摘要：近年來，鋼筋混凝土結構耐久性問題日益突出，引起了世界各國學術機構、學者和工程技術人員對加強鋼筋混凝土結構耐久性研究的重視。本文針對這一問題對銹蝕鋼筋混凝土構件的性能退化做了部分分析，對有限元模擬以及銹蝕預測模型方面進行研究，主要內(nèi)容包括：
在考慮銹蝕引起的鋼筋橫截面損失和粘結強度下降的前提下，建立銹蝕鋼筋混凝土梁的有限元分析模型。鋼筋單元采用三維桿單元，混凝土單元采用8節(jié)點實體單元，鋼筋與混凝土之間的粘結單元采用非線性彈簧單元。利用大型有限元分析軟件ANSYS，對銹蝕梁的受力性能進行模擬分析，模擬結果與實驗方法結果吻合，說明采用非線性有限元方法分析銹蝕梁受力性能正確有效。
另外，基于銹蝕鋼筋混凝土梁內(nèi)鋼筋與混凝土間粘結強度隨銹蝕量的變化，對銹蝕梁的抗彎承載力進行了研究。當鋼筋銹蝕量較小時，銹蝕梁內(nèi)鋼筋與混凝土間粘結強度隨銹蝕量變化不大，銹蝕梁的力學性能同未銹蝕梁相近，可運用傳統(tǒng)的梁理論計算銹蝕梁的抗彎承載力；但隨著鋼筋銹蝕量的增加，鋼筋與混凝土間粘結強度發(fā)生退化，銹蝕梁的力學性能介于粘結完好梁與無粘結梁之間，與傳統(tǒng)計算梁的抗彎承載力方法不同，應考慮梁各截面間的相互作用。基于梁整體的受力平衡和變形協(xié)調，提出了概念明確、通用性強的銹蝕鋼筋混凝土梁抗彎承載力計算方法；經(jīng)試驗驗證，數(shù)據(jù)吻合很好，其結果有益于完善和發(fā)展銹蝕鋼筋混凝土梁抗彎承載力的計算方法。

關鍵詞：銹蝕鋼筋混凝土梁；抗彎承載力；退化機理；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