考虑混凝土损伤演化的钢筋混凝土梁寿命分析

为了建立能方便于工程应用并能够反映钢筋混凝土梁寿命衰减机理的钢筋混凝土梁寿命分析模型,文章研究了混凝土收缩以及荷载长期效应对结构损伤演化和服役寿命的影响,重点考虑了混凝土的损伤演化过程与拉伸区的拉应力对寿命的影响,对现有的钢筋混凝土梁的挠度计算公式进行修正,建立了新型的钢筋混凝土梁的挠度计算公式.在该挠度计算公式的基础上,获得了钢筋混凝土梁的寿命分析模型,该寿命分析模型以《公路钢筋混凝土及预应力混凝土桥涵设计规范》（JTG D62-2004）规定的桥梁长期挠度限值作为钢筋混凝土梁无法安全服役的限值.研究结果表明：文中修正的钢筋混凝土梁挠度计算公式能够较准确地计算钢筋混凝土梁在长期服役荷载下的任意时刻的挠度值,所建立的钢筋混凝土梁的寿命分析模型能方便地得到梁的安全服役寿命,并具有一定程度的可靠性.

Life Analysis of Reinforced Concrete Beam by Considering Concrete Damage

In order to establish a life analysis model of reinforced concrete beam, which would be conveniently used in engineering and could also accurately describe the life attenuation mechanism of reinforced concrete beam, the influence of concrete shrink and load long-term effect to reinforced concrete life were studied in this paper, and two key issues had been considered, including ability of concrete to undertake the tensile stress before its cracking and concrete damage evolution. A new computational formula of reinforced concrete beam deflection had been established. Based on this deflection computational formula, this paper established a life analysis model of reinforced concrete beam. In this model, the maximum value of the beam deflection used the value which set in the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts. The results showed that, the deflection computational formula could accurately compute the beam deflection at random time, and the life analysis model of reinforced concrete beam could conveniently compute the life of reinforced concrete beam.