دانلود رایگان مقاله انگلیسی پاسخ لرزه ای قاب فولادی ضد زنگ با در نظر گرفتن اثر متقابل ساختار خاک (SSI) - اشپرینگر 2018

Abstract

Conventional fixed-base analysis ignoring the effect of soil-flexibility may result in unsafe design. Therefore, to evaluate the realistic behavior of structure the soil structure interaction (SSI) effect shall be incorporated in the analysis. In seismic analysis, provision of bracing system is one of the important option for the structure to have sufficient strength with adequate stiffness to resist lateral forces. The different configuration of these bracing systems alters the response of buildings, and therefore, it is important to evaluate the most effective bracing systems in view point of stability against SSI effect. In present study, three RC building frames, G?3, G?5 and G?7 and their respective scaled down steel model with two types of steel bracing system incorporating the effect of soil flexibility is considered for experimental and analytical study. The analytical study is carried out using Elastic continuum approach and the experimental study is carried out using Shake Table. The influence of SSI on various seismic parameters is presented. The study reveals that, steel bracing system is beneficial to control SSI effect and it is observed that V bracing is more effective, in resisting seismic load considering SSI.

Conclusion

The following conclusions have been derived from the study:

1. SSI effect causes increase in the time period of structure.

2. In the present study for soil under consideration for the prototype building frame G?3, G?5 and G?7, the time period increases in the range of 15–18% as obtained by experimental study and by 5–10% as obtained by analytical study. This reveals that experimental study produces higher time period than analytical study. This is obvious because of soil mass simulation in the laboratory which in spite of all possible care the real time soil mass simulation is not possible in the laboratory.

3. The variations in experimental and analytical results are possible due to one or all of (a) The idealistic material properties in the analytical study are not matching with the material of model. (b) The idealistic stiffness of joints difficult to reproduce in the model. (c) The theoretical boundary condition may not possible to reproduce in the experimental study. (d) Due to repeated test the performance of the model is likely to vary. This is due to geometrical distortion of the model or fatigue developed in the model.

4. The SSI results into the increase in the time period leading to high lateral displacement which in turn results to P-D effect causing distress to structure. The effect of SSI is observed to be controlled by providing bracing in the structure. The study reveals that both diagonal and V bracing are effective. Among these V bracing are observed to be marginally more effective than diagonal bracing. This inference is based on various building frames considered for the study for the soil under consideration. However in order to derive more comprehensive conclusion study needs to be carried out on verity of building frames resting on various types of soil.

5. The present study demonstrates that, it is possible to estimate the various parameters of the prototype structure by performing the test on scaled down models and mapping the results to prototype structure using similitude laws. This will assist to evaluate most realistic behavior of prototype structure.

6. The actual performance of the model is possible to investigate by conducting the test under the typical earthquake by providing the time history to shake table.