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Item type:Publication, Damping modification factors for the design of seismic isolation systems in Peru(SAGE Publishing, 2020-11-01)This study proposed a simple nonlinear equation to estimate damping modification factors (DMFs) to modify the elastic response spectral values for damping ratios between 10% and 50%. The DMFs are computed from the displacement, acceleration, and velocity response spectral of single-degree-of-freedom (SDOF) systems of 198 earthquake acceleration time histories from 40 earthquakes events of Peruvian database, grouped into three types of soil: hard soil, intermediate soil, and soft soil. For each soil group, 11 scaled records were selected according to the ASCE 7-16 standard to match the design spectrum of the Peruvian technical standard for seismically isolated structures E.031. Simplified approximate nonlinear period-dependent expressions were provided to compute DMFs from the Peruvian strong-motion database and were compared with DMFs available in the literature and national seismic design codes. The study showed discrepancies with the regulations worldwide. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Parametric evaluation of the response modification factor R considering bidirectional ground motions(Elsevier Ltd, 2024-11-01)The current research on evaluating the response modification factor R, related to the lateral strength demand of structures, has been generally based on inelastic single-degree-of-freedom systems. Nevertheless, most structures have more than one main analysis component and will be subjected to bidirectional ground motions. In this study, the results of the parametric evaluation of the response modification factor considering the bidirectional interaction (Rb) of inelastic two-degree-of-freedom systems (2DOF) are presented. The effects on the factor Rb of the vibration period, the ductility capacity, the hysteretic model, the seismic incidence angle, and the period ratio were evaluated. Analysis results show that the bidirectional interaction could increase the lateral strength demand of the 2DOF systems because of the coupling effect of the two components’ responses. To make this research useful for improving engineering practice and code provisions, the main contribution is the proposal of a simplified expression for estimating the factor Rb. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Displacement-Based Seismic Performance of RC Bridge Pier(Springer, 2023-12-01)To correctly manage the road infrastructure before and after an earthquake, it is necessary to estimate and even predict the seismic performance of the bridge. The quantification of the bridge's seismic performance response was present in terms of displacement and also based on previous research of reinforced concrete bridge pier models. The displacement did define from a force lateral-displacement response diagram corresponding to the capacity curve, calculated through a non-linear static pushover analysis of the reinforced concrete bridge pier model for each limit state, from intact state to collapse. Thus, six defined displacements correspond to the cracking displacement, the yielding displacement, the spalling displacement, the crushing displacement, the buckling displacement, and the fracturing displacement. The six defined limit states correspond to the cracking limit state, the yielding limit state, the spalling limit state, the crushing limit state, the buckling limit state, and the fracturing limit state. Also, parametric analysis did carry out to evaluate the influence, relative importance, and trend of the input parameters in response to the seismic performance of the reinforced concrete bridge pier model. Eleven input parameters did analyze as the concrete compressive strength, the yield stress of reinforcing steel, the concrete cover thickness, the pier aspect ratio, the configuration of the transverse reinforcement, the spacing of the transverse reinforcing steel, the transversal diameter of the transverse reinforcing steel, the longitudinal reinforcement ratio, the transversal diameter of the longitudinal reinforcing steel, the axial load ratio, and coefficient of subgrade reaction. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Scale Factor Model to Estimate the Maximum Bidirectional Spectral Demand in the South American Region(Wiley, 2025-09-01)The intensity of seismic motion varies considerably with changes in direction, which is commonly known as the directionality of ground motion (GM). Different seismic design codes have adopted various methods for combining the intensity of horizontal GMs. These methods typically use the median spectral ordinate over all non‐redundant orientations, referred to as RotD50, and the maximum spectral ordinate over all non‐redundant orientations, referred to as RotD100. More recently, an intensity measure called MaxRotD50 has also been proposed and considered, which is calculated as the 50th percentile of the maximum spectral ordinates from two orthogonal horizontal directions for all non‐redundant rotation angles. This measure, which always lies between RotD50 and RotD100, offers several advantages over other intensity measures. In contrast to the approach in ASCE 7 (2010, 2022), which uses RotD100 for the design of all structures, this study proposes to use RotD100 only for the design of axisymmetric structures, that is, structures with vertical cylindrical symmetry and similar properties in terms of mass, lateral stiffness and strength. It is also proposed to use MaxRotD50 for the design of structures where the probability of exceeding the intensity of GM in at least one of the two horizontal principal components is high. Likewise, this study complements and compares the RotD100/RotD50 and MaxRotD50/RotD50 ratios, which can be used as a multiplicative factor with the RotD50 predictions to predict the RotD100 or MaxRotD50 of the GM intensity. A database of 3853 seismic acceleration records from 283 events in the South American subduction region is used for this purpose. The influence of GM parameters such as moment magnitude, significant duration, rupture distance, and mean soil period, was evaluated. The results were compared with those of previous studies for different regions of the world. It was found that the RotD100/RotD50 ratios in South America are like those in other subduction regions such as Taiwan and Japan and that the Max RotD50/RotD50 ratios are comparable to other shallow crustal earthquakes in active tectonic regions. Finally, equations are also proposed to estimate ratios depending on the different parameters of the evaluated GM to account for the found influence on the ratios.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Numerical study on frequency limit states in seismic performance of RC bridge pier(Springer Nature, 2026-12-01)This study presents a numerical investigation of the natural frequency of Reinforced Concrete (RC) bridge piers, which progressively decreases as seismic damage develops. The objective was to evaluate whether variations in natural frequency can reliably identify post-seismic damage states. To this end, a numerical RC bridge pier model was developed to quantify the evolution of its natural frequency across different stages of seismic performance, considering the full range of collapse mechanisms from undamaged to severely damaged conditions. Two post-seismic indicators, such as the Frequency Reduction Coefficient and the Frequency Decay Index, were defined to characterize changes in the natural frequency of bridge piers. Based on these indicators, six progressive frequency limit states were systematically established: Cracking, Yielding, Spalling, Crushing, Buckling, and Fracturing, providing a logical framework for post-seismic structural evaluation. A backbone curve of the numerical RC bridge pier was developed to assess stiffness degradation and the evolution of natural frequency during damage progression. In addition, an extensive literature synthesis was conducted to compile an experimental database to develop a baseline RC bridge pier model for comparative analysis. Results show that the natural frequency declines consistently with increasing damage, decreasing by approximately 30% from the elastic condition to the cracking stage and by nearly 70% at the fracturing stage, corresponding to overall structural collapse. The findings confirm that natural frequency thresholds can provide a systematic framework for assessing the condition of RC bridge piers after severe earthquakes. A key contribution of this study is the proposal of initial natural frequency thresholds associated with different damage levels, offering practical guidelines for bridge structural engineers. Furthermore, the compiled tables integrate experimental and numerical frequency data from multiple studies, forming a valuable reference dataset for future research on frequency-based seismic damage assessment.1