钢筋锈蚀影响下桥墩抗撞击能力劣化机理研究

发布时间：2018-05-31 19:13

本文选题：钢筋锈蚀 + 桥墩碰撞　；参考：《重庆交通大学》2016年硕士论文

【摘要】：船舶撞击荷载对钢筋混凝土桥墩会造成不利影响,受碰撞后桥墩可能出现开裂、剥落等局部损伤,剧烈碰撞则会使桥墩出现墩体移位、断裂甚至整体垮塌等严重事故。钢筋混凝土桥墩因钢筋锈蚀会引起承载能力的下降和抗撞击能力的劣化,尤其是处于海洋或沿海环境中浪溅区的桥墩,在干湿循环作用下桥墩出现钢筋锈蚀病害的现象非常普遍,同时该区域也是船桥碰撞的集中区域。本文结合桥墩碰撞和钢筋锈蚀两大问题,研究钢筋锈蚀影响下桥墩受碰撞荷载作用时的动力响应和损伤破坏性状,进而定性地揭示桥墩抗撞击能力劣化机理。论文从模型试验和有限元数值模拟两种方法开展探究,主要研究内容和结论如下:(1)对钢筋混凝土桥墩模型进行电加速锈蚀试验,获取具有不同钢筋锈蚀程度的桥墩模型。对锈后桥墩模型进行动力碰撞试验,通过桥墩的动力响应和损伤破坏性状研究了钢筋锈蚀对桥墩碰撞性能的影响。结果表明:钢筋锈蚀程度的加深显著加剧了桥墩的整体动力响应,桥墩局部的损伤程度也逐渐变大。(2)设置不同碰撞速度和不同混凝土强度两个因素,探究钢筋锈蚀后桥墩的整体动力响应和局部损伤破坏性状受撞击速度和混凝土强度的影响规律。结果显示:锈蚀后桥墩的动力响应和局部损伤会随着撞击速度的增加而加大,随着混凝土强度的增加而减小。(3)通过分析锈蚀后桥墩受碰撞荷载时的动力响应和损伤破坏性状,得出钢筋锈蚀影响下桥墩抗撞击能力劣化的机理:(1)钢筋锈蚀引起钢筋自身有效面积减小,甚至出现钢筋的断裂,其受力性能剧烈下降;(2)钢筋锈蚀导致钢筋与混凝土间的粘结强度被削弱,桥墩的整体性遭到破坏;(3)混凝土弹性模量下降,强度与刚度持续走低,甚至出现混凝土的开裂和剥落;(4)桥墩整体的刚度、抗压承载能力和抗弯承载能力明显下降。
[Abstract]:The ship impact load will have a negative effect on the reinforced concrete pier, the pier may be cracked, spalling and other local damage after the collision, and severe collision will lead to the pier displacement, fracture and even overall collapse and other serious accidents. The corrosion of reinforced concrete piers may lead to the decrease of bearing capacity and the deterioration of impact resistance, especially in the sea or coastal environment. Under the action of dry and wet circulation, the corrosion of steel bar is very common in the pier, and the region is also the concentrated area of collision between ships and bridges. In this paper, the dynamic response and damage failure behavior of pier subjected to impact load under the influence of reinforcement corrosion are studied, and the deterioration mechanism of pier anti-impact ability is revealed qualitatively by combining the two major problems of pier collision and reinforcement corrosion. In this paper, two methods of model test and finite element numerical simulation are discussed. The main contents and conclusions are as follows: (1) the model of reinforced concrete pier is tested by electric accelerated corrosion test, and the model of bridge pier with different degree of reinforcement corrosion is obtained. The dynamic impact test was carried out on the model of the rusty pier. The effect of steel corrosion on the impact performance of the pier was studied through the dynamic response of the pier and the damage and failure behavior of the pier. The results show that the depth of steel corrosion significantly intensifies the overall dynamic response of the pier, and the local damage degree of the pier increases gradually. (2) two factors, different impact velocity and different concrete strength, are set up. The dynamic response and local damage and failure behavior of the reinforced corroded piers are investigated by the impact velocity and the strength of concrete. The results show that the dynamic response and local damage of the corroded pier will increase with the increase of impact velocity, and decrease with the increase of concrete strength. The mechanism of the deterioration of the pier's impact resistance under the influence of steel corrosion is obtained.) the corrosion of steel bar causes the decrease of the effective area of the steel bar itself, and even the fracture of the steel bar. The mechanical properties of the steel bar are greatly reduced. (2) the corrosion of steel bar results in the weakening of the bond strength between the reinforcement and concrete, the destruction of the integrity of the pier and the decrease of the elastic modulus of the concrete, while the strength and stiffness of the concrete continue to decrease. Even the cracking and spalling of concrete (4) the overall stiffness, compressive bearing capacity and flexural bearing capacity of the pier are obviously decreased.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U443.22

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