An energy-based procedure for the assessment of seismic capacity of existing frames: Application to RC wide beam systems in Spain

Ductility of wide-beam RC frames as lateral resisting system

“…In Mediterranean countries, wide-beam reinforced concrete moment resisting frames (WBF) are a common structural solution for both code conforming and non-conforming ("substandard") buildings in low-to-moderate seismic prone areas (Arslan and Kormaz, 2007;Vielma et al, 2010;Benavent-Climent and Zahran, 2010;Inel et al, 2013;De Luca et al, 2014;López-Almansa et al, 2013;Domínguez et al, 2014Domínguez et al, , 2016. On the other hand, such widespread employment of wide beams (WB) instead of conventional deep beams (DB) in seismic regions is more justified by architectural requirements rather than by a broad understanding of their structural behaviour -sometimes considered as intermediate between a common frame and flatslab system (Benavent-Climent, 2007).…”

Seismic performances and behaviour factor of wide-beam and deep-beam RC frames

“…(6,7) DCH (q=3.5) ≈30dbi ≈48 (6,7) -0.25hc (9,11) 0.25hc 0.25hc (16) min{L/8;8hf;hb; hc·{0.5;0.75} (18) }; min{L/8;8hf;3hb} (19) 0.25hc (22) 90% (24) Spain: NCSE-02 (2002) [14] -33%) ≈36dbi ≈55 (6,7) min{0.5hb; 0.5bc (8) } (10) -0.5bc (14) 0.25hc (8) hf·{0;2;0;2} (17) - (21 Current version of EC8 does not cover flat slab, 1.5 is the basic assumption for elastic design; new version in progress (1) For DLS but obtained from ULS displacements (2) Specific for ULS (3) Obtained from specific DLS demand spectrum (4) Depending on ag and number of storeys (5) Sufficient stiffness to ensure frame -not cantilever-behaviour in all columns (6) Formulation depending in most of the cases on ductility class, material strengths, axial load, reinforcement ratios and location of the joint (7) Considering ϕw=16mm (8) Edge beams not explicitly considered (9) Not for low-ductility design (10) Referred to gross section, not to web (11) Referred to the 90% of the required flexural reinforcement; remaining 10% within (19) (12) Required transverse beam for external connections or internal connections with moment inversion (13) Not mandatory, only for taking advantage of the column compression on the bond behaviour (14) Higher values only if proper perpendicular reinforcement is placed (15) Further research is needed (16) Also reciprocal requirement for columns in the case of wide column -narrow beam connection (17) Exterior connection with and without transverse beam, and anal...…”

Would RC wide-beam buildings in Spain have survived Lorca earthquake (11-05-2011)?

“…Such tests took profit of previous studies by other researchers [Popov et al 1992;Gentry, Wight 1994;Quintero-Febres, Wight 2001;Siah et al 2003]; these studies proposed detailing strategies and concluded that beam width must not exceed bc + 2 hc (bc and hc are base and depth of column) to ensure a satisfactory seismic performance. Posterior studies investigated numerically vulnerability of code-compliant buildings [Benavent-Climent, Zahran 2010] and of non-code-compliant buildings [Domínguez 2012;López-Almansa et al 2013]; first study proposed a methodology for assessing seismic capacity of existing frames in terms of energy while second study pointed out low seismic capacity of analyzed buildings and need of considering cooperation of nonstructural walls. More recent works discuss behavior, under Lorca input, of buildings located in Lorca [Benavent-Climent et al 2013] and of non-code compliant buildings located in any zone of Spain [Domínguez et al 2014], respectively; first study concluded that pilotis configuration makes structure prone to damage concentration and reduces its seismic capacity, while second study showed that all analyzed buildings would not have survived Lorca earthquake.…”