the eccentricity of the parabola is equal to 1, the equilibrium differential equation with instability constant coefficients of a parabolic arch is established and both the in-plane and out-of-plane buckling critical loads of parabolic arch are derived. (2) Considering effects of creep of the core concrete, the analytic solutions for out-of-plane buckling critical loads of HSCFST arches are derived by using the principle of virtual work. The analytic solutions and simplified formulas are verified by the viscoelastic finite element results (3) Based on a large number of nonlinear elastic-plastic finite element results in association with the experimental results and analytical solutions, under the action of uniform compression, central force and combination of loads, simplified calculation formulas for in-plane and out-of-plane stability coefficients are proposed ,design formulas for bearing capacities of HSCFST arches accounting for the effects of creep of the core concrete are developed. Using the design formulas, the influences of creep of the core concrete and various other design parameters on instability and strength of HSCFST arches are analyzed and the disaster mechanism owing to instability failure of HSCFST arches is revealed. The achievements of this project will provide comprehensive and deep understanding of instability and strength of HSCFST arches including the influences of creep of the core concrete, and provide effective and efficient design and calculation methods.

随着材料制备和施工技术的发展，高强钢管混凝土（HSCFST）以其众多优势，广泛应用成为必然趋势。HSCFST拱长细比大，且以受压为主，稳定性问题是控制设计的主要因素，但目前并未见相关研究公开报道。本项目以HSCFST抛物线拱为研究对象，采用理论推导、有限元数值模拟和模型试验研究方法，展开以下系列研究：(1)从抛物线线型焦准距恒定为常数和离心率恒定为1的特性出发，建立HSCFST抛物线拱失稳常系数平衡微分方程，推导抛物线拱面内外弹性失稳临界荷载，给出临界荷载与修正长细比的简化计算公式；(2)考虑徐变效应，采用虚功原理推导HSCFST抛物线拱面外弹性失稳临界荷载，分析徐变对HSCFST拱稳定性影响；(3)提出均布荷载、集中力以及各种荷载组合下HSCFST抛物线面内、外非弹性稳定系数简化计算公式，以及对应的弹塑性稳定承载能力设计公式，揭示HSCFST抛物线拱面内外失稳机理。