High strength steel in chevron concentrically braced frames designed according to Eurocode 8

Abstract The use of high strength (HS) steel is becoming very popular thanks to their economical and mechanical benefits. Seismic applications represent the rational field to exploit the high performance of HS steel, by means of the “dual-steel” concept that combines the HS with Mild Carbon (MC) steel in order to increase the strength of non-dissipative elements, thus enforcing a ductile overall failure mode. In this paper, a comprehensive parametric study devoted to investigate the seismic performance of EC8-compliant dual-steel chevron Concentrically Braced Frames (CBF) is presented and discussed. Both static and dynamic nonlinear analyses were carried out to investigate the seismic performance for three limit states: damage limitation (DL), severe damage (SL) and near collapse (NC). The investigated parameters cover both geometric and mechanical variables, as the type of columns, span length, number of stories and spectral shape. The analyses showed that the use of HS steel in EC8-compliant CBFs is effective to avoid the damage in the brace-intercepted beams. However, due to the flexibility of the brace-intercepted beams made of HS steel, the bracing members are characterized by severe deformation demand in compression and elastic response in tension. Also, the behavior factors evaluated by means of dynamic analyses are smaller than those recommended by Eurocode 8. The comparison between dual steel CBFs with those entirely made of MC steel showed that in the second case the use of heavier profiles for braced-intercepted beams can be beneficial to reduce the brace ductility demand in compression and to activate their yielding in tension. Thereby, numerical results show that for chevron CBFs it seems more efficient to guarantee adequate stiffness than increasing the material strength for beams. On the contrary, the use of HS steel is effective for columns of the braced spans, reducing the material consumptions while providing satisfactory structural efficiency.

[1]  Raffaele Landolfo,et al.  The influence of out‐of‐straightness imperfection in physical theory models of bracing members on seismic performance assessment of concentric braced structures , 2015 .

[2]  Vincenzo Piluso,et al.  Theory of plastic mechanism control: State-of-the-art , 2015 .

[3]  Francisco Virtuoso,et al.  Nonlinear Analysis of Space Frames , 2006 .

[4]  F. Filippou,et al.  Mixed formulation of nonlinear beam finite element , 1996 .

[5]  Vincenzo Piluso,et al.  Failure Mode Control of X-Braced Frames Under Seismic Actions , 2008 .

[6]  Edoardo M. Marino.  A unified approach for the design of high ductility steel frames with concentric braces in the framework of Eurocode 8 , 2014 .

[7]  Demonceau Jean-François,et al.  Field of application of high strength steel circular tubes for steel and composite columns from an economic point of view , 2011 .

[8]  A. S. Elnashai,et al.  Confined concrete model under cyclic load , 1997 .

[9]  Vincenzo Piluso,et al.  FAILURE MODE CONTROL OF MRF-CBF DUAL SYSTEMS , 2010 .

[10]  Robert Tremblay,et al.  Seismic performance of low- and medium-rise chevron braced steel frames , 2001 .

[11]  Hanbin Ge,et al.  Uniaxial stress–strain relationship of concrete confined by various shaped steel tubes , 2001 .

[12]  Suhaib Salawdeh,et al.  Validation of nonlinear time history analysis models for single‐storey concentrically braced frames using full‐scale shake table tests , 2013 .

[13]  Raffaele Landolfo,et al.  The influence of beam stiffness on seismic response of chevron concentric bracings , 2015 .

[14]  R. Landolfo,et al.  Modelling aspects of the seismic response of steel concentric braced frames , 2013 .

[15]  R. Landolfo.  Assessment of EC8 provisions for seismic design of steel structures , 2013 .

[16]  Hervé Degée,et al.  Optimizing the seismic performance of steel and steel-concrete structures by standardizing material quality control (OPUS) , 2008 .

[17]  Vincenzo Piluso,et al.  Failure Mode and Drift Control of MRF-CBF Dual Systems , 2010 .

[18]  Stephen A. Mahin,et al.  Model for Cyclic Inelastic Buckling of Steel Braces , 2008 .

[19]  A. Y. Elghazouli,et al.  Behaviour of tubular steel members under cyclic axial loading , 2006 .

[20]  Vincenzo Piluso,et al.  Influence of homoschedasticity hypothesis of structural response parameters on seismic reliability of CB-frames , 2011 .

[21]  Bulent Akbas,et al.  Seismic demand on brace-intersected beams in two-story X-braced frames , 2014 .

[22]  Dimitrios G. Lignos,et al.  Dynamic Response of a Chevron Concentrically Braced Frame , 2013 .

[23]  Vincenzo Piluso,et al.  Seismic reliability of traditional and innovative concentrically braced frames , 2011 .

[24]  K. S. Kölbig,et al.  Errata: Milton Abramowitz and Irene A. Stegun, editors, Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, National Bureau of Standards, Applied Mathematics Series, No. 55, U.S. Government Printing Office, Washington, D.C., 1994, and all known reprints , 1972 .

[25]  Vincenzo Piluso,et al.  Influence of Design Criteria on the Seismic Reliability of X-braced Frames , 2008 .

[26]  B. Borzi,et al.  Refined force reduction factors for seismic design , 2000 .

[27]  Vincenzo Piluso,et al.  PLASTIC DESIGN OF CB-FRAMES WITH REDUCED SECTION SOLUTION FOR BRACING MEMBERS , 2010 .

[28]  Yoshihiro Kimura,et al.  Effect of Column Stiffness on Braced Frame Seismic Behavior , 2004 .

[29]  Vincenzo Piluso,et al.  Seismic design of chevron braces cupled with MRF fail safe systems , 2015 .

[30]  Bulent Akbas,et al.  Mechanisms in two-story X-braced frames , 2015 .

[31]  Dan Dubina,et al.  Dual high‐strength steel eccentrically braced frames with removable links , 2008 .

[32]  Luís Simões da Silva,et al.  Design of Steel Structures: Eurocode 3: Design of Steel Structures, Part 1-1: General Rules and Rules for Buildings , 2010 .

[33]  Vincenzo Piluso,et al.  Advances in theory of plastic mechanism control: closed form solution for MR‐Frames , 2015 .

[34]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[35]  Luciano R. O. de Lima,et al.  Seismic performance of dual-steel moment resisting frames , 2014 .

[36]  Vincenzo Piluso,et al.  On the use of HSS in seismic-resistant structures , 2014 .

[37]  Gian A. Rassati,et al.  Modeling of different bracing configurations in multi-storey concentrically braced frames using a fiber-beam based approach , 2014 .

[38]  Vincenzo Piluso,et al.  Moment frames – concentrically braced frames dual systems: analysis of different design criteria , 2016 .

[39]  Vincenzo Piluso,et al.  Theory of plastic mechanism control for MRF–CBF dual systems and its validation , 2014, Bulletin of Earthquake Engineering.

[40]  Ahmed Y. Elghazouli,et al.  Assessment of European seismic design procedures for steel framed structures , 2010 .

[41]  Dan Dubina,et al.  DUAL-STEEL FRAMES FOR MULTISTORY BUILDINGS IN SEISMIC AREAS , 2010 .

[42]  Edoardo M. Marino,et al.  Seismic performance and new design procedure for chevron-braced frames , 2006 .