Bulletin of Earthquake Engineering最新文献

The evaluation of post-earthquake functional recovery of buildings is pivotal for seismic resilience assessment and underpins resilience-oriented seismic design. This study proposes a generalized method that can predict the potential functional recovery trajectory of any occupancy type of building. This method distinctly models delay time and repair time. Delay time accounts for the duration required for building mobilization activities and the recovery of utility systems to full functionality. The triggering conditions for mobilization activities are clarified by component damage severity and the repair cost ratio of buildings. The repair time is modeled by embedding the critical path method into an Activity-on-Edge network, incorporating the procedure importance coefficient under limited floor space to optimize labor allocation, thus achieving dynamic coupling of repair processes and labor resource scheduling. Utilizing Monte Carlo simulation as the underlying mechanism, the method enables probabilistic modeling of the functional recovery trajectory and subsequent calculation of the seismic resilience index. A case study of a teaching building demonstrates the method’s efficacy in pinpointing critical recovery bottlenecks, optimizing labor allocation, and delivering recovery trajectory simulations. It exhibits robust adaptability and scalability, providing an effective analytical tool for seismic resilience assessment, enhancement, and design across diverse occupancy types of buildings.

Accurate estimation of the seismic demand of buildings requires carefully considering both the ground motion group size (n) and the angle of seismic input (ASI). Existing studies focus more on the relative effect of either n or ASI on evaluation results. There is ongoing debate on the n and ASIs required in deterministic and probabilistic seismic performance assessments, and no specific guidelines have been established for engineering practice. To address this concern, this study proposes a framework for assessing statistical bias of response and providing engineering-oriented recommendations for n and ASI in nonlinear response history analysis of mid-rise buildings. Firstly, a regrouping procedure is presented to generate 100 suites of ground motions with a specified smaller size of n from a benchmark large dataset of ground motions. Next, three statistical indices are defined to precisely characterize the bias between the small-sample and benchmark large-sample ground motions, namely bias(µ), sdev(µ), and bias(β), which quantifies the effects of n and ASI on errors of the estimated central tendency and variability of response in deterministic and probabilistic analyses. Based on an acceptable statistical bias, the required values of n and ASI for different conditions are recommended. Finally, to facilitate practical application, a simple yet efficient model of the correction coefficient (κ) of variability is proposed to save computational time and improve assessment accuracy. Results show that at least 10 pairs of records and 4 input directions are required to ensure reliable estimates of expected seismic response for mid-rise buildings. The bias in variability can be adjusted using the κ. These engineering-practical recommendations contribute to resolving the ongoing debate regarding the necessary n and ASI in seismic performance assessments of mid-rise buildings.

Tunnel-form buildings represent the main typology used in mass housing projects in Türkiye, with their heights continually increasing to meet the rising demand for land. Research has shown that low- and mid-rise tunnel-form buildings performed satisfactorily even under earthquake ground motions exceeding their design intensity. However, only a limited number of studies examined the performance of high-rise tunnel-form buildings. These structures are characterised by inherent vulnerabilities due to the use of lightly reinforced slender shear walls and conventionally reinforced squat coupling beams as primary structural members. The present study numerically examines the seismic performance of such structures and offers recommendations to enhance their design. A 14-storey tunnel-form building, representative of a large percentage of mass housing projects across Istanbul, is selected for case study purposes. A state-of-the-art three-dimensional non-linear finite element model is created in OpenSeesPY. Prominent failure modes of the components are incorporated into the model. The modelling strategy is validated at the component level using experimental results and at the system level using the results of ambient vibration tests conducted on an existing building. Standard and multi-mode adaptive pushover analyses are used to provide insights into the evolution of damage and define a damage scale. The seismic performance is evaluated through a Multiple Stripe Analysis procedure, and fragility functions are derived at both component- and system-levels. The fragility analysis shows that high-rise tunnel-form buildings have a very high probability of providing life safety even in very rare, high-intensity earthquakes. However, immediate occupancy of the building is likely to be jeopardised due to the severity of the incurred damage. The study offers several insights into the seismic performance assessment of such structures and provides guidance on how to improve their design.

This study investigates the evolution and current status of seismic design regulations in Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela, using a pre-established methodology previously applied for Europe. It introduces a simplified methodology to estimate the proportion of buildings designed under four seismic code levels: no code, low code, moderate code, and high code. By analysing the progression of seismic design standards across South America, the study determines lateral force coefficients for a typical mid-rise reinforced concrete structure corresponding to each seismic code level. The findings reveal that approximately 20% of the total building stock, and 55% of reinforced concrete buildings, were constructed while regulations with some seismic provisions were followed. This research offers essential tools to enhance seismic risk assessment models and provides a dynamic framework for integrating new data, technological advancements, and local expertise into exposure modelling. Furthermore, it contributes to a global initiative led by the Global Earthquake Model (GEM) Foundation aimed at improving accessibility to information on seismic regulations and seismic hazard design demand maps.

Seismic Microzonation studies aim to map and determine the seismic ground response and the susceptibility to instability phenomena, such as liquefaction, landslides or surface faulting. According to Italian government laws, seismic microzonation is evaluated following three Levels of detail (I, II and III), with increasing complexity. In areas susceptible to instability phenomena, in-depth investigations typical of Level III are necessary to verify the safety conditions. In this framework, the liquefaction potential was evaluated for a zone prone to seismically induced liquefaction located on the eastern Sicily (Italy). The stress-based method was employed to evaluate the susceptibility to seismic-induced liquefaction considering the results derived from Dynamic Probe Super Heavy tests. They have the advantage, compared to Standard Penetration Tests, of providing continuous values with depth. Three different approaches were used to define the seismic action: the simplified approach proposed by the Italian seismic code, the selection of a suite of ground motion records and the definition of a combination of synthetic seismograms reproducing the 1908 seismic event. The results show that the use of a suite of ground motion records compatible, on average, with the target spectrum built according to the Italian seismic code, is conservative compared to the other two approaches. Furthermore, the level of liquefaction severity encountered in the investigated area is high, demonstrating the need for mitigation actions. The findings obtained in this study allow to optimize the allocation of economic resources and are useful for future similar works.

The Applied Element Method (AEM) has in the recent years been increasingly employed to assess the failure mechanisms developed by structures subjected to dynamic loading. However, its use in the detailed estimation of local response parameters such as strains, curvature, and other localised deformations of reinforced concrete (RC) elements under seismic excitation, is not common. In this context, we explore the feasibility of using the AEM to reproduce, in blind-prediction fashion, the recent shake-table axial-flexural-torsional response of a 40-ton half-scale reinforced concrete U-shaped wall specimen. The accuracy of the adopted modelling approach in capturing the experimentally observed translational-torsional structural response of the tested structure is demonstrated through the comparison between numerical predictions, obtained before the publication of the test results (and thus without post-test model improvements), and the experimental measurements, considering both global and local response quantities. On a somewhat separate note, this study also examined the manner in which currently available formulations are capable of estimating residual drifts in RC walls, and proposes an updated equation that is shown to predict, with a good degree of accuracy, post-earthquake shaking residual displacements for this type of structures.

Seismic rehabilitation of precast concrete structures is today implemented with both traditional and innovative, dissipation-based solutions. The relative scarcity of available works focussing on dissipative bracing systems, especially those equipped with external dissipaters, motivated this research, whose main goal is to analyse an innovative technique comprising dissipative steel braces embedding sacrificial elements, coupled with a friction rotation damper for beam-to-column connections. Both devices can be replaced after a seismic event and put in place by dry installation. With reference to a single-storey precast building, representative of the Italian construction period of the ‘70s and hypothetically located in three Italian cities characterised by increasing levels of seismic hazard, the proposed solution was compared with two traditional rehabilitation techniques, featuring low and high invasiveness, respectively. After addressing the retrofit design phase, nonlinear three-dimensional models of three variants of the building in their unretrofitted and retrofitted configurations were created in OpenSees and subjected to nonlinear static and dynamic analyses. The latter were carried out within a multiple-stripe analysis framework. The comparative evaluation, undertaken in terms of pushover curves and demand-over-capacity ratio median curves for two limit states, provided reassurance on the efficacy of the proposed dissipation-based strategy, as well as the more invasive traditional solution, in effectively improving the seismic response of this construction system.

This study investigates the seismic performance and strengthening of the historic Cimcime Hatun Cupola, a representative example of Turkish-Islamic masonry heritage. A detailed finite element (FE) model was developed using material parameters derived from established design codes and literature. Nonlinear time-history and pushover analyses were conducted to assess structural behavior under seismic loading and evaluate a proposed internal steel plate retrofit system. The reinforcement increased the first modal frequency by 2.2 times and improved lateral load capacity by 3.375 times, demonstrating substantial gains in global stiffness and stability. The retrofit strategy, designed to be reversible and minimally intrusive, offers a practical and conservation-compatible solution for similar mausoleum-type structures. The findings contribute to advancing heritage engineering practices by providing a validated numerical approach and a case-specific strengthening methodology applicable to other historical masonry monuments.

The frame structure comprised infilled walls and constructional columns. The finite element model was established based on full-scale model experiments, which were used to evaluate the seismic performance of a frame-infilled wall withouta constructional column, with a cast-in-place constructional column, and with a fabricated constructional column. The action mechanism of the constructional columns in a frame-infilled wall was summarized. The experimental and numerical analysis results showed that the in-plane load-displacement response and load-bearing capacity variation of the frame-infilled wall with a fabricated constructional column were comparable to the frame-infilled wall without a constructional column. The height of the frame had a significant effect on the load-bearing capacity of the frame-infilled wall with a constructional column. When the height increased, the bearing capacity of the frame-infilled wall decreased. The existing three-strut models were modified. The errors of both the modified three-strut model and the bearing capacity calculation model for computing the load-bearing capacity of a frame-infilled wall with a constructional column were under 11%, which can be used to predict the behavior of a frame-infilled wall with a constructional column.