| Since the concept of structure vibration control has been put forward, many research results have been achieved, making the concept a hot topic in structure seismic field. Various kinds of damping devices have been used to suppress the structure response under vibration, which is a typical pattern in passive control method. Due to their merits of simplified device, easy construction, good aseismic behaviors and so on, dampers are practically used in civil engineering structures. Roof garden plays an important role in improving urban living environment, and it also has remarkable value in vibration reduction.Based on the study of various dampers, combined roof garden and phenomenon of silt liquefaction, this paper proposes a kind of damping device, which can be applied in civil engineering. This device makes full use of the phenomenon of soil liquefaction and integrates vibration mitigation mechanism of tuned liquid damper, tuned mass damper, viscous damper, and particle damper. The equipment which can be installed together with roof garden, is mainly made up of container, saturated silty soil or silt, balls or pebbles. When suffered earthquake, liquefied silty soil loses the shear strength and looks like liquid, which may promote the objects movement inside it. The process above is a good manner for energy dissipation. This kind of damper is valuable for study, because it not only has the characteristic of good robustness, but also has the advantages of good aseismic behaviors, low cost, easy maintenance and environmental protection. Moreover, the thought can achieve good combination of architectural aesthetics and seismic design.Firstly, this paper introduces the composition of the device and theory of tuned damper. Secondly, soil test is conducted to confirm the category of the soil used in the research. Basic rule and phenomenon of silt vibration liquefaction are obtained by operating small shaking table test, which provides basic information for large scale shaking table test. Thirdly, the large earthquake simulation shaking table test is conducted to verify the effect of vibration reduction. Besides, some meaningful conclusions are got by analyzing the data. At last, finite element software of ANSYS and Housner lumped-mass method are used to carry on numerical simulation of TLD, and the comparisons are made between TLD and the new damper. Moreover, the state of liquid sloshing is simulated by regarding soil and water mixture as a kind of viscous liquid, and the vibration frequency is compared with the theoretical calculation results.The following conclusions are obtained through the research:(1)The phenomenon of silty soil liquefaction can be obtained by increasing the amplitude and frequency of excitation wave.(2)The new damper has certain effect in suppressing vibration of structure. Under the action of sine wave, the device shows good function of vibration reduction when excitation frequency closed to the basic liquid sloshing frequency. Under the action of earthquake wave, including El Centro wave and Taft wave, the damper performs well in suppressing response of structure.(3)The performance of device in reducing structure’s vibration is enhanced by adding iron balls into soil. Aseismic ratio is increased respectively under the action of both sine wave and earthquake wave.(4)The comparison of results between test and simulation shows that TLD with the same condition has no effect in decreasing structure’s vibration. The principle of TLD differs from the damper.(5)With the consideration of fluid-structure coupling, sloshing frequency of liquid is obtained and the results is closed to theoretical value.Innovation points of the paper(1)The research make full use of the negative impact of sand liquefaction, which is usually regarded as harmful phenomenon.(2)The device integrates vibration mitigation mechanism of various dampers and is of good robustness.(3)The device can be constructed with roof gardens and has the advantages of low cost, environmental protection, easy construction and so on. |
PDF Full Text Request