Evaluation and suggestions for improvement of seismic design procedures for R/C walls in dual systems

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. SUMMARY This paper aims to shed some further light on the seismic behaviour and design of reinforced concrete (R/C) walls which form part of dual (frame + wall) structures. The significance of post-elastic dynamic effects is recognized by most seismic codes in the definition of the design action effects on walls, i.e. bending moments and shear forces. However the resulting envelopes are not always fully satisfactory, particularly in the case of medium-to-high-rise buildings. Relevant provisions of modern seismic codes are first summarized and their limitations discussed. Then an extensive parametric study is presented which involves typical multi-storey dual systems that include walls with unequal lengths, designed according to the provisions of Eurocode 8 for two different ductility classes (M and H) and two effective peak ground acceleration levels (0.16g and 0.24g). The walls of these structures are also designed to other methods, such as those used in New Zealand and Greece. The resulting different designs are then assessed by subjecting the structures to a suite of records from strong ground motions, carrying out inelastic time history analysis, and comparing the results with the design action effects. It is found that for (at least) the design earthquake intensity, the first two modes of vibration suffice for describing the seismic response of the walls. The bending moment envelope, as well as the base shear of each wall, are found to be strongly dependent on the second mode effect. As far as the code-prescribed design action effects are concerned, only the NZ Code was found to be consistently conservative, while this was not always the case with EC8. A new method is then proposed which focusses on quantifying in a simple way the second mode effects in the inelastic response of the walls. This procedure seems to work better than the others evaluated herein. Permanent repository link

Betonarme Perdelerin Kesme Güvenliğinin TBDY-2018’e Göre İncelenmesi

“…Bu çalışmada, örnek olarak seçilen 20 katlı betonarme perdeli-çerçeve sistemin dikdörtgen ve L-kesitli perde elemanlarında tasarım kesme kuvvetlerinin yeterliliği TBDY-2018 [29] esasları doğrultusunda araştırılmıştır. Literatürde yer alan çalışmalarda [24,[30][31][32] değinilen eksikliği gidermek üzere, doğrusal/doğrusal olmayan sayısal analizler incelenen binanın 3boyutlu sonlu eleman modelleri dikkate alınarak gerçekleştirilmiştir. Analizler neticesinde, L-kesitli perdede TBDY-2018'e [29] göre hesaplanan tasarım kesme kuvvetinin, mühendislik kabulleri ve tasarım varsayımları çerçevesinde kabul edilebilir bir oranla da olsa aşılmış olması, süneklik düzeyi yüksek betonarme perdelerde gevrek kırılma riskine işaret etmiştir.…”

Dynamic shear force amplification in regular frame–wall systems

“…Of course, the regression analysis here covers the number of stories up to 12 and structural periods up to 1.5 s. For the structures in the high‐rise range, generally period dependent amplification factors that yield larger values are proposed, e.g. β v = 2.9 T −1.0 ≥ 1.0 (Kappos and Antoniadis, ).…”