Dynamic Time History Analysis Research Articles

A Novel Approach to Linear and Nonlinear Time-History Analysis of Structures: Gauss–Lobatto–Hermite 4-Point (GLH-4P) Method

An efficient time integration scheme has been devised for conducting time-history dynamic analysis of single-degree-of-freedom (SDOF) structural systems. The developed scheme belongs to Runge-Kuta family. The primary innovation of the new formulation lies in the constructive cooperation between the Hermite interpolation and the Gauss–Lobatto integration, linked to address the second-order ordinary differential equation of motion (DEOM). To put the idea into practice, several Hermite interpolators are generated to exploit the information of the internal points of Gauss-Lobatto integrator. The 4-point Gauss–Lobatto formula is employed to numerically integrate acceleration and velocity functions. This novel methodology has been designated the Gauss–Lobatto–Hermite 4-point (GLH-4P) method. GLH-4P furnishes a generally applicable implicit algorithm for conducting both linear and nonlinear analyses of structures subjected to seismic excitation. The advantage of the proposed algorithm over the conventional techniques is its higher accuracy level. Besides, it offers better stability compared with the conventional methods such as the Newmark-β and Wilson-θ methods. Unlike the other methods, GLH-4P can handle high-frequency systems without reducing the step size. Numerical examples reveal the efficacy of the GLH-4P method when juxtaposed against existing methodologies.

Assessment on detailed regional seismic damage risk of buildings based on time-history dynamic analyses

Assessment on detailed regional seismic damage risk of buildings based on time-history dynamic analyses

Fragility Analysis and Resilience Assessment of the Single-Column Pier Steel-Concrete Composite Bridge Subjected to Seismic Loads

Abstract With the advantages of a small footprint, wide under-bridge view, and beautiful appearance, single-column pier bridges are widely used in urban bridge networks. However, single-column pier bridges are prone to damage during earthquakes or heavy vehicle use, which can seriously affect normal operations and postdisaster recoveries. Therefore, there is an urgent need to carry out seismic resilience assessments of single-column pier bridges and formulate disaster prevention and mitigation measures from the aspects of design, maintenance, and postearthquake recovery. This paper first establishes a resilience assessment framework for the single-column pier bridge and optimizes a functionality recovery model after an earthquake. Then, a numerical model of a sample bridge is built for resilience fragility analysis. Nonlinear dynamic time history analysis is performed to build a probabilistic seismic demand model, and moment–curvature analysis is performed to build a probabilistic seismic capacity model. Finally, a seismic resilience assessment of the single-column pier bridge is obtained based on the seismic fragility, and a sensitivity analysis is carried out for the pier height, pier section dimension, span and vehicle load level to improve the resilience of the single-column pier bridge.

Effects of Inclination of Longitudinal and Vertical Acceleration Components of Near-Field Earthquake Records on Seismic Responses of Pile Foundation-Superstructure Systems in Liquefiable Soil Bed

The inclination angle of such components with respect to the principal orthogonal axes cannot be neglected in the direct seismic analysis of soil-foundation-superstructure systems, specifically in a piled liquefiable soil bed. This study validated numerical simulations and numerically modeled a concrete moment frame on a pile foundation within a liquefiable soil bed. The direct seismic analysis of the superstructure-foundation-soil system was carried out in a single step (through nonlinear dynamic time-history analysis) under longitudinal and vertical near-field seismic acceleration component records. The effects of the inclination of longitudinal and vertical acceleration components on the seismic responses of the soil-foundation-superstructure system in the liquefiable soil bed were explored, evaluating the critical inclination based on the near-field earthquake magnitude. It was observed that the simultaneous application of longitudinal and vertical near-field seismic acceleration components substantially changed the liquefiable soil bed drift of the pile foundation-superstructure system, significantly altering [Formula: see text] in depth, particularly in the middle of the pile depth. The change in [Formula: see text] and its effects on the seismic responses of the superstructure and piles (interstory drift and pile shear force and bending moment) were different upon a 30° change (rotation) in the acceleration records from 0 to 90° with respect to the orthogonal principal axes.

Numerical study on optimized application of engineered cementitious composites in RC coupled shear wall structures

Due to the superior tensile strain-hardening and multi-cracking properties, engineered cementitious composites (ECC) can be adopted in reinforced concrete (RC) shear walls and coupling beams to improve the seismic performance and damage tolerance with simplified reinforcement details. This study numerically investigates the optimized application of ECC in coupled RC shear wall structures based on refined two-dimensional finite element models incorporating constitutive models of ECC and concrete for nonlinear shear behaviors. The balance between cost and performance is adequately considered from the material, member, and structural levels. At the material level, the reasonable tensile properties of ECC are suggested based on the parametric analysis of coupling beam and shear wall specimens. At the member level, the effect of diagonal bar ratios on the seismic performance of coupled walls is investigated to propose reasonable diagonal bar ratio of ECC coupling beams. Finally, at the structural level, nonlinear dynamic time-history analysis of a typical 11-story coupled wall structure based on practical engineering is conducted to investigate the influence of the application ranges of ECC on the seismic performance of the wall system. The damage indexes, including story curvature and crack width, are analyzed and compared. Based on the analytical results, recommendations related to some key issues on the application of ECC in traditional RC structures are provided, including the application range and tensile properties of ECC, as well as the reinforcement details.

Research on seismic response and dynamic lateral pressure of the silo model under dynamic interaction between granular materials and the silo wall

AbstractThe purpose is to study seismic response and dynamic lateral pressure of the silo wall with different storage conditions under the earthquake. FEM was used to conduct dynamic time history analysis of the silo. The seismic response of the empty silo was smaller than that of the filled silos, and for the latter, under seismic action, the bulk sand particles and the silo wall had a more complex dynamic interaction, and nodes displacements on the wall and columns mainly fluctuated rising. For the deformation of the bulk sand, it was similar to a parabolic pattern in section, the closer to the silo center the greater the deformation was, and the farther away from the silo center the smaller the deformation was. The maximum acceleration was near the top of the wall in the empty silo, near the middle of the wall in contact with bulk sand in the filled silos. Nodes maximum overpressure coefficient was 1.6 and 2.9 in half fully and fully filled silos, respectively, but the coefficient 2.9 was greater than the standardized value of 2.0, therefore, the suggested overpressure coefficient was proposed. Meanwhile, Mises stress was investigated, and it was smaller in the empty silo, but larger in the filled silos, particularly in and around the ring beam due to the dynamic interaction between the sand and the silo wall, where the stiffness had a sudden change, and the maximum stress at the ring beam increased gradually with the seismic action.

Study on the Influence and Optimization Design of Viscous Damper Parameters on the Damping Efficiency of Frame Shear Wall Structure

This study investigates the influence of viscous damper parameters on the damping efficiency of frame shear wall structures. Taking a specific frame shear wall structure as the background, a three-dimensional finite element model is established using a nonlinear dynamic time–history analysis method. The damping ratio, reduction in vertex displacement, reduction in base shear, and inter-story drift utilization rate are selected as the damping performance indicators. Firstly, a sensitivity analysis is conducted to study the influence of different viscous damper parameters on these indicators. Then, the relationship models between the viscous damper parameters and the indicators are fitted using the response surface method, and the fitting effect is evaluated through an F-test and determination coefficient R2. Finally, an objective function based on key damping performance indicators is established to solve for the optimal parameters. The results show that the traditional sensitivity analysis method is unable to comprehensively consider the combined effects of different damping efficiency indicators. The response surface method has high fitting accuracy and good predictability and can serve as an optimization model. Considering the stiffness of supporting components matched with the viscous damper parameters, the feasibility of the optimal damping parameters is demonstrated from an engineering application perspective. A simple and easy-to-operate damping design flowchart is proposed, providing important guidance and reference for designers in frame shear wall structure damping design in the future.

Wind-Induced Response Analysis of the Transmission Tower-Line System Considering the Joint Effect

Wind load is one of the main control loads of transmission tower-line systems. Numerical simulation is the main method for studying the structural wind-induced response. The establishment of a refined transmission tower simulation model is the basis for accurately analyzing the dynamic response of a transmission tower-line system under a wind load. This paper first considered the mechanical properties of bolted joints under cyclic loading and established a transmission tower-line system model considering the joint effects. Then, the wind load was generated by the harmonic superposition method, and the wind dynamic time-history analysis of the tower-line system was conducted. The influence of the joint effect on the wind-induced response of the transmission tower-line system was studied, and the effects of turbulence intensity and wind attack angle on the bolted joint slip effect were discussed. The results showed that the joint effect significantly increased the displacement response of the transmission tower subjected to wind loads and affected the normal service performance of the tower-line system. When the turbulence intensity is 10%, the top displacement of the tower model considering the joint effect is approximately 2 times that of the ideal rigid frame model. After considering the joint effect, the additional [Formula: see text] effect caused by the increased displacement resulted in an increase in the stress of 75.6% members, and the maximum stress of the main member was located near the upper diaphragm of the tower leg. Therefore, considering the joint slip effect in angle steel transmission towers can improve the accuracy of the dynamic response analysis of transmission lines.

Comparative Analysis of Structural Reinforcement with Viscoelastic Energy Dissipators, Friction and Metal Creep in Tall Buildings

Seismic risk is a challenging problem in tall buildings due to the possibility of loss of human life and economic caused by seismic events. Peru is located at the interaction of the South American plate and the Nazca plate, which is why various seismic events of moderate to large magnitude occur. Today there are many ways to solve these problems and it is a very challenging case to reinforce tall buildings. In addition, technological advances in software facilitate and help through programmed models in tall buildings that analyze their structure characteristics such as drift, shear and others. This article proposes a comparative analysis of three types of dissipators: viscous fluid, friction, and metal creep through a Time-History analysis in a 15-story high-rise building located in Peru. The proposed methodology considers three stages: (i) definition of the characteristics and properties of the structure in accordance with Peruvian Standard E.030, in addition three accelerograms are used for the dynamic time-history analysis and maximum displacements and drifts are determined by ETABS software. (ii) calculate the design drift of the tall building and the properties of the viscous fluid, friction, and creep dissipator. In addition, calculations are made for the design parameters of each dissipator, and it is modeled as required for the case study. (iii) the new drifts and the damping values that the building presents for each dissipator are analyzed. According to the results obtained, the dissipator with the best results is of the flow type, since it has better performance in drifts and manages to produce an average damping of 96.87% for tall buildings. While the viscous dissipators obtain a 57.85% damping and the friction ones are estimated at 81.57%.

Shaking-Table Test and Finite Element Simulation of a Novel Friction Energy-Dissipating Braced Frame

To enhance the effect of seismic mitigation in medium-sized buildings, this study introduced a novel friction damper within a braced frame, forming a friction energy-dissipating braced frame (FDBF). The seismic reduction mechanism of the FDBF was examined, and its performance was evaluated through shaking-table tests and finite element simulations. The hysteresis performance of the novel damper was assessed through low-cycle repeated loading tests, which yielded predominantly rectangular and full hysteresis curves, exemplifying robust energy dissipation capacity. The shaking-table tests of the FDBF indicated significant modifications in the dynamic characteristics of the original frame structure, which notably reduced the natural vibration period and enhanced the damping. Additionally, the FDBF remarkably reduced both acceleration and displacement responses during seismic excitation. Optimizing the orientation of the energy dissipation brace significantly improved seismic reduction efficiency. A dynamic time history analysis, employing finite element software, was conducted on the FDBF equipped with a friction energy dissipation brace at each level. Comparative analysis with both the moment-resistant frame and ordinary braced frame revealed that the FDBF substantially lowered the peak acceleration at the apex of the structure, achieving a reduction rate of 40–50%. Under both design and rare earthquake conditions, the FDBF demonstrated superior seismic mitigation capabilities, especially under rare earthquakes. Future studies should investigate various structural types with energy dissipation braces at different levels to identify the most efficient layout for the novel friction energy dissipation brace, thereby guiding relevant engineering practices.

Seismic behavior of steel frames with H-shaped damper

This paper investigates the effect of dampers on the seismic performance of steel frames with unequal depth beam-column (UDBC) joints. First of all, the finite element (FE) models of the UDBC joint and steel frame were regenerated by ABAQUS and verified by experimental results. Secondly, the design method for three H-shaped dampers with different web perforation forms (vertical, elliptical, and diamond) was provided. Finally, five steel frames were built using ABAQUS, and pushover analysis and dynamic time-history analysis were performed on them. The results indicated that dampers could decrease the maximum vertex displacement and inter-story shift angle of steel frames with UDBC joints under three seismic waves by 4.47% to 17.17% and 7.71% to 23.88%. The effect of H-shaped dampers was similar to that of T-shaped connectors. Under the action of the Kobe wave and the Qian'an wave, the H-shaped damper exhibited more excellent seismic performance. Compared with frames with T-shaped connectors, the maximum vertex displacement and the maximum inter-story shift angle of frames with H-shaped dampers decreased by 3.44% to 12.39% and 9.55% to 16.15%. The web perforation form of H-shaped dampers somewhat affected the seismic behavior of steel frame structures. Among them, diamond dampers could minimize structural deformation.

Effect of Ground Motion Time–Frequency Non-Stationarity on Seismic Response of High-Speed Railway Simply Supported Bridge Based on Wavelet Packet Transform

Time–frequency non-stationarity is a ground motion characteristic which is frequently neglected in current seismic design and research. This paper studies its impact on the seismic response of high-speed railway simply supported bridge (HSRSSB). A method for generating time–frequency stationary earthquakes (TFSEs) and time–frequency non-stationary earthquakes (TFNSEs) using wavelet packet transform is proposed. A finite element model of a three-span HSRSSB is established using OpenSees. The seismic response is obtained through non-linear dynamic time history analysis, and the fragility curves of bridge components and system are calculated through incremental dynamic analysis. Finally, the reasons for the differences are analyzed by comparing the differences in seismic response of bridge, component fragility and system fragility under two groups of ground motion. The results show that the time–frequency non-stationarity of ground motion has an effect on the bridge response and fragility under strong earthquakes. TFNSE will lead to larger ground motion response, and the damage probability of bridge components and systems is higher. The reason is related to the damage and period extension of bridges under ground motion. Structures with prolonged period anti-seismic measures need to pay attention to this effect.

Effects of important characteristics of earthquake ground motions on probabilistic seismic demand assessment of long-span cable-stayed bridges

The uncertainties of earthquake ground motions have the most important effects on seismic responses of bridge structures, especially long-span bridges, because of complex and special dynamic properties. The nonlinear dynamic time-history analysis is conducted for a two-pylon long-span cable-stayed highway bridge by using real earthquake ground motions rationally selected. The correlation between the important characteristics of earthquake ground motions and the probabilistic seismic demand assessment of the cable-stayed bridge reveals that the geometric means and dispersions of response spectra from selected ground motions have very significant effects on mean values, dispersions and probabilistic distributions of seismic demands of long-span bridges. The spectral shape of geometric mean spectra in the period ranges with large cumulative modal mass participation factors that should be well matched to the target spectrum to improve the precision and computational efficiency of probabilistic seismic demand assessment. If earthquake ground motions are rationally selected, response spectral values at the periods with comparatively large modal participation mass ratios or PGA can be used as intensity measures and even provide more precise probabilistic seismic demand assessment than response spectral values at the fundamental periods.

Seismic Performance Assessment of Composite Frame–High-Strength Steel Plate Wall Core Tube Resilient Structural System

Against the backdrop of China’s continuous promotion of green and low-carbon transformation and the development of construction industrialization, high-strength composite structural systems have significant development prospects. However, their research and application in the field of construction are insufficient. In response to this issue, the study proposes a new high-performance structural system, namely the composite frame–high-strength steel plate wall core tube resilient structural system, which includes a core tube composed of double steel plate concrete composite shear walls and replaceable energy dissipation coupling beams, as well as composite frames. The highest strength grades of the steel plate and concrete used in the composite walls of the core tube are Q550 and C100, respectively. Using a 200 m building as an example, this study designs and establishes models for this high-performance structure and a conventional reinforced concrete frame–core tube structure. Subsequently, the dynamic elastoplastic time history analysis and seismic resilience assessment of structures are conducted under design basis earthquakes (DBEs), maximum considered earthquakes (MCEs), and extremely rare earthquakes (EREs). Research has shown that, compared to conventional structures, the thickness of shear walls of new high-performance structures can be effectively reduced, which helps decrease the self-weight of the structure and improve the available space in buildings. Additionally, high-performance structures exhibit a better performance in controlling the story drift ratio, lower plastic damage and overall stiffness degradation of the structure, and better seismic performance. The seismic resilience of the high-performance structure has been significantly enhanced, especially in terms of minimizing casualties, thereby better ensuring the safety of people’s lives and property.

Seismic Response Analysis of Rectangular Reinforced Concrete Tank Constructed on Loess Soil

Introduction: Liquid storage tanks are an essential container structure widely used in various industries. In earthquake disasters, liquid storage tanks cause not only direct disasters but also induce secondary severe disasters, such as fires, explosions, nuclear leaks, and human and animal poisoning. The latest research on seismic analysis of structures showed that soils with different stiffness can affect the seismic response characteristics of surface structures, and various irregular topographies can also alter the degree of seismic-induced damage to surface structures. Studying the seismic response of liquid storage tanks can mitigate the risk of earthquake damage to these vital structures. Methods: This study used finite element simulations. Three sizes of liquid storage tanks with different aspect ratios were selected, including the squat, square, and slender tanks. Three conditions were considered for the tanks' liquid: empty, half-filled, and fully filled. Two types of topographies were considered, including flat and step-like slope topography with an inclination angle of 116.6°. Nine natural earthquake records were used for seismic analysis and divided into three categories: high-frequency, medium-frequency, and low-frequency. Established finite element models were validated through comparison with the results of other studies. The dynamic time history analysis was carried out for each finite element model. The tank's base shear forces, the normal stress in the tank wall, the shear stress in the tank bottom, and the maximum displacement of the tank wall were measured and compared. Results: The step-like slope topography and loess soil significantly amplified the seismic response of the liquid storage tank. Moreover, as the liquid height and the tanks’ aspect ratio increased, the seismic damage intensity also increased. The seismic response of the liquid storage tank was generally more sensitive to low-frequency and medium-frequency seismic records. The Eurocode 8’s equation underestimated tanks’ base shear when located on a step-like slope topography. Conclusion: The obtained results demonstrated the significant effect of irregular topography and loess soil on the seismic response of liquid storage tanks. Therefore, it was concluded that they should be considered when liquid storage tanks are designed for seismic actions.

Design and commissioning of novel test apparatus for underground structures and its application in seismic damage testing of prefabricated subway station

AbstractThis paper presents the design and commissioning of a novel pseudo‐static test apparatus for underground structures that accounts for soil‐structure interaction by simulating the soil with suitably designed springs. The developed apparatus was employed to conduct 1:10 large scale tests on a two‐story three‐span prefabricated subway station structure. Two comparative cyclic load tests were conducted: one involved the developed springs‐structure system; and one involved the structure alone (no springs). The test results demonstrated important differences in the damage location, damage degree, bearing capacity, and deformation capacity of the prefabricated subway station structure under the two loading conditions (i.e., with and without springs). The presence of springs (i.e., soil‐structure interaction) enhanced the lateral collapse resistance of the underground structure and affected the inter‐story displacement ratio (IDR) between the upper and lower layers of the two‐story prefabricated subway station structure. However, it did not affect the deformation coordination of the walls and columns of each layer. A finite element model of the prototype station was also established to conduct dynamic time history analysis simulating the soil‐structure interaction. The results from the dynamic analysis validated the effectiveness of the pseudo‐static test method employing the spring‐structure system. The excellent agreement between the calculated dynamic responses and the responses obtained from the pseudo static tests confirmed the ability of the developed apparatus to conduct seismic tests on complex large‐scale underground structures such as prefabricated subway stations. Thus, this test methodology might be utilized to attain valuable insights into the seismic performance of prefabricated subway stations at a relatively low cost and effort.

Seismic performance and vulnerability analysis for bifurcated tunnels in soft soil

This paper investigates the seismic performance of complex comprehensive interchange underground structures. As an example, the seismic performance of Nanjing underground bifurcated tunnels constructed in soft soil is analyzed. A three-dimensional (3D) numerical finite element analysis model is established considering soil-tunnel interaction to analyze the seismic response characteristics and failure mechanism of the bifurcated tunnels. The results show that the tunnel damage degree is closely associated with the deformation response, and that the inter-story drift ratio of the lower layer is significantly greater than that of the upper layer. The pushover analysis method is used to obtain the seismic performance curve of the tunnel, and inter-story drift ratio limits are defined. The IDA procedure is then used to conduct multiple non-linear dynamic time history analyses based on the 3D finite element model, and IDA curve clusters are drawn with peak ground acceleration (PGA) as the earthquake intensity measures and the peak inter-story drift ratio as the damage measures of tunnels. The corresponding IDA percentiles lines are calculated, and the seismic fragility curves of the bifurcated tunnels are established. The post-earthquake functional failure probability of the bifurcated tunnels is obtained under different seismic fortification performance level.

Interference effects on the wind loads and wind-induced responses of parallel-arranged rectangular-planed air-supported membrane structures

In many practical projects, two air-supported membrane structures are parallel-arranged. The interference effects of parallel-arranged rectangular-planed air-supported membrane structures are important in the wind-resistant design. In order to address this issue, the wind pressures on isolated and parallel-arranged structures are obtained through pressure measurement wind tunnel tests. The wind-induced responses are calculated via nonlinear dynamic time–history analysis. Consequently, the interference effects on wind loads and wind-induced responses are analyzed. The results show that the wind suctions of downstream structures are amplified by the interferences of parallel-arranged structures particularly under oblique wind directions. The mean wind loads on the most disturbed zone are amplified up to about 65 %. The interference characteristics of wind-induced displacement are basically similar to mean wind loads. The membrane stresses and cable forces are significantly interfered only in oblique wind directions, which are amplified up to about 15 % in all zones of downstream structures. The strongest interference effects can be observed with a spacing-span ratio of 0.2 when the wind direction is oblique or parallel to the gap between neighboring structures. The interference factors for zones are provided to analyze the interference characteristics. In addition, recommendation values of the overall response interference factors are summarized for design reference. The overall response interference factors for displacement, membrane stress, and cable force should be considered as 1.21, 1.33, and 1.20, respectively.

Strengthening of an existing RC building with superelastic SMAs

Retrofit of deteriorated Reinforced Concrete (RC) structures has been widely investigated to enhance their performance and avoid the environmental impact due to demolishing and reconstruction. As conventional design concept is oriented to a predictable, ductile behavior allowing for significant inelastic deformation, implying extensive damage of structural members and leading to costly repairs after serious earthquake incidents, smart materials occupied with an inherent re-centering ability have been investigated for retrofit applications to reduce structural damage, constituting potential candidates for innovative interventions that can improve the structural resilience under seismic actions. In this work, a RC building situated in Athens, Greece is used as a case study to evaluate the potential of Shape Memory Alloys (SMAs) in structural retrofit, exploiting their property to reset inelastic deformations by unloading exhibiting the superelastic effect. Different types of SMAs are investigated to assess the effectiveness of the proposed retrofit scheme as an alternative solution to conventional steel performing pushover and non-linear dynamic time history analysis with SeismoStruct software. Results show maximum and residual displacement reduction and provide useful information on the application of SMAs as a damage-control and cost-efficient scheme in structural retrofit with the view to deal with the issue of significant residual deformation after earthquake action.

Comparative analysis of seismic performance enhancement in irregular RC buildings using friction and viscous dampers

The purpose of this study is to demonstrate the impacts of friction dampers (FD) or fluid viscous dampers (FVD) in irregular (in plan and elevation) reinforced concrete (RC) buildings. The buildings (a four-story, a nine-story, and a twenty-story skyscraper) were analyzed using nonlinear dynamic time-history analysis on earthquake-recorded accelerograms, three of which were real while the other four were artificial. For this purpose, 70 nonlinear dynamic analyses were carried out. This paper describes the optimal design of FDs and FVDs, with a focus on minimizing the following parameters: (i) maximum displacement (top of the structures), (ii) building torsion, and (iii) maximum horizontal inter-story drift. Two different placements of the dampers have been studied in each building. The consequences of each strengthening method are shown, and other relevant results were obtained from this creative comparison (optimal design, two passive energy systems, and three different story numbers). The comparable results show that in low-rise structures, FD was more successful than FVD in reducing torsional moment; however, in medium and high-rise buildings, VDF was more effective at improving the seismic performance of the structures.