- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
Friction-based structural control is an available strategy for reducing the seismic response of buildings. The friction dampers in such systems can be operated using passive and semiactive control. Passive dampers with constant, pre-defined capacity are effective and simple, but their adaptability to a broad range of frequency excitations is limited and their optimal configuration is complex. Semiactive control provides a means to vary the dampers’ capacity to their optimum levels in real-time, but time delays in the control action may affect their performance. In this investigation, a passive system is initially introduced in a multi-storey steel frame to identify a threshold of optimum control force demand related to the limits of the building’s elastic response. A new semiactive algorithm is then introduced to adjust the dampers’ capacity based on the current deformation state across the building. From simulations of the non-linear response of the frame, the semiactive system reduced the structural response to levels similar to the optimum passive control, with more uniform distributions of storey drift. The control system had optimum performance when a range of time delays was included to simulate different regulator mechanisms.
Passive friction dampers were used as initial retrofit solution for a low-rise moment resistant steel frame. The optimum performance varied for different capacity of the dampers and different ground motions. A threshold of control forces was identified for a set of six earthquake records scaled to the same PGA to provide similar levels of intensity, but different frequency content. The AδVG semiactive control was presented as a possible solution to the difficulty of finding the optimum configuration of passive dampers. The semiactive control allowed real-time variation of slip-loads based on minimal feedback of the actual deformation state across the building. The comparison of the structural response with both control schemes demonstrated advantages of the semiactive system, including: (i) self-regulation that results in optimum performance when compared to passive control, (ii) increased adaptability to different ground excitations; (iii) narrow range of control force demand that is correlated with the actual resistance of the building, hence limiting excessive additional loads in structural elements; and (iv) more uniform distributions of inter-storey drift. The numerical results, including time delays to simulate different regulator mechanisms showed a comparable performance for the system with and without delays.