RESEARCH ARTICLE
Seismic Design of Steel Frames Equipped by Control Devices
Nikos G. Pnevmatikos*, 1, George Hatzigeorgiou2
Article Information
Identifiers and Pagination:
Year: 2014Volume: 8
First Page: 300
Last Page: 309
Publisher ID: TOBCTJ-8-300
DOI: 10.2174/1874836801408010300
Article History:
Received Date: 21/6/2014Revision Received Date: 15/09/2014
Acceptance Date: 30/09/2014
Electronic publication date: 31/12/2014
Collection year: 2014
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
The design philosophy of EC8 is to ensure that in the event of the design earthquake, human lives are protected and no collapse will occur, while extended damages will be observed. This is achieved by ductility and capacity design. This design philosophy drives to an additional cost for repairing damage of structures. On the other hand, it is costly and uneconomic to design structures behaving in elastic range, especially under high level of earthquake excitation. An alternative direction to this strategy, which is examined in this paper, is to design a controlled structure capable to resist a design earthquake loads, remaining in elastic range and thus without damage. The idea behind this philosophy is that one portion of earthquake loading will be resisted by a control system while the rest will be resisted by the structure. The structure, initially, is analyzed and designed according to the current codes. The elastic and design earthquake forces are first calculated according to the elastic and the design spectrum. The required control forces are calculated as the difference between elastic and design forces. The maximum value of capacity of control devices is then compared with the required control force. If the capacity of the controlled devices is higher than the required control force then the control devices are accepted and installed to the structure. Then, the structure is designed according to the design forces. In the case where the maximum available control device capacity is lower than the demanded control force then an additional portion of control forces should be resisted by the building. In that case, an iterative procedure is proposed and a scale factor, , that reduces the elastic response spectrum to a new design spectrum, is calculated. The structure is redesigned based on the new design spectrum and then the devices are installed to the structure. The proposed procedure imposes that the controlled structure will behave elastically for the design earthquake and no damage will occur, consequently no additional repair cost will be needed. An initial cost of buying and installing the control devices is required. In order to ensure that the controlled structure behaves elastically, a dynamic control analysis with saturation and time delay control is performed. Following the proposed procedure the numerical results show that the structure remains in elastic and no damage occurs.
