Design and experimental verification of a new multi-functional bridge seismic isolation bearing

A new multi-functional bridge seismic isolation bearing(MFBSIB) is designed and its mechanical model is developed in this paper.Combining an upper sliding device and a lower energy dispassion isolation device effectively,the new MFBSIB can adjust the deformation caused by temperature,vehicle breaks,and concrete creep,etc.,in addition to dissipating energy.The switch of 'slide-isolation' is achieved and the efficiency of both upper and lower parts is validated through experiment with a model.The shear performance curve established in this paper is verified to be efficient in describing the mechanical characteristics of the bearing through experiment.It is proved through both numerical calculation and experimental analysis that the new MFBSIB is endowed with enough vertical rigidity,good energy dissipation ability,stable overall performance,and good realization in expected goals.Its performance is slightly influenced by shear stress,while affected by vertical pressure,loading frequency,slide limit,etc.,diversely.The results could provide reference for study and application of the new MFBSIB.

Characteristics of strong winds at the Runyang Suspension Bridge based on field tests from 2005 to 2008

Field measurement of strong wind characteristics is of great significance for the development of bridge wind engineering. Located in east China, the Runyang Suspension Bridge (RSB) with a main span of 1490 m is the longest bridge in China and the third longest in the world. During the last four years, the RSB has suffered from typhoons and strong northern winds on more than ten occasions. To determine the strong wind characteristics of the RSB, wind measurement data obtained from field tests during strong winds and data from the wind environment monitoring subsystem of the structural health monitoring system (SHMS) of the RSB were combined to analyze the wind speed and direction, variation in wind speed with height, turbulence intensity, turbulence integral length, wind friction speed and the power spectrum. Comparative studies on the characteristics of these different strong winds were carried out based on the current wind-resistant design specification for highway bridges. Results showed that some regularity in wind characteristics can be found in these different typhoons passing through the RSB. The difference between a strong northern wind and a typhoon is relatively clear, and in summer the typhoon is the dominant wind load acting on the RSB. In addition, there were some differences between the measured strong wind characteristics and the values suggested by the specification, especially in respect to turbulence intensity and turbulence integral length. Results provide measurement data for establishing a strong wind characteristic database for the RSB and for determining the strong wind characteristic parameter values of this coastal area in east China.

基于改进和声搜索算法识别门式起重机结构空间模态的传感器优化布置方法研究(英文)

目的:采用一种新型改进的和声搜索算法,对基于空间模态识别的传感器布置的优化方法进行研究。根据对门式起重机结构动力特性研究,得到更为理想的测点布置方案和优化结果。创新点:1.研究和声搜索算法的参数合理取值范围,提高计算效率;2.利用和声搜索算法结合模态置信度准则对起重机梁的空间模态识别进行研究,提出测点布置的合理优化方案。方法:1.基于一种改进的和声搜索算法与模态置信度准则相结合的方法对最优的传感器布置方案进行研究,通过建立的评估函数对优化得到的布置方案进行评估比较,得到近似最优的测点位置和传感器数目;2.结合门式起重机结构的动力学特性研究结果,对其在二维和三维空间的振动模态分别进行研究比较,得到更为理想的优化布置方案。结论:1.和声搜索算法具有程序实现简单和搜索能力较强的优点,本研究得到了其参数的合理取值范围,提高了其优化搜索的能力;2.研究得到了较为理想的测点位置和合理的传感器数目;3.根据起重机结构的动力特性,考虑其空间模态可得到更为理想的优化方案和识别能力。