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Study on the effect of ground motion direction on the response of engineering structure

Earthquake Engineering and Engineering Vibration 2016年第4期15卷 649-656页

作者： Sun Menghan Fan Feng Sun Baitao Zhi Xudong Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology School of Civil Engineering Harbin Institute of Technology Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration

Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW （East -West） direction, NS （South- North） direction and perpendicular to the surface （z） direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations：（1） the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; （2） response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and （3） the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to struct

关键词： direction of grotmd motion structure effect coordinate transformation response spectrum

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Time-dependent reliability prediction analysis of bridge members considering dependence of failure modes and proof modes

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key Engineering Materials 2015年 648卷 25-34页

作者： Liu, Yuefei Lu, Dagang Key Laboratory of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin China School of Civil Engineering Harbin Institute of Technology Harbin China

structural health monitoring systems used in bridges contain sensors providing a large amount of monitored data, such as stress, deflection and ***. In this paper, firstly, based on monitored everyday extreme stress data, time-variant proof load effects of structural members were defined, and based on the time-dependent proof load effects, the time-dependent performance functions of structural member's proof modes were built;and then based on the monitored data, the Bayesian dynamic models(BDMs) of extreme stresses were built, and based on the predicted extreme stress with BDMs, the time-variant performance functions of structural member's failure modes were given;and then based on the time-dependent performance functions of failure modes and proof modes and correlation coefficients between them, with the conditional probability method, the time-dependent reliability indices of structural members were updated and predicted;finally an actual engineering was provided to illustrate the application of the proposed models and methods. © 2015 Trans Tech Publications, Switzerland.

关键词： dynamic models

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Modeling of the effect of water ingress on the bond between carbon fiber – Epoxy resin with the molecular dynamics technique 8

Modeling of the effect of water ingress on the bond between ...

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8th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2016

作者： Xiao, Yanrong Xian, Guijun Li, Hui Key Lab of Structural Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Harbin150090 China

ISBN: (纸本)9789881448026

FRP (fiber reinforced polymer) has taken advantages of the fiber reinforcement and resin matrix, possessing excellent mechanical properties and corrosive resistances, even in harsh environments. The lack of the knowledge of the durability performances of FRPs in various environmental conditions and the related degradation mechanisms of FRPs leads to significantly conservative design. Water ingress plays a critical effect on the durability of FRP, due to susceptibility of the bond between the fibers and resin matrices. In the present paper, molecular dynamics technique was used to model the moisture effect on the fiber-resin bond. The bonding performances of the epoxy on carbon fibers under dry and wet conditions were simulated. Free energy profiles were calculated to quantify interfacial adhesion. As shown from the decline of binding free energy, the water ingress led to remarkable deterioration of the fiber bonding to the resin matrix. The study is expected to be helpful for both the development of durable FRPs, and to predict the service life of a FRP subjected to hydrothermal aging accurately. Copyright © 2016 Department of Civil and Environmental Engineering & Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University.

关键词： Molecular dynamics

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Predicting the capacity of perfobond rib shear connector using an ANN model and GSA method

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Frontiers of structural and Civil Engineering 2022年第10期16卷 1233-1248页

作者： Guorui SUN Jun SHI Yuang DENG School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China National Engineering Laboratory for High-Speed Railway Construction Changsha 410075China

Due to recent advances in the field of artificial neural networks(ANN)and the global sensitivity analysis(GSA)method,the application of these techniques in structural analysis has become feasible.A connector is an important part of a composite beam,and its shear strength can have a significant impact on structural *** this paper,the shear performance of perfobond rib shear connectors(PRSCs)is predicted based on the back propagation(BP)ANN model,the Genetic Algorithm(GA)method and GSA method.A database was created using push-out test test and related references,where the input variables were based on different empirical formulas and the output variables were the corresponding shear *** results predicted by the ANN models and empirical equations were compared,and the factors affecting shear strength were examined by the GSA *** results show that the use of ANN model optimization by GA method has fewer errors compared to the empirical ***,penetrating reinforcement has the greatest sensitivity to shear performance,while the bonding force between steel plate and concrete has the least sensitivity to shear strength.

关键词： perfobond rib shear connector shear strength ANN model global sensitivity analysis

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Analysis of micro-disturbance drilling pipe pre-reinforcement method for deep excavations above operating subway tunnels

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Frontiers of structural and Civil Engineering 2025年

作者： Tang, Wenchong Kong, Xiangxun Tang, Liang Ling, Xianzhang School of Civil Engineering Harbin Institute of Technology Harbin150090 China Chongqing Research Institute Harbin Institute of Technology Chongqing401135 China Key Laboratory of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China

This paper uses the three-dimensional numerical simulation method to analyze the first deep foundation pit project directly above the operating subway in a certain area. The monitoring data were compared with the numerical results to verify the accuracy of the numerical model, and then a series of analyses were performed. The soil beneath the tunnel is the most direct object of tunnel deformation caused by the excavation of deep foundation pits above the tunnel. The rebound deformation of the soil beneath the tunnel forces the tunnel to produce an upward deformation cooperatively. Therefore, after comparing and analyzing the prevention criteria of traditional excavation measures, which were not sufficient for this project, a new method of fortification is proposed for the foundation pit above the tunnel, which is called the micro-disturbance drill pipe pre-reinforcement method (PRM) for the soil beneath the tunnel. The comprehensive parameter analysis of the PRM shows that the PRM can effectively reduce the uplift value of the tunnel, and the reinforcement effect is obvious. © Higher Education Press 2025.

关键词： Tunneling (excavation)

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Chemically bonded multi-nanolayer inorganic aerogel with a record-low thermal conductivity in a vacuum

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National Science Review 2023年第10期10卷 96-105页

作者： Hongxuan Yu Menglin Li Yuanpeng Deng Shubin Fu Jingran Guo Han Zhao Jianing Zhang Shixuan Dang Pengyu Zhang Jian Zhou Dizhou Liu Duola Wang Chuanwei Zhang Menglong Hao Xiang Xu Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology and Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast University Key Lab of Aerospace Bearing Technology and Equipment of the Ministry of Industry and Information Technology Harbin Institute of Technology

Inorganic aerogels have exhibited many superior characteristics with extensive applications,but are still plagued by a nearly century-old tradeoff between their mechanical and thermal *** reducing thermal conductivity by ultralow density,inorganic aerogels generally suffer from large fragility due to their brittle nature or weak joint crosslinking,while enhancing the mechanical robustness by material design and structural engineering,they easily sacrifice thermal insulation and ***,we report a chemically bonded multi-nanolayer design and synthesis of a graphene/amorphous boron nitride aerogel to address this typical tradeoff to further enhance mechanical and thermal *** to the chemically bonded interface and coupled toughening effect,our aerogels display a low density of 0.8 mg cm-3with ultrahigh flexibility（elastic compressive strain up to 99% and bending strain up to 90%）,and exceptional thermostability（strength degradation <3% after sharp thermal shocks）,as well as the lowest thermal conductivities in a vacuum(only 1.57 mW m-1K-1at room temperature and 10.39 mW m-1K-1at500℃) among solid materials to *** unique combination of mechanical and thermal properties offers an attractive material system for thermal superinsulation at extreme conditions.

关键词： inorganic aerogels multi-nanolayer mechanical-thermal tradeoff flexibility thermal superinsulation

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The visualization of turbulent coherent structure in open channel flow

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Journal of Hydrodynamics 2019年第2期31卷 266-273页

作者： Xiao-dong Bai Wei Zhang Qing-he Fang Yong Wang Jin-hai Zheng An-xin Guo Ministry of Education Key Laboratory of Coastal Disaster and Defence Hohai UniversityNanjing 210098China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 21009China Science and Technology on Water Jet Propulsion Laboratory Marine Design and Research Institute of ChinaShanghai 200011China Ministry of Education Key Laboratory of Structural Dynamic Behavior and Control School of Civil EngineeringHarbin Institute of TechnologyHarbin 150090China Max Planck Institute for Dynamics and Self-Organization GottingenGermany

Due to its multiscale and multi-layer natures,the coherent structures of turbulent in the open channel flow is complex and difficult to be visualized for understanding its *** this paper,five types of methods for the vortical structure in the fluids,namely the Q-criterion,the vorticity,the Omega method,the velocity-vorticity correlation structures(VVCS)as well as the most recent Rortex method,are adopted to visualize the turbulent flow in the open *** the free surface modelled as a free slip boundary,a direct numerical simulation(DNS)is carried out to study the multi-layered flow structure characteristics under the free *** visualization results by the Q-criterion,the vorticity,the Omega method and the Rortex are firstly *** the turbulent flow layers near the free surface are identified with corresponding anisotropy ***,the VVCS within various turbulence layers are visualized *** research indicates that the VVCS can straightforwardly show the geometry information of the cohere nt structures of turbulent in different layers for the ope n channel flow.

关键词： Open channel flow flow visualization velocity-vorticity coherent structure direct numerical simulation(DNS)

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Investigation on mapping relationship between deflection and cable tension by artificial neural networks 11

Investigation on mapping relationship between deflection and...

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11th International Workshop on structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance, IWSHM 2017

作者： Tian, Yadi Li, Hui Key Laboratory of Intelligent Disaster Prevention and Mitigation for Civil Infrastructure Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters Ministry of Industry and Information Technology Key Laboratory of Structural Dynamic Behavior and Control School of Civil Engineering Harbin Institute of Technology Harbin150090 China

ISBN: (纸本)9781605953304

Cables usually serve as critical load-bearing structural components in cable-stayed bridges. Vertical deflection is an important overall indicator that directly reflects the health status of bridge. The relationship between cable tension and vertical deflection also reflects the underlying mechanism of structures. In this context, a machine learning-based approach is proposed. Cable tension and vertical deflection are caused by prestress, temperature and vehicle loads. In this study, we focus on the cable force and vertical deflection caused by vehicle loads. Artificial neural network (ANN) is employed as the supervised learning method to learn the relationship between cable tension and vertical deflection. Field monitored data of Jintang Bridge are used to test the validity of the proposed method. The results show that ANN is capable of modelling vertical deflection from cable tension data in the case of arbitrary vehicle distribution. The proposed method which integrates the local and global variables by using two different kinds of monitoring data, avoids the complicated mechanical derivations, and is proved to be environment-insensitive.

关键词： Neural networks

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Improvement of sludge dewaterability with modified cinder via affecting EPS

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Frontiers of Environmental Science & Engineering 2017年第6期11卷 179-192页

作者： Weichao Ma Lei Zhao Huiling Liu Qianliang Liu Jun Ma State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology Harbin 150090 China School of Architectural Engineering Heilongiiang University Harbin 150080 China Key Laboratory of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin 150090 China Key Laboratory of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin 150090 China

The relationship between the improvement of sludge dewaterability and variation of organic matters has been studied in the process of sludge pre-conditioning with modified cinder, especially for extracellular polymeric substances （EPS） in the sludge. During the conditioning process, the decreases of total organic carbon （TOC） and soluble chemical oxygen demand （SCOD） were obviously in the supernatant especially for the acid modified cinder （ACMC）, which could be attributed to the processes of adsorption and sweeping. The reduction of polysaccharide and protein in supernatant indicated that ACMC might adsorb EPS so that the tightly bound EPS （TB-EPS） decreased in sludge. In the case of ACMC addition with 24 g·L^-1, SRF of the sludge decreased from 7.85 × 10^12 m·kg^-1 to 2.06× 10^12 m·kg^-1, and the filter cake moisture decreased from 85% to 60%. The reconstruction of ＂floc mass＂ was confirmed as the main sludge conditioning mechanism. ACMC promoted the dewatering performance through the charge neutralization and adsorption bridging with the negative EPS, and provided firm and dense structure for sludge floc as skeleton builder. The passages for water quick transmitting were built to avoid collapsing during the high-pressure process.

关键词： Sludge conditioning Acid or alkali modified cinder TB-EPS Floc mass Floc reconstruction

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Axial compression performances of concrete filled flax-basalt hybrid fibers reinforced FRP tubes 12

Axial compression performances of concrete filled flax-basal...

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Joint Conference of the 12th International Symposium on Fiber Reinforced Polymers for Reinforced Concrete Structures, FRPRCS 2015 and the 5th Asia-Pacific Conference on Fiber Reinforced Polymers in Structures, APFIS 2015

作者： Xia, Yuanyuan Xian, Guijun Li, Hui Key Lab. of Structural Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Flax fiber reinforced polymer (FFRP) composites could be used in civil engineering as structural materials. To improve the mechanical properties and durability of FFRP, flax-basalt hybrid fiber reinforced polymer (HFRP) composite was developed. In the present study, unidirectional HFRP tubes were prepared with a winding process, and the compression performances of the concrete filled HFRP tubes were investigated. HFRP coupon was prepared and tested in tensile properties. The tensile results of the HFRP plate coupons shows linear in stress-strain, and hybrid with basalt fiber enhances the elongation at break remarkably. The tensile strength and modulus of the HFRP follow the rule of mixture. The concrete filled HFRP tubes exhibited much improved ultimate strength and ductility compared to those with the flax fiber tubes. The axial compression stress-strain curves were analyzed with the existing models. The coefficients of confinement of HFRP were higher than those of glass or carbon fiber based FRPs. © APFIS 2015. All rights reserved.

关键词： Fiber reinforced plastics

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