Editorial for Special Issue: “Advanced Research and Prospects in Seismic Performance of Buildings”

A building’s level of seismic performance remains the greatest concern for engineers and researchers in seismic-event-prone countries. The latest earthquakes, considering the damages and losses caused, have shown the flaws in current and past visions for safer buildings. On the other hand, there are plenty of examples that should be highlighted to show the advancements made in our expertise, knowledge, and know-how around adverse seismic hazards. It is widely believed that continuous investigations into present structures, construction technique flaws, and the advantages of innovative perspectives will lead to a more secure built stock. In that sense, this special issue dedicates its objective to showing updated research to better understand the seismic behavior of different structure typologies and, in some cases, discuss their real behavior during recent earthquakes. The editors believe this work collection will serve as a valuable resource for researchers, practitioners, and policymakers alike. A summary of the SI content is below.

Gómez-Martínez and Pérez-García studied the inelastic deformation of wide beams (WBs) and conventional deep beams (DBs). Their article reports that the current approach predicts larger ultimate chord rotation but lower chord rotation ductility for WBs rather than for DBs, despite the similar curvature ductility, due to the lower plastic hinge lengths in WBs. Eurocode 8 part 3 estimates the inelastic deformation in existing reinforced concrete members separately for WBs and DBs. Therefore, the authors propose some feasible corrections in the formulations for chord rotations to reduce the bias and thus increase the robustness of the model in cross-section shape variability [1].

Hussain et al. present a research work including experimental and numerical analysis. The authors studied the seismic performance of a scaled two-story reinforced concrete frame. The structure was subjected to dynamic loads via the shaking table test, and the results obtained for (i) ductility, (ii) overstrength, and (iii) joint strength were compared with ACI-318-19 code requirements. The data could serve as a reference for calibrating and validating numerical modeling techniques for performance evaluation, which is crucial in the context of performance-based engineering [2].

Harith et al. developed a seismic hazard curve based on a conventional probabilistic seismic hazard analysis of Sabah in Malaysia. The authors have combined earthquake recurrence models with selected ground motion models to calculate the expected ground motion recurrence, such as the peak ground acceleration at the site [3].

Habieb et al. propose a retrofitting strategy for masonry construction using bamboo strips, which is seen as a viable approach because of the fast growing rate and the tensile strength of bamboo. A series of experimental tests were performed by the authors, including the bamboo tensile test, the mortar flexural test, the diagonal compressive shear test on the masonry assemblages, and the in-plane pushover test on masonry wall specimens without and with bamboo reinforcement. Retrofitted specimens with different volumes of bamboo reinforcement were also considered. The results show that applying bamboo reinforcement at a proper volume significantly increases the ultimate strength and the ductility of the masonry wall [4].

Sun et al. investigated a new connection form (USCFST-LCCFST), named the upper square concrete-filled steel tube–lower circular concrete-filled steel tube, by means of finite element modeling. Simulations of the specimens showed excellent performance in terms of ductility and load bearing capacity, indicating the suitability of the use of this solution in the design of antique building columns [5].

Dai et al. studied the influence of a heterogeneous foundation on the safety of inverted cone bottom oil storage tanks during earthquakes. The authors performed numerical simulations in ANSYS, considering wind loads, hydraulic pressure loads, and seismic loads as distributed loads with varying spatial positions. The results show that under the condition of heterogeneous foundation stiffness considering seismic action, when the coefficient of the local foundation bed is higher than that of natural silty clay, the requirement for safe use in the inverted cone-bottom storage tank can be met [6]. This study is considered an important contribution to safety considerations in oil storage tanks.

Gómez-Martínez and Pérez-García discuss and compare the capacity design provisions proposed by some European current codes—Eurocode 8, Italian NTC, and Spanish NCSE-02 [7]. Although these codes generally agree with some basic principles to ensure capacity design, they show some discrepancies regarding specific strategies. The alternative formulation proposed in the Italian code for “strong column–weak beam” turn out to be not suitable under specific circumstances, such as with large gravity loads or significant cantilever deformation in lower stories. Regarding the value for axial load in columns to be considered for calculating the shear and moment capacities, the provisions in the three codes could eventually cause an unconservative design for perimeter columns. The entire set of Spanish provisions is proven to be ineffective due to its different fundamentals, which are based on overstrength instead of capacity.

Bilgin et al. studied the earthquake damage observed in residential and public buildings in the region affected by the earthquake of September 2019 that struck the shores of Albania. They present the commonly encountered building typologies in the region, photographs showing the amount of damage, and a technically substantiated description of the reasons behind those damages. Detailed surveys from the Durrës earthquakes show that there is still an important level of deficiency in current masonry buildings built using conventional methods and materials [8].

Barrera et al. report on an advanced study in which shaking table tests were performed on two-story rammed earth modules on a 1:4 scale. The experimental data indicate that a retrofit system with confining steel plates effectively reduced the seismic damage of earthen constructions. A comparison of the results of the 1:4 scale tests with the 1:2 and 1:1 scale test previously conducted by the researchers shows that the acceleration levels of the equivalent prototypes are in the same order of magnitude for the three scales [9]. This research represents an important study of a common construction technique in Latin American cities, and the installation of confining steel plates on both sides of the RE walls to form a grid is seen as an excellent retrofitting technique.

González-Rodrigo et al. investigated the post-earthquake performances of structures in four rural villages in the Moroccan Atlas Mountains. This study is based on on-site data collection, facilitating the physical assessment of earthquake-induced damage and the identification of inherent vulnerabilities in construction systems, incorporating a global geospatial approach using differential synthetic aperture radar interferometry. The proposed methodology, with field data and the analysis of remote sensing processing results, allows for the assessment of damage in other earthquake-affected areas, including those not visited in the site but also impacted by this seismic event [10].

Chen et al. introduce a novel joint for connecting square steel tubular columns and H-beams via a flange connection. This enables the rapid repair of damaged joints after earthquakes by replacing flange connectors and high-strength bolt groups. These connection joints were comprehensively evaluated for their seismic performance through static tests and theoretical analyses. The flange connection joint exhibits excellent load bearing, rotational, and energy dissipation capacities [11].

Shehu investigates the static and seismic responses of a masonry tower. These structures are known to show complex structural behavior under seismic loads, which represents a peculiar construction typology that needs to be investigated. The findings show that very slender structures do not meet the guidelines recommendations, and in such cases, the recommended values for the mechanical properties of masonry material led to the prediction of non-withstanding structural behavior. The preliminary results for the safety of Portogruaro Tower (Venice, Italy) show a significant variability in seismic safety based on the adopted scenario, highlighting the necessity of paying attention to the preservation state of this structure and similar ones [12].

Existing and new structures alike will be of great significance in the coming decades. The current key challenges cover a vast area of research activity. The twelve contributions that comprise this Special Issue cover a wide and interesting range of topics, from existing structures [4,9,12] to new structures [1,5,6,11] and from field investigations [3,8,10] to numerical and experimental simulations [2,7].