Bulletin of Earthquake Engineering最新文献

This study examines the performance of precast reinforced concrete (RC) column assemblies reinforced with glass fibre-reinforced polymers (GFRP). Four precast specimens, representing column-to-foundation/cap assemblies, along with one monolithic connection, were tested under cyclic loads. Three different construction materials were used, each with a distinct connection system, i.e. (1) conventional grouted corrugated duct connection (GCDC) using high-performance grout; (2) innovative non-contact lap splice connection filled with engineered cementitious composite (ECC); and (3) unbonded stainless steel bolts with different diameters. The cyclic performance of these columns was comprehensively analysed and compared. The results showed that precast GFRP-RC column assemblies can achieve a comparable capacity or greater than monolithic structures. Meanwhile, the failure mode, deformability, capacity, stiffness, and energy dissipation are influenced by the connection system. While the GCDC exhibited a gradual failure with a column flexural failure like the monolithic connection, it had the least initial stiffness and energy dissipation among the precast systems. Among the investigated systems, the ECC-filled pocket connection exhibited the highest overall energy dissipation and initial stiffness. Therefore, this type of connection can enhance the energy dissipation capacity of GFRP-RC structures, offering superior performance compared to monolithic structures and promoting the use of GFRP reinforcement in precast concrete for accelerated, durable construction.

Thanks to their low mass and the high ductility, Light Frame Timber structures are a valid solution for low- and mid-rise buildings in seismic-prone areas. The nailed connection between the sheathing and the wood frame allows consistent energy dissipation, ensuring optimal mechanical performances. However, some uncertainties still regard the estimation of the associated structural behaviour factor q. The present research, accordingly, faces the calibration issue for the behaviour factor for Light-Frame Timber Buildings by means of Incremental Dynamic Analysis. Compared to papers in the literature that often use static methods or simplified buildings, this study considers the cyclic behaviour of the walls and complete 3D reference buildings, subjected to couples of accelerograms. A FEM model of a Light-Frame Timber wall is previously calibrated based on a full-scale laboratory test. Then, six reference buildings are designed according to Eurocode provisions and analysed by means of non-linear incremental dynamic approach. Finally, results are presented, and a range of q-behaviour factor is proposed.

Structural glazing (SG) is a widely used technique for connecting glass elements in facade constructions, employing silicone adhesives for load transfer. While SG joints are well-studied under static and environmental loading, their performance under seismic conditions remains insufficiently understood due to the random and cyclic nature of earthquakes. This study investigates the seismic loading of SG joints using a parametric simulation approach based on a single-degree-of-freedom (SDOF) system. Experimentally derived master curves were applied to convert the response histories into equivalent constant-amplitude cycles, providing a basis for predicting fatigue and failure behavior under seismic loading. The analysis revealed that the choice of master curve and the magnitude of the earthquake have the strongest influence on the resulting number of equivalent cycles. Based on a statistical evaluation of these results, linear damage values were calculated and subsequently translated into failure load levels. These allow the definition of limit states for bonded joints and support the development of reliable design parameters for seismic applications. The findings provide a foundation for seismic design criteria for bonded glass and facade constructions. Limitations such as fixed frequency, joint geometry, and simplified damage modeling are acknowledged and should be addressed in future work.

While the growing number of seismic records enhances our understanding of ground motion, data from large earthquakes remain limited for fully supporting reliable ground-motion modeling. Efforts to integrate simulated and observed data show promise, but a quantitative framework for validation and guidelines for the use of simulated data is yet to be established. This paper addresses these challenges by developing and evaluating a hybrid data-based Ground Motion Model (GMM) using the latest generation of the CyberShake simulation dataset and the NGA-West2 observational dataset for Southern California. A GMM based on symbolic learning is proposed as the candidate equation to explore the properties of this hybrid data approach. After preprocessing the data, GMMs are constructed and compared across three scenarios: using only observed data, only simulated data, and a hybrid of both. The results show that the predicted median values from the GMM calibrated with simulated data align closely with those from the observed data. This study also demonstrates that residuals from all three types of GMMs conform to a lognormal distribution. However, the residual dispersion for simulated data is smaller than that for observed data. Moreover, the standard deviation of the hybrid model decreases progressively as the proportion of simulated data increases. This means that the simulations reproduce the average properties of the ground motion but underestimate the variability and the most severe site and source effects. Additionally, recommendations are provided for building future simulation databases and effectively combining simulated and observed data.

As urban populations grow, cities face the challenge of accommodating diverse typologies of structures in increasingly smaller spaces. Traditional seismic analysis considers buildings as stand-alone structures with no adjacent buildings (i.e. Soil-Structure Interaction); however, this is not representative of modern city planning. So, considering the dynamic interaction between neighbouring buildings through the common soil, known as Structure-Soil-Structure Interaction (SSSI), has become an important issue in recent years. This research investigates the influence of the dynamic SSSI on the seismic response of two structures, where one of the buildings is considered base-isolated. A discrete nonlinear low-fidelity parametric formulation that accounts for various building and soil parameters is proposed, facilitating extensive scenario exploration. The complex nonlinear behaviour of the lead rubber bearings is modelled using the phenomenological Bouc-Wen formulation, which can effectively simulate the rubber’s stiffening at large strains and strength degradation properties. The parametric explorations of the nonlinear system consider 17 strong ground motion records. Over one million response-history analyses evaluate SSSI impact on seismic responses while distinguishing between nonlinear SSSI and SSI analyses and identifying key governing parameters. When the interaction response scenarios are considered, the SSSI effects may amplify seismic displacements and accelerations by as much as 20% and 70%, respectively. The results presented here improve our knowledge of SSSI in urban seismic risk management since they reveal significant amplifications in the isolated building caused by the nearby structure.

The installation of Buckling-Restrained Braces (BRBs) during different construction stages will result in varying initial mechanical states upon bridge completion. To investigate the impact of BRB installation stage on the seismic performance, this study first proposed a nonlinear static-dynamic sequential analysis method capable of precisely simulating the entire cable-hoisting construction process of such bridges. Based on Pushover analysis, the seismic weak positions of the main arch were identified, and a rational BRB layout scheme with key performance parameters was developed using previously developed BRB configurations. Three installation stages for BRBs were then proposed according to the typical construction process of long-span CFST arch bridges, with their impacts on bridge construction stability analyzed and discussed. Nonlinear dynamic time-history analysis was carried out to systematically investigate the influence patterns and mechanisms of BRB installation stage on the seismic performance of long-span CFST arch bridges. The study demonstrates that different BRB installation stages exert minimal influence on the completed bridge’s structural states. However, BRBs installed at various construction stages exhibit significant differences in their own mechanical states upon bridge completion, which substantially affects their energy dissipation capacity during seismic events. BRBs with greater initial axial forces in the completed bridge state demonstrate enhanced total energy dissipation during earthquakes, resulting in more pronounced seismic mitigation effects for long-span CFST arch bridges. This effect amplifies with increasing Peak Ground Acceleration (PGA). Therefore, optimizing installation stage represents a crucial factor in effectively utilizing BRBs for seismic protection of long-span CFST arch bridges.

Earthquake-resistant design has conventionally relied on force-based methods in design codes, while displacement-based approaches remain under development. Both approaches use peak response measures such as acceleration or displacement but do not capture the cumulative effects of seismic shaking. These effects can be represented through the total input energy, which provides a more comprehensive measure of seismic demand and serves as primary step towards energy-based design. While energy-based ground motion models (eGMM) for Peninsular India and Himalaya are developed, no such model existed for ground motions in Indo Burma region (IBR) despite its significant seismic hazard. This study develops an artificial neural network (ANN)-based ground-motion model for the IBR events. The model predicts the input energy equivalent velocity (V_ea) using the NGA subduction database and regionalises for IBR events. Eight input variables are used, including magnitude, distance, site condition, depth, and fault mechanism, with outputs defined as V_ea at 23 natural periods from 0.01 to 5s. Model performance is evaluated through residual analysis, parametric studies to confirm physical trends, and Shapley Additive Explanations (SHAP) to assess variable importance. The proposed model is valid for moment magnitudes between 5.0 and 8.5 for IBR events (4.0–9.5 in NGA subduction), Joyner–Boore distances up to 500 km, and site conditions with V_s30 values up to 2000 m/s, covering the full IBR site classification range. The results demonstrate that the ANN-based eGMM provides reliable prediction of the energy spectrum and offers a practical tool for advancing energy-based earthquake-resistant design in the region.

The seismic behavior of precast concrete shear walls with varying grouted connection profiles is explored in this study. This study explores the seismic behavior of precast concrete shear walls with full and half-grouted coupler systems, focusing on their cyclic performance, structural integrity, and energy dissipation. The walls, with a 0.3 aspect ratio and ventilation provisions above the sill level, were subjected to cyclic lateral loading tests. The specimens included Precast Shear Wall with Full Grouted Coupler Connections (PCW-FGC) and Precast Shear Wall with Half Grouted Coupler Connections (PCW-HGC). Both systems exhibited similar failure mechanisms and seismic behavior, though the PCW-HGC experienced premature crushing at the grooves under lower displacements, leading to a significant reduction in load capacity and energy dissipation. The PCW-FGC outperformed the PCW-HGC, with a 38.53% increase in load-carrying capacity and a 40% improvement in displacement at peak load. Under ultimate conditions, the PCW-FGC showed a 34.73% higher load resistance and 57.14% greater displacement. Its energy dissipation capacity was 47.3% higher, due to delayed groove failures and more efficient dowel lapping. Additionally, the PCW-FGC’s ductility coefficient exceeded that of the PCW-HGC by 6.6%, indicating improved seismic resilience. These findings highlight the importance of coupler configurations and groove geometry in enhancing seismic performance. The study recommends precise design protocols for coupler positioning and groove geometry to optimize seismic performance.