Horizontal Components Of Ground Motion Research Articles

Seismic Analysis of Irregular Buildings With And Without Lead Plug Rubber Bearings (LPRB)

Base isolation has become an effective technique that aids in earthquake hazard mitigation and has been in use for the past decade. By properly separating the structure from the horizontal ground motion components, the base isolation system lowers the likelihood of resonance. Isolators are provided at the base of the structures, and decoupling is accomplished by modifying the system's flexibility and adding adequate damping. Structures with irregular plans are gaining popularity owing to their aesthetic appearance as well as architectural designs. The response of such structures to seismic action will be different from conventional structures. This paper aims to study the effect of base isolators on structures with irregular plans, while simultaneously observing the changes occurring when the height of the structures is increased. Three unique plans are chosen, namely plus, L and T shapes, whose responses are studied on 5, 10 and 15-storeyed structures. All the columns in the base-isolated structures are equipped with lead plug rubber-bearing base isolators which is the chosen isolator for this study. The base isolators are designed for each structure specifically so that the behavioural patterns observed are as accurate as possible. From the obtained results, it is discerned that base-isolated buildings exhibited better performances in comparison with fixed-base buildings, and as the height of the structure increases the effect of the base isolator tends to decrease.

A Fourier series non-stationary coherency model with respect to site conditions for the horizontal component of ground motion

A Fourier series non-stationary coherency model with respect to the site conditions for the horizontal component was developed. The evolution of the model was achieved using parameters related to the site, inter-station distance, and time. First, based on the simulation of a non-stationary ground-motion field considering the wave-passage effect and site-response effect, the approach used for the estimation of coherency using wavelet transform is presented. Subsequently, the Fourier series non-stationary coherency model is formulated. The parameters are considered piecewise constant variables to represent the non-stationarity of the estimated coherency. The effects of the site and inter-station distance on the proposed model are presented. Parameters related to the site and inter-station distance were obtained. Finally, the proposed model is compared with the ground motion records at the SMART-1 array during Event 45, the stationary model, and the data from the Argostoli rock-site dense array. This indicates that the Fourier series non-stationary coherency model with respect to site conditions for the horizontal component can well match the correlation of the realistic spatially variable seismic ground motion, which is related to the site, time, and inter-station distance.

Use of critical response spectrum for design of multi-story steel buildings under multi-component seismic excitation

During an earthquake, buildings are simultaneously excited by three-components of ground motion (two horizontal and one vertical) orientations of which are not known apriori. To take account for the uncertainty in the direction of incidence of earthquake waves, a structure is required to be designed such that it is safe for all directions of incidence. For this purpose, the combined effects of two horizontal components of motion are commonly determined using simplified methods such as the percentage rules (e.g. 100%+30%, 100%+40%), square root of the sum of squares (SRSS) and Complete Quadratic Combination (CQC-3) rules. The modern building codes recommend to estimate the orthogonal response quantities for the individual horizontal component of motion using response spectrum superposition methods with design spectrum in the principal direction of motion. In the present paper, a new method is proposed to evaluate the maximum response of multi-story buildings under the simultaneous action of two horizontal components of ground motion using the concept of critical response spectrum. The critical response spectrum is computed using the resultant response of a bidirectional single degree of freedom system at each time step under the simultaneous action of the two horizontal components of motion. For an illustration of the proposed method, steel building asymmetric in the plan is analysed using critical response spectra of the three different pairs of recorded ground motion and the results obtained are validated by comparison with the exact time-history solutions. The exact response is taken as the maximum of the responses estimated by applying the two horizontal time-histories of ground acceleration at different angles from 0 to 180 degree with respect to the structural x-axis. On the other hand, in the response spectrum method, two values of the desired response quantity are obtained by applying the critical response spectrum along the x- and y-directions of the structure and are combined using SRSS method. It has been found that the use of the critical spectrum provides a very convenient method for estimating the maximum response under multi-component excitation without the need for computation of critical incident angle of incidence.

Seismic Response of an Isolated Curved Bridge with Lead Rubber Bearing by Considering Design Aspect

Studies on the application of the lead rubber bearing (LRB) isolation system to various structures carried out as one of the measures to improve seismic performance. Curved bridges play noteworthy role in the modern transportation system. Due to complex interchange and the desire to conform to existing geometric confinements have made this type of structures more alluring. Horizontally curved bridges make up of a noteworthy portion of the bridge population in various countries. In the present study, Lead rubber bearings have been used in an Isolated Curved bridges. Seismic loadings have been considered for three recorded ground motions from PEER strong motion database (PEER 2014) without scaling viz. (1) Imperial Valley (1940) with two orthogonal horizontal ground motion components (PGA0.313g and PGA0.215g); (2) Kobe (1995) with two orthogonal horizontal ground motion components (PGA 0.83g and PGA 0.63g) and (3) Turkey (1992) with two orthogonal horizontal ground motion components (PGA 0.5g and PGA 0.39g). These three ground motions have been considered to represent conditions close to far-fault, near-fault and forward directivity of earthquakes, respectively. Unidirectional and Bi-directional loading have been considered in the present study. Design aspects of the Lead rubber bearings has been considered by deploying the interaction diagram of bearing displacement between the unidirectional and bi-directional responses. It has been found that the bidirectional loading should be considered while designing the isolators.

Seismic performance of flanged RC walls under biaxial cyclic loading

Flanged RC walls are frequently utilized to provide strength and stiffness in two horizontal directions, yet the coupling of the bidirectional horizontal components of ground motion are bound to have large impact on the seismic response of flanged walls. However, few data exist characterizing the performance of flanged walls subjected to biaxial cyclic loading. Aiming to provide an insight into the influence of the biaxial coupling effect on the seismic behavior of flanged RC walls, three T-shaped and two L-shaped walls were tested under uniaxial and biaxial loading. Subsequently, a finite element model was employed for parametric studies and generating numerical data for a detailed comparison of the seismic performance of the flanged walls under uniaxial and biaxial loading. The results showed that the coupling of alternating loadings in orthogonal directions intensified the cracking and damage of flanged walls, resulting in the reduction of the bearing and deformation capacities, an increase in the proportion of flexural deformation in the plastic hinge area, acceleration of the energy dissipation process, and a more significant shear lag effect as opposed to uniaxial loading. Furthermore, the damage aggravation as well as reduction in seismic performance of L-shaped wall due to the biaxial coupling effect were more obvious than that of T-shaped wall. Based on the test and numerical results, the reduction of the ultimate inter-story drift ratio caused by biaxial loading was quantified through statistical analysis and the derived reduction factors can provide reference for the performance-based seismic design and anti-collapse design of flanged RC walls under multi-dimensional seismic action.

Predicting permanent slope displacements due to multidirectional earthquake shaking from unidirectional shaking analyses

The current state-of-practice for time-domain modelling of seismic slope stability is to apply a single horizontal ground motion component in the downslope direction. However, several numerical and experimental studies have demonstrated the importance of multidirectional shaking on seismically induced permanent displacements. To understand better the effect of multidirectional shaking on seismically induced permanent slope displacements, we performed 28,100 three-dimensional finite element slope stability analyses using 230 ground motion record pairs, 48 soil profiles, and four different combinations of ground motion components. We then performed traditional regression analyses and applied machine learning techniques to develop simplified models that estimate the permanent displacements due to multidirectional shaking from the results of analyses where only one component of the ground motion is applied downslope. The simplified model has R2 = 0.91 and uses the displacement from a unidirectional shaking analysis as its only input variable. The standard deviation decreases as the predicted unidirectional shaking displacements increase.

Seismic reliability of base isolated systems: sensitivity to design choices

Seismic isolation is considered an effective solution to protect buildings and related content from earthquakes, and consequently reduce seismic losses. However, the overall reliability levels achieved on these systems by following the design rules suggested by codes are not uniform and they may be strongly influenced by some choices made in the structural design. This study aims to investigate the seismic reliability of structural systems equipped with high-damping rubber bearings, which is a widely used class of isolators. An extensive parametric analysis is performed to assess the influence of design choices on the failure probability, considering design parameters concerning both the isolation system and the superstructure, such as: isolation period; bearings shear strain; percentage of flat sliders (i.e., bearing shape factors); superstructure overstrength ratio. A set of case studies have been configurated by varying and combining all the aforesaid parameters. A stochastic model is used for the bidirectional seismic input and the generation of horizontal ground motion components, whereas full probabilistic analyses are performed via Subset Simulation to achieve accurate estimates of the demand hazard curves up to very small failure probabilities. To reduce the computational effort, a 3D-model with a reduced number of DOFs (Degrees of Freedoms) is adopted for each case study. It consists of an uncoupled bidirectional elastoplastic model of the superstructure, and an advanced nonlinear 3D model of the rubber isolators, accounting for the coupling between vertical and horizontal response in large displacements. For each case analysed, demand hazard curves are evaluated to illustrate the probabilistic properties of the seismic response for both isolation system and superstructure. Results show a noticeable sensitivity of the system reliability with respect to the examined design choices and in some cases the achieved structural performance can be far from the safety levels required by the Codes.

Bidirectional energy-based pushover procedure as a fast approach to establish approximate IDA curves under biaxial seismic excitations: an evaluation for medium- and high-rise buildings

This paper evaluates the accuracy of bidirectional energy-based pushover (BEP) procedure in predicting approximate incremental dynamic analysis (IDA) results for medium- and high-rise structures. BEP provides approximate IDA curves under the simultaneous effect of the two horizontal components of ground motions and is applicable to both symmetric- and asymmetric-plan buildings. The method has already proven useful in low-rise buildings, and this study aims to evaluate its suitability for mid- and high-rise structures. Six steel structures were considered in this evaluation in two groups of 9- and 20-story buildings, with each group consisting of a symmetric, a one-way asymmetric, and a two-way asymmetric-plan building. The assessment was performed for 22 pairs of far-field ground motion records. The results revealed that the accuracy of the method was satisfactory to produce approximate IDA curves for all structural models. The method had similar accuracy in the asymmetric models as it did in the symmetric models, although the accuracy showed a tendency to decrease as the height of the building increased. BEP also provided reasonable estimates of the demands in both 'flexible' and 'stiff sides' of the asymmetric buildings as well as the demands over the height of the buildings.

Vertical ground-motion prediction equation and the vertical-to-horizontal spectral ratio for crustal earthquakes in Taiwan

We develop a ground motion prediction equation (GMPE) for estimating the vertical ground motion amplitudes for crustal earthquakes in Taiwan. The data set used for the development includes strong-motion recordings mainly from Taiwan earthquakes (M3.5–7.6) and supplemented with large-magnitude earthquakes (M6.5–7.9) from other regions in the Pacific Earthquake Engineering Research Center (PEER) next generation attenuation (NGA)-West2 database. The functional form of the GMPE is similar to that of Phung et al. developed for the horizontal component (P20). The GMPE provides median and standard deviations of peak ground acceleration (PGA) and 5% damped pseudo spectral acceleration response ordinates of the orientation-independent average horizontal component of ground motion (RotD50) for the spectral period of 0.01–10 s. The vertical ground motion developed in this study can be paired with the P20 horizontal component model to estimate a vertical-to-horizontal (V/H) ratio that is unbiased. In the vertical component, we observe significant nonlinear site effects in the period of about 0.2–0.5 s, moderate nonlinear site effects in the period of about 0.01–0.04 s, and small nonlinear site effects in the period of about 0.05–0.075 s. Compared to our horizontal GMPE, anelastic attenuation is faster, VS30-scaling is reduced, and nonlinear site response is weaker for the vertical component.

The collapse margin ratio of steel frames considering the vertical component of earthquake ground motions

The FEMA P695 methodology does not consider the application of the vertical component of ground motions in nonlinear response history dynamic analyses for obtaining collapse margin ratios. The vertical component of earthquake affects the demand on the steel moment frame and flexural capacity of the columns in interaction with the fluctuating axial load. This paper investigates the effect of the vertical component of far- and near-field ground motions on the seismic collapse capacity of low-, mid-, and high-rise buildings. Various span lengths, story heights, and seismic mass ratios have been taken into account to cover the significant parameters in amplifying vertical earthquake damages. More than 50,000 nonlinear response history dynamic analyses are performed to obtain seismic collapse margin ratios considering (1) the horizontal components of ground motion, (2) the horizontal plus vertical components of the earthquake, (3) the horizontal components of ground motion along with dead load factors suggested by ASCE7–16 to represent the vertical earthquake loading. Results are compared numerically, and the robustness of the procedure suggested by ASCE7–16 is assessed. It is shown that the adverse effect of the vertical component of the earthquake on the collapse capacity of the considered archetype buildings increases with the increase in the fundamental vertical period of buildings. Finally, adjusting equations using dimensionless parameters are developed for estimating the seismic collapse margin ratio of structures considering the vertical component of the ground motion. The proposed equations adjust the corresponding collapse margin ratio obtained using the horizontal components of ground motion.

Spectral damping scaling factors for horizontal components of ground motions from subduction earthquakes using NGA-Subduction data

This article develops global models of damping scaling factors (DSFs) for subduction zone earthquakes that are functions of the damping ratio, spectral period, earthquake magnitude, and distance. The Next Generation Attenuation for subduction earthquakes (NGA-Sub) project has developed the largest uniformly processed database of recorded ground motions to date from seven subduction regions: Alaska, Cascadia, Central America and Mexico, South America, Japan, Taiwan, and New Zealand. NGA-Sub used this database to develop new ground motion models (GMMs) at a reference 5% damping ratio. We worked with the NGA-Sub project team to develop an extended database that includes pseudo-spectral accelerations (PSA) for 11 damping ratios between 0.5% and 30%. We use this database to develop parametric models of DSF for both interface and intraslab subduction earthquakes that can be used to adjust any subduction GMM from a reference 5% damping ratio to other damping ratios. The DSF is strongly influenced by the response spectral shape and the duration of motion; therefore, in addition to the damping ratio, the median DSF model uses spectral period, magnitude, and distance as surrogate predictor variables to capture the effects of the spectral shape and the duration of motion. We also develop parametric models for the standard deviation of DSF. The models presented in this article are for the RotD50 horizontal component of PSA and are compared with the models for shallow crustal earthquakes in active tectonic regions. Some noticeable differences arise from the considerably longer duration of interface records for very large magnitude events and the enriched high-frequency content of intraslab records, compared with shallow crustal earthquakes. Regional differences are discussed by comparing the proposed global models with the data from each subduction region along with recommendations on the applicability of the models.

NGA-East Ground-Motion Characterization model part I: Summary of products and model development

In this article, we present an overview of the research project NGA-East, Next Generation Attenuation for Central and Eastern North America (CENA), and summarize the key methodology and products. The project was tasked with developing a new ground motion characterization (GMC) model for CENA. The final NGA-East GMC model includes a set of 17 median ground motion models (GMMs) for peak ground acceleration and velocity (PGA, PGV) and response spectral ordinates for periods ranging from 0.01 to 10 s. The NGA-East GMMs are applicable to horizontal components of ground motions on very hard rock, for the moment magnitude range of 4.0–8.2, and distances of up to 1500 km. The aleatory standard deviations of GMMs are also provided for site-specific analysis (single-station standard deviation) and for general probabilistic seismic hazard analyses (PSHA) applications (ergodic standard deviation). In addition, adjustment factors are provided for source depth and hanging-wall effects, as well as for hazard computations at sites in the Gulf Coast Region. During the course of the project, several innovative technologies were developed and implemented to increase the transparency and repeatability of the GMC building process. This involved expanding on a set of candidate median GMMs to define and capture an appropriate range of epistemic uncertainty in ground motions. We also developed a new approach for modeling the aleatory variability that was completely independent of the median GMMs. The development made extensive use of the CENA database but also borrowed data from other parts of the world when relevant and led to an integrated suite of models. Through this repeatable process, epistemic uncertainty could be quantified more objectively than before, relying less on expert opinion. The NGA-East project went through a comprehensive Seismic Senior Hazard Analysis Committee (SSHAC) Level 3 peer review process before its release.

Bidirectional Seismic Energy Input to an Isotropic Nonlinear One-Mass Two-Degree-of-Freedom System

The test results obtained for reinforced concrete columns by several studies have revealed that the peak displacement and cumulative hysteresis energy are important parameters for evaluating the damage of columns under horizontal bidirectional and unidirectional loading. Therefore, the seismic parameters related to the nonlinear peak displacement and cumulative hysteresis energy with regard to horizontal bidirectional seismic input should be investigated. In this study, the bidirectional seismic input to an isotropic nonlinear one-mass two-degree-of-freedom system was evaluated. First, a dimensionless parameter γ, which controls the low-cycle fatigue effect, was formulated as a function of two energy input parameters (the maximum momentary input energy and total input energy) and a nonlinear system (ductility and normalized hysteresis energy absorption during a half cycle). Then, the maximum momentary input energy and total input energy were evaluated according to the ground motion characteristics (Fourier coefficient of horizontal ground motion components) and system properties. Finally, the nonlinear peak displacement and parameter γ of the nonlinear system were evaluated on the basis of the maximum momentary input energy and total input energy. The results revealed that the nonlinear peak displacement and parameter γ can be properly evaluated using two energy parameters.

Developing a multi-variable vulnerability function for a class of multi-span continuous concrete box-girder highway bridges with emphasis on near-field earthquakes

The most common tools in seismic performance assessment of highway bridges are single-variable fragility curves. However, fragility curves are not confidently reliable due to utilizing only a single intensity measure (IM). Alternatively, single- and multi-variable vulnerability functions, of which the latter is scarce and rather complex, have been proposed for that purpose, yet without considering the effects of the strong vertical component of near-field earthquakes. This study aimed to develop a multi-variable vulnerability function for multi-span continuous concrete box-girder bridges, accentuating near-field earthquakes. Ten bridge models corresponding to the 1971-1990 design era were considered and analyzed, subjected to three-component records of 164 earthquakes using OpenSees framework. First, 28 IMs related to horizontal and vertical ground motions, and 12 engineering demand parameters were utilized, and a set of potentially optimal IMs were determined through optimality investigation. Then, to ensure that identified IMs are authentically optimal candidates, Lasso regression was employed, introducing 12 IMs as optimal. Finally, Step-wise regressions were conducted to reduce the complexity of the proposed equation. Results revealed peak ground acceleration, peak ground velocity, and velocity spectrum intensity of the horizontal component of ground motion, and acceleration spectrum intensities of both horizontal and vertical components as optimal ones.

Response spectral matching of horizontal ground motion components to an orientation-independent spectrum (RotDnn)

This article presents a methodology to spectrally match two horizontal ground motion components to an orientation-independent target spectrum (RotDnn). The algorithm is based on the continuous wavelet transform decomposition and iterative manipulation of the two horizontal components of a seed record. The numerical examples presented follow current ASCE/SEI 7 specifications and therefore maximum-direction spectra (RotD100) are used as target for the match. However, the proposed methodology can be used to match other RotDnn spectra, like the median spectrum (RotD50). It is shown that with the proposed methodology the resulting RotDnn from the modified horizontal components closely match the smooth target RotDnn spectrum, while the response spectrum for each horizontal component continue to exhibit a realistic jagged behavior. The response spectra variability at the component level within suites of spectrally matched motions was found to be of the same order than the variability measured in suites composed of amplitude scaled records. Moreover, the spectrally matched records generated preserved most of the characteristics of the seed records, including the nonlinear characteristics of the time history traces and the period-dependent major axis orientations.

Liquefaction identification based on instantaneous H/V spectrum ratio

The strong vibration record contains a lot of information on the site during the earthquake, and the dynamic characteristics of the soil layer in the site can be expressed through this information. Currently, the H/V spectral ratio recorded by acceleration is often used to study the seismic effect of the site. Inspired by this, the thesis puts forward the idea of using the instantaneous H/V spectral ratio and its corresponding instantaneous frequency to judge the site liquefaction. The time-varying VARMA model is used to represent the horizontal ground motion component as the output of a time-varying system with vertical ground motion component as input. According to the time-varying VARMA parameters, the instantaneous spectral ratio, instantaneous frequency of the system and instantaneous damping ratio are used to judge the site liquefaction.

Reliability-based assessment of percentage combination rules considering the collapse performance of special concentrically braced frames

In the seismic design of structures, the combinatorial effects of multiple horizontal ground motion components are often determined using the 100/p% percentage rule (i.e. designs based on 100% in one direction and p% in the other). In this study, a reliability-based methodology is developed to explicitly link building collapse caused by percentage-rule-based-underestimation of the design force demands to the adopted p% value. The methodology is applied to three special concentrically braced frame (SCBF) buildings (4, 8, and 12 stories) with corner columns shared by orthogonal frames. Each building case is designed using the 100/30%, 100/65%, and 100/100% percentage rule. Response history analyses using bidirectional and unidirectional loading are performed on nonlinear structural models to obtain the “true” demands and percentage-rule-based demands, respectively. Models constructed with and without considering SCBF column failure are utilized within the overall reliability-based framework to isolate the effect of underestimated design force demands on collapse performance. A quantitative relationship between the adopted p% value and building structural collapse risk is established. The results show that there is a nonlinear relationship between an increase in p% and the benefits in terms of reduced collapse risk. Also, taller buildings are shown to benefit more from conservative (higher) p% values compared to shorter ones.

Characterization of ground motion intensity for the seismic fragility assessment of plan-irregular RC buildings

The identification of ground motion intensity measures (IMs) that are characterized by virtues such as efficiency, sufficiency, scaling robustness and hazard computability, has been the subject of extensive research over the past several years. In the process, there have evolved, numerous non-structure specific as well as structure specific descriptors of ground shaking severity. Most of the studies that investigated the optimality of such descriptors were, however, restricted to the seismic response of single or multi-storey planar frame buildings under unidirectional excitation. The study herein aims to examine, the efficiency and sufficiency of a wide spectrum of IMs, in predicting the maximum interstorey drift demands on plan-irregular RC moment frame buildings subjected to bi-directional ground motion. This is accomplished through a cloud analysis-based framework that integrates nonlinear response history analysis and statistical regression analysis. Further, the use of scalar bi-directional shaking intensity measures (BSIMs) derived from a vector of intensities corresponding to each horizontal component of ground motion using popular combination schemes such as geometric averaging, arithmetic averaging, SRSS and use of envelope values, is examined from the perspective of their ability to predict drift demands. Observations from the study reveal that IMs based on the geometric averaging of spectral ordinates over a range of periods are superior to the other descriptors considered, in terms of the aforementioned attributes and that combining the intensities of the two orthogonal components by geometric averaging leads to an optimal BSIM that could be used in place of vector IMs. The heteroscedasticity in the maximum interstorey drift response under different levels of the BSIM is further investigated using a Multiple Stripe Analysis framework. The optimal BSIM is observed to perform reasonably well at all target intensity levels, making it an excellent candidate to base fragility and vulnerability functions upon.

Scaling of Vertical Component of Seismic Ground Motion

Three-dimensional time history analysis has become a demand for the majority of updated building codes. A vast literature has addressed the selecting and scaling of horizontal component of earthquake ground motion. Meanwhile, the scaling of vertical component has been less of a concern. This paper investigates the suggestion of using the same scaling factor of horizontal component of ground motion to scale its vertical counterpart. A data set consists of 6409 mainshock records with vertical and orientation independent geometric rotated (GMRotD50) response spectra with 5% damping is used. Even though ASCE7-16 among other international codes recommends to use the same scaling factor for horizontal component and its vertical counterpart, this paper shows that scaling factor of vertical component trends an extreme variation from its horizontal counterpart for various soil classes, different magnitudes and over a wide range of Joyner-Boore distances. Results illustrate that the ratio of vertical to horizontal scaling factors has a strong negative relationship with the ratio of vertical to horizontal peak ground acceleration. Earthquake magnitude has no significant role on the ratio of vertical to horizontal scaling factors. A gradual increase is observed in the studied ratio over a wide range of Joyner-Boore distances. The paper ends up with simplified equations to calculate the scaling factor of vertical component in regards with the scaling factor of its GMRotD50 horizontal counterpart based on the (V/H)PGA ratio of the recorded components. Robust statistics manifest the goodness of the developed equations.

Ground motion prediction equation for crustal earthquakes in Taiwan

We develop a ground motion prediction equation (GMPE) for estimating horizontal ground motion amplitudes caused by crustal earthquakes, based on an integrated data set that includes strong motion recordings mainly from Taiwan earthquakes and only from large magnitude earthquakes in the NGA-West2 database. This GMPE is developed for probabilistic seismic hazard analysis study, which is introduced as a part of Taiwan Senior Seismic Hazard Analysis Committee Level 3 projects. The functional form developed by Chiou and Youngs was carefully studied to determine the key modeling parameters needed to regress against ground motion in the target region. Using this functional form, the GMPE achieves considerable improvement over previously developed Taiwan GMPEs. In particular, the use of a high-order function in magnitude scaling enables representation of the saturation effects of large earthquakes. Moreover, consideration of focal mechanisms, depth effects, and dip effects are used to correct the magnitude scaling; consideration of nonlinear site amplification is conditioned on VS30 and reference ground motion on rock; and consideration of basin depth effect is a function of Z1.0 in correlation with VS30. In addition, ground motion data used in this study are not only expanded by more than three times as many earthquakes and records compared with a previous Taiwan model but also provide the metadata of these records that were not available or were previously incomplete. In this study, we compare the proposed model with the NGA-West2 models and discuss the regional difference in ground motion in terms of spectral shape, magnitude scaling, distance scaling, depth scaling, style of faulting, and site effects. We provide median and single standard deviations of peak ground acceleration and 5% damped pseudospectral acceleration response ordinates of the orientation-independent average horizontal component of ground motion (RotD50) for the spectral period of 0.01–10 s.