Anti-Seismic Analysis Of Mild Steel Damper On Steel-Frame Structures In High-Intensity Earthquake Area

Under the action of a strong earthquake, the traditional structure will inevitably enter into the elastic-plastic phase because it often dissipates the seismic energy by itself, thus causing the overall structure to be damaged or even collapse and producing irreversible consequences. However, it is now possible to protect the major structure through adopting the energy dissipation and seismic reduction technology to equip the structure with some energy dissipation and seismic reduction devices that are able to dissipate part of the seismic energy impacting the structure and reduce the possibility of major structure entering into the elastic-plastic phase. Mild steel damper is a kind of passive energy-intensive device, but its position, layout and model determines the impact on the seismic behavior of the structure. For this reason, it is critical to find a way of determining reasonable parameters for the damper, but now, there is still no clear and unified norms and standards for reference. This paper compares and analyzes such seismic response parameters as interlaminar shear, inter-story displacement, interlaminar displacement angle and interlaminar acceleration of the pure steel frame structure, set mild steel damper and set common eccentric brace in the case of unusual and usual earthquake (area hit by earthquake with9-degree seismic intensity) through using the software of finite element analysis SAP2000to conduct time history analysis and building models for different plans based on the project examples in the high-intensity earthquake area. The results show that, similar to the common brace, mild steel damper can provide stronger lateral stiffness to the structure in the case of usual earthquake; and effectively reduce the seismic response of the structure in the case of unusual earthquake. Built on this, this paper also analyzes the influence of the position and layout of the mild steel damper on the energy dissipation and seismic reduction to get the most rational layout plan. And the results show that, not all complicated layout plans work well, but simple and effective plans are not only able to ensure the safety of the structure, but also save a lot of structure space, thus reducing the cost of structure. Finally, it is found that, in the aspect of energy dissipation and seismic reduction, new, mild steel damper will be a better choice for the practical engineering (especially in the high-intensity seismic area) after conducting the comparison of and analysis on two new mild steel damper and the one mentioned in the preliminary plan in the same plan, which provides certain theoretical reference.