A direct design procedure for frame structures with added viscous dampers for the mitigation of earthquake-induced vibrations

Abstract A direct procedure for the seismic design of building structures with added viscous dampers is described in this paper. The procedure is applicable to regular multi-storey frame structures which are characterized by a period of vibration lower than 1.5 s. It aims at providing practical tools for the direct identification of the mechanical characteristics of the manufactured viscous dampers as well as for the structural design of the frame members’ so that a target level of performance is achieved. The design philosophy is to limit the structural damages under severe earthquakes. First, a target damping reduction factor is selected to achieve the desired reduction in the peak structural response. The linear damping coefficients of the equivalent linear viscous dampers are calculated taking advantage of modal damping ratios properties of classically damped systems. Then, simple analytical formulas for the estimation of peak inter-storey velocities are used, together with an energy criterion to identify the non-linear mechanical characteristics of the manufactured viscous dampers. Finally, the internal actions in the structural elements are estimated through the envelope of two equivalent static analyses (ESA), namely: ESA1 in which the naked structure is subjected to a first set of equivalent lateral forces, and ESA2 in which the structure, with rigid diagonal braces substituting the added viscous dampers, is subjected to a second set of equivalent lateral forces. At this preliminary stage of the research, the procedure is targeted for the preliminary design phase, since correction factors to improve the accuracy in the estimation of the peak inter-storey velocities needs to be calibrate. Therefore, for final design, non-linear dynamic analyses are recommended.

[1]  F. Mazzolani,et al.  Design of Steel Structures for Buildings in Seismic Areas: Eurocode 8: Design of structures for earthquake resistance. Part 1-1 - General rules, seismic actions and rules for buildings , 2017 .

[2]  Tomaso Trombetti,et al.  Force reduction factor for building structures equipped with added viscous dampers , 2013, Bulletin of Earthquake Engineering.

[3]  Michael C. Constantinou,et al.  Experimental & Analytical Investigation of Seismic Response of Structures With Supplemental Fluid Viscous Dampers , 1992 .

[4]  Andrew S. Whittaker,et al.  Equivalent Lateral Force and Modal Analysis Procedures of the 2000 NEHRP Provisions for Buildings with Damping Systems , 2003 .

[5]  M. Constantinou,et al.  Elastic and Inelastic Seismic Response of Buildings with Damping Systems , 2002 .

[6]  Tomaso Trombetti,et al.  On the modal damping ratios of shear-type structures equipped with Rayleigh damping systems , 2006 .

[7]  Tomaso Trombetti,et al.  On the dimensioning of viscous dampers for the mitigation of the earthquake-induced effects in moment-resisting frame structures , 2013, Bulletin of Earthquake Engineering.

[8]  Oren Lavan,et al.  Fully stressed design of passive controllers in framed structures for seismic loadings , 2006 .

[9]  Andrew S. Whittaker,et al.  Validation of the 2000 NEHRP Provisions’ Equivalent Lateral Force and Modal Analysis Procedures for Buildings with Damping Systems , 2003 .

[10]  Tomaso Trombetti,et al.  A Five-Step Procedure for the Dimensioning of Viscous Dampers to Be Inserted in Building Structures , 2010 .

[11]  Michael C. Constantinou,et al.  Seismic response of structures with supplemental damping , 1993 .

[12]  Tomaso Trombetti,et al.  Peak velocities estimation for a direct five-step design procedure of inter-storey viscous dampers , 2016, Bulletin of Earthquake Engineering.