Limit Period Based on Approximate Analytical Methods Estimating Inelastic Displacement Demands of Buildings

Abstract

The Algerian seismic design code (RPA99) recommends a limit on the elastic period as a governing factor in the design process of low and mid‐rise buildings, function of the structural system regardless of the related ductility level. The recommended limit criterion is evaluated through approximate analytical methods using drift limit. The assignable displacement ductility ratio for the force reduction factor is derived from some well established R‐μ‐Tn expressions. The limit period evaluation procedure (proposed in this paper) agrees with a capacity design approach since it allows for adjusting the required resistance demand level function of a ductility level resulting from code's steel recommendations. This will enhance seismic design procedure based on a target‐period approach such as in the Algerian seismic design code RPA99, to fulfil the minimum required two performance levels or to satisfy three performance levels if a damage control is considered. A critical study is carried out considering three regular earthquake‐resistant concrete framed structures and taking into account the specificity of various types of soils, namely rock, firm and soft. A comparison of the obtained results shows clearly that the RPA99 recommended limit is only valid for nude moment resisting frames.

A displacement-based seismic design for reinforced concrete structures

“…It should be noted that this limit corresponds to the immediate occupancy performance level (Djebbar et al, 2007) and dynamic loading (Oller et al, 1990;Belytschko, 2007 and2008;Rabczuk and Eibl, 2006;Belytschko et al, 2000;Saatci and Vecchio, 2009). As: 0 < T < T 1 , substituting in Eq.…”

Limited Deformability Design of High-Strength Concrete Beams in Low to Moderate Seismicity Regions / Stipriojo Betono Sijų Ribinio Deformatyvumo Skaičiavimas Žemo Ir Vidutinio Seismingumo Regionuose

“…This is understandable because the deformability demand in non-seismic region is not very large and that provided by the existing deemed-to-satisfy rules has been proven to be sufficient for RC beams made of normal-strength concrete (NSC) and normal-strength steel (NSS) (Park and Ruitong 1988;Kwan et al 2006). However, for RC beams located in regions of low to moderate seismicity, the design for sufficient deformability to cater for the imposed seismic demand (Kuang and Atanda 2005;Djebbar and Chikh 2007;Seifi et al 2008;Tsang et al 2009) is as crucial as the design of sufficient flexural strength. Furthermore, the deformability provided to these beams should be larger than that provided to those in non-seismic regions.…”