Test And Design Method Research Of Friction Sliding Isolation For Frame Structure

Friction sliding isolation is one of the main type of vibration isolation structure. The vibration isolation effect depends on the performance of the sliding isolation bearing, and friction coefficient is the main factors to influence the bearing performance. In general, the smaller the friction coefficient is, the better the isolation effect is. But the smaller friction coefficient will cause the larger slip displacement, which increases the difficulty of the limit and reset and even affects the use function of the building. Molybdenum disulfide has good adhesion, high temperature and high pressure resistance, and low grinding etc, which is known as the "advanced solid lubricating oil king". The MoS2 solid lubricant was adopted as isolation bearing friction materials, with mild steel entity conical rod as limit energy dissipation device, and a new sliding isolation device was designed and made. It was Apply to a five layer reinforced concrete frame structure, the Simulink simulation analysis and shaking table test research were done, and the design methods of the friction sliding isolation structure were discussed. The main work and research content is as follows:(1) The new design points and working principle of sliding isolation bearings were analysed, the performance and advantages of molybdenum disulfide were introduced, By using the MTS electro-hydraulic servo test system, the friction performance under different vertical load was test. It was discussed that whether the molybdenum disulfide could be taken as the slip materials of the new vibration isolation system. and the function relation of friction coefficient was established by function fitting. The results show that the friction isolation bearing restoring force curve is in line with the coulomb friction model. MoS2 coating material friction performance is stable and the friction coefficient is about 0.04 to 0.05, which shows that MoS2 can be the slip materials of friction sliding isolation system.(2) Based on the dimensional theory and comprehensive consideration of vibration table bearing capacity, a 1:5 five layer reinforced concrete frame structure test model was designed according to the consistency similar relationship. The simulated earthquake shaking table test was done. The results show that the friction sliding isolation technique extends structure natural cycles. Compared with 10 Hz harmonic, isolation layer produces much larger slippage at 2Hz harmonic, and isolation layer displacement is sensitive on the spectrum characteristic. Displacement between structure layers is very small at pure sliding and limit slip. The acceleration distribution is “K” glyph, and reaches the ideal damping effect. Isolation layer slippage of XYZ earthquake is larger than X earthquake. The acceleration response of XYZ earthquake is between X earthquake’ and X slip’, and the biggest shock absorption effect reaches 51.46%, which shows that the friction sliding isolation technology is effective at the vertical earthquake. After using the tank sliding isolation technology, the tank’ acceleration response has an obvious attenuation. Whiplash effect of roof Protrusions has been well suppressed. And the seismic response of the main structure is reduced to a certain extent, which indicates that sliding isolation measures of additional layer can be used as the second seismic line of structure seismic design.(3) A five layers framework prototype was treated as the calculating model. The Stateflow finite state machine is used to simulate the coulomb friction. Bouc-Wen model is used to describe hysteretic characteristics of elastoplastic conical rod limiter. With the integrated use of MATLAB programming language, GCI tools and SIMULINK module, the slipping isolation simulink simulation model was established, including the simulation model of upper structure, isolation layer, energy response, limiter and friction. The energy response and the dynamic responses of structures was Analyzed under different seismic wave. The results showed that the pure slip structure has good effect of shock absorption. The upper structure is close to the translation. the acceleration response, displacement response and interlayer shear response are better inhibited. With the increase of friction coefficient, total input energy is generally on the rise. When the friction coefficient increases to 0.15, total input energy’s change is not obvious. With the increase of reserve slip, total input energy gradually reduces, and the isolation performance increase gradually. But the total hysteretic energy dissipation of isolation layer is also gradually decreases, and the hysteretic energy dissipation rate has little change, at around 0.86. Compared to the aseismic structure, isolation layer under different slippage all can well help to the hysteretic energy dissipation, and the damping effect is fairly. The Maximum slippage of isolation layer increases with increase of reserve slip. Hysteretic curves of isolation layer are full, limit devices have good limit energy dissipation effect, and friction sliding isolation structure shows good damping effect.(4) According to the relevant design standards and specifications codes at home and abroad as well as the previous theoretical analysis and experimental research results, combined with valuable experience of the project summary, and current design methods of sliding isolation structures are summarized and discussed, including preliminary design, the isolation layer design, the limit energy dissipation device design, the structural design method of the superstructure, the substructure and foundation, etc. A certain reference basis is provided for the posterity to design sliding isolation structure. It help that sliding isolation structure can be used widely in practical engineering. Finally by using the finite element software SAP2000, a engineering example of multilayer frame structure was carried out to make sliding isolation design. The damping effect was analyzed.