Bulletin of Earthquake Engineering最新文献

In this paper, a fiber-section model for the seismic analysis of ductile reinforced concrete columns with ribbed bars is proposed. The model is based on the simulation of the results of uniaxial-bending experimental tests and is built by using OpenSees software. Material models are proposed to replicate the response of cover concrete, of core concrete, and of steel rebars. A modelling strategy already proposed in the literature is incorporated in the proposed model to account for strain penetration effects. Correction coefficients are calibrated to account for the additional confinement provided to the end sections of structural members by other structural members, such as foundation elements. Literature formulations are applied to account for the fracture in tension of longitudinal rebars after buckling in compression. The proposed model can be adopted for the seismic nonlinear static and dynamic analysis of reinforced concrete structures.

Implementing advanced material-specific hysteretic models in structural analysis has opened new possibilities for post-earthquake damage assessment. This study introduces a novel methodology for estimating maximum seismic displacements utilizing the Takeda model for reinforced concrete and the AlBermani model for steel structures in single-degree-of-freedom systems. The research establishes correlations between residual and maximum displacements based on an extensive series of numerical simulations incorporating far-field and near-fault earthquake records. The developed mathematical relationships account for the distinct hysteretic behavior of different structural materials, providing a practical tool for post-earthquake evaluation. Field measurements of residual deformations can be directly applied to these relationships, enabling rapid assessment of maximum displacement demands experienced during seismic events. Statistical validation demonstrates the reliability of the proposed approach across various ground motion characteristics and structural parameters.

This study presents an investigation on the effects of damage and strengthening on the dynamic behavior of buildings. Forced vibration tests were carried out on the shake table of two 1/3 scale, 3D, 2-story, single-span reinforced concrete frame specimens produced in laboratory. The damage was created by weakening the joint areas. Then the damaged zones were repaired and strengthening methods using in-plane reinforced concrete shear walls and X-shaped steel diagonal bracings were applied. The aim here is to perform a dynamic-based performance evaluation of these two commonly used global systemic strengthening techniques in practice. A total of more than 105 forced vibration experiments were carried out under 4 different intensities of dynamic load in different conditions of the specimens. Dynamic parameters were determined with the experimental modal analysis method. Moreover, story displacements time history, base shears time history, base shear-top displacement hysteresis curves, and lateral translational stiffnesses were obtained. In addition, numerical analyses using ETABS finite element software were also conducted. As a result, it was observed that the damage reduced the lateral translational stiffnesses by about 50%, steel bracings increased the stiffness in the damaged condition by 147% and RC shear walls increased it by 381%. On average, the 1st natural frequency decreased by 36.5% in the damaged conditions, increased by 83% in the strengthened conditions compared to the damaged conditions. Strengthening of the members tends to limit the soft story behavior. In general, although its application is difficult, the best performance in all studied parameters was obtained from the specimen strengthened with in-plane reinforced concrete shear walls.

This paper investigates the seismic response of the three-story Cross-Laminated Timber (CLT) building of the SOFIE project subjected to the Near-Field (NF) Far-Field (FF) ground motions according to FEMA P-695. The numerical models have been developed in connector, wall and full-scale building levels in OpenSees. Nonlinear nonlinear springs have been utilised to model the behaviour of CLT connectors while considering Gap joints only to transfer compression forces between panels and the rigid foundation without the ability to carry tensile forces. The CLT panels have been modelled as moment-resisting frames by applying elastic beam elements with high stiffness. The panel-to-panel and panel-to-foundation friction has also been considered by modifying the initial stiffness of the CLT connector springs. The building was analysed using Incremental Dynamic Analysis (IDA), including 2450 time-history simulations, to assess its behaviour during ground motions. Significant Damage (SD) and Near-Collapse (NC) damage stated have been identified for the building based on EN12512 standard through Modal Push-over Analysis (MPA). Subsequently, the fragility curves have been developed for the CLT building under NF and FF ground motions. The IDA curves prove that the CLT building considered in this paper is more affected by Near-Field Pulse-like (NF-P) than by Near-Field No-Pulse (NF-NP) and FF ground motions. Moreover, the modelled building is significantly more affected by NF-P ground motions than by NF-NP and FF motions, with a higher probability of collapse under NF-P conditions.

The IFMIF-DONES project will carry out the design and construction of a scientific facility near Granada (Spain), whose purpose is irradiation of materials with a neutronic spectrum similar to what is obtained within a nuclear fusion reactor. In the framework of the seismic hazard assessment for the IFMIF-DONES site, this paper compares two approaches to correct the overdamped high-frequency response of soil columns computed via regular equivalent-linear analyses. The site has a soft soil profile, with a V_s30 around 375 m/s. For soft soils, when introducing site effects in seismic hazard assessments, equivalent-linear analyses are known to overdamp high-frequency responses. This may result in unrealistically small relative amplification factors (RAFs) with respect to the host profile response, which is the reference in Ground Motion Prediction Equations. In this paper the overall methodology for derivation of RAFs is presented, based on equivalent-linear analyses, and two approaches to RAF correction are described: an empirical lower bound on the RAFs, taken from accepted practice, and the so-called kappa2 correction of the Fourier Amplitude Spectra. For small ground motions, differences in RAFs computed by the two methods are minimal, since soil degradation is limited. For higher-severity events, significant differences appear beyond 8 Hz. Two empirical RAF lower bounds, 0.5 and 0.6, were tested. The results for the IFMIF-DONES site suggest that the 0.6 lower bound provides a good average fit to the results obtained using kappa2 correction. For the stronger motions, the 0.5 lower bound provides a better fit in the 2.5–10.0 Hz band.

Analytical studies have demonstrated that tunnel-form system possesses relatively high strength and rigidity. However, in seismic evaluations of this system, only peak ground acceleration and spectral acceleration have traditionally been considered as the primary intensity measures representing earthquake ground motions. While this approach aligns with current seismic guidelines, it overlooks the importance of other critical ground motion characteristics. The present study introduces the time scaling of earthquake record method and, for the first time, employs it to modify the primary characteristics of input ground motions for the seismic evaluation of tunnel-form buildings. For the analyzed models of 2-, 5-, and 10-story, the findings reveal that significant duration, peak ground acceleration, and peak ground velocity have direct effects on the seismic responses of the system. Results indicate that, at a given hazard level, accurate predictions of seismic performance and demands require simultaneous consideration of all three parameters. Analyses show that at high hazard levels, an increase in velocity while keeping acceleration and significant duration constant can change the performance level of the system from immediate occupancy to collapse prevention. This highlights the critical role of velocity in seismic performance. Similarly, variations in acceleration and significant duration yielded comparable results. Under constant conditions for the other parameters, increases in acceleration and significant duration led to performance levels of life safety and immediate occupancy in the worst cases, respectively. Accordingly, these parameters rank second and third in importance when estimating seismic performance levels. Furthermore, the findings demonstrate that code-based relationships fail to predict the seismic demands of tunnel-form systems accurately. Consequently, revisions and modifications are necessary to incorporate the effects of ground motion characteristics.

Post-earthquake reconnaissance of engineering structures aims to collect the essential data required for forensic investigations of failures. These investigations inform time-critical repair, stabilisation and demolition decisions after an earthquake. Current reconnaissance procedures rely on visual observations and manual surveying, which do not provide adequate data for the forensic analysis of historic masonry structures. This study shows how an alternative form of data, point clouds from laser scanning and photogrammetry, can be used to conduct detailed forensic work. Case studies from the 2023 Turkey earthquakes are used to illustrate how point clouds were employed to 1) quantify the geometry of load-bearing systems, 2) assess construction quality, 3) detect geometric distortions and defects, and 4) provide data to generate and evaluate numerical models. The examples highlight the new insight provided by this alternative form of data. The dataset collected as a part of this study is shared open access to enable further investigations: https://github.com/Yilong-Yang/Shared-Data---BEE-2025.

Ageing and deterioration of Reinforced Concrete (RC) bridges can significantly increase their seismic vulnerability and have a significant impact on expected economic losses. In this study, the seismic performance of typical single-shaft piers with corroded rebars is examined through extensive Multi-Stripe non-linear response time-history Analyses (MSA). Piers with different cross sections and heights, featuring different deterioration scenarios, characterized by different corrosion patterns and severity levels of corrosion, are investigated. MSA are performed using twenty pairs of ground motion records consistent with the seismic hazard of the cities of L’Aquila (central Italy) and Naples (southern Italy), for nine different earthquake intensity levels with return periods ranging from 50 to 100.000 years. Lognormal fragility curves associated with pier collapse are derived to account for record-to-record variability. Finally, the annual failure rates associated with collapse are derived to evaluate the structural reliability of each model both in the as-built and deteriorated conditions.

The two devastating earthquakes of 6 February 2023 in Kahramanmaraş, Türkiye, highlighted the poor seismic performance of many existing reinforced concrete (RC) buildings and created an urgent need for rapid, large-scale reconstruction. This study evaluates the feasibility of using a modern mass-timber structural system as an alternative to conventional RC construction for mid-rise residential buildings in Turkish seismic regions. A seven-story residential building was designed in two forms – one with a standard RC shear-wall structure and one with an equivalent mass-timber (cross-laminated timber, CLT) structure – and compared their seismic performance, environmental impacts, and construction costs. Nonlinear static (pushover) and response spectrum analyses were conducted for both designs in accordance with applicable seismic design standards. A cradle-to-gate life-cycle assessment (LCA) was performed to quantify embodied carbon and energy, and a cost analysis was carried out using local 2023 material prices. The CLT building achieved adequate seismic performance, with fundamental periods about twice as long as the RC building and base shear forces roughly one-third as large. Although the CLT structure experienced larger lateral drifts, these remained within serviceable limits. In terms of sustainability, the mass-timber design showed dramatically lower environmental impacts – roughly an order of magnitude reduction in embodied carbon and energy – compared to the RC design. The primary trade-off was economic: due to current material pricing and supply constraints, the mass-timber building’s estimated construction cost was approximately 5–6 times higher than the RC building. Overall, the results indicate that mass-timber is a structurally viable and environmentally advantageous option for post-earthquake reconstruction of mid-rise buildings in Türkiye, provided that issues of cost and material supply can be addressed through future policy and market developments.

Seismic vulnerability is a core element of earthquake risk and the development of large-scale regional seismic resilience models. Low-rise masonry structures have a long history and wide application in different regions worldwide. However, relatively few studies have investigated the seismic vulnerability and risk assessment of low-rise masonry structures while considering the influence of temperature. This paper proposes a simplified evaluation function for evaluating the seismic vulnerability of low-rise masonry structures. A seismic risk method considering improved vulnerability levels and temperature field effects is innovatively proposed, and an optimized vulnerability probability matrix based on two typical earthquake damage datasets from China (the Wenchuan (WC) earthquake in Sichuan (1228 buildings) and the Zhaosu (ZS) earthquake in Xinjiang (1640 buildings)) is established. Additionally, 2108,103 acceleration records of the WC earthquake were selected from 12 real seismic stations, and dynamic time history and spectral analyses were conducted. To explore the impact of different temperature fields on the vulnerability of low-rise masonry structures, the structural damage data of two typical earthquakes (WC and ZS) with temperature effects were classified and statistically analysed. A comparison curve of the seismic vulnerability in different intensity zones considering the influence of temperature was innovatively established using a nonlinear regression algorithm. An updated seismic vulnerability and risk index function was developed to evaluate the damage modes of low-rise masonry structures. Typical structural failure fields based on field observations of the WC earthquake have been reported. The results indicate that the developed simplified vulnerability regression model can effectively evaluate the seismic risk and vulnerability of low-rise structures, contributing positively to the establishment of large-scale regional structural seismic risk and resilience distributions.