【作者】 陈坤；

【导师】 许明财； 吴国民；

【作者基本信息】 华中科技大学 ， 机械（专业学位）， 2022， 硕士

【摘要】 随着经济不断的增长,跨海大桥的数量不断增加,船舶的吨位和数量也在不断提升,导致船-桥碰撞事故造成的影响更加巨大。针对大吨位船舶撞击或桥墩自身较弱情况,采用附着式防撞设施的形式无法通过吸能满足防撞要求。目前跨海大桥的防撞设施多采用在桥梁周围设置防撞墩的形式,现有防撞墩的设计方法主要考虑桥梁或桩基设计规范,主要用于桥梁静力弹性设计方法中,其中船撞力的计算把被撞结构假设为刚性,没有考虑被撞结构自身的变形,导致船撞力的计算值偏大。另外防撞墩为临时结构而且可以允许部分损伤,其抗撞设计方法应该不同于桥梁。如果防撞墩的设计也采用规范里的静力弹性方法会导致设计的结构过于保守。针对该问题,本文采用规范中的弹性静力方法、弹塑性动力方法分析了防撞墩的抗撞性能,对于船舶碰撞下防撞墩动力响应及安全评估方法开展研究具有重要的理论和现实意义。主要研究内容及结论:1)针对某跨海大桥的实际情况,按照主墩的抗撞要求设计了三种防撞墩方案,并采用静力弹性方法讨论了不同的桩基础配置、桩直径等参数对防撞墩影响,讨论方案的可行性,最终获得合理的防撞墩设计方案。2)针对目前没有防撞墩安全评估问题,基于塑性条件,采用数值方法分析了不同的船撞荷载加载方式对防撞墩的变形、应力分布以及撞击力等方面的影响,并通过与静力弹性设计方法的结果进行对比,分析不同计算方法的差异,并给出合理的分析建议。3)基于船-刚性墙、船-刚性防撞墩以及规范公式法对防撞墩设计中所需要船撞力的计算方法适用性进行了分析和讨论;进一步分析对防撞墩覆盖钢板后,防撞墩结构的动态响应、变形破坏和能量耗散,结果表明覆盖钢板后,船撞力能够更好地传递到整个防撞墩结构上。基于此模型,分析了船舶排水量、船舶撞击速度等因素对防撞墩性能的影响。更多还原

【Abstract】 With the continual development of the economy,the number of cross-sea bridges and ships is increasing and the tonnage of ships becomes higher and higher,which has a greater impact on ship-bridge collisions.Because the large-tonnage ships are characterized by the stronger collision and the bridge piers are weak in anti-collision,the use of attached anticollision facilities cannot meet the anti-collision requirements by energy absorption.Currently,the anti-collision facility adopted by the sea-crossing bridge is the form of setting up anti-collision piers around the bridge.Tt is common for the design method of anticollision piers to consider the design specifications of bridges and pile foundations,and to adopt the static elastic design method of bridges.When it comes to this design method of anti-collision piers,for one thing,in the calculation of the collision force of ships,the crashed structure is assumed to be rigid and the deformation of the structure itself is not taken into account,resulting the collision force of ships tending to be larger;for another thing,the anti-collision pier is characterized by the temporary structure and can withstand partial damage so that its anti-collision design method is supposed to be different from that of bridges.Therefore,if the design of the anti-collision pier also adopts the static elastic method in the code,the designed structure of anti-collision piers will be too conservative.As for this problem,this paper adopts the elastostatic method and elastoplastic dynamic method in the code to analyze the anti-collision performance of the anti-collision pier,which has theoretically and practically significant effect on the study of the dynamic response and safety assessment method of the anti-collision pier under ship collision.The main research contents and conclusions are as follows:1)In view of the actual situation of one sea-crossing bridge,three anti-collision pier schemes are designed according to the anti-collision requirements of the main pier,and the elastic static method is used to discuss the influence of different pile foundation configuration and pile diameter on anti-collision pier,and the feasibility of the scheme is analyzed,and finally a reasonable anti-collision pier design scheme is obtained.2)Aiming at the problem that there is no safety assessment of anti-collision piers at present,based on the plastic condition,the paper adopts the numerical methods to analyze the loading ways of the different ships exert influence on anti-collision piers’ displacements,stress distribution and collision force.Comparing with the results of the static elastic design method,analyzes the differences of calculation method are analyzed and reasonable analytical suggestions are given.3)Based on ship-rigid wall,ship-rigid anti-collision pier and code formula method,the paper analyzes and discusses the applicability of the calculation method of the collision force of ships required in the design of anti-collision pier.After covering the anti-collision piers with steel plates,the dynamic response,deformation failure and energy dissipation of the anti-collision pier structure is analyzed deeply,and it is turned out that the collision force of ships can be better transferred to the whole structure of anti-collision piers.Based on this model,the influences of ship tonnage and ship speed on the performance of anti-collision piers are analyzed.更多还原