ABSTRACT To enhance the seismic performance of arch-shaped segmental piers, a novel rocking mechanism has been developed to maintain a low-damage state. The proposed system combines a double sliding mechanism with rocking behavior, supported by the arch-shaped pier to achieve self-centering capability. Horizontal cyclic loading tests demonstrate its feasibility and effectiveness. Finite element simulations confirm the reliable activation of rocking behavior under severe seismic excitations, significantly reducing horizontal displacements. Fragility analyses using a simplified model further indicate that the rocking mechanism improves the pier’s resilience against short-period and long-period ground motions.

ABSTRACT Countries having low to medium seismicity experience rare large, far-distance earthquakes. The development of its ground motion model is difficult due to data scarcity. Thus, the applicability of the LSTM recurrent neural network is explored, due to its ability to predict sequential data. Earthquakes from databases are collected with magnitudes larger than 6.5 Mw and distances between 200 and 500 km. The network is constructed with five input data, two LSTM layers, and 23 sequential outputs. The results show that the network underestimates the amplification at lower periods while predicting larger motions at higher periods, typical for far-source earthquakes.

ABSTRACT This study finds the overall seismic fragility of an integral abutment bridge typology while integrating the demands of all damageable components, as very high to moderate correlations are identified between most component pairs. It highlights significant misjudgement of the bridge vulnerability when represented through a single component, particularly up to moderately high ranges of the adopted intensity measures, where the bridge shows considerable relative fragilities with all components. In most instances, conventional peak ground acceleration tentatively overestimates individual fragilities and underestimates the relative fragilities between individual components, and between each component and the bridge compared to the optimal intensity measure.

ABSTRACT Near-fault pulse-like ground motions may increase the risk of earthquake-induced collapse, as structures subjected to strong velocity-pulses must dissipate large amounts of seismic energy in a short duration. These velocity-pulses can arise from either low-frequency acceleration pulses (acc-pulses) or high‐frequency, one‐sided acceleration spikes (non-acc-pulses). This study introduces a novel approach for automatically classifying acc-pulses and non-acc-pulses, which can accurately identify pulse-starting and -ending time without any filtering techniques. Comparative analysis demonstrates that the proposed algorithm outperforms existing methods in both accuracy and computational efficiency, eliminating pulse period calculation errors caused by inconsistent filter parameters in previous studies.

ABSTRACT This paper demonstrates the requirement of considering multi-level seismic shaking simultaneously, while finding the optimal isolator properties. A novel seismic risk-based multi-objective optimization framework considering three levels of earthquake excitation is proposed in the context of scenario-specific ground motions. It is found that the single scenario-based optimal parameters for one such scenario do not perform satisfactorily for others. The proposed multi-objective optimization-based isolator parameters perform satisfactorily for all three seismic scenarios simultaneously. Finally, the effects of source to site distance and local soil condition on the optimal isolator parameters are also studied, which reveals their significant influence.

ABSTRACT Lateral-torsional coupling effect leads to poor seismic performance in eccentric structures, while traditional methods have their own limitations. This paper proposes an inerter-based solution to improve the seismic performance and develops the corresponding optimal design method. Comparative analysis under different control strategies is conducted to evaluate the vibration-suppressing effect of the inerter system by finite element simulation. The results show that inerter system can significantly reduce the seismic response, especially the torsional response, and exhibits greater efficiency than viscous damper with the same damping coefficient. Thus, the proposed inerter-based solution can effectively control the vibration of eccentric structures.

ABSTRACT This study introduces performance-based fragility curves for buried pipelines affected by seismic landslides employing numerical simulations with an advanced constitutive model for dynamic analysis. The seismic analysis was carried out using a dataset comprising 70 earthquake records from Iran. The results of this study show that the landslide boundary interface has an important role in slope failure geometry and buried pipe response patterns. By increasing the stiffness in the landslide boundary interface (from smooth to hard), the pipe’s maximum deformation decreases. The deformation predictive model of the pipeline is a function of slope length, slope height, pipe diameter, and Arias intensity as an optimal seismic intensity measure. The developed fragility curves indicate that the probability of pipe failure can significantly decrease in specific slope locations by increasing the pipe diameter.

ABSTRACT This study developed methods to quantify static (SRD) and dynamic residual displacement (DRD) in reinforced concrete (RC) structures with energy dissipation dampers, including pure energy dissipation dampers (PED) and self-centering energy dissipation dampers (SCED). Definitions of SRD and DRD were introduced, and restoring force models for PED and SCED were presented. Quadrilinear restoring force models for RC structures were created considering different failure modes (flexure, flexure-shear, and shear). Simplified SRD calculation formulas were proposed and validated. DRD analysis considered uncertainties in structural hysteresis and ground motion (GM) characteristics, showing SRD as the upper limit of DRD.

ABSTRACT An approach is proposed to optimize the selection of seismic inputs to be used in local seismic response modeling for seismic microzonation studies. It integrates real and simulated accelerograms consistent with seismic scenarios that significantly contribute to the local seismic hazard. The use of simulated accelerograms allows to extend the considered scenarios and to improve the compatibility with the design spectrum locally prescribed by building codes for an outcropping bedrock. This procedure has been tested within the seismic microzonation of the Apulia region (south-east Italy), in a variety of geological and seismo-tectonic contexts, with encouraging results.

ABSTRACT Reinforced concrete (RC) frame structures often feature misaligned columns to satisfy aesthetic and architectural purposes. Nevertheless, the joint region may exhibit unfavorable seismic behavior, posing significant challenges in seismic areas. This study proposes a reinforced concrete (RC) corbel-type misaligned column-beam joint (MCBJ) for engineering applications. Four MCBJ specimens with different variables were designed and subjected to cyclic loadings, and their seismic behaviors were discussed meticulously. Test results revealed that the MCBJ specimens suffered ductile flexural failure, whereas the shear failure was prone to emerge as the misaligned length increased. The hysteresis curves displayed asymmetry due to the eccentric effect. Moreover, the beam reinforcement ratio and misaligned length were found to have a substantial impact on the joint’s behavior, and the steel panel at the beam end could effectively alleviate the eccentric effect of the MCBJ. Finally, numerical models of the joint specimens were established to evidence the test results. The hysteresis curves and failure modes in the numerical analysis were in good agreement with the test results.