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The new trend toward modern earthquake-resistant design of buildings based on nonlinear dynamic analysis accounting for peak and energy demands requires efficient ground motion record selection procedures. For this reason, in the present work, two record selection strategies based on acceleration and input energy spectrum considering the spectral shape via Np are presented. Furthermore, both record selection strategies are optimized by means of four artificial intelligence (AI) techniques: Genetic Algorithms (GA), Harmony Search (HS), Particle Swarm Optimization (PSO) and Vibrating Particle System (VPS). In particular, the effectiveness of each AI approach toward the best set of ground motion records for nonlinear dynamic analysis is compared. For this aim, spectral acceleration and input energy design spectra were considered, as well as 1024 seismic records obtained from the Pacific Earthquake Engineering Research Center. For all the AI or meta-heuristic approaches, the fitness function used is focused on minimizing the difference between the average spectrum of eleven ground motion records and the design spectrum using the well-known parameter Np, which represents the spectral shape in a range of periods. In addition, a penalization is included for those spectra with very large or low demands. Thus, 24 sets of eleven seismic records that can be used for nonlinear dynamic analysis of structures with a fundamental period of vibration of 0.6, 1.2 and 1.8 seconds were obtained and purposes. The results demonstrate the ability of the two records selection strategies analyzed and the four meta-heuristic procedures, achieving results quickly and simply regardless of the type of demands, intensities and periods considered. Finally, it is concluded that the VPS algorithm is better in comparison with GA, HS, and PSO since it obtains superior results in almost all the selected cases. [ABSTRACT FROM AUTHOR]

This study investigates the seismic response of archetype infilled reinforced concrete buildings representative of the existing Italian residential building stock by focusing on the modelling aspects of the existing infills, including their failure modes and interaction with the frame. The study compares the seismic response of the considered buildings, investigated through nonlinear static and dynamic analysis, with reference to two Performance Levels. The main variables considered are the construction period, the site hazard, the number of stories and the infill configuration. The observed return period capacity of the buildings mainly depends on the site hazard and on the construction period. [ABSTRACT FROM AUTHOR]

Correlating different intensity measures (IMs) enables the joint consideration of multiple IMs in various performance-based earthquake engineering applications, such as ground motion selection. The correlations between the spectral input energy and spectral accelerations have not been previously examined. This study develops a correlation model quantifying the uncertainties due to GMPE selection and a finite sample size. The results show a strong correlation between the spectral amplitudes at the same period, and the correlation decreases as the period difference increases. With the proposed model, ground motion characteristics reflected by the input energy can be explicitly considered in performance-based earthquake engineering applications. [ABSTRACT FROM AUTHOR]

This study investigates the seismic response of reinforced concrete buildings designed according to Italian regulations and construction practices for three different post-WWII periods, up to the 1990s. Additional key investigated parameters are the number of stories and the site hazard. The main issues related to non-seismic and early seismic design practices are discussed. The study compares the seismic response of the buildings, investigated through nonlinear static and dynamic analyses, with reference to two performance levels, confirming and quantifying the increase in performance with the design codes evolution. The seismic behavior of infilled frames is investigated in the companion paper. [ABSTRACT FROM AUTHOR]

Existing masonry buildings show significant vulnerability to seismic sequences. This topic has so far received limited attention, concentrated on simplified simulations of the global response, governed by in-plane wall behaviour, or on a very detailed representation of monumental buildings. This paper looks at the out-of-plane response of an ordinary-building wall restrained by an elastoplastic tie-rod under Italian seismic sequence conditions. A recently proposed model is extended to account for a flexible interface defined by its compressive strength and stiffness. Response to 30 series of four events belonging to six seismic sequences shows limited damage accumulation in most cases, with most hysteretic energy dissipated in a single plastic cycle. In these cases, we find a strong correlation between the maximum rotation and intensity measures such as peak ground acceleration, peak ground velocity and acceleration spectrum intensity. This suggests that current hazard studies are adequate and that design can be based on the features of the maximum event expected. However, exceptions are noticed for the 2016 Central Italy Earthquakes, in which the considered sequence is made of multiple mainshocks inducing significant damage accumulation, but can still be resolved by a practitioner resorting to equivalent static procedures by reducing the commonly assumed behaviour factor. [ABSTRACT FROM AUTHOR]

This study investigates the seismic response of reinforced concrete buildings designed according to the current Italian building code. Number of stories, site hazard, presence and distribution of masonry infill panels, and type of lateral resisting system are the key investigated parameters. The main issues related to design and modeling are discussed. Two Limit States are considered, namely Global Collapse and Usability-Preventing Damage. The main aim of the study is a comparison between the seismic response of the buildings, investigated through nonlinear static and dynamic analyses. Irregularity in the distribution of infill panels and site hazard emerge as the most influential parameters. [ABSTRACT FROM AUTHOR]

The objective of this article is to study the effects of structural nonlinear behavior on Floor Response Spectra (FRS) of existing reinforced concrete frames. This study examines how the FRS vary with the level of post-elastic behavior in buildings of different number of stories and masonry infill wall configurations. The effect of damping modeling assumptions is also investigated. Differences and similarities with findings from the literature are discussed. On the basis of the obtained results, a commentary on the adequacy of basic assumptions used in predictive equations proposed by different seismic codes is offered. [ABSTRACT FROM AUTHOR]

The new trend toward modern earthquake-resistant design of buildings based on nonlinear dynamic analysis accounting for peak and energy demands requires efficient ground motion record selection procedures. For this reason, in the present work, two record selection strategies based on acceleration and input energy spectrum considering the spectral shape via Np are presented. Furthermore, both record selection strategies are optimized by means of four artificial intelligence (AI) techniques: Genetic Algorithms (GA), Harmony Search (HS), Particle Swarm Optimization (PSO) and Vibrating Particle System (VPS). In particular, the effectiveness of each AI approach toward the best set of ground motion records for nonlinear dynamic analysis is compared. For this aim, spectral acceleration and input energy design spectra were considered, as well as 1024 seismic records obtained from the Pacific Earthquake Engineering Research Center. For all the AI or meta-heuristic approaches, the fitness function used is focused on minimizing the difference between the average spectrum of eleven ground motion records and the design spectrum using the well-known parameter Np, which represents the spectral shape in a range of periods. In addition, a penalization is included for those spectra with very large or low demands. Thus, 24 sets of eleven seismic records that can be used for nonlinear dynamic analysis of structures with a fundamental period of vibration of 0.6, 1.2 and 1.8 seconds were obtained and purposes. The results demonstrate the ability of the two records selection strategies analyzed and the four meta-heuristic procedures, achieving results quickly and simply regardless of the type of demands, intensities and periods considered. Finally, it is concluded that the VPS algorithm is better in comparison with GA, HS, and PSO since it obtains superior results in almost all the selected cases. [ABSTRACT FROM AUTHOR]