锈蚀钢筋混凝土受弯构件.doc
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锈蚀钢筋混凝土受弯构件,摘要：近年来，钢筋混凝土结构耐久性问题日益突出，引起了世界各国学术机构、学者和工程技术人员对加强钢筋混凝土结构耐久性研究的重视。本文针对这一问题对锈蚀钢筋混凝土构件的性能退化做了部分分析，对有限元模拟以及锈蚀预测模型方面进行研究，主要内容包括：在考虑锈蚀引起的钢筋横截面损失和粘结强度下降的前提下，建立锈蚀钢筋混凝土梁的...
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摘要：近年来，钢筋混凝土结构耐久性问题日益突出，引起了世界各国学术机构、学者和工程技术人员对加强钢筋混凝土结构耐久性研究的重视。本文针对这一问题对锈蚀钢筋混凝土构件的性能退化做了部分分析，对有限元模拟以及锈蚀预测模型方面进行研究，主要内容包括：
在考虑锈蚀引起的钢筋横截面损失和粘结强度下降的前提下，建立锈蚀钢筋混凝土梁的有限元分析模型。钢筋单元采用三维杆单元，混凝土单元采用8节点实体单元，钢筋与混凝土之间的粘结单元采用非线性弹簧单元。利用大型有限元分析软件ANSYS，对锈蚀梁的受力性能进行模拟分析，模拟结果与实验方法结果吻合，说明采用非线性有限元方法分析锈蚀梁受力性能正确有效。
另外，基于锈蚀钢筋混凝土梁内钢筋与混凝土间粘结强度随锈蚀量的变化，对锈蚀梁的抗弯承载力进行了研究。当钢筋锈蚀量较小时，锈蚀梁内钢筋与混凝土间粘结强度随锈蚀量变化不大，锈蚀梁的力学性能同未锈蚀梁相近，可运用传统的梁理论计算锈蚀梁的抗弯承载力；但随着钢筋锈蚀量的增加，钢筋与混凝土间粘结强度发生退化，锈蚀梁的力学性能介于粘结完好梁与无粘结梁之间，与传统计算梁的抗弯承载力方法不同，应考虑梁各截面间的相互作用。基于梁整体的受力平衡和变形协调，提出了概念明确、通用性强的锈蚀钢筋混凝土梁抗弯承载力计算方法；经试验验证，数据吻合很好，其结果有益于完善和发展锈蚀钢筋混凝土梁抗弯承载力的计算方法。
关键词：锈蚀钢筋混凝土梁；抗弯承载力；退化机理；有限元
Abstract：In recent years,durability of reinforced concrete structures is becoming increasingly prominent which have been attracted by worldwide academic organizations,scholars,engineers and technicians to pay attention to the research on the durability of RC structures.Some studies on finite element model and predication model of RC members are presented in this paper.The main contents are as follows.
The section loss of steel bars and degradation of bond intensity were taken into consideration in this study,establishment of corroded reinforced concrete beam finite element model.The three-dimensional rod element was taken as the steel bar element, the eight-node solid element as the concrete element, and the nonlinear spring element as the bonding element between the steel bars and concrete. The bearing capacity of the reinforced concrete beam with corroded steel bars was simulated by making use of the large-scale finite element software ANSYS. Similarity of the ANSYS simulation results to experiment results manifested that the nonlinear finite element analysis for the reinforced concrete beam with corroded steel bars was reliable and accurate.
In addition,Flexural carrying capacity of corroded reinforced concrete beams is modeled and calculated on the basis of the change of bond strength between corroded steel and concrete. At lower degrees of corrosion level,bond strength between steel and concrete doesn’t have great changes with increasing degrees of corrosion, the mechanical behavior of the corroded RC beams is the same as that of the non-corroded ones, flexural carrying capacity of corroded RC beams can be calculated by conventional theory of the beam. When reduction of bond strength occurs due to higher degrees of corrosion, the mechanical behavior of the corroded RC beams lies in between that of the perfectly bonded and unbonded beam. It is different from the traditional way in RC beams, the interaction between cross sections of beams should be considered. In the present paper, the change of bond strength between corroded steel and concrete is considered, and on the basis of the condition of equilibrium of forces and compatibility of deformations forwhole beams,a calculation method for flexural capacity,conceptually explicit and widely applicable,was proposed,taking consideration of both corrosion degree and reinforcement index. The results were useful to perfect the calculation method of the flexural bearing capacity of corroded reinforced concrete beams.
Key words：corroded reinforced concrete beam、flexural bearing capacity、deterioration mechanism、finite element
在考虑锈蚀引起的钢筋横截面损失和粘结强度下降的前提下，建立锈蚀钢筋混凝土梁的有限元分析模型。钢筋单元采用三维杆单元，混凝土单元采用8节点实体单元，钢筋与混凝土之间的粘结单元采用非线性弹簧单元。利用大型有限元分析软件ANSYS，对锈蚀梁的受力性能进行模拟分析，模拟结果与实验方法结果吻合，说明采用非线性有限元方法分析锈蚀梁受力性能正确有效。
另外，基于锈蚀钢筋混凝土梁内钢筋与混凝土间粘结强度随锈蚀量的变化，对锈蚀梁的抗弯承载力进行了研究。当钢筋锈蚀量较小时，锈蚀梁内钢筋与混凝土间粘结强度随锈蚀量变化不大，锈蚀梁的力学性能同未锈蚀梁相近，可运用传统的梁理论计算锈蚀梁的抗弯承载力；但随着钢筋锈蚀量的增加，钢筋与混凝土间粘结强度发生退化，锈蚀梁的力学性能介于粘结完好梁与无粘结梁之间，与传统计算梁的抗弯承载力方法不同，应考虑梁各截面间的相互作用。基于梁整体的受力平衡和变形协调，提出了概念明确、通用性强的锈蚀钢筋混凝土梁抗弯承载力计算方法；经试验验证，数据吻合很好，其结果有益于完善和发展锈蚀钢筋混凝土梁抗弯承载力的计算方法。
关键词：锈蚀钢筋混凝土梁；抗弯承载力；退化机理；有限元
Abstract：In recent years,durability of reinforced concrete structures is becoming increasingly prominent which have been attracted by worldwide academic organizations,scholars,engineers and technicians to pay attention to the research on the durability of RC structures.Some studies on finite element model and predication model of RC members are presented in this paper.The main contents are as follows.
The section loss of steel bars and degradation of bond intensity were taken into consideration in this study,establishment of corroded reinforced concrete beam finite element model.The three-dimensional rod element was taken as the steel bar element, the eight-node solid element as the concrete element, and the nonlinear spring element as the bonding element between the steel bars and concrete. The bearing capacity of the reinforced concrete beam with corroded steel bars was simulated by making use of the large-scale finite element software ANSYS. Similarity of the ANSYS simulation results to experiment results manifested that the nonlinear finite element analysis for the reinforced concrete beam with corroded steel bars was reliable and accurate.
In addition,Flexural carrying capacity of corroded reinforced concrete beams is modeled and calculated on the basis of the change of bond strength between corroded steel and concrete. At lower degrees of corrosion level,bond strength between steel and concrete doesn’t have great changes with increasing degrees of corrosion, the mechanical behavior of the corroded RC beams is the same as that of the non-corroded ones, flexural carrying capacity of corroded RC beams can be calculated by conventional theory of the beam. When reduction of bond strength occurs due to higher degrees of corrosion, the mechanical behavior of the corroded RC beams lies in between that of the perfectly bonded and unbonded beam. It is different from the traditional way in RC beams, the interaction between cross sections of beams should be considered. In the present paper, the change of bond strength between corroded steel and concrete is considered, and on the basis of the condition of equilibrium of forces and compatibility of deformations forwhole beams,a calculation method for flexural capacity,conceptually explicit and widely applicable,was proposed,taking consideration of both corrosion degree and reinforcement index. The results were useful to perfect the calculation method of the flexural bearing capacity of corroded reinforced concrete beams.
Key words：corroded reinforced concrete beam、flexural bearing capacity、deterioration mechanism、finite element
