Time History Response Research Articles

Numerical modelling of dual function tanks for fire suppression and tuned liquid damper applications

Exceeding serviceability limits due to wind-induced motions in tall buildings can cause discomfort for residents and adversely affect auxiliary building services, such as elevator operations. A tuned liquid damper (TLD) is an attractive type of dynamic absorber because of its simplicity and affordability. However, its dimensions and geometry can be limited by available floor space. Utilizing dual-purpose water tanks for both damping and fire suppression purposes can be a feasible resolution to fire code requirements and building motion control. Several design criteria need to be considered to accommodate the fire code requirements and the proper tuning of the TLD. Consequently, in this study, a TLD tank is fitted with a perforated floor to divide it into two compartments that allow water transmission to meet fire code requirements. However, the sloshing motion within the tank is complex and computationally expensive to capture when using traditional simulation models. This paper presents a 2D ISPH code equipped with a macro-level model to capture the effect of the perforated floor on the overall sloshing response of the tank. The model is first evaluated using existing results from previous studies on tanks with horizontal baffles. Next, the ISPH model is used to numerically model the perforated floor using the Ergun resistance (ER) macro-level model. In addition, the perforated floor is also explicitly micro-level modelled using rigid boundary particles to validate the proposed ER model. A numerical analysis is then conducted under different excitation amplitudes and frequencies, with both time history and frequency response results being presented. A structure-TLD model is subsequently used to capture the structure-TLD system response under random excitation. Results show that the ER model can efficiently model tanks with dual functions under both harmonic and random excitation and across a wide range of amplitudes and frequencies, with appreciable computational time savings. The proposed tank with a perforated floor is found to be effective in serving as a dual-purpose TLD and storage tank for fire suppression in buildings.

Simplified optimization of inerter-enabled tuned mass damper for lightweight-oriented seismic response mitigation of long-span domes

Suspending tuned mass dampers (TMDs) from long-span domes has been studied to mitigate seismic responses of long-span domes. However, the strict weight limitations on the suspension mass in conventional tuned mass dampers (TMDs) hinder their widespread adoption. To address this issue, we introduce the inerter-enabled tuned mass damper (IeTMD) that consists of a suspension mass, tuning spring, and a tuned viscous mass damper (TVMD) sub-system into the seismic vibration mitigation of long-span domes. Under the assumption that long-span domes remain within the elastic range and adhere to the small deformation hypothesis, we have proposed simplified design formulae for IeTMDs, guided by the lightweight-based seismic vibration control criterion. Parametric studies are conducted to illustrate the degree to which an IeTMD can improve the performance of the long-span dome when its key parameters change within certain ranges. The effectiveness of the design strategy in exploiting the damping enhancement effect is confirmed. Time history responses of a benchmark long-span dome demonstrate that the IeTMD has high control efficiency, as bi-directional displacements, accelerations, and base shear are significantly reduced. Comparative analyses between the proposed IeTMD and conventional TMD are conducted. Results show that the IeTMD designed by the simplified design formulae can achieve the target control performance with less suspension mass. Furthermore, the frequency analysis shows that the proposed IeTMD contains a wider control frequency band than conventional TMD, illustrating the promising approach for long-span domes.

Field monitoring of vibration characteristics during advanced ductule installation in sandy cobble stratum

The sandy cobble stratum presents a high risk for underground tunnel construction due to its low cohesive properties and susceptibility to loosening and falling. The use of Advanced ductule for grouting reinforcement inevitably results in vibrations, and understanding how these vibrations propagate is crucial in selecting tunnel engineering support schemes and responding to accident risks. Based on a bored tunnel under construction in Xi’an, field vibration propagation characteristics testing were carried out for advanced ductile installation. The time-history response and frequency distribution characteristics of the vibration velocity within the tunnel face under sandy cobble stratum conditions were studied, and the law of vibration propagation attenuation within the tunnel face range was obtained. The results showed that: 1) During the conduit drilling process, the tunnel face mainly experienced vertical vibrations, with the horizontal velocity amplitude accounting for only 15%–20% of the vertical velocity amplitude. At a distance of 1.0 m from the conduit, the vertical velocity amplitude reaches 10.602 mm/s, and the vibration energy concentrates mainly in the frequency range of 150–250 Hz. At a distance of 1.5 m from the conduit, the bidirectional vibration velocity significantly attenuates; 2) The vibration characteristics within the tunnel face can be classified into three primary areas: “Loose and Falling” area, “Significant Vibration” area, and “Vibration Attenuation” area. Loose, falling and significant vibrations occurred mainly within a range of about 1.25 m around the conduit. 3) As the diameter of the conduit decreases, the amplitude of vertical vibration velocity decreases by about 20%. By reducing the design diameter of the advanced ductule in a reasonable manner, it is possible to effectively mitigate the impact of vibration caused by the sandy cobble stratum during installation. This can yield a positive impact, curtailing the occurrence of the tunnel’s collapse phenomenon and ensuring its stability.

A floating system integrating a wind turbine with a steel fish farming cage: Experimental validation of the hydrodynamic model

This paper is dedicated to comparing the numerical results of the dynamic responses of a floating offshore wind turbine integrated with a steel fish farming cage (FOWT-SFFC) under wind and waves against the experimental data. FOWT-SFFC's numerical model is built with OrcaFlex where the potential flow theory and quadratic drag formula are used to calculate the hydrodynamic loads on the structural components of the floater, while Morison-type formulation is employed to model the force on fish nets. The numerical model is tuned in terms of the measured data. The simulated motion response amplitude operators and stochastic responses under irregular waves are compared with the experimental results to fathom the influence of drag's modeling on the simulation outcome. The effects of additional damping and 2nd-order wave forces are also investigated to determine the optimal simulation method. With the selected numerical model, the responses of FOWT-SFFC with and without nets under 100-year extreme waves, combined wind and irregular waves are calculated. The simulated response time histories, spectra and statistics are in good agreement with the experimental data. Besides, it is revealed that the effects of 2nd-order wave forces are important for the accurate simulation of low-frequency pitch motion, but unfavorable to the prediction of other responses.

Rapid damage assessment of regional beam bridges after earthquake based on simplified models and different seismic inputs

As the hub of the traffic network, the rapid damage assessment of bridges after earthquake is of great significance for post-disaster rescue. Traditional vulnerability-based method can only provide the probability of different damage states of structures under different earthquake intensity indicators, which confuses the selection of post-disaster rescue routes. Therefore, this paper proposes a post earthquake damage assessment technique for regional bridges based on nonlinear dynamic time-history response analysis. First, a simplified mechanical model for a single pier was established for a large number of beam bridges in the region, achieving standardized and batch rapid finite element model establishment. Secondly, using Kriging interpolation method and continuous wavelet transform technology, the surface seismic response of geological drilling points is calculated to obtain the seismic motion history of any bridge site in the region. Finally, using parallel computing technology, nonlinear dynamic time-history response analysis was conducted on the simplified beam bridge model, and the bridge damage status was quantitatively evaluated based on the calculation results. Eighty-five bridges in a specific area are considered as an example to verify the proposed method. The results show that the proposed method has high calculation efficiency and can consider the site characteristics and structural design parameters. Also, the calculation results can better reflect the actual earthquake damage distribution, providing strong technical support for post-disaster rescue.

PERFORMANCE ANALYSIS OF HORIZONTAL IRREGULAR BUILDINGS BASED ON RESPONS SPEKCTRUM AND TIME HISTORY METHODE

Indonesia is geographically located in the Pacific Ring of Fire, Especially on Java Island, which has the densest infrastructure and population and is located between the Indo-Australian plate and the Eurasian plate, causing this area to have many active volcanoes and has a high potential for earthquakes. Therefore, it is necessary to pay the planned earthquake load in planning the building structure design to minimize losses due to the earthquake. This study aims to determine the structure's performance against safeguards, deviations between levels, and structural stability limits against earthquake loads and to review horizontal structural irregularities based on SNI 1726: 2019 regulations in existing buildings at the Simpang Temu MRT Dukuh Atas Jakarta Building. The analysis process was carried out by 3D building modeling using the ETABS software program, analysis based on time history and spectrum response. Time History analysis uses recorded earthquakes of Kobe Japan, ChiChi Taiwan, and El Centro which match the earthquake response spectrum, the results of the analysis based on the program were carried out to compare the two methods used. Based on the results of the analysis, the building is classified into horizontal irregularities with excessive torque ratio > 1.4, average displacement value from the 2nd to 12th floor in the horizontal direction X exceeds the drift value limit. The results of the instability limit for structural stability against displacement based on the P-Delta effect still meet the structural stability limits so it can be stated that the structure is stable and safe.

Reliability of inelastic wind excited structures by dynamic shakedown and adaptive fast nonlinear analysis (AFNA)

The ever-growing interest in performance-based wind engineering has created a need for assessment frameworks that can efficiently deal with inelasticity. The computationally efficient strain-driven dynamic shakedown approach has provided a solution that is not only capable of identifying failure mechanisms that are potentially critical during extreme winds, e.g., low cycle fatigue and ratcheting, but also allows direct estimation of inelastic deformations. This approach, however, can only solve problems at dynamic shakedown, i.e., with limited nonlinearity, and is not capable of providing response time histories. To address these limitations, this paper presents an efficient framework for reliability assessment of inelastic structures at dynamic shakedown and beyond. To this end, a novel step-by-step integration algorithm is developed for rapid response time history analysis within the setting of dynamic shakedown. The method is based on advancing fast nonlinear analysis through introducing schemes for enabling at each time step the adaptive selection of the step size, number of modes to be included, and number of potentially nonlinear elements. Inelasticity is modeled as distributed at the level of the stress resultants through a return mapping scheme based on the Haar–Kàrmàn principle, therefore enabling the integrated estimation of the state of dynamic shakedown. The scheme is seen to preserve the efficiency of recently developed strain-driven dynamic shakedown algorithms while providing a full range of response time histories at and beyond the state of dynamic shakedown. To enable reliability analysis, the scheme is embedded in a general uncertainty propagation framework.

Anti-shock performance of a cockroach-inspired structure

Shock leads to negative impacts on both engineering practices and human comfort in daily life. Many species in nature possess significant shock resistance capacities. This paper introduces a cockroach-inspired structure (CIS) for effectively isolating large-amplitude shocks. The shock responses of CIS are evaluated using the Runge-Kutta method and assessed by four indices: time history response, energy conversion, shock transmissibility, and shock response spectrum. The numerical results show that the hardening effect induced by CIS leads to a leftward shift phenomenon, which can reduce transient response time and expand shock isolation area. By adjusting the geometric parameters, the damping force can be increased to improve the shock isolation performance; the stored potential energy and converted kinetic energy can be minimized, enabling the payload to quickly stabilize its position. The experimental results show that CIS achieves a significant 91.5% reduction in peak absolute acceleration. In summary, this study lays the groundwork for exploring the potential of insect-inspired structures in mitigating shocks.

Seesaw-arm energy dissipation system with U-shaped steel dampers

This paper presents an investigation of the extended seesaw system using a seesaw-arm member with U-shaped steel dampers for improving the seismic energy dissipation in building structures. One of the notable features of the existing seesaw system is its usage of a quasi-linear motion mechanism, which allows the bracing members to remain tensile during vibration. In addition, a seesaw-arm concept is proposed for magnifying the damper deformation. Evaluation methods for the lateral stiffness and strength of the proposed system were derived. Then, cyclic loading tests were performed on six specimens, revealing that the proposed system has a stable hysteretic property and large energy-dissipation capacity. The accuracy of the stiffness and strength evaluation was assessed through comparisons with the test results. The evaluation of the displacement amplification factor of the damping system agreed well with the test results. Seismic-response analyses of five-story steel frame models adopting the proposed system were conducted. The maximum story drift angle, time-history responses of displacement and energy, and plastic-hinge formation were compared with those of the bare frame model. The analysis results revealed the efficiency of the proposed system for reducing seismic responses. Furthermore, a larger shape factor of the seesaw-arm member corresponded to better seismic performance.

A machine learning-based hybrid seismic analysis of a lead rubber bearing isolated building specimen

This paper presents the first experimental validation of the hybrid seismic analysis, previously developed by the authors, by simulating the structural behavior of a full-scale base-isolated building specimen tested at the E-Defense. The two-dimensional structural behavior of the lead rubber bearings (LRBs) is predicted by a machine learning model (MLM) previously developed by the authors, whereas analytical models describe the response of the superstructure. A Python script has been developed to incorporate both analytical models and MLMs into an explicit time integration method to perform three-dimensional hybrid seismic analyses. Moreover, conventional time history analyses have been carried out using a bilinear model for the isolation devices. Experimental, ML-based, and conventional analysis responses of 14 shake table motions are processed and compared in terms of hysteresis curves of the isolation layer, roof displacement and peak floor acceleration. Overall, hybrid seismic analysis showed better results than conventional one in terms of capturing the energy dissipation capacity of the isolation layer (maximum a20-index of 0.859 for the drift and 0.720 for the shear with respect to experiment). Similarly, roof displacement was predicted with a maximum a20-index value of 0.832. Besides, the maximum average computation time of hybrid seismic analysis was 1.78 s per integration time-step. Therefore, the efficiency of the hybrid seismic analysis is experimentally proven in this paper in terms of both accuracy and applicability. This machine learning-based analysis method is strongly recommended to simulate time-history response of complex structures.

Visualization of regional seismic response based on oblique photography and point cloud data

Efficient and realistic visualization of regional seismic response is of great significance for risk education and emergency response. This study proposes an efficient visualization framework for seismic response of regional buildings, which consists of three parts: (1) oblique photography-based three-dimensional (3D) point cloud modelling of regional buildings; (2) time-history response analysis of regional buildings; and (3) hybrid processing for dynamic visualization. Specifically, the unmanned aerial vehicle (UAV) is adopted for oblique photography. The building coordinate extraction with the least square method and point cloud data segmentation with the clustering algorithm are implemented for the pre-processing. The simplified multi-degree-of-freedom (MDOF) model is developed for the time-history displacement analysis of buildings. Then, the MDOF model is used to match the point cloud model of the buildings for visualization. Preset rendering parameters and dynamic geometrical updating are used to further improve the visualization quality. Taking the Southeast University Jiulonghu campus in Nanjing, China for example, a case study is conducted to validate the feasibility of the developed framework.

Structural Damage Identification considering Uncertainties in Nonuniform Measurement Conditions Based on Convolution Neural Networks

Dynamic-vibration-based structural damage identification (SDI) represents the main target for structural health monitoring (SHM). It is significant to consider the unavoidable uncertainties arising from both the structure and measuring noise. On the other hand, nonuniform measurement conditions often appear in actual SHM applications, which consist of two parts, i.e., spatial nonuniform characteristics for noises are induced by various intensities of input noise in every single sampling channel and multisensor stays in a damaged state. This paper proposes a new method for the SDI considering uncertainties in nonuniform measurement conditions integrating convolutional neural network (CNN). Herein, the great ability of feature extraction from the measurement associated with the convolutional network is used to handle the input data, and the mapping connection between the selected features and damage states is established. Time histories of structural responses, such as acceleration, are applied for damage identification. The application and accuracy of the CNN, which is trained with input uncertain parameters contaminated by stochastic noises, are verified by the finite element numerical and experimental results. Both uncertain parameters and measurement conditions are considered in the verification. The responses obtained from the numerical and experimental approach show that the proposed neural network model can identify the structural damage with high accuracy. The great robustness of the proposed method is examined by studying the influence of uncertainties, even considering the nonuniform measurement condition.

Fatigue reliability analysis for suspenders of a long-span suspension bridge considering random traffic load and corrosion

For suspension bridges, suspenders are critical load transferring components that connect girder to main cable, the safety of the suspenders conduces to maintain the structural integrity of the bridge. The cyclic stress and corrosion environment are the main reasons for the failure of suspenders. To evaluate the fatigue status of suspenders under the combined action of traffic load and corrosion, this paper presented a time-variant fatigue reliability analysis framework based on in-site measured traffic data and corrosive deterioration model for suspenders. First, the refined vehicle parameter models are established by statistical analysis. An elaborate random traffic flow model that involves car-following theory and Monte-Carlo method is developed. Then, a practical FEM-based method is used to simulate vehicle induced response time history. The fatigue loading effects, namely equivalent stress range and corresponding cyclic number are subsequently obtained. Finally, the time-variant fatigue reliability for suspenders considering corrosion and traffic growth is evaluated. A case study was performed for suspenders of an in-service sea-crossing suspension bridge in China. The results indicate that corrosion and growing traffic density would greatly shorten the service life of suspenders of a suspension bridge, among which corrosion has the most significant influence. Fatigue reliability index of the shortest critical suspender at 1/2 mid-span of the case bridge would lower than target value at the 18th service year in the most serious marine corrosion environment, which resulted in references for suspender maintenance and replacement.

NUMERICAL ANALYSIS OF SEISMIC RESPONSE OF STEEL CYLINDRICAL LNG STORAGE TANKS

Numerical analysis of the seismic response of steel cylindrical LNG (liquified natural gas) storage tanks is essential to designing such structures to ensure their safety and structural integrity during earthquake events. The seismic analysis involves the assessment of the tank's response to ground motion and evaluating its structural performance under seismic loads. The LNG storage tanks' seismic behavior is rarely reported when the tank is subjected to strong earthquakes. This paper evaluates the vibration characteristic (modal analysis) and the seismic response analysis, e.g., time history response, displacement vs. time, and distribution of the maximum Von-Mises stresses of the perfect cylindrical storage tanks. This paper uses the finite element analysis (FEA) technique using ABAQUS CAE-2019 to evaluate the seismic capacity in peak ground acceleration (PGA). Three perfect cylindrical tanks (PCT) have been considered first for modal analysis, with two having high-yielding strength and the rest with low-yielding strength. Then El-Centro 1940 seismic waves are applied as a horizontal ground motion at the fixed base of the tanks. Finally, the results from the modal analysis regarding the first natural frequency of the tank models are compared with those obtained from experiments. The result’s comparisons illustrate that the numerical simulation agrees well with the experimental test results.

Signal complexity approach based investigation of flutter instability in sectional models of bridges in wind tunnel

Signal complexity analysis based entropy measure has been used to propose a model-free approach towards assessment of flutter critical wind speed and identification of the type of flutter in wind tunnel testing of long span bridges. The approach is based only on the measured output responses from the structure, which accounts for appropriate effects that stem from the non-linearity of the structure and fluid structure interaction. The usefulness of the proposed approach has been demonstrated with dynamic sectional models of two deck cross-sections in wind tunnel. The gain in regularity of responses on approaching the flutter critical wind speed, demonstrated with time history of responses and recurrence quantification plots, has been quantified using sample entropy. Based on the sensitivity of the sample entropy values on the embedding dimension, it has been suggested to adopt embedding dimension in the range of 2 and 5, to obtain a swift estimate of the state of the dynamic system. The proposed approach has shown potential to provide valuable insight about the flutter instability and distinguish between different types of flutter without requiring prior knowledge about the system under consideration. The study offers a promising complementary methodology to the conventional model-based approaches for evaluating flutter critical wind speed.

The Influence of Aeroelastic Effects on Wind Load and Wind-Induced Response of a Super-Tall Building: An Experimental Study

To investigate the wind-induced response and equivalent wind load of a super-tall building, an aeroelastic model of the building was designed to measure aerodynamic interference in wind tunnel tests. Experiments on pressure and vibration measurements were conducted in both uniform and turbulent wind fields, and the displacement response and surface wind pressure at different locations of the model were recorded. The displacement time-history response spectrum and aerodynamic spectrum in both fields were compared and analyzed. The research showed that the mean displacement responses of the model in the across-wind and along-wind directions gradually increased with velocity under different wind attack angles. The mean displacement response of torsion moment in a uniform wind field changed very little, and the mean and fluctuating wind pressures in each layer were significantly stratified, making it is easy to generate a coupled vortex-induced resonance. On the other hand, the mean displacement response of torsion moment in a turbulent field increased with wind velocity. Strong turbulence made the fluctuating wind pressure at the top and bottom of the model slightly more significant than in a uniform field. The resistance of super-tall buildings came from turbulence excitation in the along-wind direction and the self-excited resistance generated by the across-wind direction. The test methods and main research conclusions may provide a reference for glass curtain walls and the structural wind-resistant design of super-tall buildings.

Construction of a reduced-order model based on tensor decomposition and its application to airbag deployment simulations

We present a construction method for reduced-order models (ROMs) to explore alternatives to numerical simulations. The proposed method can efficiently construct ROMs for non-linear problems with contact and impact behaviors by using tensor decomposition for factorizing multidimensional data and Akima-spline interpolation without tuning any parameters. First, we construct learning tensor data of nodal displacements or accelerations using finite element analysis with some representative parameter sets. Second, the data are decomposed into a set of mode matrices and one small core tensor using Tucker decomposition. Third, Akima-spline interpolation is applied to the mode matrices to predict values within the data range. Finally, the time history responses with new parameter sets are generated by multiplying the expanded mode matrices and small core tensor. The performance of the proposed method is studied by constructing ROMs for airbag impact simulations based on limited learning data. The proposed ROMs can accurately predict airbag deployment behavior even for new parameter sets using the Akima-spline interpolation scheme. Furthermore, an extremely high data compression ratio (more than 1000) and efficient predictions of the response surfaces and Pareto frontier (2000 times faster than that of full finite element analyses using all parameter sets) can be realized.

Damage Identification of Simply Supported Bridges Using Static Responses: Unified Framework and Feasibility Study

Simply supported bridges are the main bridge types in many transportation systems, and their damage can significantly reduce their load-carrying capacity. To detect possible damage, the time history and spatial distribution of the static responses of bridges (deflection, rotation, and strain influence lines/deformation curves) have recently been proposed as important indicators due to their good local damage detection ability and low testing cost. This paper attempts to establish connections between different static curve-based damage indicators through the various forms of Maxwell-Betti’s law. Damage indicators related to seven static curves are then rewritten as a unified framework. The framework states that all these static curves are directly related to the flexural stiffness distribution of the main girder for the simply supported bridge. Then, the theoretical formulations for the difference between the static curves of bridges in intact and damaged states are derived, and the response difference surfaces (RDSs) are plotted to visualize the sensitivity of different static curves to damage. Sensor placement suggestions for stiffness degradation evaluation are presented based on the damage sensitivity analysis at the end of this paper. The results of this study provide comprehensive theoretical support for static response-based damage identification of simply supported bridges.

EVALUASI KINERJA STRUKTUR BANGUNAN GEDUNG TAHAN GEMPA DENGAN METODE ANALISIS RESPONS SPEKTRUM DAN TIME HISTORY

The city of Bandung is one of the cities that is prone to earthquakes because it is passed by the Lembang fault. Therefore, buildings in the city of Bandung should have implemented the concept of earthquake-resistant buildings in their construction. To avoid the occurrence of damage or collapse of the structure of the building against an earthquake, it is necessary to analyze the building against the earthquake. This study aims to determine how many deviations occur in the building due to the earthquake and the performance of the building structure. The method used is the response spectrum and time history analysis method and then evaluates the performance of the structure against earthquakes using the ATC-40 standard. The building that is the case study is the Directorate of Drugs and the Directorate of Intelligence and Security for the West Java Police, which consists of 5 floors. Structural modeling and analysis were performed using ETABS v20. Earthquake records used are Imperial Valley, Kobe and Trinidad earthquakes. Based on the results of the analysis of the maximum deviation with the response spectrum method 26.74 mm in the X direction and 26.46 mm in the Y direction. Meanwhile, for the time history analysis, it was obtained 33.05 mm in the X direction and 28.96 in the Y direction. The maximum value of the total deviation obtained 0.0016 m and the maximum value of inelastic deviation obtained 0.0014 m so that it shows the level of performance of this building structure based on ATC-40 is Immediate Occupancy (IO), which means the structure is in a safe condition.Keywords : ATC-40, earthquake resistant buildings, spectrum response, time history,

Seismic damage characteristics of high arch dams under oblique incidence of SV waves

This study investigates the seismic damage characteristics of high arch dams considering the oblique incidence of seismic waves. Based on the dynamic implicit finite element method, a viscous-spring artificial boundary is applied to consider radiation damping of the infinite foundation, the seismic wave input is converted into an equivalent nodal force of the artificial boundary, and the equivalent nodal loads of the wave input under oblique incidence of the SV wave is deduced. Taking JP Ⅰ arch dam as an example, combined with the concrete damaged plasticity (CDP) model, the nonlinear dynamic response of the dam under 25° oblique incidence of the SV wave is conducted considering the geometrical nonlinearity of contraction joints and the dynamic mechanical properties of concrete materials. Based on the incremental dynamic analysis (IDA) method, the relative displacement and transverse joint opening are selected as the damage measures for fragility analysis of the arch dam. According to the damage distribution from the analysis of a large number of seismic time-history responses, the damage levels of the arch dam are classified. Three limit states of slight damage, moderate damage and severe damage are proposed for the arch dam. The average responses of the 10 earthquakes are considered as the limit values to quantitatively describe the damage of the arch dam. By fitting the results of incremental dynamic analysis, the seismic probabilistic demand model and seismic fragility curves for the two damage measures to predict the probability of the arch dam reaching damage levels under different seismic actions have been established. The fragility curve shows that the probability of severe damage is almost zero under the maximum design earthquake (PGA = 0.1971 g) and less than 5% under the maximum credible earthquake (PGA = 0.2299 g). It is concluded that JP Ⅰ arch dam has a high degree of safety redundancy and fully satisfies the “two levels” design requirements.