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1
Sayginer, O., R. di Filippo, A. Lecoq, A. Marino e O. S. Bursi. "Seismic Vulnerability Analysis of a Coupled Tank-Piping System by Means of Hybrid Simulation and Acoustic Emission". Experimental Techniques 44, n. 6 (1 settembre 2020): 807–19. http://dx.doi.org/10.1007/s40799-020-00396-3.
Testo completoAbstract (sommario):
AbstractIn order to shed light on the seismic response of complex industrial plants, advanced finite element models should take into account both multicomponents and relevant coupling effects. These models are usually computationally expensive and rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, which requires a solid background of experimental data. Vulnerability and reliability analyses both depend on the adoption of a significant number of seismic waveforms that are generally not available when seismic risk evaluation is strictly site-specific. In addition, detection of most vulnerable components, i.e., pipe bends and welding points, is an important step to prevent leakage events. In order to handle these issues, a methodology based on a stochastic seismic ground motion model, hybrid simulation and acoustic emission is presented in this paper. The seismic model is able to generate synthetic ground motions coherent with site-specific analysis. In greater detail, the system is composed of a steel slender tank, i.e., the numerical substructure, and a piping network connected through a bolted flange joint, i.e., the physical substructure. Moreover, to monitor the seismic performance of the pipeline and harness the use of sensor technology, acoustic emission sensors are placed through the pipeline. Thus, real-time acoustic emission signals of the system under study are acquired using acoustic emission sensors. Moreover, in addition to seismic events, also a severe monotonic loading is exerted on the physical substructure. As a result, deformation levels of each critical component were investigated; and the processing of acoustic emission signals provided a more in-depth view of the damage of the analysed components.
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Havlíček, Peter, e Július Šoltész. "Applicability of Commercial Software for Bridge Design with Consideration of Seismic Loading Effects". Solid State Phenomena 272 (febbraio 2018): 313–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.313.
Testo completoAbstract (sommario):
The construction of bridges with use of seismic isolation is a less-used concept in Slovakia and the Czech Republic. The concept of seismic isolation of bridges is a way of protecting bridge construction without damaging the pillars and substructure unlike the currently used methodology of consideration and development of plastic joints. When using this concept correctly, it is possible to prevent serious damage of construction and greatly reduce economic losses. Creation of a FEM (Fine Element Method) model, that is capable of correct description of the bridge behavior during a seismic event is often problematic. In this paper, the features of designing and modeling of bridge constructions with use of seismic insulation based on elastomeric bearings are presented. Furthermore, the calculations of stiffness constants required for numerical modeling are presented as well. In this paper are described methods of modeling of seismic isolations in a commonly and commercially available FEM based software. The work also contains a comparison of possibilities as well as limits of these programs. We further present recommendations for correct modeling by use of nonlinear material properties or elastic bonds between elements.
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Casolo, Siro, Siegfried Neumair, Maria A. Parisi e Vincenzo Petrini. "Analysis of Seismic Damage Patterns in Old Masonry Church Facades". Earthquake Spectra 16, n. 4 (novembre 2000): 757–73. http://dx.doi.org/10.1193/1.1586138.
Testo completoAbstract (sommario):
The semi-empirical assessment of seismic vulnerability of ancient church buildings is possible only if sufficient knowledge of the expected seismic behavior is available for a wide variety of typologies. For this reason, the information inferred from seismic damage observation may need to be complemented by numerical analysis. A simplified material model is proposed here for predicting the damage from out-of-plane behavior of large walls in old masonry churches subjected to seismic loading. For a specific substructure, the church façade, the effects of geometry, strength and post-elastic behavior of the material, as well as excitation characteristics are then analyzed with reference to the formation of a collapse mechanism. Comparison with observed damage thoroughly confirms the crack patterns developed numerically. Thence, the material model proposed may be considered satisfactory and suitable for use in seismic vulnerability studies.
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Belostotsky, Alexander M., Pavel A. Akimov e Dmitry D. Dmitriev. "ABOUT METHODS OF SEISMIC ANALYSIS OF UNDERGROUND STRUCTURES". International Journal for Computational Civil and Structural Engineering 14, n. 3 (28 settembre 2018): 14–25. http://dx.doi.org/10.22337/2587-9618-2018-14-3-14-25.
Testo completoAbstract (sommario):
As is known, underground facilities are an integral part of the infrastructure of modern society. These objects have some specific characteristics such as complex construction, high cost, long life cycle, etc. Once it is destroyed, the direct and indirect losses are more seriousness than the general structure in the ground. Under-ground facilities built in areas subject to earthquake activity must withstand both seismic and static loading. Therefore, it is very important to carry on the seismic design of the underground structure in a safe and economi-cal way. The distinctive paper presents a summary of the current state of seismic analysis for underground struc-tures. Classification and brief overview of methods of seismic analysis of underground structures (force-based methods, displacement-based methods, numerical methods of seismic analysis of coupled system “soil – under-ground structure”) are presented, problems of soil-structure interaction are under consideration as well. So-called static finite element method with substructure technique for seismic analysis of underground structures is de-scribed.
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Jia, Hongxing, Shizhu Tian, Shuangjiang Li, Weiyi Wu e Xinjiang Cai. "Seismic application of multi-scale finite element model for hybrid simulation". International Journal of Structural Integrity 9, n. 4 (13 agosto 2018): 548–59. http://dx.doi.org/10.1108/ijsi-04-2017-0027.
Testo completoAbstract (sommario):
Purpose Hybrid simulation, which is a general technique for obtaining the seismic response of an entire structure, is an improvement of the traditional seismic test technique. In order to improve the analysis accuracy of the numerical substructure in hybrid simulation, the purpose of this paper is to propose an innovative hybrid simulation technique. The technique combines the multi-scale finite element (MFE) analysis method and hybrid simulation method with the objective of achieving the balance between the accuracy and efficiency for the numerical substructure simulation. Design/methodology/approach To achieve this goal, a hybrid simulation system is established based on the MTS servo control system to develop a hybrid analysis model using an MFE model. Moreover, in order to verify the efficiency of the technique, the hybrid simulation of a three-storey benchmark structure is conducted. In this simulation, a ductile column—represented by a half-scale scale specimen—is selected as the experimental element, meanwhile the rest of the frame is modelled as microscopic and macroscopic elements in the Abaqus software simultaneously. Finally, to demonstrate the stability and accuracy of the proposed technique, the seismic response of the target structure obtained via hybrid simulation using the MFE model is compared with that of the numerical simulation. Findings First, the use of the hybrid simulation with the MFE model yields results similar to those obtained by the fine finite element (FE) model using solid elements without adding excessive computing burden, thus advancing the application of the hybrid simulation in large complex structures. Moreover, the proposed hybrid simulation is found to be more versatile in structural seismic analysis than other techniques. Second, the hybrid simulation system developed in this paper can perform hybrid simulation with the MFE model as well as handle the integration and coupling of the experimental elements with the numerical substructure, which consists of the macro- and micro-level elements. Third, conducting the hybrid simulation by applying earthquake motion to simulate seismic structural behaviour is feasible by using Abaqus to model the numerical substructure and harmonise the boundary connections between three different scale elements. Research limitations/implications In terms of the implementation of the hybrid simulation with the MFE model, this work is helpful to advance the hybrid simulation method in the structural experiment field. Nevertheless, there is still a need to refine and enhance the current technique, especially when the hybrid simulation is used in real complex engineering structures, having numerous micro-level elements. A large number of these elements may render the relevant hybrid simulations unattainable because the time consumed in the numeral calculations can become excessive, making the testing of the loading system almost difficult to run smoothly. Practical implications The MFE model is implemented in hybrid simulation, enabling to overcome the problems related to the testing accuracy caused by the numerical substructure simplifications using only macro-level elements. Originality/value This paper is the first to recognise the advantage of the MFE analysis method in hybrid simulation and propose an innovative hybrid simulation technique, combining the MFE analysis method with hybrid simulation method to strike a delicate balance between the accuracy and efficiency of the numerical substructure simulation in hybrid simulation. With the help of the coordinated analysis of FEs at different scales, not only the accuracy and reliability of the overall seismic analysis of the structure is improved, but the computational cost can be restrained to ensure the efficiency of hybrid simulation.
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Chang, Guang Ming, Guo Hua Xing e Bo Quan Liu. "Equivalent Ductility Damage Model for Seismic Response of RC Structures: Test and Verification". Advanced Materials Research 163-167 (dicembre 2010): 1714–18. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1714.
Testo completoAbstract (sommario):
. It is possible to quantify the damage to reinforced concrete members under cyclic loading through a nondimensional parameter known as a “damage index”. The damage index can be either a global damage index for the total structure, or a local damage index for the element level. In this paper, a new damage model termed “equivalent ductility damage model” has been suggested for evaluation of the damage index, which is consistent with accepted definitions of ductility. Substructure method was applied to verify the suggested new damage model. A total of 3 identical half-scale reinforced concrete columns were tested under variable amplitude cyclic loading up to the ultimate failure of the specimens. The imposed displacement histories were obtained from analytical simulations of the model column subjected to a series of earthquakes. Test observations indicate that the proposed model predicts 100 percent damage at the ultimate failure state of the element. The proposed damage index model can be extended to other structural elements, such as shear walls, beams, beam-column junctions, etc.
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Skokandić, Dominik, Anđelko Vlašić, Marija Kušter Marić, Mladen Srbić e Ana Mandić Ivanković. "Seismic Assessment and Retrofitting of Existing Road Bridges: State of the Art Review". Materials 15, n. 7 (30 marzo 2022): 2523. http://dx.doi.org/10.3390/ma15072523.
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The load-carrying capacity assessment of existing road bridges, is a growing challenge for civil engineers worldwide due to the age and condition of these critical parts of the infrastructure network. The critical loading event for road bridges is the live load; however, in earthquake-prone areas bridges generally require an additional seismic evaluation and often retrofitting in order to meet more stringent design codes. This paper provides a review of state-of-the-art methods for the seismic assessment and retrofitting of existing road bridges which are not covered by current design codes (Eurocode). The implementation of these methods is presented through two case studies in Croatia. The first case study is an example of how seismic assessment and retrofitting proposals should be conducted during a regular inspection. On the other hand, the second case study bridge is an example of an urgent assessment and temporary retrofit after a catastrophic earthquake. Both bridges were built in the 1960s and are located on state highways; the first one is a reinforced concrete bridge constructed monolithically on V-shaped piers, while the second is an older composite girder bridge located in Sisak-Moslavina County. The bridge was severely damaged during recent earthquakes in the county, requiring urgent assessment and subsequent strengthening of the substructure to prevent its collapse.
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Madhuri, Seeram, SiteshSubhra Bera e Brajkishor Prasad. "Dynamic Analysis of Offshore Wind Turbine Supported by Jacket Substructure under Wind and Wave Loading". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, n. 1 (19 dicembre 2022): 1749–55. http://dx.doi.org/10.38208/acp.v1.714.
Testo completoAbstract (sommario):
Burning of fossil fuel for the production of energy causes severe global warming effects. Renewable energy sources like solar, wind and tidal etc. are the alternative renewable energy sources which contribute in the reduction of adverse global warming effects. Wind turbines are being used for extracting wind energy from several years. Wind blow is continuous with limited disturbance in the offshore region when compared with main land. Offshore wind energy extraction is in research stage at many locations and implemented in European countries. Prediction of response of wind turbine supporting systems is essential in the design to withstand the environmental loads such as wind, wave, current and seismic etc. In the present study, a horizontal axis offshore wind turbine (HAWT) supported on an offshore jacket structure is considered and the response studies are performed. The jacket is considered at a water depth of 51m, thus total height of the jacket is 61m with a free board of 10m. A wind turbine of 5MW capacity is considered to be on top of jacket structure. The height of the wind tower is assumed as 70m, and a transition structure of 4m height is positioned in between jacket and tower. A free vibration analysis is performed to estimate the natural frequencies and mode shapes of the jacket supported wind turbine. The modal analysis is carried out using ANSYS static structural module. The response analysis under wind, wave, current and aerodynamic drag loads is performed using SACS 13.2 software. Wind force is estimated based on API 2005 provisions. The aerodynamic forces on the wind turbine blades are evaluated using Betz Theory. Wave loading is calculated using Morison equation and linear Airy’s wave theory. A parametric study is carried out by varying wave period from 6s to 20s. As the structure is symmetric about longitudinal and lateral directions, a wave directional analysis is also carried by considering 0o and 45o wave directions. The structural responses are studied for the combined wind, wave and current loads. Cut-in, rated, cut-out and storm conditions are simulated by modelling wind and aerodynamic loads on the tower, wind interacting area of the jacket and blades. Wave period and direction are varied to simulate different wave conditions. It is observed that the structural response is increasing as the wind velocity is increasing and wave period is decreasing.
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YUAN, Yong, Hirokazu IEMURA, Akira IGARASHI, Tetsuhiko AOKI e Yoshihisa YAMAMOTO. "INVESTIGATION OF SEISMIC PERFORMANCE OF HIGH DAMPING RUBBER BEARINGS FOR ISOLATED BRIDGES USING REAL-TIME SUBSTRUCTURE HYBRID LOADING TEST METHOD". Doboku Gakkai Ronbunshuu A 63, n. 1 (2007): 265–76. http://dx.doi.org/10.2208/jsceja.63.265.
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Hughes, Jake Edmond, Yeesock Kim, Jo Woon Chong e Changwon Kim. "Particle Swarm Optimization for Active Structural Control of Highway Bridges Subjected to Impact Loading". Shock and Vibration 2018 (14 agosto 2018): 1–12. http://dx.doi.org/10.1155/2018/4932870.
Testo completoAbstract (sommario):
The application of active structural control technology to highway bridge structures subjected to high-impact loadings is investigated. The effects of high-impact loads on infrastructure, like heavy vehicle collisions with bridge piers, have not been studied as much as seismic load effects on structures. Due to this lack of research regarding impact loads and structural control, a focused study on the application of active control devices to infrastructure after impact events can provide valuable results and conclusions. This research applies active structural control to an idealized two-span, continuous girder, concrete highway bridge structure. The idealization of a highway bridge structure as a two degree-of-freedom structural system is used to investigate the effectiveness of control devices installed between the bridge pier and deck, the two degrees of freedom. The control devices are fixed to bracing between the bridge pier and girders and controlled by the proportional-integral-derivative (PID) control. The PID control gains are optimized by both the Ziegler–Nichols ultimate sensitivity method (USM) and a new method for this impact load application called particle swarm optimization (PSO). The controlled time-domain responses are compared to the uncontrolled responses, and the effectiveness of PID control, USM optimization, and PSO is compared for this control device configuration. The results of this investigation show PID control to be effective for minimizing both superstructure and substructure responses of highway bridges after high-impact loads. Deck response reductions of greater than 19% and 37% were seen for displacement and acceleration responses, respectively, regardless of the performance index used to analyze them. PSO was much more effective than USM optimization for tuning PID control gains.
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Skalomenos, Konstantinos A., Tadahisa Takeda, Masahiro Kurata e Masayoshi Nakashima. "On-Line Testing of Steel Brace Connections Using Non-Linear Substructuring and Force-Displacement Combined Control". Key Engineering Materials 763 (febbraio 2018): 510–17. http://dx.doi.org/10.4028/www.scientific.net/kem.763.510.
Testo completoAbstract (sommario):
The present paper suggests an on-line hybrid test environment for evaluating the seismic performance of steel bracing connections. The test method combines substructuring techniques and finite element analysis. The behavior of the brace member is simulated by the finite element analysis program ABAQUS, while the bracing end connections are physically tested. Two actuators are used to simulate the physical continuity between the analytical and experimental substructures by controlling axial load and out-of-plane rotation. A MATLAB user subroutine is created as the interface between the main control program and ABAQUS to impose the target rotation and axial force to the connection quasi-statically. A gusset plate connection designed to behave as a pin connection is tested and its efficiency to accommodate inelastic rotations up to a 4.0% story drift is evaluated. The test method is reasonable and smooth operation is achieved. The test system ensures pragmatic loading and boundary conditions to the brace connections, which are tested in full interaction with the brace member until failure. The maximum strength and rotation capacity of the connection can be clarified under actual cyclic inelastic rotations and varying axial loads derived from the inelastic behavior of the brace member.
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Wang, Jian, Ming Fang e Hui Li. "An Adaptive Model Order Reduction Method Based on the Damage Evolution for Nonlinear Seismic Analysis". Advances in Civil Engineering 2020 (16 settembre 2020): 1–15. http://dx.doi.org/10.1155/2020/8865255.
Testo completoAbstract (sommario):
Nonlinear seismic analysis, an approach to evaluate the seismic performance of a structure, is facing the challenge of computational efficiency for large-scale and high-fidelity simulation. This paper proposes an adaptive model order reduction (MOR) method based on the damage evolution among the overall structure to alleviate the computational burden. The damage state of each component during seismic loadings is distinguished as the initial-elastic phase, the plastic-damage phase, and the residual-elastic phase. In order to exploit the potential of model order reduction based on the damage evolution, a duration spectrum analysis is utilized to evaluate the characteristics of the residual-elastic phase for SDOF systems with bilinear hysteretic behaviour. Thus, an adaptive MOR method has been proposed to handle the nonlinear dynamic analysis of structures during different damage evolution phases. The overall structure is adaptively partitioned into linear substructures and nonlinear substructures on the basis of the time-varying damage distribution. The model order of linear substructures is reduced using the initial stiffness-based vibration modes, while nonlinear substructures that keep in the residual-elastic phase are reduced using the tangent-stiffness-based vibration modes. The residual displacements of nonlinear substructures are treated as the initial deformation during the residual-elastic phase. Compared with the traditional time step integration method, the proposed adaptive MOR method is able to increase the computational efficiency as yielding comparative results.
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Bard, Pierre-Yves. "Seismic loading". European Journal of Environmental and Civil Engineering 15, sup1 (gennaio 2011): 141–84. http://dx.doi.org/10.1080/19648189.2011.9695307.
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Jiang, Nan, Lanfang Luo e Chongxiang Zhang. "Seismic analysis method of equipment–high rise structure–nonlinear soil system". Advances in Mechanical Engineering 10, n. 10 (ottobre 2018): 168781401880733. http://dx.doi.org/10.1177/1687814018807337.
Testo completoAbstract (sommario):
Based on the principle of real-time substructure shaking table test, an interactive numerical computation method which built the calculation model of each substructure in different software programs was proposed for seismic analysis of equipment–high rise structure–soil systems in order to account the effect of nonlinear soil. Considering that the response of soil under strong earthquakes does not totally enter the nonlinear stage, a locally nonlinear soil model was introduced as the numerical substructure, and the equipment–high rise structure subsystem was treated as an experimental substructure in this method. The equation of motion for the equipment–high rise structure–soil system was derived through a combination of the branch modal substructure and linear–nonlinear hybrid constraint modal substructure approaches. A 13-layer steel framework system model is used as an analytical example that the equipment–high rise structure system and local nonlinear soil computing model are built by MATLAB and ANSYS, respectively. The time histories of the system dynamic responses were obtained by interactive numerical computation, to investigate the effects of equipment–high rise structure–soil interaction on the seismic performance of the equipment and structure.
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ISHIZAKI, Hiroshi, e Nobuhiko HAMADA. "Restoration and Seismic Retrofit of Highway Substructure". IABSE Congress Report 16, n. 7 (1 gennaio 2000): 1523–30. http://dx.doi.org/10.2749/222137900796314185.
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Chatzimarkou, Eirinaios, e Constantine Michailides. "A Comparative Study of Breaking Wave Loads on Cylindrical and Conical Substructures". Water 13, n. 7 (28 marzo 2021): 924. http://dx.doi.org/10.3390/w13070924.
Testo completoAbstract (sommario):
In the present paper, a comparative study of different cylindrical and conical substructures was performed under breaking wave loading with the open-source Computational Fluid Dynamics (CFD) package OpenFoam capable of the development of a numerical wave tank (NWT) with the use of Reynolds-Averaged Navier–Stokes (RANS) equations, the k-ω Shear Stress Transport (k-ω SST) turbulence model, and the volume of fluid (VOF) method. The validity of the NWT was verified with relevant experimental data. Then, through the application of the present numerical model, the distributions of dynamic pressure and velocity in the x-direction around the circumference of different cylindrical and conical substructures were examined. The results showed that the velocity and dynamic pressure distribution did not change significantly with the increase in the substructure’s diameter near the wave breaking height, although the incident wave conditions were similar. Another important aspect of the study was whether the hydrodynamic loading or the dynamic pressure distribution of a conical substructure would improve or deteriorate under the influence of breaking wave loading compared to a cylindrical one. It was concluded that the primary wave load in a conical substructure increased by 62.57% compared to the numerical results of a cylindrical substructure. In addition, the secondary load’s magnitude in the conical substructure was 3.39 times higher and the primary-to-secondary load ratio was double compared to a cylindrical substructure. These findings demonstrate that the conical substructure’s performance will deteriorate under breaking wave loading compared to a cylindrical one, and it is not recommended to use this type of substructure.
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Guo, Lina, Yong Ding e Yifei Zhang. "Seismic Damage Assessment for Isolated Buildings with a Substructure Method". Buildings 12, n. 8 (8 agosto 2022): 1185. http://dx.doi.org/10.3390/buildings12081185.
Testo completoAbstract (sommario):
A seismic damage detection method for isolated buildings is proposed based on substructure identification with incomplete contaminated measurements. A concept of a pseudo substructure with virtual conditions is constructed for the proof of the proposed substructure identification method. This identification method is implemented in a two-stage procedure. The interface forces of the target substructure are identified in the first stage and the parameter of the target substructure is updated in the second stage, which can enable the parameter identification of substructures with unknown input. Two computational methods are also proposed to improve the two-stage identification algorithm. A sub-time zone identification method is utilized to reduce the computation effort and the simultaneous identification of the unknown force and initial structural responses is presented in the first-stage identification for a general case in practical engineering. Numerical studies of a shear frame with nonlinear base isolation subject to earthquake ground motion are investigated to validate the proposed seismic damage detection method. A fourteen-storey concrete shear wall building with a two-storey steel frame on top connected by isolation is studied experimentally with shaking table tests to further validate the proposed method. The shear wall structure is taken as the target substructure for damage assessment. The interface force and parameter of the concrete shear wall building are estimated with the proposed method. Results from both the numerical simulations and laboratory tests indicate that the proposed method can estimate seismic isolated structures and detect damage effectively based on only a few accelerometers. It is also demonstrated that the parameter identification results based on the structure response measurement during the earthquake are more accurate than the identification with post-earthquake structural response measurement.
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Zhou, Li Jian, Bin Gao, Yuan Gang Fan e Xiang Ying Wang. "Feasibility of Substructure Pseudo Dynamic Test on the Tanks in Seismic Research". Applied Mechanics and Materials 405-408 (settembre 2013): 1063–66. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1063.
Testo completoAbstract (sommario):
Modern structures tend to be more and more complicated, setting up the complete calculation model and getting each part of the dynamic response is almost impossible and unnecessary. The substructure analysis technology is effective for the dynamic analysis of large and complex structure. The substructure theory has become increasingly mature and perfect, and has been widely used in structural analysis and calculation. This article simply introduces the principle of substructure pseudo dynamic test, and using the finite element software—ADINA simulates a steel frame.
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Bao, Xin, Jingbo Liu, Dongyang Wang, Shutao Li, Fei Wang e Xiaofeng Wang. "Modification Research of the Internal Substructure Method for Seismic Wave Input in Deep Underground Structure-Soil Systems". Shock and Vibration 2019 (19 agosto 2019): 1–13. http://dx.doi.org/10.1155/2019/5926410.
Testo completoAbstract (sommario):
A new internal substructure method for seismic wave input in soil-structure systems was recently proposed. This method simplifies the calculation of equivalent input seismic loads and avoids the participation of artificial boundaries in the process of seismic wave input. However, in previous research and applications, the internal substructures are usually intercepted down from the free surface, which forms large substructures and increases the computational effort for data management on the substructure nodes, especially for deep underground structures. In this study, the internal substructure method is modified by intercepting the internal substructures entirely beneath the free surface and adjacently around the underground structures. Then, the equivalent input seismic loads are obtained through the dynamic analysis of the internal substructures and applied to the corresponding positions of the total soil-structure models. Thus, the earthquake energy can be more efficiently input into the region near the underground structures without losing computational accuracy. We provide the detailed implementation procedures of this modified method and validate its applicability and accuracy through the scattered problems of underground cavities in homogeneous and layered half-space sites.
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Liu, Weiheng, Jianwei Zhang, Hang Liu, Fei Wang, Juan Liu e Mingjie Han. "Seismic Fragility Analysis of Existing RC Frame Structures Strengthened with the External Self-Centering Substructure". Buildings 13, n. 8 (21 agosto 2023): 2117. http://dx.doi.org/10.3390/buildings13082117.
Testo completoAbstract (sommario):
Based on a practical engineering case of seismic strengthening, this paper used the enlarging cross-section method and an external self-centering substructure to improve the seismic performance and seismic resilience of existing frame structures. Among them, the external self-centering substructure included setting a self-centering precast beam and diagonal braces. Utilizing the OpenSees finite element platform, a seismic fragility analysis was carried out to compare the improvements in seismic performance and seismic resilience before and after strengthening. The analysis results show that the proposed modelling method could be simulated satisfactorily. The maximum inter-story drift and the residual inter-story drift of the strengthened frame structures decreased significantly under the same peak ground acceleration. The peak ground acceleration of the strengthened frame structures significantly increased under different performance levels. Additionally, the exceedance probability of the strengthened frame structures was obviously reduced, which reflected that the seismic performance and seismic resilience of the strengthened frame structures were significantly improved.
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Qamaruddin, M., A. S. Arya e Brijesh Chandra. "Seismic Response of Brick Buildings with Sliding Substructure". Journal of Structural Engineering 112, n. 3 (marzo 1986): 558–72. http://dx.doi.org/10.1061/(asce)0733-9445(1986)112:3(558).
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Qamaruddin, Mohammed, Rasheeduzzafar, Anand S. Arya e Brijesh Chandra. "Seismic Response of Masonry Buildings with Sliding Substructure". Journal of Structural Engineering 112, n. 9 (settembre 1986): 2001–11. http://dx.doi.org/10.1061/(asce)0733-9445(1986)112:9(2001).
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Zhang, Qi, Mi Zhao, Jingqi Huang e Xiuli Du. "Parameter Analysis on Seismic Response of Long Lined Tunnel by 2.5D Substructure Method". Applied Sciences 13, n. 7 (5 aprile 2023): 4593. http://dx.doi.org/10.3390/app13074593.
Testo completoAbstract (sommario):
When the numerical analysis of a long lined tunnel is carried out, the calculation amount of the finite element model becomes restricted large-scale parameter analysis. In this paper, an efficient and high-precision 2.5-dimensional (2.5D) frequency-domain finite element method is used to simulate the three-dimensional response of tunnels under the action of oblique incident plane seismic waves. This method can save calculations and avoid the boundary effect caused by the longitudinal truncation of the tunnel. The 2.5D zigzag-paraxial boundary is developed. The artificial boundary is attached to the structure’s surface. The substructure method for oblique plane seismic waves is established. Comparing the substructure method with the analytical solution, the correctness of the site response is verified first. The accuracy of the 2.5D finite element substructure method is further verified. The parameter analysis of different incident angles and conversion angles shows that the underground tunnel does not reach the maximum of structural seismic response when the seismic wave is vertically incident. The location of the soil–rock interface on the tunnel is further discussed. The results show that when the underground tunnel crosses the location of the soil–rock interface, the seismic response of the tunnel will be amplified.
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Yang, Dabin, Litai Sun, Hao Wang, Lei Liu, Mingjin Li e Xiangyi Sun. "A Structural Configuration with Separate Substructures towards Reducing the Seismic Damage of Spatial Structures with Rectangular Plan". Shock and Vibration 2020 (13 ottobre 2020): 1–13. http://dx.doi.org/10.1155/2020/8880747.
Testo completoAbstract (sommario):
Seismic damage of spatial structures of rectangular plan with RC substructures was observed in several earthquakes, especially in the RC substructures. In order to reduce the seismic damage potential, a new structural configuration of spatial structure of rectangular plan is proposed, the substructures of which are composed of the steel substructure and the RC substructure. The latter only bears the vertical load of roof by the arrangement of horizontal sliding bearings between the roof and the RC substructure. The pushover analyses are performed on a steel braced frame and an RC frame with similar lateral stiffness, and the results show that the lateral capacity of the steel structure is much larger than those of the RC structures. A spatial structure of rectangular plan with two different substructures is designed according to Chinese structural designing codes. Seismic time history analyses are carried out for the spatial structure under five ground motions. The results show that the damage mainly concentrates on the substructures, and the seismic performance of the structure with steel and RC substructures is much better than that of the structure with RC substructures.
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Tran, Thanh-Tuan, Sangkyun Kang, Jang-Ho Lee e Daeyong Lee. "Directional Bending Performance of 4-Leg Jacket Substructure Supporting a 3MW Offshore Wind Turbine". Energies 14, n. 9 (10 maggio 2021): 2725. http://dx.doi.org/10.3390/en14092725.
Testo completoAbstract (sommario):
A comprehensive investigation of the directional bending performance of a 4-leg jacket substructure, supporting a 3 MW offshore wind turbine, has been carried out in this study. The jacket substructure with a Pratt bracing system which is already installed in the southwest offshore wind farm in South Korea has been chosen as a reference support structure. A numerical model of the 3MW support structure (i.e., tower, transition piece, and jacket structure) is configured, and its structural performances are evaluated under the conditions of (1) extreme environmental loads (Env), (2) critical Design Load Cases (DLCs), and (3) a total of 288 combined load cases (CBs). For the case of Env (i.e., wind, wave, and current loads), loading directions varying from 0° to 360° at intervals of 15° are considered. The DLCs are provided from the 3 MW wind turbine manufacturer, in a 6 × 12 matrix format. The selected 4-leg jacket substructure in this study showed the smallest bending stiffness at the loading angles of 135° and 315° under the condition of Env, and at the loading angles between 105° and 150° under the CBs. From these results, critical bending directionality of the 4-leg jacket substructure is identified. This study also found that the effects of Env loads are not small compared to the total structural responses of the 4-leg jacket substructure which is supporting a 3 MW offshore wind turbine.
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Cai, Xin Jiang, e Shi Zhu Tian. "Stability Analysis Research of Modified CD-Newmark Numerical Integral Method in Seismic Pseudo-Dynamic Test". Applied Mechanics and Materials 638-640 (settembre 2014): 1869–72. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1869.
Testo completoAbstract (sommario):
The characteristics of explicit numerical integral method is without iteration, and the characteristics of inexplicit numerical integral method is unconditionally stable. The traditional CD-Newmark method has the shortcoming of the bigger upper frequency leads to a small time step, a modified combined integral method named MCD-Newmark release the fixed DOF of numerical substructure, then obtained the parameters range of stable condition of experimental substructure, and the unconditionally stable of numerical substructure is also researched,then the strict stability conditions of the traditional CD-Newmark algorithm is resolved. The study provides reference for structural seismic test.
27
Panji, Pringga Satria, Tommy Ilyas e Erly Bahsan. "Assessment of Bridge Substructure in Java Island". MATEC Web of Conferences 147 (2018): 07005. http://dx.doi.org/10.1051/matecconf/201814707005.
Testo completoAbstract (sommario):
Bridges play important roles in transportation system. Hazard to substructure of bridges become amplified. Based on previous year data, at least one-third of total bridges in Indonesia are damaged in certain level of defect. The performance of existing bridges shall be in-check everytime. Substructure of bridge itself is prone to hazards such as ground displacement, slope instability, seismic-related hazard and scour. Traffic data and soil investigation data will be used to analyse ground displacement and slope instability where the bridge located. Local geological and seismic data will be used to assess seismic-related hazard. Quantitative data is technical information and analyses from geotechnical aspects. Qualitative data is an expert system collected from bridge expert and local goverment. The expert system will have a rating system for each aspect. Fuzzy-based method is an effective tool for modeling some vague datas and this ease the decision-making process. Fuzzy Analytical Hierarchy Process (FAHP) will be used to analyses geotechnical aspect and expert system. Hazard identification, risk rating, risk analysis, and risk assessment are steps conducted in FAHP method. Classification and rating of risk can be done with proposed method. This assessment can be a tool or recommendation for local government where the bridge located.
28
Xu, Liying, Youqin Lin e Yingxiong Wu. "Seismic response analysis of a first-story isolated reinforced concrete frame building with independent columns". Advances in Structural Engineering 23, n. 14 (19 giugno 2020): 3140–52. http://dx.doi.org/10.1177/1369433220933460.
Testo completoAbstract (sommario):
This study aims to better understand the seismic responses and isolation effect of a first-story, independent, column-top isolation structure with concrete frames. A series of shaking table tests and a numerical simulation were performed on a seven-story reinforced concrete–framed structure with first-story isolation, using rubber bearings. A non-isolated, structural model was used as a reference for comparison. The testing and numerical results showed that the story acceleration and inter-story displacement of the superstructure in the isolation model were significantly reduced, indicating the good damping effect of the isolation system. This system, which composed of rubber bearings, could absorb most of the seismic energy. The inter-story displacement of the substructure in the isolation model was also significantly reduced, while the acceleration was slightly reduced. The horizontal deformation of the column was not severe, and the seismic capacity of the substructure was higher than that of the superstructure. It is suggested that to guarantee the seismic security of reinforced concrete–framed structures with the first-story column-top isolation under extremely rare strong earthquakes, the stiffness of columns in the substructure should be further strengthened. Moreover, it is effective and reasonable to adopt the first-story column-top isolation method to improve the seismic capacity of reinforced concrete–framed structures with a weak first story.
29
Huang, Jun-Qi, Xun Chong, Qing Jiang, Xian-Guo Ye e Han-Qin Wang. "Seismic Response Reduction of Megaframe with Vibration Control Substructure". Shock and Vibration 2018 (26 agosto 2018): 1–14. http://dx.doi.org/10.1155/2018/9427908.
Testo completoAbstract (sommario):
Megaframe with vibration control substructure (MFVCS) is a tuned mass damper system, which converts the substructures into the tuned mass. In this study, a kind of MFVCS using both lead-rubber bearings and viscous dampers to connect the vibration control substructure with the megaframe was proposed. Then, based on a validated finite element model, a parametric analysis was conducted to study the effect of two parameters, the tuning frequency (i.e., the frequency of the substructure) and the damping provided by the lead-rubber bearings and viscous dampers on the seismic response reduction of the MFVCS under both frequent and rare earthquakes (i.e., probability of exceedance of 63% and 2% in 50 years, resp.). Furthermore, the optimized values of these two parameters were achieved. The results indicated that (1) the proposed MFVCS could provide a considerable seismic response reduction under frequent earthquake and showed a strong robustness; (2) the optimized values of the frequency ratio (ratio of tuning frequency to the megaframe’s natural frequency) and damping scale factor (ratio between the investigated damping and a standard value) were 0.96 and 1.0, respectively; and (3) the seismic response reduction of the MFVCS under rare earthquake was lower than that under frequent earthquake.
30
Bi, Jihong, Lanfang Luo e Nan Jiang. "Seismic energy response analysis of equipment-structure system via real-time dynamic substructuring shaking table testing". Advances in Structural Engineering 23, n. 1 (23 luglio 2019): 37–50. http://dx.doi.org/10.1177/1369433219864458.
Testo completoAbstract (sommario):
Dynamic equations are presented that have been deduced for a real-time dynamic substructuring shaking table test of an equipment-structure system, based on the branch mode substructure method. The equipment is adopted as the experimental substructure, which is loaded by the shaking table, while the structure is adopted as the numerical substructure. Real-time data communication occurs between the two substructures during the test. A real-time seismic energy calculation method was proposed for the calculation of energy responses, both in the experimental substructure and the numerical substructure. Taking a representative four-story steel frame/equipment model, real-time dynamic substructuring shaking table tests and overall model tests were executed. The proposed real-time dynamic substructuring shaking table testing method was verified by comparing the test results with shaking table test results for the overall model. The energy responses of each component in the equipment-structure system, using different connection types, also were studied. Changes in the connection types can lead to changes in the energy responses of the equipment-structure system, especially with respect to the equipment. The choice of the connection for the equipment-structure coupled system should take into account the operational performance objective of the equipment.
31
Jin, Jian Min, Ping Tan, Fu Lin Zhou, Yu Hong Ma e Chao Yong Shen. "Shaking Table Test Study on Mid-Story Isolation Structures". Advanced Materials Research 446-449 (gennaio 2012): 378–81. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.378.
Testo completoAbstract (sommario):
Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with lead rubber bearing are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.
32
Luo, Lanfang, Nan Jiang e Jihong Bi. "Analysis of the Effects of Soil on the Seismic Energy Responses of an Equipment-Structure System via Substructure Shaking Table Testing". Shock and Vibration 2019 (16 gennaio 2019): 1–11. http://dx.doi.org/10.1155/2019/4351329.
Testo completoAbstract (sommario):
This study investigated the real-time substructure shaking table testing (RTSSTT) of an equipment-structure-soil (ESS) system and the effects of soil on the seismic energy responses of the equipment-structure (ES) subsystem. First, the branch modal substructure approach was employed to derive the formulas needed for the RTSSTT of the ESS system. Then, individual equations for calculating the energy responses of the equipment and the structure were provided. The ES subsystem was adopted as the experimental substructure, whereas the reduced soil model was treated as the numerical substructure when the RTSSTT was performed on the ESS system. The effectiveness of the proposed testing method was demonstrated by comparing the test results with those of the integrated finite element analysis. The energy responses of the ES subsystem in the case of rigid ground (i.e., the ES system) were compared with those considering the effects of soil (i.e., the ESS system). The input energy responses of the ES subsystem were found to decrease significantly after taking the effects of soil into account. Differences due to the soil effects should be considered in the seismic design for the ES system.
33
Shavrin, O. I., e A. N. Skvortsov. "Nanostructured Strengthening of Springs and Spring Steels". Materials Science Forum 870 (settembre 2016): 40–45. http://dx.doi.org/10.4028/www.scientific.net/msf.870.40.
Testo completoAbstract (sommario):
The paper considers the problem of nanostructured strengthening of spring steels and springs, the idea of steel nanostructured strengthening determined not only by grain sizes but also by subgrain sizes is justified. Design schemes of thermal strain nanoscale substructure patterning in spring material produced by hot and cold coiling were implemented. Patterning of nanoscale substructure was experimentally proved. Strength analyses of spring steels and springs showed the dominant effect of nanoscale substructure on spring limited life increasing not less than 10 times at cyclic fatigue tests. Spring compression at cyclic loading decreases 10 times.
34
Jin, Jian Min, Ping Tan, Fu Lin Zhou e Xiang Yun Huang. "Shaking Table Test Study on Mid-Story Isolation Structures with Viscous Damper". Applied Mechanics and Materials 226-228 (novembre 2012): 1149–52. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1149.
Testo completoAbstract (sommario):
Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with linear natural rubber bearing and viscous damper are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.
35
Lazarević, Luka, Dejan Vučković, Milica Vilotijević e Zdenka Popović. "Application of seismic tomography for assessment of the railway substructure condition". Structural Health Monitoring 18, n. 3 (29 maggio 2018): 792–805. http://dx.doi.org/10.1177/1475921718774778.
Testo completoAbstract (sommario):
This article presents results obtained in the research conducted on railway infrastructure in Serbia, which aimed at prediction of substructure condition based on the analysis of track quality. It presents the results of seismic tomography application as non-destructive procedure for assessment of railway substructure condition. Track geometry quality was assessed according to analysis of longitudinal level data, which was recorded during regular track geometry inspections. Track section for application of seismic tomography was chosen on the basis of analysed track geometry data recorded during the regular track geometry inspections in 2006, 2008, 2009, 2012, 2013 and 2014. Tomographic imaging of railway platform on Test Section enabled the creation of two-dimensional finite element model, which was used for determination of propagation speed of seismic P-waves. Seismic tomography on Test Section, which is the part of the international railway line Belgrade–Vrbnica, was performed in 2014. Obtained tomographic image was discussed and compared to track geometry data recorded during the regular track geometry inspections.
36
Liao, Yiping, Xiaoshan Liu, Guoqiu He, Zhiqiang Zhou, Yinfu Liu, Qigui Wang e Qiao He. "Path-dependent multiaxial fatigue behavior of A319 aluminum alloy under non-proportional loading conditions". Materials Testing 65, n. 5 (1 maggio 2023): 684–98. http://dx.doi.org/10.1515/mt-2022-0287.
Testo completoAbstract (sommario):
Abstract In the multiaxial low fatigue test study, four multiaxial non-proportional fatigue loading paths were used including rectangular, square, rhombic and circular. The effect of loading condition changes on the fatigue behavior and cyclic damage characteristics of A319 aluminum alloy was investigated by means of stress response curves, stress–strain hysteresis lines, fatigue fracture morphology, and dislocation substructure morphology in combination with material microstructure. The non-proportional hardening behavior exhibits strong loading path dependence, and the fatigue plastic deformation in the torsional direction is greater in the circular and rhombic paths, and the fatigue damage is more severe, resulting in a shorter fatigue life of A319 aluminum alloy. The axial directions under non-proportional multiaxial loading all have tensile and compressive asymmetric behavior. The differences in loading paths result in different fatigue crack expansion modes. The non-proportional additional hardening behavior under different loading paths is closely related to the dislocation substructure. In the rhombic and circular paths, the alloys have higher dislocation density and strong interaction between dislocations and precipitation phases, which is macroscopically expressed as stronger non-proportional hardening ability in the rhombic and circular loading paths.
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Hadibrata M., Miftah, e Andi Indianto. "EVALUASI KAPASITAS STRUKTUR BAWAH JEMBATAN INTEGRAL". Construction and Material Journal 4, n. 2 (30 ottobre 2022): 129–35. http://dx.doi.org/10.32722/cmj.v4i2.4759.
Testo completoAbstract (sommario):
The construction of integral bridge Overpass Cilenggang 1 on the Serpong – Balaraja Section 1A Toll Road Construction Project was built on soft soil. This evaluation aims to analyze the strength of the integral bridge substructure and justify the strengthening of the substructure if it is not strong enough to withstand the load in accordance with SNI 1725:2016. The evaluation substructure of the integral bridge capacity used SAP2000 software with the load accordance to SNI 1725:2016 for bridge loading. The result of the research show that the capacity of the integral bridge Overpass Cilenggang 1 structure is strong enough to withstand the working load because the reinforcement capacity used for the substructure is stronger than the reinforcement from the result of analysis with SAP2000 software. Based on the result of the research, it can be concluded that the reinforcement used for Overpass Cilenggang 1 substructure is strong enough to withstand the load working on structure and there is no need to justify the reinforcement for the integral bridge substructure. Keywords: Evaluation, Integral Bridge, Load, Reinforcement, Substructure.
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Guan, Feng, Chuan Xi Zhou, Jian Xu, Bo Zhou e Xian Zhong Yi. "An Assessment of Carrying Capacity for Substructure of Offshore Modular Drilling Rig". Applied Mechanics and Materials 575 (giugno 2014): 521–25. http://dx.doi.org/10.4028/www.scientific.net/amm.575.521.
Testo completoAbstract (sommario):
Substructure of offshore modular drilling rig has complex loading. It is necessary that a 3D finite element analysis has been conducted by using finite element software for substructure. The distributions of integrated displacement and stress have been obtained. The results show that the axial strength and stiffness of the substructure are sufficient. The relevant evaluation methods were summarized and integrated into the finite element software, and the command flow program of post-processing is written. Through post-processing graphical display, the carrying capacity of substructure is presented. The results show that the carrying capacity of substructure can meet the requirements in the combination condition which contains the maximum rotary load and the maximum setback load. This research method can provide pertinent reference for carrying capacity assessment of steel structure, and have some practical significance for field operation.
39
Dong, Bai Ping, Richard Sause e James M. Ricles. "Seismic Performance of Steel MRF Structures with Nonlinear Viscous Dampers from Real-Time Hybrid Simulations". Key Engineering Materials 763 (febbraio 2018): 967–74. http://dx.doi.org/10.4028/www.scientific.net/kem.763.967.
Testo completoAbstract (sommario):
Real-time hybrid earthquake simulations (RTHS) were performed on steel moment-resisting frame (MRF) structures with nonlinear viscous dampers. The test structures for the RTHS contain a moment-resisting frame (MRF), a frame with nonlinear viscous dampers (DBF), and a gravity load system with associated seismic mass and gravity loads. The MRFs have reduced beam section beam-to-column connections and are designed for 100%, 75%, and 60%, respectively, of the base shear strength required by ASCE 7-10. RTHS were performed to evaluate the seismic performance of these MRF structures. Two phases of RTHS were conducted: (Phase-1) the DBF is the experimental substructure in the laboratory; and (Phase-2) the DBF with the MRF is the experimental substructure. Results from the two phases of RTHS are evaluated. The evaluation shows that the RTHS provide a realistic and accurate simulation of the seismic response of the test structures. The evaluation also shows that steel MRF structures designed with reduced strength and with nonlinear viscous dampers can have excellent seismic performance.
40
Davies, Trevor G., Rowland Richards e Kuang‐Hsiang Chen. "Passive Pressure During Seismic Loading". Journal of Geotechnical Engineering 112, n. 4 (aprile 1986): 479–83. http://dx.doi.org/10.1061/(asce)0733-9410(1986)112:4(479).
Testo completo
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Guo, Wei, Chen Zeng, Xu Xie e Dan Bu. "Pseudodynamic Hybrid Simulation of High-Speed Railway Bridge-Track System with Rotational Friction Damper". International Journal of Structural Stability and Dynamics 20, n. 06 (giugno 2020): 2040014. http://dx.doi.org/10.1142/s0219455420400143.
Testo completoAbstract (sommario):
This paper evaluates seismic performance of a three-span high-speed railway (HSR) simply supported bridge-track system equipped with multi-joints rotational friction damper (MRFD) using pseudodynamic hybrid simulation. In hybrid simulation, a simplified nonlinear model based on the reference of high-speed railway model is used as a numerical substructure. The experimental substructure is a rotational friction damper (RFD) specimen consisting of two rotational joints. The feedback-force of the RFD specimen is multiplied in different multiples to consider the different clamping force of MRFD with more rotational joints. Results of cyclic tests indicate that the RFD specimen has a good ability to mitigate seismic damage of bridge-track system. Then, pseudodynamic hybrid simulations were performed in the longitudinal direction of the bridge to examine the seismic performance of MRFD. The effect of various ground motions and the influence of different clamping forces of MRFD were investigated. Test results confirmed the applicability of MRFD in HSR bridge-track system.
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Yang, Cheng-Yu, Xue-Song Cai, Yong Yuan e Yuan-Chi Ma. "Hybrid Simulation of Soil Station System Response to Two-Dimensional Earthquake Excitation". Sustainability 11, n. 9 (5 maggio 2019): 2582. http://dx.doi.org/10.3390/su11092582.
Testo completoAbstract (sommario):
Soil station system seismic issues have been highly valued in recent years. In order to investigate the dynamic seismic behaviors of the intermediate column in soil station systems, a hybrid test of a soil station system was conducted. The soil station model was performed with OpenSees. Virtual hybrid simulation was fulfilled with adapter elements. A hybrid model, composed of the steel column specimen and the remainder numerical model, was assembled using the OpenFresco framework. An intermediate column was treated as the physical substructure, while the rest of the soil station system was treated as the numerical substructure in a hybrid simulation. The hybrid test results are compared with the analytical results. The data obtained from such tests show that the system can accurately reflect the mechanical properties of intermediate columns in soil station systems. A hybrid simulation would be a proper way to assess the seismic performance of a soil station system.
43
Li, Xiangxiu, Ping Tan, Xiaojun Li e Aiwen Liu. "Seismic Performance Evaluations of Mega-Sub Isolation System". Mathematical Problems in Engineering 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/7031712.
Testo completoAbstract (sommario):
This paper presents mega-sub isolation system. Shaking table test of the mega-sub isolation system is carried out in this paper. Three test models have been developed. One is called aseismic model, in which all the substructures are fixedly connected with the megastructures. The second one is known as isolated model, where the substructures are connected with the megastructures with isolators, and the last one is called the lower substructure consolidated (LSC) model, in which all the substructures except for the substructures at the lowest level, in other words, substructures at the second mega floor, are isolated from the megastructures. Nonlinear dynamic time analysis of the test models is conducted by SAP2000. Acceleration responses of the megastructure, story drift responses of the megastructure and the substructure, and the deformations of the isolation layer are compared between experimental and numerical simulation results. The results show that the experimental results and numerical simulation results agree well with each other, and the isolated model and LSC model perform better than the counterpart aseismic model. The structures with isolation devices can reduce the structural responses effectively and are much safer than the structure without isolation devices.
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Indulkar, Nitin, Prof A. N. Humnabad e Prof Dr Navnath V. Khadake. "Comparative Study of Seismic analysis of Bridge Substructure in different Seismic Zones as per IRC Guidelines". International Journal for Research in Applied Science and Engineering Technology 10, n. 5 (31 maggio 2022): 3551–57. http://dx.doi.org/10.22214/ijraset.2022.43016.
Testo completoAbstract (sommario):
Abstract: The capacity design philosophy has currently become design norm for the seismic design of structural systems. it is necessary to assess the overstrength capacity of piers before proceeding with the design of the foundation and superstructure. This paper is devoted to developing deterministic procedures for the seismic analysis of substructure and foundation. Therefore, a moment-curvature approach is analysed. A parametric study is then conducted to investigate the factors that causes the seismic forces in the system. A simplified analysis methodology is put forward based on IRC SP 114; 2018. It is applicable for seismic design of bridges with a design service life of 100 years, considering Design Basis Earthquake (DBE). It has covered the seismic map and spectral acceleration graphs as specified in IS: 1893-Part-I- 2016. It also adopts the method prescribed for evaluation of liquefaction possibility, as specified in IS: 1893-Part-I- 2016. For the evaluation of seismic forces, Elastic Seismic Acceleration method, Elastic Response Spectrum method and Linear Time History method are specified. The IRC Guidelines describe the various types of special investigations to be carried out for bridges to be constructed in near field zones, skew, and curved bridges and so on. For loads and load combinations, IRC 6-2017 provides the guidelines and specifications. Objective of this code is to provide common procedure for design of bridges. It deals with the various loads such as vehicular loads, braking forces, wind load, water current forces and their combinations. Keywords: Seismic design of Bridge Substructure, IRC guidelines, Seismic design, Seismic analysis, seismic zones.
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Hateley, James C., Jay Roberts, Kyle Mylonakis e Xu Yang. "Deep learning seismic substructure detection using the Frozen Gaussian approximation". Journal of Computational Physics 409 (maggio 2020): 109313. http://dx.doi.org/10.1016/j.jcp.2020.109313.
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Joshi, Sharad, Ishwer Datt Gupta, Lalitha R. Pattanur e Pranesh B. Murnal. "Investigating the Effect of Depth and Impedance of Foundation Rock in Seismic Analysis of Gravity Dams". International Journal of Geotechnical Earthquake Engineering 5, n. 2 (luglio 2014): 1–18. http://dx.doi.org/10.4018/ijgee.2014070101.
Testo completoAbstract (sommario):
The inhomogenieties of the foundation can be modeled explicitly in standard FEM procedure, however, the results vary significantly with the extent of foundation block modeled and mechanism of applying the input earthquake excitation. The substructure approach provides mathematically exact solution but assumes average properties for the entire foundation as viscoelastic half space. This paper has carried out detailed investigations with varying impedance contrasts and different size of foundation block to show that the results, with suitably deconvoluted free-field ground acceleration time-history applied at the base of foundation block in the FEM approach, are in good agreement with the substructure approach. However, the other variants of the FEM approach may lead to erroneous and overestimated stresses in the dam body. As the foundation of gravity dams can generally be approximated as an equivalent homogeneous half-space, the more accurate and efficient substructure approach can be used to model the dam-foundation rock interaction (SSI) effects in most practical situations.
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Itani, Ahmad M., e Prem P. Rimal. "Seismic Analysis and Design of Modern Steel Highway Connectors". Earthquake Spectra 12, n. 2 (maggio 1996): 275–96. http://dx.doi.org/10.1193/1.1585880.
Testo completoAbstract (sommario):
This paper discusses the seismic analysis and design of modern steel plate girder connectors. Full 3-D finite element analyses were conducted on a two-span two-girder bridge to determine its seismic load path and to establish the seismic performance of the bridge with several cross frame configurations. The results of the study showed that the cross frames play a significant role in the seismic behavior since they transfer the inertia forces to the substructure, a phenomenon not accounted for in the current design bridge codes.
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Ji, Jinbao, Zhen Ding e Chenguang Wang. "Study of shaking table substructure test loading by inertial mass". Journal of Physics: Conference Series 1732 (gennaio 2021): 012141. http://dx.doi.org/10.1088/1742-6596/1732/1/012141.
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Huang, Liang, Xiang Gao, Chu Xian Shi e Sheng Yun Chen. "The Seismic Response of 1/4-Scale Frame — Supported Reinforced Masonry Shear Wall". Key Engineering Materials 400-402 (ottobre 2008): 725–30. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.725.
Testo completoAbstract (sommario):
The study of this paper focuses on the seismic performance of a new complex tall building-FSRMW (frame-supported-reinforced-masonry-shear-wall).The new structure combines the advantages of RMW (reinforced-masonry-shear-wall) and FSRCW (frame-supported- reinforced- concrete-shear-wall) and have good economic value and extensive use value.Big space can be gained by using the structure, which provide a new appropriate selection for the design of hotel, multifunctional office building and dwelling house with shop at bottom. Substructure pseudodynamic testing were adopted to carrying out the seismic testing of 1:4 Reduced-scale models of FSRMW.Seismic evaluation of this structure has been carried out by substructure pseudodynamic testing of 1/4-scale specimen.The dynamic response of the tested structure under the influence of earthquake excitation is analyzed.The horizontal bearing capacity and the damage degree of the test model are investigated. The testing are cited to illustrate that the seismic performance of the structure(frame-shear-wall-supported reinforced masonry shear wall) is better than that structure(frame- supported reinforced masonry shear wall) and can be satisfied with the design request of 6-8 degree seismic zone.
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Chen, Yan Jiang, Da Xing Zhou, Wei Ming Yan e Zhen Yun Tang. "Shaking Table Test of a Long-Span Continuous Girder Bridge". Advanced Materials Research 446-449 (gennaio 2012): 242–46. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.242.
Testo completoAbstract (sommario):
Compared with middle-span bridges, seismic response of long-span bridges is more complicated, and so is seismic design. For example, influence of high order modes is obvious, as well as multi-support excitation, all kinds of nonlinear factors and soil and structure interaction (SSI). It is necessary to study on seismic behavior of a long-span continuous girder bridge. With the help of shake table array and substructure test technology, study on seismic performance of a long-span continuous girder bridge has been done and some useful conclusions have been got.