No abstract

No abstract

SUMMARY The paper proposes a systematic comparison between two methods of analysis that are well established in the field of earthquake engineering: nonlinear dynamic analysis and nonlinear static procedure (NSP), applied to the out‐of‐plane seismic response of two masonry façades representative of many ancient Italian churches. The comparison is based on extensive numerical analyses, which focus on the flexural and torsional mechanisms, while the in‐plane damage mechanisms and the possible detachment between the façade and the lateral walls because of a poor connection have been presently disregarded. The computations, both in the static and in the dynamic field, are based on a rigid body and spring model specifically implemented for this issue, computationally efficient and equipped with a realistic model of damage and hysteresis at the mesoscale. An innovative aspect of this study is the heuristic modelling of three‐wythe masonry, to include some typical texture effects on the macroscale nonlinear response. For each façade, two different masonry textures were considered, performing extensive dynamic analyses that offered a detailed overview about the performance under earthquakes of different intensities. In parallel, NSP and the classical N2‐based seismic assessment were applied. A critical discussion and comparison of the results of the two methods is presented to rationally appraise limits and opportunities. In particular, flexural and twisting out‐of‐plane mechanisms were clearly appraised in the dynamic field, whereas NSPs were not always able to describe the collapse, because they missed the partial failures determined by higher vibration modes, as could be expected. Copyright © 2012 John Wiley & Sons, Ltd.

The 2017 New Zealand Society for Earthquake Engineering (NZSEE) guidelines for seismic assessment of buildings recommends using SLaMA before implementing numerical analyses. The method and the NZSEE guidelines have been enhanced from the 2006 version, resulting into an efficient procedure, balancing simplicity and accuracy. This paper presents a numerical study, initiated as part of the development of the SLaMA-2017 method, to investigate the accuracy of the analytical approach via comparison with numerical 2D-pushover on 40 RC frames. SLaMA is effective in capturing the plastic mechanism of the frames, including global or soft-storey mechanisms. Further-yet-simple refinements of the procedure are suggested.

No abstract

No abstract

The simple lateral mechanism analysis (SLaMA) is an analytical method to assess the force-displacement capacity curve of Reinforced Concrete (RC) structures composed of frames, cantilever walls or dual wall/frame systems. The current version of the method was proposed in the 2017 New Zealand guidelines for the seismic assessment (NZSEE in New Zealand Society for Earthquake Engineering, the seismic assessment of existing buildings-technical guidelines for engineering assessments, Wellington, 2017). Regarding frame structures, the possible influence of infill walls is currently considered locally with checks on the RC members. However, it is universally known that infills have a major effect on the global capacity curve of the frame. In this paper, a comprehensive SLaMA method for infilled frames is proposed, which allows considering the influence of the infills on the global force-displacement curve without any numerical algorithm. The extended SLaMA method is herein formalised and it is validated in a companion paper (part 2) through an extensive parametric analysis. The extended SLaMA is based on the possibility to separately calculate the base shear contributions of the frame and the infills, in turn based on global equilibrium considerations. Such considerations also allow defining a novel procedure to post-process the results of pushover or time-history analyses where infills are modelled as diagonal struts, or to interpret experimental tests. This allows, within a single numerical analysis, to decouple the frame and infills contributions to the base-shear capacity. The decoupling procedure is herein demonstrated for an ideal two-storey, one-bay masonry-infilled frame with different infills configurations.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

No abstract