دانلود رایگان مقاله انگلیسی طراحی بهینه میراگرهای ویسکوز غیرخطی برای ساختارهای قاب - الزویر 2017

ABSTRACT

It is well-known that in order to decrease displacements and accelerations in a frame structure during earthquakes, purely viscous dampers can be effectively employed, allowing for a remarkable dissipation of seismic input energy. The design of such devices, however, is still an open issue, since it is often carried out by means of inefficient trial-and-error procedures, or simplified analytical approaches which do not guarantee the optimal exploitation of the dampers. This work investigates the use of an optimisation-based approach for the design of nonlinear purely viscous dampers, aimed at improving the seismic behaviour of frame structures. The potential and the flexibility of the method are shown through an illustrative example displaying how different structural requirements (limitation or minimisation of inter-storey drifts and/or forces transferred by the devices) can be easily taken into account by means of a suitable formulation of a constrained optimisation problem.

4. Conclusions

In this work, a methodology for the design of nonlinear dampers for seismic retrofitting of existing frames or for newly designed structures is described. The procedure is based on an optimal-design paradigm, in which the best configuration for the dampers is sought by considering pre-defined objectives and constraints. The process is managed by an optimisation software utilising Genetic Algorithms. Through a simple example taken from the literature, it is showed how this type of approach based on the optimisation of the structural response has great potential and flexibility. In fact, it allows one to consider a wide range of possibilities both in the input variables (number and characteristics of the devices) and objectives (interstorey drifts, forces transmitted by the dampers, etc).

Future works will focus on the extension of the method to ULS design by means of more accurate representation of nonlinear behaviour of the RC members and to 3D structures and loadings. Multi-objective optimisation will also be investigated.