Seismic Ground Acceleration Research Articles

Discrete-element analysis of floor influence on seismic response of masonry structures

Traditional masonry buildings are highly vulnerable to earthquake loading and their dynamic response is strongly influenced by the in-plane deformability of the timber floors and the quality of the wall-to-floor connections. Understanding the behaviour of timber floors and roofs and their interaction with masonry walls is therefore fundamental for the protection of historical buildings. In a previous research project, different timber-based dry-connected strengthening solutions for timber floors were tested under in-plane loading. The experimental results showed a significant increase in shear strength and stiffness. In the current study, the discrete-element method (DEM) was used to model a simple masonry structure and evaluate the effectiveness of strengthening solutions to avoid triggering first-mode mechanisms, namely out-of-plane collapse of masonry walls. The structure was stressed by seismic ground accelerations. The unreinforced and reinforced floors were modelled with non-linear springs that reproduced their experimental hysteretic response. Parametric analyses were performed, changing the geometry of the structure and the masonry wall thickness. The comparison highlighted the effectiveness of the proposed wood-based strengthening solutions for reducing out-of-plane displacements of masonry walls, potentially matching the performance of rigid floors.

A comparative study of the main factors controlling geohazards induced by 10 strong earthquakes in Western China since the Wenchuan earthquake in 2008

Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response. By studying these factors, the geomorphic and geological factors controlling the nature, condition, and distribution of earthquake-induced geohazards can be analyzed. Such insights facilitate earthquake disaster prediction and emergency response planning. The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events, examining ten earthquakes including the Wenchuan, Yushu, Lushan events, to elucidate the main control factors of seismic geohazard. The authors observed that seismic geohazard occurrence is usually affected by many factors, among which active nature of the seismogenic fault, seismic peak ground acceleration (PGA), topographic slope and geomorphic height differences, and distance from the fault zone and river system are the most important. Compared with strike-slip earthquakes, thrust earthquakes induce more high-altitude and high-speed remote landslides, which can cause great harm. Slopes of 0°–40° are prone to secondary seismic geohazards, which are mainly concentrated 0–6 km from the river system. Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area. The maximum seismic PGA and secondary seismic geohazard number are positively correlated, and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation, respectively. Through the research, the spatial distribution of seismic geohazards is predicted, providing a basis for the formulation of emergency response plans following disasters.©2023 China Geology Editorial Office.

Detection of oriented fractal scaling components in anisotropic two-dimensional trajectories

We propose a novel class of mixed fluctuations with different orientations and fractal scaling features as a model for anisotropic two-dimensional (2D) trajectories hypothesized to appear in complex systems. Furthermore, we develop the oriented fractal scaling component analysis (OFSCA) to decompose such mixed fluctuations into the original orientation components. In the OFSCA, the original orientations are detected based on the principle that the original angles are orthogonal to the angles with the minimum and maximum scaling exponents of the mixed fluctuations. In our approach, the angle-dependent scaling properties are estimated using the Savitzky–Golay-filter-based detrended moving-average analysis (DMA), which has a higher detrending order than the conventional moving-average-filter-based DMA. To illustrate the OFSCA, we demonstrate that the numerically generated time-series of mixed fractional Gaussian noise (fGn) processes with non-orthogonal orientations and different scaling exponents is successfully decomposed into the original fGn components. We demonstrate the existence of oriented components in the 2D trajectories by applying OFSCA to real-world time-series, such as human postural fluctuations during standing and seismic ground acceleration during the great 2011 Tohoku-oki earthquake.

Stability Analysis of Fragile Rock Pillars and Insights on Fault Activity in the Negev, Israel

AbstractFragile geologic features (FGFs) are used as negative indicators of strong ground motion. By evaluating the stability of FGFs and determining their age, it is possible to constrain the local maximum seismic ground acceleration that has occurred during their lifetime. This methodology was originally developed to analyze precariously balanced rocks (a subset of FGFs) and has been used to assess long‐term fault activity and improve seismic hazard analyses. In the Negev desert of Israel, several in situ, slender rock pillars exhibit natural frequencies within the range of seismic waves (1–10 Hz) and therefore constitute an important FGF subset. However, the motion of such pillars may be complex with an initial stage of swaying followed by basal detachment, rocking and toppling, or failure within the pillar. To demonstrate that pillar stability can be analyzed using the existing FGF methodology, we show that the tensional stresses developed at the base of a pillar swaying at its fundamental modes of motion are comparable or larger than the typical tensile strength of Negev pillars. Finally, we demonstrate how a newly documented data set of Negev FGFs can be used to provide new insights on fault activity along the Negev‐Sinai Shear Zone and the Arava Fault. Assuming a plausible range of motion amplification, the stability analysis of long‐standing FGFs yields significant constraints on fault seismicity parameters (Mmax < 7 for a section of the Arava Fault). Extending the regional data set would provide important insights for regional seismic hazard along the Dead Sea Transform.

Are seismic fragility curves fragile?

A hypothetical seismic site is constructed for which the probability law of the seismic ground acceleration process X(t) is specified. Since the seismic hazard is known, the performance of the incremental dynamic analysis- (IDA) and multiple stripe analysis- (MSA) based fragilities, which are used extensively in Earthquake Engineering, can be assessed without ambiguity. It is shown that the IDA- and MSA-based fragilities are unsatisfactory for moderate and large seismic events, are sensitive to the particular parameters used for their construction, and may or may not improve with the sample size. Also, the usefulness of the optimization algorithms for selecting ground motions records is questionable.

Spatial distribution characteristics of landslides in Xiluodu Reservoir Area

There are many landslides in Xiluodu Reservoir Area. 161 landslides were interpreted to investigate. The key influential factors including the formation lithology, faults, rainfall, earthquake, reservoir water level and the Geodetecter methods was used to explore the relative impact of the factors and the interaction of the two factors on the spatial distribution of landslides. The results show that: (1) Due to the differences in the properties of different rock groups, the landslides show significant regional differences; (2) The landslides are mostly distributed in the range of 600~1200 m, 10°~40°, Ordovician-Silurian (O-S) strata, areas within 4 km of the fault, areas where the average annual rainfall is 800~900 mm and seismic peak ground acceleration of 0.15g; (3) There are 53 landslides affected by reservoir water. The effect is most obvious when the water level acts on the middle and front of the landslide. The effect time is gradually weakened with the annual deformation and stress adjustment; (4) Multi-factor interaction presents more clear relationship with the spatial distribution of landslides. The interaction of lithology and rainfall can explain 45.9 % of the spatial variation of landslides, which means that lithology and rainfall factors have the greatest influence on the spatial distribution of landslides. The results provide a certain basis for the prevention and control of landslides in Xiluodu Reservoir Area.

An empirical attenuation model of the peak ground acceleration (PGA) in the near field of a strong earthquake

Empirical methods are commonly employed to predict the PGA distribution of an earthquake and are widely used. However, current empirical methods assume the seismic source to be a point source, a line source, or a plane source, where the energy is concentrated and released uniformly. An empirical attenuation model of the near-field peak ground acceleration (PGA) was proposed that considers a nonuniform spatial distribution of seismic fault energy and its 3D scale. Then, this model was used to reconstruct the PGA distribution of the 2008 Wenchuan, China, Mw7.9 earthquake based on the data of a seismic fault model and ground acceleration records of the mainshock and aftershocks collected by seismic stations. The predicted PGA values show similar attenuation characteristics to the interpolated map of the PGA recorded by seismic stations. A comparison with the results of a finite-fault model developed by the USGS indicates that the proposed model can provide more details and give a more precise result in the near field. The analysis of landslides triggered by the Wenchuan earthquake demonstrates that the PGA distribution estimated by this model can be used to validate the findings of other researchers.

Fragility Analysis of Gantry Crane Subjected to Near-Field Ground Motions

A gantry crane located in a near-field earthquake-prone area is selected in this paper as an example, and the nonlinear finite element (FE) model is used considering the material nonlinearity including plastic hinges and the second order (P − Δ ) effect with a comprehensive consideration of the components including sill beams, support beams, legs, and trolley girders. The local displacement ratio (LDR) and deflection ratio (DR) are proposed as demand measures (DMs) of the gantry crane, which are utilized to construct a probabilistic seismic demand model (PSDM). Then, the capacity limit states for the gantry crane are defined in this study by performing pushover analysis (POA), known as serviceability, damage control, and collapse prevention, respectively. Moreover, the operating capacity of the crane during an earthquake is further investigated and quantified by operating seismic peak ground acceleration, which is defined as the maximum acceleration when the failure probability is 50%. Finally, the fragility curves and the failure probability of the gantry crane are derived by the above definitions, all of which are pioneering in the seismic design of gantry cranes subjected to near-field ground motions. Some major conclusions are drawn that the horizontal component of an earthquake has a more notable effect on the structural damage of the gantry crane compared to the vertical component, and incremental dynamic analysis can take seismic uncertainty into account and quantify the deformation of gantry crane in more detail.

A simple and rapid approach for the numerical simulation of non-linear elements and examples of its application

In earthquake design philosophy non-linear inelastic damage is concentrated at predetermined locations in a structure, with the aim being to keep structural members critical for collapse avoidance, elastic. Non-linear elements can include the beam column joints in steel and reinforced concrete moment resisting frames, the nail connections of timber sheathing-to-framing shear walls, and the hold-down connectors of shear walls. To numerically model the seismic behaviour of these structures, it is critical to be able to quickly and simply model their respective hysteretic behaviours. It is particularly important to identify the parameters that will allow for the accurate replication of the degrading and pinching qualities of the force-displacement relationships. The authors summarise the use of a proprietary multi-linear plastic link, available in most finite element packages, in order to achieve this. A step-by-step process to model the links, from previous research, is described. This process considers the initial elastic stiffness, the force-displacement curve up to ultimate-strength, the post ultimate-strength degrading stiffness, and the reversing stiffness. The procedure can be adopted for both linear and rotational cyclic excitation. The modelled individual elements are subjected to a series of displacement-controlled time-history schedules and validated against the results from experimental tests. These elements, representing non-linear behaviour, are in turn implemented in various numerical models of shear walls. The authors apply cyclic loading to a model wall, and then for a separately designed wall apply seismic ground accelerations associated with the 2011 Canterbury earthquakes in New Zealand, and the results are presented. While the examples provided in this paper involve timber shear walls, the numerical modelling method will be equally useful for a variety of structures of different material types and configuration.

Telecom, Traffic Cones, and the Big One: Identifying Transportation and Communications Emergency Support Workforces and Calculating Their Exposure to Seismic Peak Ground Accelerations

Successful post-disaster response and recovery depends on prompt restoration of infrastructure, including transportation or communications. However, disasters can have an impact on the workforce responsible for restoration, for example, by damaging their homes. This study has two goals: 1. Identify workers potentially participating in restoring transportation and communications infrastructure; 2. Calculate these workers’ exposure to the peak ground accelerations (PGAs) of a 7.8 magnitude earthquake in a Southern California scenario, and compare it with the rest of the working population’s exposure. Four steps are required. First, calculate the mean PGA for each affected public use microdata area (PUMA). Second, identify the infrastructure restoration workforce by specifying Standard Occupational Classification (SOC) and North American Industry Classification System (NAICS) codes. When specifying, use the Emergency Support Function (ESF) Annexes for Transportation (ESF#1) and Communications (ESF#2) to clarify workers’ roles and responsibilities. This ESF-specific listing of codes is a novel contribution. Third, via frequency table, calculate the mean and standard deviation of transportation and communications workers’ exposure to PGAs in their PUMAs of residence. Finally, test the difference in mean PGA exposures between two populations: (a) transportation or communications workers and (b) the rest of the working population. This study finds that, for this scenario, transportation workers are exposed to statistically significant higher PGAs than non-transportation workers, and communication workers to significantly lower PGAs. For practitioners, knowing which worker categories a disaster disproportionately affects could justify pre-event investments in workforce preparedness and recovery planning efforts.

Seismic analysis of nonlinear offshore moored floating structures

This article presents a numerical model for solving the nonlinear random vibrations of offshore moored floating structures under seismic excitation. The offshore moored floating structure consists of the floating platform and mooring cables. The floating platform is considered as a rigid body with 3 degrees of freedom. The nonlinear equations of motions of the mooring cables are established using the nonlinear cable elements that are formulated based on the extended Hamilton principle. The nonlinear hydrodynamic drag forces that act on both the floating platform and cables are considered. In order to carry out the random vibrational analysis, the connection conditions between the floating structure and mooring cables are given to formulate the equations of motions of the whole system. Finally, the moored floating structure under horizontal seismic ground accelerations with Kanai–Tajimi model are analyzed using Monte Carlo simulation method. The probability density functions of the displacements of the moored floating structure and the maximum tensile force in cables are presented. The influences of different sag-to-span ratios or inclined angles of the mooring cables on the mean value and standard deviation of the displacements of the floating structure and the maximum tensile force in cables are analyzed.

Predictive model for site specific simulation of ground motions based on earthquake scenarios

SummaryA predictive stochastic model is developed based on regression relations that inputs a given earthquake scenario description and outputs seismic ground acceleration time histories at a site of interest. A bimodal parametric non‐stationary Kanai‐Tajimi (K‐T) ground motion model lies at the core of the proposed predictive model. The functional forms that describe the temporal evolution of the K‐T model parameters can effectively represent strong non‐stationarities of the ground motion. Fully non‐stationary ground motion time histories can be generated through the powerful Spectral Representation Method. A Californian subset of the available NGA‐West2 database is used to develop and calibrate the predictive model. Samples of the model parameters are obtained by fitting the K‐T model to the database records, and the resulting marginal distributions of the model parameters are efficiently described by standard probability models. The samples are translated to the standard normal space and linear random‐effect regression models are established relating the transformed normal parameters to the commonly used earthquake scenario defining predictors: moment magnitude Mw, closest‐to‐site distance Rrup, and average shear‐wave velocity at a site of interest. The random‐effect terms in the developed regression models can effectively model the correlation among ground motions of the same earthquake event, in parallel to taking into account the location‐dependent effects of each site. For validation purposes, simulated acceleration time histories based on the proposed predictive model are compared with recorded ground motions. In addition, the median and median plus/minus one standard deviation elastic response spectra of synthetic ground motions, pertaining to a variety of different earthquake scenarios, are compared to the associated response spectra computed by the NGA‐West2 ground motion prediction equations and found to be in excellent agreement.

Implementation of smart-passive dampers combined with double concave friction pendulum devices to retrofit an existing highway viaduct exploiting the seismic early warning information

The seismic events occurred in recent years have highlighted the extreme vulnerability of a large part of existing Italian highway infrastructure. The principal skeleton of Italian highway network was built during the mid-century, where the knowledge of seismic engineering was still limited. Also, the old age of structures with the need of seismic assessment, is forcing highway stakeholders to give an answer to a strategic query: should thousands of highway bridges be destroyed and re-built with in force regulations, or do they just need a retrofit? The objective of this work is to reply concretely to that issue, investigating the combined use of a dissipative smart-passive control strategy and an innovative isolation system to protect seismically excited structures. It is based on the use of seismic early warning information (SEWI) to optimally calibrate variable dampers for a higher reduction of the structural response. In particular, the adoption of dissipative magnetorheological (MR) dampers calibrated according to the forecasted value of the seismic peak ground acceleration, and a new adaptive control algorithm, are herein proposed. Moreover, to reduce the influence of support devices in the global viaduct behavior, a prototype of double concave friction pendulum (DCFP), with a very low value of friction coefficient, is implemented. The effectiveness and robustness of the DCFPs system with smart-passive MR dampers driven by the SEWI, are demonstrated with reference to an existing Italian highway viaduct for the first time. The results of non-linear time history analysis using seismic registrations of natural events are then compared with a consolidate passive technique characterized by lead rubber bearings (LRB), applied to the same structure. The control technique results were promising for the ease of implementation for structures, effectiveness, even compared with a widespread passive system and robustness, given an estimate of the incoming earthquake by a seismic early warning system.

A seismologically consistent expression for the total area and volume of earthquake‐triggered landsliding

AbstractWe present a new, seismologically consistent expression for the total area and volume of populations of earthquake‐triggered landslides. This model builds on a set of scaling relationships between key parameters, such as landslide spatial density, seismic ground acceleration, fault length, earthquake source depth, and seismic moment. To assess the model we have assembled and normalized a catalog of landslide inventories for 40 shallow, continental earthquakes. Low landscape steepness causes systematic overprediction of the total area and volume of landslides. When this effect is accounted for, the model predicts the total landslide volume of 63% of 40 cases to within a factor 2 of the volume estimated from observations (R2=0.76). The prediction of total landslide area is also sensitive to the landscape steepness, but less so than the total volume, and it appears to be sensitive to controls on the landslide size‐frequency distribution, and possibly the shaking duration. Some outliers are likely associated with exceptionally strong rock mass in the epicentral area, while others may be related to seismic source complexities ignored by the model. However, the close match between prediction and estimate for about two thirds of cases in our database suggests that rock mass strength is similar in many cases and that our simple seismic model is often adequate, despite the variety of lithologies and tectonic settings covered. This makes our expression suitable for integration into landscape evolution models and application to the anticipation or rapid assessment of secondary hazards associated with earthquakes.

Dynamic Analysis of AP1000 Shield Building Considering Fluid and Structure Interaction Effects

The shield building of AP1000 was designed to protect the steel containment vessel of the nuclear reactor. Therefore, the safety and integrity must be ensured during the plant life in any conditions such as an earthquake. The aim of this paper is to study the effect of water in the water tank on the response of the AP1000 shield building when subjected to three-dimensional seismic ground acceleration. The smoothed particle hydrodynamics method (SPH) and finite element method (FEM) coupling method is used to numerically simulate the fluid and structure interaction (FSI) between water in the water tank and the AP1000 shield building. Then the grid convergence of FEM and SPH for the AP1000 shield building is analyzed. Next the modal analysis of the AP1000 shield building with various water levels (WLs) in the water tank is taken. Meanwhile, the pressure due to sloshing and oscillation of the water in the gravity drain water tank is studied. The influences of the height of water in the water tank on the time history of acceleration of the AP1000 shield building are discussed, as well as the distributions of amplification, acceleration, displacement, and stresses of the AP1000 shield building. Research on the relationship between the WLs in the water tank and the response spectrums of the structure are also taken. The results show that the high WL in the water tank can limit the vibration of the AP1000 shield building and can more efficiently dissipate the kinetic energy of the AP1000 shield building by fluid-structure interaction.

Seismic lateral earth pressure analysis of retaining walls

Based on limit equilibrium principles, this study presents a theoretical derivation of a new analytical formulation for estimating magnitude and lateral earth pressure distribution on a retaining wall subjected to seismic loads. The proposed solution accounts for failure wedge inclination, unit weight and friction angle of backfill soil, wall roughness, and horizontal and vertical seismic ground accelerations. The current analysis predicts a nonlinear lateral earth pressure variation along the wall with and without seismic loads. A parametric study is conducted to examine the influence of various parameters on lateral earth pressure distribution. Findings reveal that lateral earth pressure increases with the increase of horizontal ground acceleration while it decreases with the increase of vertical ground acceleration. Compared to classical theory, the position of resultant lateral earth force is located at a higher distance from wall base which in turn has a direct impact on wall stability and economy. A numerical example is presented to illustrate the computations of lateral earth pressure distribution based on the suggested analytical method.

Proposal of new ground-motion prediction equationsfor elastic input energy spectra

In performance-based seismic design procedures Peak Ground Acceleration (PGA) and pseudo-Spectral acceleration (Sa) are commonly used to predict the response of structures to earthquake. Recently, research has been carried out to evaluate the predictive capability of these standard Intensity Measures (IMs) with respect to different types of structures and Engineering Demand Parameter (EDP) commonly used to measure damage. Efforts have been also spent to propose alternative IMs that are able to improve the results of the response predictions. However, most of these IMs are not usually employed in probabilistic seismic demand analyses because of the lack of reliable Ground Motion Prediction Equations (GMPEs). In order to define seismic hazard and thus to calculate demand hazard curves it is essential, in fact, to establish a GMPE for the earthquake intensity. In the light of this need, new GMPEs are proposed here for the elastic input energy spectra, energy-based intensity measures that have been shown to be good predictors of both structural and non-structural damage for many types of structures. The proposed GMPEs are developed using mixed-effects models by empirical regressions on a large number of strong-motions selected from the NGA database. Parametric analyses are carried out to show the effect of some properties variation, such as fault mechanism, type of soil, earthquake magnitude and distance, on the considered IMs. Results of comparisons between the proposed GMPEs and other from the literature are finally shown.

Seismic Intensities, PGA, and PGV for the 20 April 2013, Mw 6.6 Lushan, China, Earthquake, and a Comparison with North America

Online Material: Seismic intensity map with observation points; table of geographical coordinates, MMI values. The 20 April 2013 M w 6.6 Lushan earthquake occurred at the geologic boundary between the western Sichuan basin and the eastern flank of the Tibetan plateau. This earthquake occurred 100 km south‐southwest of the epicenter of the 2008 M w 7.9 Wenchuan earthquake (Fig. 1). In response to the deadly Wenchuan earthquake, there has been a significant increase in the density of seismographic, strong‐motion, and Global Positioning System (GPS) stations throughout western Sichuan Province, including the vicinity of the Lushan earthquake. This increased level of earthquake monitoring has provided a dense array of coseismic recordings of the Lushan earthquake. These data have been used for numerous studies of the source properties, aftershock distribution, and the crustal strain field associated with this earthquake (Fang et al. , 2013; Liu et al. , 2013; Shan et al. , 2013; Xie et al. , 2013, 2014; Xu et al. , 2013; Han et al. , 2014; Zhang et al. , 2014). Figure 1. (a) Topographic map of Longmen Shan, western Sichuan Province, with the epicenters of the 2008 Wenchuan and 2013 Lushan earthquakes obtained from China Earthquake Network Center and the focal mechanisms (Global Centroid Moment Tensor project). The black lines show the extent of the rupture planes of the Wenchuan earthquakes (Zhang et al. , 2010; Hartzell et al. , 2013). (b) Finite‐fault slip model for the Lushan earthquake (Liu et al. , 2013); maximum slip is 150 cm and the rupture dimension for slip >25 cm is 20 km by 20 km. We report a field investigation of seismic intensities in the immediate vicinity of the epicenter of the Lushan earthquake. We compare these results with the recorded seismic ground accelerations and ground …

설계기준 개선에 따른 기존 고속철도 교량 내진보강 필요성 고찰

본 논문은 등가정적하중법에 의해 설계된 경부고속철도 구간 중 PSC Box Girder 대표 교량들을 대상으로 등가정적법과 응답스팩트럼법을 이용하여 지진력이 산정되었고, 지진력의 차이가 확인된다. 해석법 비교를 위하여 상용유한요소 프로그램을 이용하여 5개 교량에 대한 3차원 유한유소 모델이 구성되었고, 각 해석법의 의한 지진력이 비교되었다. 고유주기가 저차에서 지배되는 경우, 지반조건과 고유주기의 따라 지진가속도가 산정되는 응답스팩트럼법과 등가정적하중법과의 차이가 커지는 것이 확인되었다. 이렇게 산정된 지진력에 차이에 따른 내진성능 평가 결과 설계 지진력 보다 큰 지진력의 적용으로 인한 것으로 내진 보강의 필요성을 의미한다. This paper was calculated the earthquake load using ELFP(Equivalent Lateral Force Procedure) and RSA(Response Spectrum Analysis) for PSC Box Girder representative bridges by the Phase of KTX designed by ELFP and verified the difference of these analyses. It have been modeled 3 dimensional FE model of 5 bridges using a commercial FEM program for the comparison of these analyses using a commercial FEM program and were compared the earthquake load. It has been to confirm the increase of the difference ELFP of RSA calculated to seismic ground acceleration according to the ground condition and natural period. It is mean that the necessity of seismic reinforcement due to the application of a larger of earthquake load than designed earthquake load form the seismic performance evaluation result according to the difference of calculated earthquake loads.

Seismic Fragility Evaluation with Incomplete Structural Appraisal Data: An Iterative Statistical Approach

This paper presents an iterative statistical approach to evaluating seismic structural safety using incomplete appraisal data. Despite the continuous improvement to traditional structural assessment procedures and the recent progress in structural health monitoring methodologies, practically acquired structural appraisal data may often be incomplete. The occurrence of the appraisal data missingness could be ascribed to the malfunction of data acquisition systems, the abnormality during data transfer, and the inaccessibility of critical quantities, among other reasons. The study begins with a quantitative investigation into the sensitivity of the seismic fragility evaluation with respect to the structural appraisal data missingness through the defined additional information loss and probability of noninformativeness. Subsequently, a remedy for the missingness of the structural appraisal data, instead of a precaution against it, is formulated by employing the expectation-maximization (EM) algorithm. With synthetic or real seismic ground accelerations involved, the efficacy of the EM algorithm embedded remedy is demonstrated by examples of typical linear or nonlinear hysteretic systems in the framework of statistical hypothesis testing. Resorting to the bootstrap technique, the influence of the related correlations and missingness probability is also examined.