Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibra...Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equa- tion of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal super- position. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.展开更多
A wind-vehicle-bridge system can be regarded as an interaction result of wind-bridge interaction, wind-vehicle interaction and vehicle-bridge interaction, which is determined by nature wind, dynamic characteristics of...A wind-vehicle-bridge system can be regarded as an interaction result of wind-bridge interaction, wind-vehicle interaction and vehicle-bridge interaction, which is determined by nature wind, dynamic characteristics of vehicle and bridge structures, interrelationship between bridge and vehicle dynamic properties and so on. Firstly, based on the traffic loading investigation on the expressway bridge within 24 hours a day, all the critical parameters of traffic flow, such as the vehicle type, weight, separation space and speed are all recorded and analyzed to extract its statistical characteristics, which are used to work out random traffic flow simulation program RTF. This RTF program can be embedded with the other general FEM software. Secondly, a dynamic analysis module RTFWVB of the wind-vehicle-bridge coupling vibration under random traffic flow is presented, which can consider arbitrary number of vehicles, multi-lanes and traffic flow direction. Finally, Hangzhou Bay Bridge in China is selected as a numerical example to demonstrate dynamic interaction of the RTFWVB system. The results indicate that the traffic flow direction has just a little influence on bridge dynamic response, that the mean responses are mainly determined by the moving vehicle loads, and that the fluctuating components will increase with the increase of wind speed.展开更多
文摘在交通荷载观测及统计分析的基础上,获得交通状况的代表性数据,对记录的车型、车重、车距和车速进行统计,在此基础上进行随机车流模拟,编制随机车流模拟程序RTF(Random Traffic Flow),程序中首次全面引入车型、车重、车距和车速4个参数;建立可以考虑任意车辆数目、不同车道以及车辆相向行驶功能的随机车流下的风-汽车-桥梁系统空间耦合振动分析框架,编制相应的分析模块RTFWVB(Wind-Vehicle-Bridge system analysis)。以杭州湾跨海大桥为工程实例,详细研究密集、稀疏运营状态,车流单向、相向行驶以及侧风与车辆移动荷载对桥梁关键部位动力响应的影响。分析表明:密集运营状态下桥梁动力响应明显大于一般运营状态下的相应值;车流方向对桥梁振动影响不大;密集运营状态下车辆移动荷载主要决定桥梁动力响应的均值,而侧风主要影响桥梁动力响应的脉动部分,风速越大波动越显著。
基金supported by the Funds for Creative Research Groups of China(51021001)the National Natural Science Foundation of China(51078351)Program for New Century Excellent Talents in University,Fund of Key Laboratory of Bridge-structure Engineering and Open Fund of Key Laboratory of Road & Bridge and Underground Engineering of Gansu Province(KFJJ-11-03)
文摘Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equa- tion of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal super- position. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.
基金supported by the Fundamental Research Funds for the Central Universities of China (No.CHD2011JC012)the National Natural Science Foundation of China(No.51278064)
文摘A wind-vehicle-bridge system can be regarded as an interaction result of wind-bridge interaction, wind-vehicle interaction and vehicle-bridge interaction, which is determined by nature wind, dynamic characteristics of vehicle and bridge structures, interrelationship between bridge and vehicle dynamic properties and so on. Firstly, based on the traffic loading investigation on the expressway bridge within 24 hours a day, all the critical parameters of traffic flow, such as the vehicle type, weight, separation space and speed are all recorded and analyzed to extract its statistical characteristics, which are used to work out random traffic flow simulation program RTF. This RTF program can be embedded with the other general FEM software. Secondly, a dynamic analysis module RTFWVB of the wind-vehicle-bridge coupling vibration under random traffic flow is presented, which can consider arbitrary number of vehicles, multi-lanes and traffic flow direction. Finally, Hangzhou Bay Bridge in China is selected as a numerical example to demonstrate dynamic interaction of the RTFWVB system. The results indicate that the traffic flow direction has just a little influence on bridge dynamic response, that the mean responses are mainly determined by the moving vehicle loads, and that the fluctuating components will increase with the increase of wind speed.
