混凝土梁桥火灾后技术状况评定技术研究

发布时间：2019-06-11 03:09

【摘要】：随着我国公路交通的不断发达,桥梁的数量也越来越多。近年来,公路桥梁突发事故频发,事故原因有火灾、超载车辆、洪水灾害、地震损毁、车船撞击等,对公路桥梁的安全运营造成巨大的隐患,而火灾以它巨大的破坏力,是最严重的桥梁灾害之一,桥梁火灾与其他突发事故相比,其显著特点在于:火灾发生突然,不仅对桥梁混凝土结构部件本身因力学性能发生改变而造成破坏,从微观角度讲,火的物理和化学作用使钢筋混凝土材料的微观颗粒也发生质的变化,对桥梁的承载能力和耐久性造成长期的影响。混凝土梁桥为公路桥梁中的主体桥型。近年来,火灾事件频频发生,使桥梁承载能力和交通能力都发生不同程度的下降和损失,火灾后又不适宜做荷载试验检测,那么如何能够快速的对火灾梁桥的技术状况进行评定?当前规范《公路桥涵养护规范》(JTG H11--2004)及交通部推荐性标准《公路桥梁技术状况评定标准》(JTG/T H21--2011)中均未明确火灾桥梁的灾后检测评估标准,我认为,对于火灾后桥梁的检测还应该有更加具体、明确、行之有效的方法。本文将针对混凝土梁桥火灾后损伤病害的特殊情况,结合其与常规病害的相似度,基于《公路桥涵养护规范》(JTG H11--2004)和相关桥梁检测指标,将外观测量、检测数据、损伤计算结合起来,从桥梁检测评定的角度出发,研究混凝土梁桥火灾后检测和评定方法:(1)通过研究火源火势的普遍特点从而引入混凝土梁桥遭遇火灾时的火源火势特征分析,深入研究高温下混凝土、钢筋、混凝土与钢筋的握裹力等变化特征。(2)通过研究混凝土梁桥各部件的火灾病害损伤特点,提出火灾后现场检测程序、检测指标、推导计算过程方法,从而确定火灾后各部件的检测指标情况。(3)针对火灾病害情况,提出各类部件权重的修订方案、各部件评度标准、计算方法,从而得出钢筋混凝土梁式桥火灾后的评定标准方法;(4)以某钢筋混凝土梁桥火灾后的检测评定为实例验证以上方法,最后提出问题与展望。
[Abstract]:With the continuous development of highway traffic in China, the number of bridges is increasing. In recent years, highway bridge accidents occur frequently, the causes of accidents are fire, overloaded vehicles, flood disasters, earthquake damage, vehicle and ship impact and so on, which cause great hidden dangers to the safe operation of highway bridges, and fire has great destructive power. It is one of the most serious bridge disasters. Compared with other sudden accidents, bridge fire is characterized by sudden fire, which not only destroys the mechanical properties of bridge concrete structural components, but also from a micro point of view. The physical and chemical effects of fire make the microscopic particles of reinforced concrete materials also change qualitatively, which has a long-term impact on the bearing capacity and durability of bridges. Concrete beam bridge is the main bridge type in highway bridge. In recent years, fire incidents occur frequently, which makes the bearing capacity and traffic capacity of bridges fall and lose in varying degrees, and it is not suitable for load test and detection after fire. So how to quickly evaluate the technical status of fire beam bridge? The current code "maintenance Code for Highway Bridges and culverts" (JTG H11 / 2004) and the recommended Standard "Technical condition Assessment Standard for Highway Bridges" (JTG/T H212011) do not specify the post-disaster detection and evaluation criteria of fire bridges. I think, There should be more specific, clear and effective methods for bridge detection after fire. In this paper, according to the special situation of damage disease after fire of concrete beam bridge, combined with the similarity between concrete beam bridge and conventional disease, based on the maintenance Code for Highway Bridge and culvert maintenance Code (JTG H11 / 2004) and the related bridge detection index, the appearance measurement and test data will be carried out. Combined with damage calculation, from the point of view of bridge detection and evaluation, The detection and evaluation methods of concrete beam bridge after fire are studied: (1) by studying the general characteristics of fire source fire of concrete beam bridge, the fire source fire characteristic analysis of concrete beam bridge in the event of fire is introduced, and the concrete and steel bar at high temperature are deeply studied. The holding force of concrete and steel bar is changed. (2) by studying the damage characteristics of fire diseases of each part of concrete beam bridge, the field detection program, detection index and calculation process method after fire are put forward. In order to determine the detection index of each component after the fire. (3) according to the fire disease situation, the revision scheme of the weight of all kinds of components, the evaluation standard of each component and the calculation method are put forward. Thus, the evaluation standard method of reinforced concrete beam bridge after fire is obtained. (4) taking the detection and evaluation of a reinforced concrete beam bridge after fire as an example to verify the above method, and finally put forward the problems and prospects.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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