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This paper aims to show the application of site-specific response spectra in the analysis of buildings that are supported by lightly reinforced precast concrete walls. Previous surveys on load-bearing precast reinforced concrete walls in multi-storey buildings in low-to-moderate seismic regions have found that many existing precast walls are lightly reinforced with a connection reinforcement ratio less than the wall reinforcement ratio. When these precast walls are subjected to reversed cyclic loads, the lateral response is typically controlled by rocking and the ultimate performance is governed by the ruptures of connection dowels. This paper uses moment–curvature analyses in combination with plastic hinge analyses to evaluate the force–displacement capacity of planar lightly reinforced load-bearing precast walls. The seismic performance of a building supported by these lightly reinforced precast walls can then be assessed by superimposing the capacity curve and the inelastic site-specific response spectra developed for the building site. The proposed analytical approach is illustrated through a case study building. By comparing a lightly reinforced precast wall with a comparable limited ductile reinforced concrete wall, it is also found that, although these two walls exhibit similar force capacities, the ultimate displacement capacity of the lightly reinforced precast wall is significantly lower. This finding highlights the potential seismic vulnerability of lightly reinforced precast walls in some existing buildings.

This paper aims to show the application of site-specific response spectra in the analysis of buildings that are supported by lightly reinforced precast concrete walls. Previous surveys on load-bearing precast reinforced concrete walls in multi-storey buildings in low-to-moderate seismic regions have found that many existing precast walls are lightly reinforced with a connection reinforcement ratio less than the wall reinforcement ratio. When these precast walls are subjected to reversed cyclic loads, the lateral response is typically controlled by rocking and the ultimate performance is governed by the ruptures of connection dowels. This paper uses moment–curvature analyses in combination with plastic hinge analyses to evaluate the force–displacement capacity of planar lightly reinforced load-bearing precast walls. The seismic performance of a building supported by these lightly reinforced precast walls can then be assessed by superimposing the capacity curve and the inelastic site-specific response spectra developed for the building site. The proposed analytical approach is illustrated through a case study building. By comparing a lightly reinforced precast wall with a comparable limited ductile reinforced concrete wall, it is also found that, although these two walls exhibit similar force capacities, the ultimate displacement capacity of the lightly reinforced precast wall is significantly lower. This finding highlights the potential seismic vulnerability of lightly reinforced precast walls in some existing buildings. [ABSTRACT FROM AUTHOR]

Ground motion prediction equations (GMPEs), which give estimates of ground motion parameters for any given earthquake scenario expressed in terms of magnitude, distance and site class, have been an essential element in probabilistic seismic hazard assessment for development of seismic hazard maps. Traditionally, most designers of built infrastructure do not become involved directly with their use although seismic hazard maps are being used in the design of structures. In pursuing site-specific seismic design of a civil engineering structure, it is necessary of engineers to make direct use of GMPEs to construct the conditional mean spectra, as this forms part of the advanced design process. This article is written for engineers who have interests in going for site-specific seismic design in a stable (low-to-moderate seismicity) tectonic environment including countries like Australia, most part of India, Malaysia and Western Europe. The development of stochastic GMPEs in a stable region involves seismological modelling and stochastic simulations (leading to the development of stochastic GMPEs) which have been evolving for almost half a century. This article aims at presenting the state-of-art review for this specialised field of technology. The targeted readers are engineers who have no prior knowledge in engineering seismology. Summarising decades long of research and development in one article serves the purpose of facilitating the uptake of GMPEs and site-specific seismic design by engineering practitioners. Thus, many seismological phenomena are explained in engineering terms. This review article should also be beneficial to researchers who are engaged into investigation into the seismic performance of structures. [ABSTRACT FROM AUTHOR]

Owing to the new rules of the German National Annex to EN 1998‐1, the relevance of the seismic action has increased, materialising in extended seismic areas and higher spectral accelerations. This may lead to seismic loading being decisive on the design of steel and composite frames. However, the demand is lower in Germany than in other seismic areas. Consequently, these challenges are addressed in an ongoing German national research project, by developing joints with dissipative connections, classified as semi‐rigid and partial‐strength, for steel and composite frames that could allow for the use of behaviour factors in the range of 1.5 to 3. The development started with typical connections from the German catalogue, designed to withstand static loads in the elastic range, followed by performance and detailing improvements. Developments (e.g., increase in sagging/hogging bending: 125 %/18 % of steel joints and 70 %/40 % of partially composite joints) resulted from pre‐test finite element analyses (FEA) on joints and frame models. Improvements to joint detailing were made according to the provisions of the newest draft of Eurocode 8. The optimised joints were integrated in frame specimens, which are currently being tested under monotonic and cyclic loads at RWTH‐Aachen University. This article introduces the developed joint solutions, describes the experimental and numerical programs and presents the monotonic response of frame specimens based on the results of FEA, as well as the main conclusions. [ABSTRACT FROM AUTHOR]

Tall buildings featuring transfer structures are commonly constructed in lower seismicity regions. Discontinuities in load paths of structural systems in the building were found to compromise ductility of the building. In a force-based seismic design procedure, response modification (R) factor is uncertain to cater for the undesirable features. This article presents a methodical approach for evaluating the seismic performance of such buildings. Results of incremental dynamic analyses of case study buildings indicated a high R-factor, due to the inherent over-strength. A local amplification factor ( β D T ) is recommended to account for localised shear at structural walls above the transfer floor level. [ABSTRACT FROM AUTHOR]

Automated Multi-Depth Shuttle Warehouses (AMSWs) are compact storage systems that provide a large surface occupation and therefore maximum storage density. AMSWs represent the future of storage technology, providing substantial savings in terms of cost, space, and energy with respect to traditional warehouses. Currently, designers refer to the standard building codes for the seismic design of AMSWs. Since structural characteristics of AMSWs are considerably different from the steel structures of typical buildings, this current approach used by designers is questionable in terms of safety and efficiency. In this article, the behavior of 5 AMSW structures has been studied performing 150 time-history analyses by direct integration including P-Delta effects. Demand/capacity ratios calculated for each element showed the dominance of the brittle failure mechanism in AMSWs subjected to low-to-moderate seismic actions. These mechanisms mainly took place in upright columns and their base connections prior to the activation of ductile energy dissipation mechanisms of the structure. Based on the results, further improvements have been recommended for the future design provisions, which may lead to a safer seismic design of AMSWs. [ABSTRACT FROM AUTHOR]

Assessing seismic risk in low-to-moderate seismic activity areas like French mainland is a challenge. In these areas, the estimation of large earthquake hazard calls for models driven by sparse observation data and interpretative seismic knowledge. This leads models used in probabilistic seismic hazard assessment (PSHA) and declustering algorithms to large epistemic uncertainties that are overrepresented due to the large amount of parameters used in it. To concentrate epistemic uncertainties into one single method, we intend to limit the number of parameters under consideration by using the non-parametric inter-event time method. This method is empirical and needs a lot of data to be accurate. In the context of sparse large earthquake data, this paper proposes an implementation of the inter-event time method that ensures the stability of main shock proportions for sparse seismic data. We call this implementation magnitude of inferred main shock proportion (MIMP). This method is applied to the historical French seismic catalogue. We use a Monte Carlo Markov Chain to sample the whole space of magnitude uncertainties contained in this catalogue. We produce a set of equiprobable main shock proportion–magnitude and frequency–magnitude distributions. Results are discussed in the light of reference works published in the literature. [ABSTRACT FROM AUTHOR]

Mainland France is characterized by low-to-moderate seismic activity, yet it is known that major earthquakes could strike this territory (e.g., Liguria in 1887 or Basel in 1356). Assessing this French seismic hazard is thus necessary in order to support building codes and to lead prevention actions towards the population. The Probabilistic Seismic Hazard Assessment (PSHA) is the classical approach used to estimate the seismic hazard. One way to apply PSHA is to generate synthetic earthquakes by propagating information from past seismicity and building various seismic scenarios. In this paper, we present an implementation of a stochastic generator of earthquakes and discuss its relevance to mimic the seismicity of low-to-moderate seismic areas. The proposed stochastic generator produces independent events (main shocks) and their correlated seismicity (only aftershocks). Main shocks are simulated first in time and magnitude considering all available data in the area, and then localized in space with the use of a probability map and regionalization. Aftershocks are simulated around main shocks by considering both the seismic moment ratio and distribution of the aftershock’s proportion. The generator is tested with mainland France data.

Steel concentrically braced frame (CBF) configuration is a common construction application in Europe. In the low-to-moderate seismicity context, European building codes provide two alternative design methods for CBFs; engineers have to choose between a “non-dissipative” method (DCL) neglecting all seismic provisions, and a “dissipative” one (DCM), applying its complex and expensive ductility requirements. Currently, the preferred method is the former one, because of its simplicity. Such a choice may lead on one side to oversized profiles that are unduly expensive, on the other side to possibly unsafe solutions due to the unpredictable nature of the regions characterized by low-to-moderate seismicity, where rare but strong earthquakes are foreseeable. On the other hand, enforcing engineers to apply strict “high-dissipative” rules seems too conservative for this case, which would result in over-safe, but uneconomic structures. This article proposes an adjusted design approach for the low-to-moderate seismicity design of CBF structures, aiming to satisfy both economy and safety criteria. The proposed approach is based on the exploitation of the three features of CBF systems, which have not been deeply investigated so far: “frame action provided by gusset plates”, “contribution of compression diagonal and its post-buckling strength and stiffness”, and “energy dissipation capacity of non-ductile bracing joint connections”. The paper investigates these aspects by means of incremental dynamic analysis of case studies, based on the numerical models calibrated on full-scale experimental tests published elsewhere by the authors. As a result, it provides design recommendations and presents economic comparisons between the buildings designed with current Eurocode approach and the proposed one. [ABSTRACT FROM AUTHOR]

In low-to-moderate seismicity regions, the limited seismic displacement demands could probably render tall buildings remaining nearly elastic during a maximum considered earthquake. Previous studies have shown the capability of the uniform Timoshenko beam model in resembling the dynamic behaviors of regular buildings. This article describes response spectrum analyses on the non-uniform Timoshenko beam model, considering the first four vibration modes to assess the seismic demands on various building types, which encompass low-rise wall or frame buildings and high-rise shear wall buildings with or without transfer structures. Simplified design charts correlating the global seismic demands – spectral accelerations, maximum interstory drift ratios, roof drift ratios and required shear areas – to the fundamental translational period of each building are developed. The structural periods could be determined from in-situ dynamic tests, full frame models or an appropriate period-height equation, the latter of which is provided here by calibrating from in-situ vibration tests of regional buildings constructed in compliance with British Standards. This simplified approach provides a fast track to seismic performance for both existing and new buildings, which could easily be comprehended by engineers without prior knowledge of seismic design. [ABSTRACT FROM AUTHOR]