Nonlinear Time History Analysis Research Articles

Nonlinear Dynamic Analyses Utilising Macro-Models of Reinforced Concrete Building Structures and Site-Specific Accelerograms

This paper aims to guide structural engineers on how to apply the rapid nonlinear time history analysis (RNLTHA) procedure effectively to predict seismic demand, taking into account ductility and overstrength, and effects of dynamic phenomena including cyclic degradation of strength and stiffness in structures, in a direct and expedient manner. The shortcoming of the conventional force-based approach of design involving the use of a force reduction factor to account for nonlinear effects is well recognised. Nonlinear static (pushover) analysis and dynamic nonlinear time history analysis (NLTHA) are offered as alternative methods of analysis by major codes of practices to achieve better optimisation in the use of materials. NLTHA has advantages over pushover analysis in being more direct and capable of capturing cyclic response behaviour. Despite the merits of NLTHA, its adoption in the industry has been limited, mainly because of the complexity and the higher analysis cost involved. RNLTHA proposed in this article uses a macroscopic model of the building to fulfil the purpose of NLTHA, whilst saving computational time and achieving a good degree of accuracy, as verified by comparison with results generated from SeismoStruct.

Resilience of Medium-to-High-Rise Ductile Coupled Shear Walls Located in Canadian Seismic Zones and Strengthened with Externally Bonded Fiber-Reinforced Polymer Composite: Nonlinear Time History Assessment

Coupled shear walls (CSWs) are structural elements used in reinforced concrete (RC) buildings to provide lateral stability and resistance against seismic and wind forces. When subjected to high levels of seismic loading, CSWs exhibit nonlinear deformation through cracking and crushing in concrete and yielding in reinforcements, thereby dissipating a significant amount of energy, leading to their permanent deformation. Externally bonded fiber-reinforced polymer (EB-FRP) sheets have proven to be effective in strengthening RC structures against various loading and environmental conditions. In addition, their high strength-to-weight ratio makes them an attractive solution as they can be easily applied without significantly increasing the structure’s weight. This study investigates the effectiveness of using EB-FRP sheets to reduce residual displacement in CSWs during severe earthquake loadings. Two series of 15-story and 20-story CSWs in Western and Eastern Canadian seismic zones, which serve as representative models for medium- and high-rise structures, were evaluated through nonlinear time history analysis. The numerical simulation of all CSWs and strengthened elements was carried out using the RUAUMOKO 2D software. The findings of this study provided evidence of the effectiveness of EB-FRP sheets in reducing residual deformation in CSWs. Additionally, significant reductions in the rotation of the coupling beams (CBs) and the inter-story drift ratio were observed. The results also revealed that bonding vertical FRP sheets to boundary elements and confining enhancement by wrapping CBs and wall piers is a very effective configuration in mitigating residual deformations.

Hybrid force-displacement-based design methods for self-centering wall structures

Self-centering wall structures (SCWs) are well-developed resilient structures and are being gradually implemented in practical engineering. The direct displacement-based design (DDBD) method is commonly adopted for the seismic design of SCWs due to its predictable displacement pattern. Due to the complexity of DDBD, practical engineers still commonly use the present force-based design (FBD) methods. However, the existing FBD method is inapplicable when the deformation of SCWs is large. To make the design procedure more acceptable to engineers and promote SCWs in real practice, three design methods were proposed: a force-based design method by empirical formula, a force-based method by iteration, and a hybrid force-displacement-based design method (HBD). The applicability of FBD by existing empirical formulas of structural periods in several codes for SCWs was discussed. In FBD by iteration, the initial prestress is iterated to determine secant stiffness and the structural period so that SCWs can be designed following its constitutive relationships. HBD is carried out by comparing the resistance of the structure under the target displacement with the earthquake demand according to the deformation mode of the SCWs. Compared with the existing DDBD methods, the proposed design methods can simplify the design process in engineering applications while keeping the design outcomes consistent with DDBD and proved to be reasonable with nonlinear time history analysis. In addition, the FBD method by empirical formula and the HBD method can be implemented in the four-level seismic fortifications currently proposed in China. The proposed methods solve the issues of the existing FBD and could be a reference for engineers to design SCWs in engineering practice.

Multi-hazard assessment of transmission line systems subjected to independent non-concurrent turbulent winds and ground accelerations

The design of transmission lines is based on the Load and Resistance Factor Design approach, considering that their collapse limit state is governed by climatic actions (wind and ice). Even so, accident reports indicate the regular observation of moderate to severe damage of towers after strong ground motions, affecting the structure’s capacity to withstand future load events. Therefore, integrating the concepts of Performance-Based and Multi-Hazard Design, successfully applied to buildings and still embryonic to transmission lines, seems to be promising. With such performance-based multi-hazard approaches, intermediate performances can be evaluated even when they are controlled by a non-dominant hazard. Hence, the present paper aims at performing an original multi-hazard assessment of a Chilean 230kV transmission line segment. For this purpose, direct geometric and material nonlinear time history analysis, using a finite element suitable for eccentrically loaded angle profiles (L-shaped cross-sections), is employed to construct the fragility curves. In addition, uncertainties in loads and material properties are accounted for to address the transmission line system failure probability. In the existing literature, fragility analysis has been performed through pushover approaches, whereas reliability has been assessed for a single structure rather than for the transmission line system, as recommended by line codes. Contrary to design practice, the results show that seismic loads control all limit states in TLs located from central to northern Chile. Numerical results presented in this paper are based on 5000 h of total computation time.

Study on the seismic mitigation effects of inerter isolated storage tanks

Liquefied Natural Gas (LNG) storage tanks can ensure national energy sufficiency, but they are vulnerable to earthquakes. Although ordinary seismic isolation bearings can effectively reduce the base shear force and overturning moment, they tend to amplify the height of the sloshing wave. In this paper, a hybrid vibration control method for LNG storage tanks is proposed, paralleling the series viscous mass damper (SVMD) devices with Lead-core rubber bearings (LRB). The seismic mitigation effects of this parallel seismic isolation scheme were investigated. First, three-dimensional finite element models of fixed base, LRB isolated and SVMD isolated tanks were established, and nonlinear time history analyses were performed for the three types of tanks to compare the seismic responses. It was concluded that SVMD can effectively control the sloshing wave height. In addition, the effects of site types, storage liquid heights, and SVMD's performance parameters on the seismic mitigation effects were also studied. It was found that the softer the site soil, the higher the storage liquid height would make seismic isolation less efficient. The increase of SVMD's additional equivalent mass reduces the sloshing wave height, increases the shear-to-weight ratio, and has little influence on the base displacement. The increase of SVMD's additional equivalent damping reduces the sloshing wave height, base shear force, and base displacement of the tank. The final conclusion is that SVMD can effectively control the sloshing wave height and has a good seismic mitigation effect.

Seismic Response and Recentering Behavior of Reinforced Concrete Frames: A Parametric Study

The inelastic response of reinforced concrete (RC) frames under seismic loading is influenced by mechanical and geometrical properties and by the reinforcement arrangement of the beam–column members. In this paper, the seismic response and recentering behavior of RC frames is investigated numerically via cyclic pushover analysis and described by means of three synthetic behavioral indexes, namely a recentering index, a hardening index, and a ductility index. A fiber–hinge formulation is used to describe the inelastic behavior of the RC elements, and the versatile pivot hysteresis model is implemented at the material level to capture the possible pinching effects ascribed to the weak transverse reinforcement and to poor construction details that might be observed in the existing RC structures. This model is first validated against the experimental results from the literature and then applied, within a wide parametric study, to a set of 80 RC frame scenarios featured by various combinations of axial load levels and reinforcing details. As the output of this parametric study, practical design abacuses are constructed to describe the trends of the above-mentioned behavioral indexes, which are usefully related to specific mechanical and loading features of the analyzed RC frames. The reliability of the obtained results and the usefulness of the constructed abacuses in anticipating the overall cyclic behavior of a generic RC building, depending on the actual mechanical parameters of the RC sections at each story level, is finally demonstrated through a nonlinear time history analysis of an eight-story RC frame, representative of the substandard RC frames built in the 1970s in Italy.

The Effect of Magnitude Mw and Distance Rrup on the Fragility Assessment of a Multistory RC Frame Due to Earthquake-Induced Structural Pounding

The effect of an intensity measure’s (IM’s) sufficiency property on the probabilistic assessment of reinforced concrete (RC) structures due to floor-to-floor structural pounding conditions is examined. In the first part of this investigation, efficiency and sufficiency properties of 23 scalar IMs are verified. Then, the magnitude Mw and the distance Rrup are examined as elements in a vector with an efficient scalar IM to evaluate whether they have any significant effect on the structural response. Subsequently, probabilistic seismic demand models (PSDMs) are developed using linear regression analyses based on a scalar IM and a vector-valued IM. Fragility curves are developed based on these PSDMs, and the influence of Mw and Rrup on the evaluation of the minimum required separation gap distance dg,min due to the pounding effect is examined. More than two hundred nonlinear time history analyses are performed based on the Cloud Analysis method. Seismic displacement demands that control of the global state of the structure, as well as the probability of structural pounding, are examined. The results of this research indicate that once Mw or Rrup is increased, fragility curves are shifted to greater values of IM, and the probability of the exceedance of a certain performance level is reduced. Also, the predictive power of Rrup seems to be greater than the one of Mw. On the other hand, it is revealed that Mw and Rrup induce variabilities in the demand solutions for adequate separation gap distance between the adjacent structures. Therefore, variation in Mw or Rrup may lead, in some cases, to unacceptable evaluations of the pounding effect in the capacity levels of structures.

Artificial Neural Networks for seismic demand prediction of a single degree of freedom

This paper proposes using an artificial neural network (ANN) to estimate and predict the seismic demand of Single Degree of Freedom (SDOF) systems. Our methodology entails the production of a comprehensive dataset containing SDOF and earthquake characteristics. Nonlinear Time History Analysis (NL-THA) is performed on a randomly generated SDOF system using thirty-one artificial ground motions (GMs) matched to the EuroCode-8 (EC8) response spectrum to train the ANN model. To assess the performance of the ANN model, we compare the Incremental Dynamic Analysis (IDA) curves, the median IDA curve, and the 3D fragility surface in a case study. This analysis assists in determining the precision and dependability of the predicted maximum displacement of the SDOF system. The results showed a remarkable reduction in processing time without losing prediction accuracy. . It was concludedthat the ANN-based method can be used as an alternative for the current method for estimating the performance points and the fragility assessment of buildings.

Seismic fragility of non-ductile RC frames for pounding risk assessment

Building structures subjected to seismic excitation tend to vibrate with a unique set of dynamic characteristics, such as natural frequencies, fundamental mode shapes etc. In series-configured structural systems, a difference in such characteristics induces a phase difference between the structures’ oscillations, leading to structural collisions or pounding. Pounding often becomes a cause of catastrophic failures, hence an accurate estimation of structural integrity with respect to pounding is of paramount importance. This study aims to examine different fragility curve development methodologies available in the literature to assess the seismic performance of adjacent Reinforced Concrete (RC) structures subjected to structural pounding. The study primarily focuses on displacement-based fragility curves for the highly critical floor-to-column interactions of an eight-storey non-ductile RC frame, non-eccentrically adjacent to a three-storey rigid RC frame having different storey heights. Nonlinear time–history analyses have been performed to simulate pounding, and fragility curves have been generated using five methodologies. The direct Monte-Carlo Simulation technique has been used to benchmark against the obtained results to identify the suitability of each fragility assessment technique. Results indicate that even though there is no effect of the choice of assessment methodology on the estimated risk at low performance levels and intensity measures, the disparity becomes clearly visible at higher levels. The study presents alternate ways of developing accurate fragility curves by keeping in mind the need for computational efficiency without compromising the accuracy of results. The High Dimensional Model Representation meta-model is found to efficiently represent target pounding fragilities while incurring minimal computational costs.

Seismic response of multi-storied building with shear wall considering soil-structure interaction in Patna, India

The structural response of a building on soft or loose soil differs from that on hard and rocky soil. Investigating the behaviour of buildings with shear walls on such soft soil is essential. This study considers four structural models of the nine-storied building with and without infill walls. The modelled buildings represent the existing buildings in the Patna, India region. The frame was analysed in four different conditions: (1) Fixed base bare frame building, (2) Flexible base bare frame building, (3) Fixed base building with shear walls (4) Flexible base building with shear walls. Twenty-four pairs of scaled ground motion from the PEER Ground Motion Database were selected, and a nonlinear time history analysis was performed in SAP2000v20.0. Understanding that soil-structure interaction is paramount for building on soft soil, the study quantified the seismic response for the building in the Patna region, a region of high seismicity.Moreover, in current scenarios, multistorey buildings with an open ground storey and shear walls are prevalently found owing to their advantage for parking and enhancing the seismic capacity. The result shows that base flexibility significantly increases the peak floor displacement, total floor acceleration, inter-storey drift and displacement ductility for bare frame structures. At the same time, consideration of shear and infill walls only affects the flexible base structures. While shear and infill walls significantly affect the seismic behaviour of the fixed base structure. It was also found that the shear and infill walls increase the structure’s stiffness and thus reduce the fundamental vibration period of the structure. The study’s significant findings are (1) the shear and infill wall significantly reduces the seismic responses of the building, (2) base flexibility (SSI) increases the seismic vulnerability of the buildings, (3) the displacement ductility significantly depends on the aspect ratio (height/width) of the building, and (4) the inter-storey drift is relatively higher in the lower and mid storey of buildings.

Selection of Seismic Acceleration for Non-linear Analysis Of Rc Buildings in Bangladesh

Seismic acceleration selection is a vital issue of non-linear time history analysis for reinforced concrete (RC) buildings. The propagation characteristic of selected seismic acceleration through soil medium depends on the material properties of the soil and reflected waves from the structure are absorbed by the adjacent soil medium. Stiffnesses of structural members are degraded by exciting and internal waves because of storing the hysteretic strain energy inside structural members. However, this study proposes a finite element model for the selection of seismic acceleration considering specific site classes in Bangladesh based on the soil stratum because seismic excitation varies with the site class. In addition, the structural response depends on the selected acceleration, and non-linear time history analysis represents the more reliable inelastic response of the structure due to this acceleration. Variation of seismic storey drift within allowable limit indicates appropriate selection of the seismic acceleration by the non-linear response history analysis. Also, lower rates of output acceleration intensities for upper stories may inform the majority of reflected waves absorbed by the soil medium. For this reason, proper selection of seismic acceleration may enhance the accurate non-linear response of RC buildings in Bangladesh. Journal of Engineering Science 14(1), 2023, 95-109

Improvement in the Seismic Performance of a Super-Long-Span Concrete-Filled Steel-Tube-Arch Bridge

The applicability of current seismic-performance-improvement technologies needs to be studied. This research took a super-long-span CFST arch bridge with a total length of 788 m as the object on which to perform a non-linear time-history analysis and a seismic-check calculation according to the seismic response, so as to reveal the seismic weak points of the arch bridge. After the completion of the bridge’s construction, we arranged and utilized the stayed buckle cables (SBCs) reasonably. The seismic performance of the super-long-span CFST arch bridge was improved through friction-pendulum bearings (FPBs) and SBCs. The research shows that FPBs can solve the problem of the insufficient shear resistance of bearings, and SBCs can address the problem whereby the compressive stress of the transverse connection of the main arch exceeds the allowable stress. Moreover, SBCs can increase the transverse stiffness of arch bridges and reduce their seismic responses. Finally, a combination of FPBs and SBCs was adopted to improve the overall seismic performance of the arch bridge and obtain the best seismic-performance-improvement effect.

Numerical Assessment of the Seismic Vulnerability of Bridges within the Italian Road Network

The safety of existing bridges represents a serious problem in Italy since these structures are fundamental for the national transportation system and, at the same time, can be subject to significant deterioration phenomena linked to the fact that the construction period typically dates back to the 1960s. This study involves the seismic analysis of five case study bridges belonging to the Italian Road Network. Using nonlinear time–history analysis with sets of code-spectrum compatible ground motions, analytical fragility curves have been constructed for each of the five bridges. The results obtained interpreting the analytical fragility curves agree with the fact that the seismic behavior of existing bridges can be problematic and that higher seismicity can be associated with more detrimental behavior. In particular, the results reveal that in regions with higher seismicity, the main problems in bridges are related to bearings and connecting elements located in the piers. Five case studies have also been analyzed to determine the Structural and Foundational Class of Attention and Seismic Class of Attention, following the approach proposed by the 2020 Italian Guidelines. In this way, it is possible to compare two different assessment approaches with different safety levels. The results obtained with the two approaches are in good agreement considering bridges in high seismicity regions, while the procedure of the Guidelines could lead to not reflecting the seismic behavior of bridges when the seismicity of the area is lower.

Impact of ground motion directionality (RotDnn) on the coupled and uncoupled inelastic response of RC circular cantilever columns

Directionality in the representation of earthquake demand for structural seismic design has surfaced as a subject of debate in recent years. Design spectra, as defined in building and bridge codes, account for directionality by considering the peak response in all possible orientations of the motion using the RotDnn measure, where “nn” is the percentile of the peak response. Current seismic hazard maps are based on ground motion models that use the RotD50 spectra (median peak response). However, since 2009, building codes have adopted RotD100 spectra (maximum peak response), raising concern among researchers and engineers. The first objective of this study is to evaluate the impact of design spectra definition, RotD50 or RotD100, on the bidirectional inelastic response of azimuth-independent RC systems. Upcoming updates to seismic hazard maps highlight the need of understanding the implication of this choice in bridge design. While previous research focused on the relationship between RotD50 and RotD100, this work assesses the impact of each definition on the inelastic seismic response of RC circular columns designed following the Direct Displacement-Based Design approach and verified through nonlinear time history analyses (NTHA) using ground motions from shallow crustal active and subduction zone regions. The ratios of NTHA to design displacement confirm that RotD100 spectra should be used to design azimuth-independent RC systems and provide the first known verification of DDBD for bidirectional loading (second objective). These ratios are a function of ductility level, tectonic regime, effective period, and coupling (which is the third objective). Overall results show that RC circular cantilever columns designed to RotD100 spectra show less deviation from the expected design displacement than columns designed to RotD50 spectra. This study presents the first step in resolving the ongoing debate over spectra definition and provides recommendations for displacement demand estimations for response spectra-based design approaches.

Seismic response of elevated RC tanks equipped with the seesaw system

This paper investigates the effectiveness of the seesaw system when applied to elevated tanks in order to mitigate their seismic response to strong seismic motions. In particular, non-linear time-history analyses (NLTH) are conducted on an elevated steel frame reinforced concrete tank (RC), equipped with the seesaw system. Both the horizontal and vertical components of a set of seismic motions are used for the NLTH analysis, whereas two cases of water height within the RC tank are assumed. A rigid or flexible foundation of the RC tank is considered in order to assess the effects of soil-structure interaction (SSI). The seismic response indices monitored are the drift ratio and the residual drift ratio of the tank, the maximum moments of the tank wall, the maximum force of the members of the seesaw system and the exhibition of plastic hinges to the ends of the columns of the steel frame. From the results obtained it is concluded that a properly detailed seesaw system can be a good solution in improving the seismic behavior of elevated RC tanks.

Study on seismic safety evaluation of crossover pipeline connecting containment and turbine building in three-dimensional isolated nuclear power plant

Isolation design enhances the safety of nuclear islands during earthquakes. Magnification of isolation layer displacement increases the damage risk of the nuclear pipeline crossing the isolation gap. A simplified safety evaluation procedure for pipelines based on elbow displacement limits and damage indices was proposed. An analytical model of the nuclear elbow was first developed for unidirectional and multi-directional displacement loading. The failure point is determined based on the elbow force–displacement curve and adjusted to obtain a safe displacement limit. Subsequently, a 3DBNL model with a horizontal isolation frequency of 0.5 Hz and a vertical isolation frequency of 1.25 Hz was proposed based on the BNL model. Nonlinear time history analysis was performed to obtain the dynamic responses such as nuclear island acceleration, isolation layer displacement, and pipe relative displacement. Finally, the damage index was calculated as the ratio of the peak relative displacement to the elbow displacement limit. The damage index and the distribution interval under multi-directional seismic input were calculated separately to assess pipeline safety. The results indicate that the three-dimensional isolated nuclear island remains safe under the horizontal 0.6 g and vertical 0.4 g seismic input, while the pipeline failed under the horizontal 0.3 g and vertical 0.2 g seismic input.

Probabilistic seismic performance assessment of steel moment‐resisting frames considering exposed column‐base plate connections with ductile anchor rods

AbstractThis paper presents a numerical study assessing the seismic performance of steel moment‐resisting frames (SMRFs) designed with ductile exposed column‐base plate (ECBP) connections employing yielding anchor rods. For their potential use as weak bases, the proposed ECBP detail is designed to accommodate plastic deformations in the anchors. The seismic performance of 2‐ and 4‐story archetype SMRFs with ECBPs is investigated to examine the effects of various base‐connection strengths on the frame collapse mechanisms and probabilities. To this aim, the ECBP connections of each frame are designed for a set of three strength levels, ranging from reduced seismic loads to capacity‐designed forces of the adjoining columns. These designs enable the base responses to vary from highly inelastic (i.e., weak‐base design) to elastic (i.e., strong‐base design) when subjected to earthquake‐induced ground shaking. Nonlinear time history analysis (NLTHA) is extensively performed, applying a suite of assembled ground‐motion sequences (i.e., two ground motions in series) to assess the ECBP connection response and the corresponding frame behavior. Fragility analyses accounting for only the first ground motions in each considered sequence (to derive fragility curves), and the entire ground‐motion sequences (to derive fragility surfaces) are also performed to evaluate the probabilities of frame collapse and base connection failure. Finally, key findings regarding the seismic performance of ductile ECBP connections and their effects on the frame collapse are discussed. The limitations of the study are also outlined.

Full-scale shaking table tests and numerical studies of structural frames with a hybrid isolation system

A typical hybrid isolation system (HIS) incorporating natural-rubber bearings (NRBs) and nonlinear fluid viscous dampers (NFVDs) is proposed for seismic protection of critical equipment in nuclear power industrial buildings (NPIBs) under strong earthquakes. Design procedure with a parametric study towards the HIS considering various stiffness and damping values is first investigated via extensive nonlinear time history analyses. Then a preliminary recommendation for the specific structural demands of the considered system is proposed to direct the seismic design for both member- and system-level tests. Through a suite of full-scale shaking table tests on two typical NPIBs, the efficiency and reliability of the HIS are verified, in comparison to the structure with conventional rubber isolation system (RIS). The shaking table test results exhibit a superior behavior of the HIS in structural dual control strategies, i.e., transient acceleration control in critical equipment and bearing deformation control. Also, the HIS presents stable and resilient performances in both negligible residual bearing deformation and undetectable damage to structural/nonstructural components (containing the seismic isolated devices, i.e., NRBs and NFVDs). Finally, a three-dimensional finite element (FE) structural model and a single-degree-of-freedom (SDOF) system are successively developed to simulate the dynamic responses of the test structures. The well-validated SDOF FE model, serving as a reliable alternative for the isolated NPIBs, can be further utilized to facilitate practical design.

Hybrid Vibration Control of Hospital Buildings against Earthquake Excitations Using Unbonded Fiber-Reinforced Elastomeric Isolator and Tuned Mass Damper

Lifeline structures such as hospital buildings need to be specifically designed such that they experience reduced vibrations when subjected to earthquake excitations because it will be difficult to vacate hospital buildings under the event of any earthquake. Therefore, to ensure operational condition under earthquake excitations in an existing hospital building, the present study utilizes flexible unbonded fiber-reinforced elastomeric isolators (UFREIs) for its seismic isolation. The UFREI-based isolation system is designed to restrict the structural acceleration within the tolerable limits for the building inhabitants even during earthquake hazards. However, the use of such flexible isolators results in excessively large bearing displacements, which either may not be practical and/or pose several serviceability issues. Therefore, tuned mass damper (TMD) is attached to the base floor of the UFREI-isolated hospital building to reduce the large isolator displacements. Properties of the hybrid vibration control system are designed according to the site-specific scenario in New Delhi, India. Further, nonlinear time-history analyses of the UFREI-isolated hospital building with the TMD are carried out, and responses are compared with its uncontrolled response. Results show that the peak bearing displacement response of the UFREI-isolated hospital building is reduced by 9% to 27%, due to the addition of the TMD. Importantly, the required design displacement of the UFREI-based isolation system is decreased by 27%, without compromising the effectiveness of base isolation. In fact, the performance of the hybrid vibration control system is superior to the base isolation system alone.

Seismic Uplift Effect at End Spans of Long-Span Rigid-Frame Bridges Subjected to Near-Fault and Far-Fault Ground Motions

Miaoziping Bridge, a long-span rigid-frame bridge, uplift appeared at the end spans in the 2008 Wenchuan earthquake. Bearings and pad stones were damaged during the earthquake. In the past, the uplift mechanism and the seismic response under near-fault and far-fault ground motions were not sufficiently recognized. Here, a refined finite-element model of the Miaoziping Bridge was established considering the initial stress state and the nonlinear characteristics of the girder (e.g., cracking of concrete). The Wenchuan strong motion records and other 40 near-fault pulse-type and 40 far-fault ground motions were selected for nonlinear time history analysis. The uplift effect was realized by considering the compressive-only behavior of bearings. The results show that the seismic responses of the bridge under Wenchuan earthquake ground motions are in good agreement with the real seismic damage observed after the Wenchuan earthquake. The excitation of the near-fault pulse-type ground motion along the longitudinal direction is the dominant factor of the uplift at the end spans. When peak ground acceleration of the near-fault pulse-type ground motion is greater than 0.3g, the end spans are prone to uplift, and the maximum uplift displacement responses can reach 50 cm. There is little uplift possibility subjected to the far-fault ground motions. When the pulse period is in the range of 1–3 s, the pulse effect equals or even exceeds the full-wave effect. The end spans can hardly uplift subjected to vertical or transverse excitation individually. There is a slight difference between the uplift displacements subjected to single longitudinal ground motions and three-directional ground motions. The time of maximum uplift displacement is delayed considering the wave-passage effect. When the wave velocity is less than 1,000 m/s, the adverse effects of the wave-passage effect may be considered.