Component Of Motion Research Articles

Effects of the soil–structure interaction and seismic vertical component on the response of a concrete surge tank

The seismic safety of hydroelectric power plants is of high concern in earthquake-prone regions. Of specific interest to this paper is the seismic performance assessment of a critical item of a typical plant, which is represented by the surge tank, via dynamic analyses both using rigorous and complex models, and both recurring to different assumptions and simplifications. Dynamic time–history analysis, considering non-linearities in the soil but constraining the structure to remain in the elastic uncracked state, is recognized as a suitable analysis method for the problem at hand. In this context, the contribution focuses on a specific Italian case study with the aim of assessing the influence of two main modeling assumptions that engineers could include: (i) considering vs neglecting the soil–structure interaction phenomena; (ii) considering vs ignoring the vertical component of the ground motion. To this aim, 7 seismic inputs have been defined starting from compatibility criteria with a spectrum provided by a site-specific seismic-tectonic study. First, they have been used in a non-linear propagation analysis, to assess the waveform propagation from the bedrock up to the foundation basis. Then, 3D Finite Element (FE) analyses of an empty surge tank have been conducted to assess the effect of the dynamic soil–structure interaction on its seismic response. The effects of the vertical component of the ground motion have been investigated, thus providing some guidance on the modeling choices that should be adopted for a safe assessment of the seismic performance of such kind of structures.

A Modified Aeromagnetic Compensation Method Robust to the Motion State of Aviation Platform Part

Aeromagnetic compensation is a signal-processing method to suppress the magnetic interference from the airborne platform that far exceeds the target magnetic signal. With the development of measurement technology, the traditional aeromagnetic compensation model in which the motion platform is considered as a rigidly connected whole cannot satisfy the request for high-quality aeromagnetic detection, and the magnetic interference generated by the small relative motion components needs to draw our attention. In this paper, the source of maneuver magnetic interference on the aircraft platform is split into two parts, i.e., the rigidly connected main body part (MBP) and moving part (MP), and their compensation models can be both built by referring to the Tolles–Lawson (TL) model. The key factor in these two models is how to obtain the direction cosine that describe the maneuvering actions of aircraft. In the MBP compensation model, the direction cosine can be directly obtained by the onboard fluxgate magnetometer. However, those in the MP model cannot be directly obtained because there is no any monitoring equipment for it. Therefore, a scheme for calculating the direction cosine of the MP compensation model is proposed. This scheme combines the direction cosine obtained by the onboard fluxgate magnetometer with the relative motion angles. And considering the influence of geomagnetic gradient magnetic interference, its compensation model is brought to form a new aeromagnetic compensation model, herein called the TLGM model. This model is different from the traditional TL model and is nonlinear since the three unknown relative motion angles, so the quantum genetic algorithm (QGA) is introduced to combine with recursive least-squares to estimate those unknowns. Some field experiments were conducted, and the results show that the proposed method reduces the standard deviations and figures of merit by over 42% and 39%, respectively, compared with those using the previous model. Also, the proposed compensation method requires no additional motion monitoring sensors and is more convenient for practical applications.

Integration of statistical shape modeling and alternating interpolation-based model tracking technique for measuring knee kinematics in vivo using clinical interleaved bi-plane fluoroscopy.

A 2D fluoroscopy/3D model-based registration with statistical shape modeling (SSM)-reconstructed subject-specific bone models will help reduce radiation exposure for 3D kinematic measurements of the knee using clinical alternating bi-plane fluoroscopy systems. The current study aimed to develop such an approach and evaluate in vivo its accuracy and identify the effects of the accuracy of SSM models on the kinematic measurements. An alternating interpolation-based model tracking (AIMT) approach with SSM-reconstructed subject-specific bone models was used for measuring 3D knee kinematics from dynamic alternating bi-plane fluoroscopy images. A two-phase optimization scheme was used to reconstruct subject-specific knee models from a CT-based SSM database of 60 knees using one, two, or three pairs of fluoroscopy images. Using the CT-reconstructed model as a benchmark, the performance of the AIMT with SSM-reconstructed models in measuring bone and joint kinematics during dynamic activity was evaluated in terms of mean target registration errors (mmTRE) for registered bone poses and the mean absolute differences (MAD) for each motion component of the joint poses. The mmTRE of the femur and tibia for one image pair were significantly greater than those for two and three image pairs without significant differences between two and three image pairs. The MAD was 1.16 to 1.22° for rotations and 1.18 to 1.22 mm for translations using one image pair. The corresponding values for two and three image pairs were 0.75 to 0.89° and 0.75 to 0.79 mm; and 0.57 to 0.79° and 0.6 to 0.69 mm, respectively. The MAD values for one image pair were significantly greater than those for two and three image pairs without significant differences between two and three image pairs. An AIMT approach with SSM-reconstructed models was developed, enabling the registration of interleaved fluoroscopy images and SSM-reconstructed models from more than one asynchronous fluoroscopy image pair. This new approach had sub-millimeter and sub-degree measurement accuracy when using more than one image pair, comparable to the accuracy of CT-based methods. This approach will be helpful for future kinematic measurements of the knee with reduced radiation exposure using 3D fluoroscopy with clinically alternating bi-plane fluoroscopy systems.

Nonlinear earthquake responses of unanchored cylindrical liquid storage tanks on flexible soil

A sophisticated and versatile finite-element model of the nonlinear behavior of unanchored cylindrical liquid storage tanks on flexible soil is proposed and applied for nonlinear earthquake response analysis of the system. The tank is modeled using shell finite elements with material and geometric nonlinearities. The hydrodynamic pressure is represented by acoustic finite elements. The effects of the base uplift are considered by nonlinear springs with negligible and large stiffness coefficients in tension and compression, respectively. The flexible soil is modeled using mechanical springs and dashpots. The effects of base uplift and soil flexibility are examined for typical unanchored tall and broad tanks on flexible soil with various shear-wave velocities. It is observed that the structural responses and hydrodynamic pressure, including the convective pressure of an unanchored tall tank on rigid/flexible soil, are significantly influenced by the base uplift. Although the base uplift in a broad tank is not as large as that in a tall tank, the structural responses and hydrodynamic pressure of an unanchored broad tank can be different from those of an anchored system. However, the convective pressure of the broad tank is not significantly affected by the base uplift. The earthquake responses of the system are principally influenced by the horizontal component of the earthquake ground motion rather than the vertical component.

A Novel Eddy Current Sensor for Displacement Measurement With High Accuracy and Long Range

To enlarge the measurement range of traditional eddy current displacement sensors, a novel eddy current linear sensor for displacement measurement with high accuracy and long range is proposed in this paper. The sensor consists of a stationary component with metal reflection conductors and a movable component with spiral coils. The metal reflection conductors below the movable component will generate an eddy current and radiate an eddy current magnetic field after the high-frequency alternating excitation signal is applied to field spiral coils. The inductive electromotive forces (EMFs) will be generated in inductive spiral coils. The measurement of displacement relies on the inductive EMFs variation of inductive spiral coils caused by the change of coupling areas between the spiral coils and the metal reflection conductors. The absolute positioning is realized by the combination of a coarse measurement channel and a fine measurement channel. The structure and measurement principle are described in detail. A sensor prototype is fabricated by PCB technology, and the experiments are carried out. Based on the experimental results, some error sources are analyzed and the sensor is optimized. The experimental results show that the sensor can achieve absolute positioning, and the worst-case error is 6.75 μm within the measurement range of 500 mm.

Broadband ground motion simulation using a hybrid approach of the May 21, 2021 M7.4 earthquake in Maduo, Qinghai, China

In this study, the broadband ground motions of the 2021 M7.4 Maduo earthquake were simulated to overcome the scarcity of ground motion recordings and the low resolution of macroseismic intensity map in sparsely populated high-altitude regions. The simulation was conducted with a hybrid methodology, combining a stochastic high-frequency simulation with a low-frequency ground motion simulation, from the regional 1-D velocity structure model and the Wang WM et al. (2022) source rupture model, respectively. We found that the three-component waveforms simulated for specific stations matched the waveforms recorded at those stations, in terms of amplitude, duration, and frequency content. The validation results demonstrate the ability of the hybrid simulation method to reproduce the main characteristics of the observed ground motions for the 2021 Maduo earthquake over a broad frequency range. Our simulations suggest that the official map of macroseismic intensity tends to overestimate shaking by one intensity unit. Comparisons of simulations with empirical ground motion models indicate generally good consistency between the simulated and empirically predicted intensity measures. The high-frequency components of ground motions were found to be more prominent, while the low-frequency components were not, which is unexpected for large earthquakes. Our simulations provide valuable insight into the effects of source complexity on the level and variability of the resulting ground motions. The acceleration and velocity time histories and corresponding response spectra were provided for selected representative sites where no records were available. The simulated results have important implications for evaluating the performance of engineering structures in the epicentral regions of this earthquake and for estimating seismic hazards in the Tibetan regions where no strong ground motion records are available for large earthquakes.

True relationship between tricuspid annular motion and velocity displacement components: Potential role in assessing right ventricular decoupling.

Although measures of longitudinal displacement of the tricuspid annulus measured by M-mode as tricuspid annular systolic plane excursion (TAPSE) and systolic velocity by tissue Doppler imaging (TA TDI s) are routinely used for assessment of right ventricular (RV) systolic function; these measures describe different phenomena and should not be used interchangeably. Previously published data was used to determine the individual relationship between TAPSE and TA TDI s with increasing pulmonary artery systolic pressures (PASP). In this retrospective analysis, 488 patients were divided into 2 groups based on TAPSE (Group 1:<1.8cm and Group 2: ≥1.8cm). A robust correlation (R=.79) between TAPSE and TA TDI s noted for the entire population. However, a statistically lower correlation (R=.43) was seen between Group 1 and Group 2 (R=.65; p<.0047). With increasing pulmonary pressures, only PASP (p<.0001) and TA TDI s (p<.0001) discriminated between low and normal TAPSE/PASP values. Suggesting that a TA TDI s/PASP ratio would be most useful than TAPSE/PASP with a specificity of 80%. Significant differences exist between TAPSE and TA TDI s, particularly at low TAPSE values with increased PASP, were uncoupling occurs. Our data seems to suggest that TA TDI s/PASP would be most useful than TAPSE/PASP ratio. Future studies should address, if abnormalities in the material properties along the RV free wall account for these differences seen between TAPSE and TA TDI s.

Collapse risk of steel framed buildings with deep columns under tri-directional excitation

Deep steel columns are widely used in steel buildings with perimeter moment frames (PMFs). Although their seismic behavior has been well examined at the member level, their influence on frame collapse response requires further exploration, especially their interaction with composite slabs, gravity frames, and ground motion components. To address this shortcoming, the collapse risk assessment of a set of steel buildings with PMFs and deep columns is performed via two modeling approaches: the conventional planar frame and the sophisticated space frame. The models are capable of capturing the instability, fracture, and collapse behavior in frame systems. The simulation results show that each additional ground motion component applied promotes the development of collapse mechanisms and significantly increases collapse probability, and that composite slabs combined with gravity frames greatly improve collapse capacity despite introducing additional local failures. Moreover, limiting slenderness ratios and controlling local buckling of deep columns is essential to prevent frames from vertical progressive collapse (VPC) and ensure sufficient collapse resistance. The available highly ductile limits (HDLs) are accordingly critiqued and revised. Due to the large discrepancies in the collapse risks determined by the two approaches, space frame modeling is suggested to accurately assess the collapse capacity of steel PMFs involving deep columns.

An Efficient Straightforward Pushover Method for Buildings with Two-Way Unsymmetric-Plan Subjected to Two Components of Ground Motions

ABSTRACT A straightforward pushover method is developed for unsymmetric-plan buildings under bidirectional seismic excitation. To this end, a single innovative torsional-lateral load pattern is introduced based on the response spectrum analysis. The joint contribution of two horizontal seismic excitations and the joint contribution of all considered modes to internal structural forces in forming plastic hinges are considered by implementing the single load pattern. An equivalent dominant mode shape derived from the load pattern is defined to establish capacity spectra in both directions. The accuracy of the proposed procedure in estimating the seismic demands of buildings is demonstrated through two unsymmetric-plan buildings.

Recognition of Empathy from Synchronization between Brain Activity and Eye Movement.

In the era of user-generated content (UGC) and virtual interactions within the metaverse, empathic digital content has become increasingly important. This study aimed to quantify human empathy levels when exposed to digital media. To assess empathy, we analyzed brain wave activity and eye movements in response to emotional videos. Forty-seven participants watched eight emotional videos, and we collected their brain activity and eye movement data during the viewing. After each video session, participants provided subjective evaluations. Our analysis focused on the relationship between brain activity and eye movement in recognizing empathy. The findings revealed the following: (1) Participants were more inclined to empathize with videos depicting pleasant-arousal and unpleasant-relaxed emotions. (2) Saccades and fixation, key components of eye movement, occurred simultaneously with specific channels in the prefrontal and temporal lobes. (3) Eigenvalues of brain activity and pupil changes showed synchronization between the right pupil and certain channels in the prefrontal, parietal, and temporal lobes during empathic responses. These results suggest that eye movement characteristics can serve as an indicator of the cognitive empathic process when engaging with digital content. Furthermore, the observed changes in pupil size result from a combination of emotional and cognitive empathy elicited by the videos.

Dissertation Overview: Numerical modelling of the hydrodynamics and energy generation of an oscillating wave surge converter system

The Oscillating Wave Surge Converter (OWSC) is one of the most relevant systems for harnessing energy from ocean waves, generating energy by capturing the horizontal component of wave motion. This technology, which is on a pre-commercial development scale, presents one of the greatest potentials for electricity generation, due to its operating principle and the great improvement in design experienced over the last few years. Today, Computational numerical modelling is one of the main tools for the study and design of this and several other power generation systems from sea waves. In this context, a detailed study of a wave farm composed of several OWSCs is necessary, which represents a case closer to reality, since most renewable systems include several modules of the same converter. Considering the complexity of the existing hydrodynamics in these cases, a numerical modeling methodology based on the Large Eddy Simulation (LES) methodology is applied to correctly represent the oscillation of the structure and the observed flow fields. In order to achieve the objectives, the OpenFOAM v.4.1 computational code and the OlaFlow extension are used, together with the Wall Adapting Local Eddy Viscosity (WALE) LES model, which allows a representation of the system very close to real application cases. The proposed model demonstrated a good adherence of the results when compared to experimental studies present in the literature. Likewise, it was observed that changes in wave height and period, bottom slope, wave reflection, spacing between converters, and the wave farm layout can cause important variations in the energy generated by the system, increasing or reducing considerably its efficiency, emphasizing the importance of these parameters in the design and development of this technology.

Seismic protection of a single-layer spherical lattice shell structure using a separated three-dimensional isolation system

Vertical and three-dimensional (3D) isolation systems are emerging control technologies for spatial grid structures in high seismic intensity regions. Recently, multistage vertical isolation bearings (MVIBs) based on prepressed spring devices (PSDs) have been proposed to support the lattice shell and prevent the transfer of vertical ground motion components to the structure. Seismic dampers can be further combined with an MVIB to develop a hybrid bearing with a damping capacity. In this study, the vertical load-carrying and isolation mechanisms underlying the MVIB configuration were investigated in detail. A series of proof-of-concept tests were conducted on a prototype MVIB comprising four identical PSDs to study its actual mechanical behavior. The test results indicated that the MVIB specimen exhibited multilinear elastic behavior with enhanced load resistance. The key parameters of the tested bearing, such as the transition force and isolation stiffness, increased linearly with the number of PSDs. The MVIB model was subsequently refined using ABAQUS to comprehensively understand the mechanical performance of the spring isolator. Following a device-level study, a single-layer spherical lattice shell was used as the research target. The damped MVIBs and friction pendulum bearings were arranged at the roof supports and column bases, respectively, and the stiffness and energy dissipation properties of these isolators were designed. A system-level seismic analysis was conducted using OpenSees to compare the triaxial dynamic responses of the target structure before and after isolation. The results indicated that the separated 3D isolation system achieved its intended design goals and effectively protected the lattice shell structure from tridirectional seismic shaking.

Effects of the Vertical Component of Ground Motion on the Maximum-Inelastic-Horizontal-Response of SDOFs

This study investigates potential effects of the vertical-component-of-ground-motion (VCGM) on the maximum-inelastic-horizontal-response (MIHR) of single-degree-of-freedom (SDOF) systems. The effects of VCGM can be considered in two categories. First, it may initiate some modes of failure, like over-compression, and second, it might adversely influence the horizontal response through altering the P-delta effect. The latter is a result of variation of the gravitational acceleration, and hence, seismic weight, upon action of the VCGM. This study uses time-history analysis to compare the response of SDOFs in presence and absence of the VCGM. In both cases, the P-delta effect is inherent in analyses and period-dependent feature of the stability-coefficient, which is essential for reliable treatment of the P-delta effect, is explicitly reflected. Since available record selection and scaling strategies use uncoupled vibrators in vertical and horizontal directions, this research follows two steps to avoid undesirable bias. The first step, which focuses on examining the influence of some important parameters, adopts an event-based record selection scheme. Results indicate that for certain combinations of the strength reduction factor and initial period of vibration the effect of the VCGM on the MIHR is significant. Specifically, the systems with initial periods between 1.0 and 2.0 s are found most vulnerable. Moreover, the mentioned effect is not limited to near source regions. The second step evaluates capability of the VCGM to initiate dynamic instability. In this step, a set of 26 records, which resembles an assumed target spectrum at a near field site, is used. Results show that under action of some of the examined records, the presence of the VCGM leads to dynamic instability; hence, this study suggests consideration of the VCGM for collapse evaluation.

Sound detection and production mechanisms in aquatic decapod and stomatopod crustaceans.

The sensory systems of crustaceans (aquatic decapods and stomatopods) have adapted to a diverse range of aquatic ecosystems. Sound production in aquatic crustaceans is more widespread than previously thought, and has been shown to play a major role in many of their life-history strategies; however, there are still many gaps in our understanding of their sound reception abilities. Crustaceans have three main sensory receptors for sound - the statocyst, superficial hair cells and chordotonal organs - which are all sensitive to the particle motion component of the sound field, rather than the pressure component. Our current understanding of these receptors is that they are sensitive to low-frequency sounds (<2000 Hz). There are a wide variety of sound-producing mechanisms employed by these animals, ranging from stridulation to implosive cavitation (see Glossary). These signals are used for a range of social behaviours, such as courtship, territorial defence and assessing 'resource guarding'. Furthermore, there are examples of sound signals that exceed their hearing range, highlighting a mismatch in our understanding of their hearing systems. This mismatch provides weight to the suggestion that another sound transmission channel - substrate-borne vibrations - might be at play, particularly because most crustaceans live on or near the seafloor. Finally, suggestions are made regarding potential future work that is needed to fill the substantial gaps in our understanding of how crustaceans hear and produce sound.

Thesis Overview: Oscillating wave surge converters – Large eddy simulation modelling of wave farms hydrodynamics and its related energy potential

The Oscillating Wave Surge Converter (OWSC) is one of the most relevant systems for harnessing energy from ocean waves, generating energy by capturing the horizontal component of wave motion. This technology, which is on a pre-commercial development scale, presents one of the greatest potentials for electricity generation, due to its operating principle and the great improvement in design experienced over the last few years. Today, Computational numerical modelling is one of the main tools for the study and design of this and several other power generation systems from sea waves. In this context, a detailed study of a wave farm composed of several OWSCs is necessary, which represents a case closer to reality, since most renewable systems include several modules of the same converter. Considering the complexity of the existing hydrodynamics in these cases, a numerical modeling methodology based on the Large Eddy Simulation (LES) methodology is applied to correctly represent the oscillation of the structure and the observed flow fields. In order to achieve the objectives, the OpenFOAM v.4.1 computational code and the OlaFlow extension are used, together with the Wall Adapting Local Eddy Viscosity (WALE) LES model, which allows a representation of the system very close to real application cases. The proposed model demonstrated a good adherence of the results when compared to experimental studies present in the literature. Likewise, it was observed that changes in wave height and period, bottom slope, wave reflection, spacing between converters, and the wave farm layout can cause important variations in the energy generated by the system, increasing or reducing considerably its efficiency, emphasizing the importance of these parameters in the design and development of this technology.

A multi-temporal DInSAR-based method for the assessment of the 3D rigid motion of buildings and corresponding uncertainties

This paper investigates the performances of the multi-temporal DInSAR technique for the structural monitoring of single buildings. The application of the multi-temporal DInSAR technique at building or infrastructure scale is enabled by the high imaging capability of the current generation of SAR constellations. Within this framework, the paper proposes an analytical procedure for the reconstruction of the 3D rigid motion of single buildings based on SAR measurements. To successfully reconstruct the structural displacement, measurements from dual orbits are required by the method. The proposed procedure is tested through numerical analyses accounting for uncertainties affecting SAR data, both in the displacement measurements and in the positioning of the main persistent scatterers. Numerical simulation results allow for the quantification of uncertainties in the estimation of the motion parameters. An analytical model is also proposed to estimate the motion parameter uncertainties depending only on the building geometry, the satellite orbit inclinations and the number of persistent scatterers, with no need to know their exact positions. The main benefit of the proposed analytical model is that it can be adopted in real applications to a priori evaluate the precision by which the motion components can be estimated in order to assess the reliability of the structural monitoring based on SAR interferometry. A very good match between numerical and analytical motion parameter uncertainties is achieved. Finally, the proposed method to reconstruct the 3D rigid motion and assess the corresponding uncertainties is applied to a real case study in Rome (Italy).

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ РОБОТИ СУДНОВИХ СТЕРН ПРИ РІЗНИХ РЕЖИМАХ МАНЕВРУВАННЯ

The availability of adequate mathematical models of the ship propulsion system is essential for developing effective ship control systems, building high-quality simulators, and studying the ship’s maneuvering behavior. With the advancement of new computing and information technologies, the mathematical models of the ship propulsion system need to meet higher requirements and cover wider applications. This leads to the need for continuous improvement of mathematical models, especially those of non-inertial forces acting on the ship. This work investigates the influence of the ship’s curvilinear movement on the rudder performance. Mathematical models of the forces and moments acting on the rudder at different values of the local drift angle and the rudder angle are derived. The resultant force on the rudder is decomposed into components due to the rudder lift, drag, normal force, and tangential force. Expressions for the coefficients of rudder hydrodynamic quality, reverse quality, and normal force are obtained. The existing mathematical models of the rudder hydrodynamic coefficients are analyzed and their limitations and applicability are discussed. New mathematical models of the rudder lift and drag coefficients are proposed, which take into account the aspect ratio, relative thickness, and angle of attack of the rudder. The proposed models are validated by comparing them with experimental data for NACA series rudders. t is shown how the lift and drag of the rudder, as well as the components of the resulting force, change for the maximum possible range of changes in the local drift angle and the rudder angle, for different values of the rudder aspect ratio and relative thickness. Keywords: mathematical models, ship rudders, curvilinear movement, longitudinal and transverse components of forces, dimensionless hydrodynamic coefficients.

Research for Optimal Programs for Controlling the Relative Motion of a Spacecraft with Limited Thrust

The problem of optimal control of the relative motion of a spacecraft with a finite thrust engine in arbitrary circumcircular orbits using the Pontryagin’s maximum principle is considered. Motion is studied in an orbital cylindrical coordinate system, using variables written in the form of secular and periodic components of relative motion in the orbital plane. The main attention is paid to the analysis of the optimal control structure with a free and transversal orientation of the thrust vector in the presence of passive areas on the trajectory. As a criterion for choosing the optimal control, the motor operating time of the corrective motors was considered. Characteristic control structures for various areas of initial driving conditions have been determined, and estimates of the marginal costs of motor time have been obtained.

Wave Motion in a Surface Electric Charged Viscous Homogeneous Liquid

The influence of the surface electric charge on the character and properties of wave motion along the free surface of a viscous homogeneous liquid has been investigated by analytical asymptotic methods. Expressions describing the dispersion dependences of the wave motion components are obtained. The phase and group velocities of the structures forming the wave motion are determined.

Real‐time hybrid simulation for investigating the influence of vertical ground motions on the lateral response of RC piers

AbstractThe vertical component of ground motions can affect the seismic performance of reinforced concrete (RC) piers as significant as its horizontal counterpart. However, real‐time testing for RC piers subjected to both horizontal and vertical ground motions has been scarcely conducted due to the difficulty in multi‐axial control of actuators. In this study, the seismic response of a bridge RC pier was investigated by conducting real‐time hybrid simulation (RTHS), where the RC pier was physically tested in the laboratory and the bridge superstructure was numerically modeled. The test setup that can synchronously apply both horizontal and vertical ground motions was constructed by using three dynamic actuators and a flexible loading beam (FLB). The lateral response of the RC pier was investigated by varying the intensities for vertical ground motions, while the same intensity for horizontal ground motion is used. It was found that the axial force from the dead load of superstructure can significantly affect the initial stiffness, strength, and post‐yield response of the RC pier. For the selected earthquake ground motions, however, the intensity of vertical ground motion did not make a substantial difference in the lateral response, although there was a notable difference in the fracture pattern.