Because of the existence of vehicles, the tested bridge frequency(which is called loaded frequency) is actually the vibration frequency of the vehicle-bridge coupled vibration system with main vibration mode of bridge vibration in bridge dynamical tests, but not the bridge natural frequency. Based on the coupled vibration model of vehicle-bridge systems and modal analysis technology, calculation method of the bridge loaded frequency under several vehicles is proposed. In the dynamical detection of highway bridges with small or medium spans, single unit vehicle is usually used to excite bridges. And then simple calculation formula of bridge loaded frequency under single unit vehicle is derived. Based on the calculation formula of bridge loaded frequency under single unit vehicle, furthermore, the analytical expression of the natural frequency calculated based on loaded frequency. Finally, one reinforced concrete beam is taken as example, and bridge loaded frequency calculated by finite element method is used as basic data,the feasibility and effectiveness of the method in this paper are fully verified.%由于车辆的存在,在桥梁的动力试验中,测试到的桥梁频率实际上是以桥梁振动为主要振动形式的车-桥耦合系统的振动频率(工程上称为有载频率),而非桥梁自身的固有频率.基于车-桥系统的耦合振动模型和模态分析技术,提出了多个车辆作用下的桥梁有载频率计算方法.在中小跨径的公路桥梁的动态检测中,往往采用单个车辆对桥梁进行激振.对此推导出了单个车辆作用下的桥梁有载频率的简便计算公式.基于单个车辆作用下的桥梁有载频率计算公式,进一步得到了基于有载频率计算桥梁自振频率的解析表达式.最后以某钢筋混凝土梁为例,采用有限元方法计算出的桥梁有载频率为基础数据,充分验证了方法的可行性和有效性.
展开▼
