The research, led by Azlan Adnan of Universiti Teknologi Malaysia together with Yuyun Tajunnisa and colleagues at Institut Teknologi Sepuluh Nopember in Surabaya, Indonesia, combines full-scale laboratory testing with advanced computer simulation to trace the entire chain of seismic damage, from the first hairline crack in a joint to the collapse of an entire frame. The work was funded by the Indonesian Endowment Fund for Education under the EQUITY Program and supported by Malaysia’s Public Works Department, which supplied technical data for the connection details studied.

At the heart of the study is a deceptively simple structural element. In many precast industrial buildings, particularly in Southeast Asia, beams are not cast monolithically with columns. Instead, they are supported on nibs, short cantilevered projections that carry the beam’s reaction through a combination of bearing pressure, dowel action of any projecting reinforcement, and friction. This arrangement speeds up construction enormously, but it also creates a discontinuity in the load path precisely where seismic forces concentrate. When a frame sways during an earthquake, the beam-to-column interface must transfer alternating moments and shears through a joint that was never designed as a continuous monolithic element.

To understand how such a joint actually deforms, the team built a full-scale specimen of a nib connection and subjected it to cyclic loading, the laboratory equivalent of the back-and-forth shaking an earthquake delivers. The test followed internationally recognized protocols for cyclic seismic testing of components, applying progressively larger displacement cycles while measuring the force resisted by the joint. The resulting load-deformation loops, known as hysteresis curves, revealed how stiffness degrades and energy is dissipated as cracking, bond slip, and concrete crushing accumulate at the nib. These experimental curves are the gold standard for characterizing connection behavior, but they describe only a single joint, not a whole building.

That is where the hybrid modeling strategy of the study becomes significant. The researchers first constructed a detailed three-dimensional nonlinear finite element model of the tested joint in ABAQUS, using plastic-damage constitutive models for concrete that capture the material’s degradation under cyclic loading. By calibrating this micro-scale model against the full-scale test data, they ensured the simulation reproduced the real joint’s stiffness, strength, and hysteretic shape. From the validated model, they extracted a moment-rotation relationship for the connection, a curve describing how much rotational resistance the joint provides as it is progressively damaged. Because this curve was synthesized from both experiment and simulation, the authors describe it as a hybrid moment-rotation curve, and it forms the critical bridge between component-level physics and building-level analysis.

The hybrid curve was then imported into SAP2000, a structural analysis platform widely used in engineering practice, as a custom nonlinear hinge placed at each beam-to-column interface of a complete precast frame. This allowed the global model to reproduce the complex, pinching hysteretic behavior observed in the laboratory rather than assuming an idealized elastic or perfectly plastic joint. With the frame model in place, the team ran two complementary forms of nonlinear analysis. The first, nonlinear static pushover analysis, pushes the structure laterally with a monotonically increasing force pattern to identify the sequence of damage states and the governing collapse mechanism. The second, incremental dynamic analysis, subjects the frame to a suite of earthquake ground motion records scaled to ever-higher intensities, tracking how drift demands and damage accumulate as shaking intensifies.

The output of these analyses is a set of fragility curves, probabilistic functions that express the likelihood of reaching a defined damage state at a given level of ground shaking, here quantified by peak ground acceleration. Fragility curves are the workhorses of modern seismic risk assessment: they allow engineers, insurers, and code writers to translate a hazard forecast into an expected probability of damage. For the precast frame with nib connections resting on rock sites, the results are encouraging. The probability of first cracking, corresponding to the Immediate Occupancy performance level at which a building remains safe to use without significant repair, begins to rise at a peak ground acceleration of about 0.20 g. More strikingly, the probability of reaching the Collapse Prevention threshold, the point beyond which the structure is on the verge of partial or total collapse, remains a negligible one percent even at 0.30 g, a level of shaking that would be destructive in many regions.

Those favorable numbers, however, come with an important caveat that the authors emphasize through parametric variation. When the same frame is assumed to stand on softer soils, local site amplification magnifies the ground motion transmitted to the structure, and the damage probabilities climb substantially. The finding underscores that soil-structure interaction is not a secondary refinement but a first-order control on seismic risk for precast buildings. Two identical frames on the same street can face materially different fragilities depending on what lies beneath their foundations, a fact with direct consequences for site selection, foundation design, and retrofit prioritization in moderate-seismicity zones.

The study’s broader significance lies in its methodology as much as its results. In regions of low to moderate seismicity, such as much of Malaysia and Indonesia outside the great subduction zones, large destructive earthquakes are rare enough that extensive experimental databases do not exist, yet frequent enough that vulnerability assessment matters for schools, hospitals, and industrial facilities built with precast technology. By anchoring a numerical model to a full-scale test and then propagating that validated connection behavior through pushover and incremental dynamic analyses to fragility curves, the researchers have demonstrated a transferable framework. Other connection types, from dapped-end beams to grouted duct and post-tensioned joints, could be assessed with the same pipeline, filling a persistent gap between idealized code assumptions and the idiosyncratic behavior of real precast interfaces.

For the precast industry, the message is cautiously optimistic. Nib connections, when properly detailed and founded on competent ground, appear capable of delivering adequate seismic safety in moderate seismic zones, with cracking initiating only at shaking levels that would already alarm occupants and collapse probabilities remaining vanishingly small at 0.30 g on rock. But the same analysis shows that the margin evaporates as soil softens, and that the connection, not the member, is the component that governs the whole frame’s fate. As cities across Southeast Asia and beyond continue to expand with factory-built construction, studies of this kind provide the quantitative evidence base that codes and practitioners need to ensure that speed of assembly never comes at the cost of resilience when the ground finally moves.

Subject of Research: Seismic fragility assessment of precast concrete frames with nib beam-to-column connections

Article Title: Seismic performance and fragility analysis of precast concrete frames with nib connections

Article References: Adnan, A., Tajunnisa, Y., Ramli, M. Z., Falahi Abdul Halim, N. H., Ab Kadir, M. A., Nurhadi, H., Yudoprasetyo, K., & Hariyanto, I. R. (2026). Seismic performance and fragility analysis of precast concrete frames with nib connections. Bulletin of Earthquake Engineering. https://doi.org/10.1007/s10518-026-02700-9

Image Credits: AI Generated

DOI: 10.1007/s10518-026-02700-9

Keywords: precast concrete, nib connections, seismic fragility, cyclic testing, incremental dynamic analysis, pushover analysis, soil-structure interaction, finite element modeling, earthquake engineering, beam-to-column joints, moment-rotation curves, ABAQUS

The research, carried out by Vahid Mohsenian of the University of Science and Culture in Tehran and Luigi Di-Sarno of the University of Naples Federico II, is the first life-cycle cost analysis ever performed for this structural system. Life-cycle cost analysis, or LCC, is an economic evaluation framework that adds up every cost a building will generate over its entire service life: the initial construction price, plus the expected losses from earthquake damage, injuries, fatalities, relocation, lost rental income, and downtime, all discounted to present value. Instead of asking only whether a building prevents collapse under the design earthquake, LCC asks a harder question—which design choice minimizes the total bill that nature and time will present over decades?

The tunnel-form system itself is a product of industrialized construction. Derived from load-bearing wall construction, it involves casting both the walls and the floor slabs of a building simultaneously, in a single pour, using reusable steel tunnel-shaped formwork. The technique offers shorter construction times, lower costs, better quality control, and improved worker safety, which explains its popularity in large-scale housing projects. Structurally, the result is a box-like assembly of cross walls and slabs with considerable inherent lateral strength and stiffness. Field observations after recent strong earthquakes, including the devastating 2023 Kahramanmaraş earthquake sequence in Turkey, have repeatedly described the performance of tunnel-form buildings as exemplary, yet the system still has no dedicated seismic design guideline of its own and is treated in codes as a subset of the conventional reinforced concrete load-bearing wall system.

That classification matters, because the two systems behave differently, and because the latest edition of the Iranian Seismic Design Code mandates special ductility detailing for reinforced concrete shear walls. Meeting those requirements in tunnel-form construction is practically difficult given the constraints of the casting process, and many existing tunnel-form buildings simply do not comply. This raises a pressing question: are the special ductility provisions actually necessary for this system, or are they a conservative inheritance from a different structural family? Answering that question was one of the study’s central objectives.

To do so, the researchers designed two residential tunnel-form buildings—five and ten stories tall—for a highly seismic site with a design peak ground acceleration of 0.35 g and stiff soil conditions. Crucially, the walls were designed with only intermediate ductility provisions, deliberately omitting the special ductility requirements. The coupling beams connecting the walls were modeled as hybrid elements equipped with replaceable steel seismic fuses, a configuration intended to concentrate damage in sacrificial components. The buildings were then subjected to incremental dynamic analysis using twenty far-field ground motion records selected from the PEER database, scaled in steps of 0.05 g, with peak ground acceleration as the intensity measure and both horizontal components applied simultaneously.

The structural results were striking. The average peak ground acceleration corresponding to the onset of slight damage in the structural walls came out at approximately 0.6 g—well above both the design-basis earthquake of 0.35 g and the maximum-considered earthquake of 0.52 g. In probabilistic terms, the chance of the walls even reaching the slight damage state under the design-basis earthquake was estimated at less than ten percent, and the same held true for the moderate damage state under the maximum-considered earthquake. In other words, even without special ductility detailing, the tunnel-form walls showed such high strength and stiffness that the code’s special ductility mandate appears, in the authors’ assessment, to be conservative for this system.

But strength alone does not settle the economic question, and this is where the study’s accounting framework becomes important. The researchers divided the buildings into three component categories: structural elements, acceleration-sensitive non-structural components (things like ceilings, mechanical equipment, and piping that break when shaken), and displacement-sensitive non-structural components (partitions, facades, and finishes that crack when the building sways). For each category and each of four damage states—slight, moderate, extensive, and complete—they combined fragility curves derived from the dynamic analyses with the site hazard curve to compute the probability of exceeding each state over the building’s life. Those probabilities were then multiplied by detailed unit costs drawn from Iranian regulations and surveys: replacement costs per square meter, content costs of roughly 1,600 dollars per square meter, temporary accommodation at 20 dollars per person per day, lost rental income, and legal compensation values for minor injuries, major injuries, and fatalities.

The headline economic finding is remarkably consistent. Regardless of building height, and regardless of whether the losses originated from structural or non-structural damage, the total expected earthquake-induced loss for the tunnel-form system remained below one percent of the initial construction cost. For the five-story building, the expected losses attributable to structural, acceleration-sensitive non-structural, and displacement-sensitive non-structural components amounted to just 0.59, 0.94, and 0.55 percent of construction cost respectively; for the ten-story building, the figures were 0.46, 0.51, and 0.30 percent. Perhaps the most consequential detail, however, is which components dominate the bill: acceleration-sensitive non-structural elements generated the largest share of losses in both buildings, a result consistent with a growing body of research showing that in well-designed structures it is the contents and equipment, not the frame, that drive earthquake economics.

Height mattered in a subtler way. When structural components were treated as the primary source of injury, fatality, and downtime losses, the probable loss in the shorter building was roughly 48 percent lower than in the taller one; for non-structural components the gap was about 26 percent. The explanation lies in code mechanics: for shorter buildings, minimum code requirements tend to govern the design of structural elements, inflating their overstrength and seismic capacity well beyond what taller, more demand-driven designs achieve. The practical implication is that shorter tunnel-form buildings are consistently safer and cheaper over their lifetimes—a finding the authors suggest could guide developers, regulators, and insurance companies in selecting optimal building heights for industrialized housing programs.

The study’s implications reach beyond the tunnel-form system itself. Because no current seismic design guideline incorporates life-cycle cost assessment, the authors argue that codes should evolve in one of two directions: either by embedding LCC analysis directly into the design process, or by steering designers toward structural systems that inherently minimize lifetime losses—which their results suggest tunnel-form construction does. They also recommend that the system be recognized as an independent structural category with its own seismic parameters, and they caution that their conclusions are bounded by the models and assumptions used: near-fault motions, vertical ground motion components, aftershocks, soil-structure interaction, corrosion, aging, and multi-hazard scenarios all remain open questions. Still, for a construction technique already favored for its speed and economy, the new analysis adds a powerful third argument. In the world’s most earthquake-prone regions, the humble tunnel of cast concrete may be one of the cheapest insurance policies a city can build.

Subject of Research: Life-cycle cost and seismic performance assessment of concrete tunnel-form building systems in earthquake-prone regions

Article Title: Tunnel-form system as an ideal solution for seismic regions: a numerical study based on life-cycle cost analysis

Article References: Mohsenian, V., & Di-Sarno, L. (2026). Tunnel-form system as an ideal solution for seismic regions: a numerical study based on life-cycle cost analysis. Bulletin of Earthquake Engineering. https://doi.org/10.1007/s10518-026-02632-4

Image Credits: AI Generated

DOI: 10.1007/s10518-026-02632-4

Keywords: tunnel-form system, life-cycle cost analysis, earthquake engineering, seismic fragility, incremental dynamic analysis, shear walls, non-structural components, ductility provisions, seismic design codes, downtime, reinforced concrete, seismic hazard

The concept at the heart of the paper is seismic uplift fragility, defined as the conditional probability that pile uplift will occur given a particular ground motion intensity measure. Fragility analysis is a cornerstone of modern earthquake engineering because it converts the messy, uncertain physics of soil-structure interaction into probabilistic statements that can feed directly into risk assessment and design codes. Previous research had established that scour removes overburden soil around the pile cap, amplifies pile-cap rotations during shaking, and can trigger uplift of the piles themselves. But the authors note that the seismic uplift behavior of scoured pile-group foundations had never been probabilistically quantified, leaving a significant gap in multi-hazard bridge assessment.

To close that gap, the team built an extensive numerical modeling campaign. They established 49 archetype bridge configurations by varying twelve structural and geotechnical parameters, including pile length, pile spacing, axial load ratio, and the longitudinal reinforcement ratio of the piles. The bridges were founded in cohesionless soils, meaning sandy, non-clayey sediments of exactly the kind that scour attacks most aggressively and that are common beneath river and coastal crossings. Each archetype was subjected to suites of ground motions, and the resulting simulations were mined for the quantities that best track uplift behavior.

A central technical contribution of the study is the careful selection of the response metrics used in the probabilistic demand models. The researchers systematically compared candidate engineering demand parameters and intensity measures, and concluded that the peak rotation of the pile cap is the optimal engineering demand parameter for quantifying uplift, while the Housner intensity, a measure based on the energy content of the ground motion, is the optimal intensity measure. Crucially, they found that pile-cap rotation is more efficient and more practical than the pile cap’s lateral displacement for characterizing uplift demand. Rotation, it turns out, directly captures the rocking mechanism that precedes uplift, whereas lateral displacement conflates rocking with sliding and bending responses, diluting the statistical relationship.

With demand quantified, the team then turned to capacity. Uplift capacity models were derived from the pile-cap rotations at the onset of uplift, effectively defining the rotation threshold beyond which part of the pile group begins to pull free of the surrounding soil. When a rocking foundation reaches this point, load redistributes to the remaining compressed piles, soil resistance on the uplifted side vanishes, and the energy dissipation and recentering behavior of the foundation change fundamentally. Combining the probabilistic demand models with these capacity models yielded the study’s headline output: seismic uplift fragility curves for scoured pile-group foundations in cohesionless soils.

The numbers are sobering. For the base bridge model, the probability of uplift reaches 82 percent under a seismic hazard level associated with a 475-year return period, the design-level event around which many modern seismic codes are organized. In other words, a bridge whose foundations have been scoured has a very high likelihood of experiencing pile uplift when struck by an earthquake of the magnitude engineers already plan for. Because uplift initiates the transition from a ductile rocking response toward potentially uncontrolled foundation movement, an 82 percent probability at the design event represents a serious vulnerability, particularly for the aging river and coastal bridges that dominate many transportation networks.

The parametric analysis that followed is where the study becomes most directly useful to practitioners. The fragility decreases as pile length increases, as pile spacing increases, and as the axial load ratio rises, while it increases as the longitudinal reinforcement ratio of the piles decreases. Among all the parameters examined, pile length was identified as the single most influential factor. Each of these trends has an intuitive physical basis. Longer piles provide deeper embedment and greater resistance to pullout. Wider spacing reduces the overlapping stress zones between adjacent piles, letting each pile mobilize more of the surrounding soil. Higher axial load on the foundation provides a stabilizing, self-weight-driven resistance to rocking and uplift. Conversely, less longitudinal reinforcement weakens the capacity of individual piles to sustain the tension that develops during rocking, making uplift and its consequences more damaging.

These findings resonate with a broader body of experimental work on rocking foundations. Quasi-static tests and shaking table studies by the same research group and by others in recent years have shown that scoured pile-group foundations exhibit distinctive uplift behavior and energy dissipation mechanisms, and that rocking can sometimes even be harnessed as a deliberate design strategy when the foundation is detailed to recenter after shaking. The new study adds the probabilistic layer that such experimental work lacks, translating deterministic observations into fragility statements that can be integrated into regional risk models, resilience assessments, and retrofit prioritization for bridge stocks exposed to both flood scour and seismic hazard.

Recognizing that running full nonlinear finite element simulations of 49 archetype bridges is impractical for routine design offices, the authors also distilled their results into practical tools. They established and validated multivariate linear regression models that allow rapid estimation of uplift fragility from the key design parameters, without the need for expensive simulation. This surrogate modeling approach mirrors a wider trend in earthquake engineering, in which machine-learned and regression-based approximations of physics-based analyses are used to bring probabilistic assessment within reach of everyday engineering workflows. For a bridge engineer wondering whether a scour-critical crossing needs longer piles, wider spacing, or enhanced reinforcement, the regression models offer a first-order answer in seconds.

The broader significance of the work lies in its treatment of concurrent hazards. Flood-induced scour and earthquakes are usually assessed separately, yet they are physically coupled in ways that can dramatically worsen outcomes. Scour weakens exactly the soil-foundation system that must resist seismic demands, and climate-driven changes in flood frequency suggest that more bridges will spend more of their service lives with compromised foundations. By delivering the first probabilistic quantification of seismic uplift fragility for scoured pile-group foundations in cohesionless soils, the Fuzhou University and Tongji University team has given the engineering community both a warning and a toolkit: multi-hazard assessment is not optional for river and coastal bridges, and the levers that most reduce uplift risk, above all pile length, are already in the hands of designers.

Subject of Research: Seismic uplift fragility analysis of scour-affected bridge pile-group foundations in cohesionless soils

Article Title: Seismic uplift fragility of scoured bridge pile-group foundations in cohesionless soils

Article References: Wang, J., Luo, H., Wang, X., & Gu, Y. (2026). Seismic uplift fragility of scoured bridge pile-group foundations in cohesionless soils. Bulletin of Earthquake Engineering. https://doi.org/10.1007/s10518-026-02686-4

Image Credits: AI Generated

DOI: 10.1007/s10518-026-02686-4

Keywords: bridge scour, pile-group foundation, seismic fragility, pile uplift, cohesionless soils, Housner intensity, pile-cap rotation, probabilistic seismic demand, multi-hazard assessment, sensitivity analysis, regression surrogate model, earthquake engineering

The pulse period, usually written as Tp, governs the dominant timescale of a velocity pulse and wields an outsize influence on how structures respond. Whether a pulse is short and sharp or long and rolling can determine whether a frame sways mildly or lurches into its inelastic range, and the relationship between Tp and a building’s fundamental period can swing structural demands dramatically. Pulse period also feeds directly into ground-motion simulation, pulse-consistent spectral models, and probabilistic seismic hazard analysis, which means that getting Tp wrong can quietly distort downstream estimates of earthquake risk.

Yet despite decades of research, no single method for determining Tp has achieved universal acceptance. Wavelet analysis, peak-point measurements on velocity time histories, analytical pulse-model fitting, and response-spectrum-based techniques all identify the period in different ways. The most popular family of approaches reads Tp directly off a response spectrum, taking the period at the peak of the spectral velocity (the SV method) or at the peak of the product of spectral velocity and spectral displacement (the SV·SD method). These methods are attractively simple, but they hinge on picking one local maximum out of a spectrum that may be jagged, multi-peaked, or contaminated by high-frequency content, and that dependence can produce badly underestimated or overestimated pulse periods for certain records.

The new study takes a fundamentally different route. Instead of hunting for a spectral peak, the researchers define the pulse period using the relative elastic input energy spectrum, EI,r, a quantity from energy-based seismic design that reflects not only the amplitude and frequency content of a ground motion but also its duration and total energy. The rule is elegant: the pulse period is the oscillator period that bisects the area enclosed by the EI,r spectrum and the period axis, leaving exactly half of the spectral energy on each side. Rather than asking where the spectrum peaks, the equal-area criterion asks where the cumulative input energy is balanced, producing a globally representative characteristic period for the record.

To make the integration interval robust, the team devised an adaptive termination criterion. The energy spectrum is computed from 0.01 seconds in steps of 0.01 seconds, and the calculation continues until the spectral tail has decayed sufficiently: the most recent twenty consecutive ordinates must all fall below either one percent of the running spectral peak or an absolute tolerance, with tightly constrained variation between adjacent ordinates. A hard cap of 40 seconds prevents runaway extension for records with persistent long-period content. Sensitivity analyses reported in the paper confirm that the identified pulse periods are essentially insensitive to reasonable variations in these parameters.

Crucially, the authors did not simply assert that their equal-area period is physically meaningful; they tested it. The EI,r-based Tp is prescribed in the analytical pulse model of Mavroeidis and Papageorgiou, while the remaining four pulse parameters, amplitude, phase, number of oscillations, and timing, are optimized with a genetic algorithm that minimizes the squared difference between the extracted pulse and the original velocity time history. Because the pulse period is held fixed during optimization, any agreement between the extracted wavelet and the actual record must flow from the identified period itself. Across the records examined, the optimized pulses reproduced the dominant velocity features and matched the principal range of the 5-percent-damped spectral velocity, supporting the physical reasonableness of the new definition.

The method was then benchmarked against six established techniques: the continuous wavelet transform classification of Baker, a wavelet packet transform approach, variational mode decomposition combined with genetic-algorithm pulse fitting, a signal-only optimization parameterization, and the SV and SV·SD spectrum methods. Across 311 representative pulse-like records, correlation coefficients between the new method and the reference approaches ranged from 0.87 to 0.98, with most above 0.90, indicating strong overall consistency. Detailed case comparisons revealed instructive differences. On some records the SV method seized on a short-period local peak and produced a far too narrow pulse, while the SV·SD method occasionally drifted toward very long periods. The equal-area energy criterion typically landed between the two, capturing the main velocity-pulse scale without the extremes of either peak-chasing approach.

To demonstrate engineering relevance, the researchers classified pulse-like motions into short-, medium-, and long-period groups and assessed the collapse fragility of a four-story, three-bay reinforced concrete frame modeled in OpenSees. The fiber-section model, validated against shake-table test data from the European Laboratory for Structural Assessment, reproduced measured drift profiles, displacement histories, and story shears with satisfactory accuracy. Cloud analyses using the geometric-mean spectral acceleration as intensity measure and the maximum inter-story drift ratio as demand parameter showed that pulse period matters enormously: records with pulses longer than two seconds produced markedly higher collapse fragility, while the short-period group shifted fragility curves toward higher ground-motion intensities and thus more favorable collapse performance. Comparable trends emerged when records were grouped using the CWT and SV·SD methods, reinforcing the conclusion that the observed pulse-period effect is genuine rather than an artifact of one identification technique.

The authors are careful to position the new criterion as a complement rather than a replacement. Different identification methods emphasize different characteristics of complex pulse-like motions, and no single definition suits every record. What the equal-area EI,r approach offers is a measure that is less hostage to a particular local spectral peak, is grounded in the cumulative distribution of input energy that energy-based design frameworks already prize, and carries a clear physical interpretation as an energy-balanced characteristic period. The study also confirms that pulse period is a critical parameter for interpreting the collapse potential of near-fault motions and for building pulse-period-dependent fragility models.

Limitations remain, and the authors flag them candidly. The structural application covered only a four-story bare reinforced concrete frame, so the quantitative fragility results depend on that building’s dynamic properties and its 0.711-second fundamental period. Future work, they write, should extend the framework to structures with different heights, periods, and response mechanisms to probe the interaction between pulse period and structural period more deeply. Even so, the method arrives at a moment when near-fault seismic risk assessment increasingly demands pulse-aware tools, and it provides engineers and hazard analysts with a computationally light, physically grounded way to extract one of the most consequential numbers in earthquake engineering from any velocity record.

Subject of Research: An energy-based method for identifying velocity-pulse periods of near-fault ground motions

Article Title: An efficient energy-based approach for identification of velocity-pulse periods

Article References: Gao, Q., Chang, Z., Monti, G., & Mollaioli, F. (2026). An efficient energy-based approach for identification of velocity-pulse periods. Bulletin of Earthquake Engineering. https://doi.org/10.1007/s10518-026-02677-5

Image Credits: AI Generated

DOI: 10.1007/s10518-026-02677-5

Keywords: pulse period, near-fault ground motions, input energy spectrum, velocity pulse, seismic fragility, reinforced concrete frame, genetic algorithm, M&P wavelet, probabilistic seismic hazard analysis, earthquake engineering, response spectrum, collapse vulnerability