环境与荷载耦合作用下预应力混凝土桥梁服役行为演变及寿命预测

Prestressed concrete structure is widely used in the bridge because of its ultra-high strength and excellent work performance. Many factors, such as the load effects, material aging and environmental erosion, deteriorate the service performance of prestressed concrete bridge and shorten the service life. The mechanism of the coupling effect of the environmental factors and load on the service performance of prestressed concrete bridge is not clear. In the project the mathematical model of environmental factors and load in continuous space-time dimensions could be built based on the physical and chemical characteristics of environmental factors and load. For the single-span prestressed concrete bridge the decoupling condition was determined by analysing the coupling mechanism of the environmental factors and load. The time-varying model of the prestressed concrete bridge service performance could be built. Furthermore, the evolution process and law of the service performance of prestressed concrete bridge under the coupling action of the environmental factors and load during service period could be revealed. The limite state was determined. The life prediction model of the prestressed concrete bridge could be established. The theoretical support can be provide for perfecting the whole life design theory of prestressed concrete bridge, promoting the development of technology of prestressed concrete structure and ensuring the safe of the major civil engineering works.

预应力混凝土结构因其超高强度和优良工作性能在桥梁中广泛应用。在运营阶段，荷载效应、材料老化、环境侵蚀等多种因素作用劣化了预应力混凝土桥梁服役性能，缩短其寿命。但环境与荷载耦合作用对预应力混凝土桥梁结构性能劣化影响机理还不明晰。本项目基于环境与荷载作用的物理、化学特征，构建连续时空维度环境、荷载作用的数学模型，以单跨预应力混凝土桥梁结构为对象，通过研究环境与荷载耦合作用机制，确定解耦条件，实现耦合作用的解耦，建立环境与荷载耦合作用下预应力混凝土桥梁服役性能演化时变方程，揭示环境与荷载耦合作用下预应力混凝土桥梁结构服役行为演变过程及规律，确定极限状态，建立预应力混凝土桥梁寿命预测模型。为完善预应力混凝土桥梁结构全寿命设计理论、推动预应力混凝土结构技术发展、确保土木工程重大工程安全提供理论支持。

预应力混凝土桥梁结构在运营阶段受荷载效应、材料老化、环境侵蚀等多种因素的劣化作用，缩短了桥梁的寿命，但环境与荷载共同作用对预应力混凝土桥梁服役性能劣化影响机理还不明晰。本项目基于环境与荷载作用的物理、化学特征，构建连续时空维度环境、荷载作用的数学模型，以单跨预应力混凝土桥梁结构为对象，结合理论分析与试验研究，阐明环境与荷载共同作用机制，建立氯离子传输非稳态多动力模型、疲劳荷载作用下脱钝钢筋腐蚀速率模型、混凝土疲劳本构模型等。基于此，构建环境与荷载共同作用下预应力混凝土桥梁服役性能演化时变方程，揭示预应力混凝土桥梁结构服役性能演变过程及规律，制定失效准则，并基于matlab编制预应力混凝土桥梁动态寿命预测模型。此课题为完善预应力混凝土桥梁结构全寿命设计理论、推动预应力混凝土结构技术发展、确保土木工程重大工程安全提供理论支持。