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Sensitivity Analysis on Effective Parameters for Snow-Melting Performance on Automatically Snow-Melting Fabric Roof And Application on Practical structure

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SSRN 2022年

作者： Zou, Jialin Sun, Xiaoying Liu, Qing Key Lab of Structures Dynamic Behavior Control of China Ministry of Education Harbin Institute of Technology Harbin150090 China Key lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China

In recent decades, numerous membrane structures have been built in the cold region of china. Nevertheless, collapse caused by uneven snow distribution and snow sliding from the edge of roofs occur frequently. This collapse threatens the people’s lives and property. In order to prevent collapse of membrane structure, the automatically snow-melting fabric roof based on electrical-thermal system is presented in this study. Automatically snow-melting fabric roof based on electrical-thermal systems are environmental friendly and clean for eliminating snow that has accumulated on fabric roof. The main task in design the automatically snow-melting fabric roof is determining heating feasibility. A thermal simulation method for the snow melting process is described. This numerical method can predict surface temperature, snow-free area ratio and the coefficient of variation for temperature when climatic condition and heating wire layout parameters are provided. The model is validated experimentally and the influence analysis between the inputs( the heating wire power and spacing, wind velocity, solar radiation, ambient temperature and snow thickness) and the outputs of snow-melting performance are found by thermal simulation. Finally, the three layout scheme of heating wire have been proposed based on snow distribution of four prevailing wind direction and have been applied to ensure that snow-melting fabric roof based on electrical-thermal system studied are feasible to control thickness of snow layers in practical membrane structure. © 2022, The Authors. All rights reserved.

关键词： Snow

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Static and Fatigue Performances of Clip Anchoring System For Frp Rod Used in Cable

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SSRN 2024年

作者： Xian, Guijun Niu, Yanzhao Tian, Jingwei Li, Chenggao Yue, Qingrui Guo, Rui Key Lab of Structures Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education Heilongjiang Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin150090 China Research Institute of Urbanization and Urban Safety School of Civil and Resource Engineering University of Science and Technology Beijing Beijing China

To obtain the static and fatigue performances and provide the design parameters of FRP rod for the application in cable structures. In the present paper, the design and preparation method of steel clip anchor, steel clip anchor with aluminum sleeve and adhesive interlayer are presented. The effect of taper difference, preload and anchor type on static and fatigue performances is studied by tensile and fatigue test, and the optimal design and application parameters of anchor are obtained. The results show that the peak shear stress of the rod at the front end of anchor can be reduced effectively by setting 0.1 ° taper difference, and the bearing capacity of anchor is increased by 5.3%-40.7% compared with 0 ° and 0.2 ° taper difference. The slippage of anchor can be reduced effectively with the increase of preload, which improves the critical slippage load of anchor. In addition, the stress concentration of rod inside the anchor can be reduced with the added of low modulus adhesive layer between steel clip and rod, which reduces the sensitivity of tensile performances to taper difference and delays the fatigue damage accumulation process of rod inside the anchor, the anchoring efficiency and fatigue resistance increases by 10.9% and 61.4% compared with steel clip anchor, respectively. © 2024, The Authors. All rights reserved.

关键词： Fatigue testing

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Efficient Two-Stage Strain/Temperature Measurement Method for Botda System Based on Bayesian Uncertainty Quantification

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SSRN 2022年

作者： Meng, Xianghao Zhang, Dongyu Li, Hui Huang, Yong Key Lab of Structures Dynamic Behavior and Control The Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin China

Brillouin optical time-domain analysis (BOTDA) is an efficient distributed structural strain/temperature measurement technology by identifying the Brillouin frequency (BF) of the fiber. The original BF identification method involves gradually tuning the scanning frequency of the probe laser light, which is time-consuming. To improve the sensing efficiency of BOTDA, a novel two-stage strain/temperature measurement method is proposed based on Bayesian uncertainty quantification. The method uses the information of a small amount of wide range frequency scanning data in the 1st stage to guide a concentrated scanning of the frequency points in the 2nd stage by employing transitional Markov chain Monte Carlo (TMCMC) algorithm. The second-stage scanning strategy based on Bayesian uncertainty quantification ensures the high confidence for BF identification, so that the number of required scanning points can be significantly reduced without sacrificing the measurement accuracy. Finally, the efficacy of the proposed method is verified using numerical and experimental data. © 2022, The Authors. All rights reserved.

关键词： Uncertainty analysis

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Water absorptivity and frost resistance performance of self-ignition coal gangue autoclaved aerated concrete

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Journal of Infrastructure Preservation and Resilience 2021年第1期2卷 1-10页

作者： Cong, Xinyu Tan, Yiqiu Lu, Shuang Wang, Zhaojia Huang, Tianyong School of Transportation Science and Engineering Harbin Institute of Technology Huanghe Road 73 Harbin150090 China School of Civil Engineering Harbin Institute of technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education 9 Harbin Institute of Technology Harbin150090 China State Key Laboratory of Solid Waste Reuse for Building Materials Beijing Building 11 Materials Academy of Science Research Beijing100041 China

Self-ignition coal gangue (SCG) used as one of precursors to fabricate autoclaved aerated concrete (AAC). Aiming at studying water absorptivity and frost resistance performance of SCG-based AAC (SCGAAC), three-period water absorption tests and freeze-thaw tests were carried out and the corresponding results were recorded and analyzed. In order to modify the water absorptivity of SCGAAC, foam stabilizer was applied to adjust pore structure while calcium stearate was expected to change hydrophilic feature of SCG. It was demonstrated that the compressive strength of SCGAAC containing foam stabilizer or calcium stearate declined at different levels. For water absorption, foam stabilizer failed to decrease the water content and even increased water absorption rates. Calcium stearate controlled water absorption rate successfully although the ultimate water content hardly reduced. All of the SCGAAC samples exhibited intact appearance after 50 freeze-thaw cycles and showed excellent frost resistance performance. Three models were proposed to predict water absorptivity and frost resistance performance of SCGAAC and the corresponding prediction results matched test resulted well. © The Author(s) 2021.

关键词： Coal

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An Adaptive Substructure-Based Model Order Reduction Method for Nonlinear Seismic Analysis in OpenSees

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Computer Modeling in Engineering & Sciences 2020年第7期124卷 79-106页

作者： Jian Wang Ming Fang Hui Li Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin150090China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin150090China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China.

Structural components may enter an initial-elastic state,a plastic-hardening state and a residual-elastic state during strong seismic *** the residual-elastic state,structural components keep in an unloading/reloading stage that is dominated by a tangent stiffness,thus structural components remain residual deformations but behave in an elastic *** has a great potential to make model order reduction for such structural components using the tangent-stiffness-based vibration modes as a reduced order *** this paper,an adaptive substructure-based model order reduction method is developed to perform nonlinear seismic analysis for structures that have a priori unknown damage *** method is able to generate time-varying substructures and make nonlinear model order reduction for substructures in the residual-elastic *** finite element program OpenSees has been extended to provide the adaptive substructure-based nonlinear seismic *** the low level of OpenSees framework,a new abstract layer is created to represent the time-varying substructures and implement the modeling process of *** the high level of OpenSees framework,a new transient analysis class is created to implement the solving process of substructure-based governing *** with the conventional time step integration method,the adaptive substructure-based model order reduction method can yield comparative results with a higher computational efficiency.

关键词： Adaptive substructure modeling model order reduction nonlinear seismic

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Effect of Fiber Reinforcement on Self-Healing Ability of Asphalt Mixture Induced by Microwave Heating

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SSRN 2022年

作者： Yang, Hanwen Ouyang, Jian Jiang, Zhao Ou, Jinping School of Civil Engineering Dalian University of Technology Dalian116024 China School of Transportation and Logistics Dalian University of Technology Dalian116024 China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education China

Microwave heating is considered to be an effective method for accelerating the healing of the cracked asphalt mixture containing microwave-absorbing materials. However, the effects of fiber content and the microwave healing conditions on the selfhealing ability of fiber modified asphalt mixture are not clear. Moreover, the degree of freeze-thaw damage is a crucial aspect that might influence the self-healing ability and mechanical properties of the mixture. To obtain an asphalt mixture with both better selfhealing ability and mechanical properties, the healing index and the mechanical properties of fiber modified asphalt mixtures with three microwave-absorbing fibers additive (i.e. carbon fiber, steel fiber and steel wool) are studied by the semi-circular bending test in this paper. The results show that the freeze-thaw cycles have a great effect on self-healing ability and mechanical properties. However, the addition of fibers can improve the mechanical properties of asphalt mixtures under the initial state. Since the strength of steel fiber and steel wool cannot easily be affected by the action of bending and tensile load, the two fibers can provide better cohesive and adhesive strength with asphalt mastic in the fracture surface, attenuating the effect of freeze-thaw cycles on the self-healing ability of asphalt mixtures. Therefore, it is recommended that 3% of steel fiber and 4% of steel wool can be used as microwave-absorbing materials to enhance the self-healing ability of the asphalt mixtures. © 2022, The Authors. All rights reserved.

关键词： Microwaves

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Evaluating Progressive Collapse with Automatic Check Vba Programming and Identifying Optimal Performance Bracing of Systems

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SSRN 2024年

作者： Bigonah, Mohammad Ali, Barham Haidar Rashed, Parya Li, Shuang Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Faculty of Engineering Civil Engineering Department Tishk International University Erbil Iraq School of Civil Engineering Iran University of Science and Technology Narmak Tehran16765-163 Iran

Braced frames are among the most effective systems for resisting progressive collapse;however, determining the optimal bracing system remains a challenge. In this study, several bracing systems were evaluated using a flowchart that satisfied the regulations UFC (chapter 4). VBA programming tools were employed to facilitate the evaluation process. The utilization of the control process and automated VBA programming proved beneficial in the inspection of plastic hinges and ensuring compliance with UFC regulation. The behaviour of four types of braced frames, including concentrically and eccentrically braced frames (CBF and EBF), was investigated under three scenarios involving member removal. The results demonstrated that the inverted V-braced CBF and EBF systems exhibited superior performance by minimizing vertical displacement and redistributing forces on the remaining connected members. In this scenario, despite experiencing significant vertical displacement, lower global forces were observed in all beams and columns. However, the frame without any bracing system failed to meet the regulatory standards, as determined by the control flowchart. Conversely, the remaining structural systems performed exceptionally well. © 2024, The Authors. All rights reserved.

关键词： Compliance control

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Experimental and Modelling Investigation on Chloride Transport and Flexural Behaviour of Rc Beams Subjected to Simultaneous Deteriorating Factors of Carbonation, Ft Cycles and Multiple-Type Sustained Stress

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SSRN 2022年

作者： Chen, Dingshi Guo, Wenhua Kang, Jiayuan Shi, Jun School of Civil Engineering Central South University Changsha410075 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Reinforced concrete (RC) structures are often exposed to coinstantaneous deterioration effects such as carbonation, chloride corrosion, freeze-thaw cycles and external loads which causing deterioration of concrete and reinforcement. This paper discussed the effects of carbonation, freeze-thaw cycles and sustained loads on chloride ion transport and proposed a chloride ion transport model taking porosity as the main coupling variate. The attenuation law of the corroded beams under coupling corrosion factors was studied. Through chloride immersion tests, it was found that applying freezing and thawing cycles and sustained tensile stress can enhance chloride transport capacity by coarsening pores;Carbonation and low compressive stress can repress the chloride ion transport by densifying concrete, but the compressive stress beyond about 0.7 times the compressive strength and tensile stress would enhance the transmission capacity due to the damage of the internal microstructure of concrete. Then, a comprehensive and unified theoretical model of chloride ion transport considering the coupling of carbonation, freeze-thaw cycle, sustained loading and other factors was proposed and verified by taking porosity as the main coupling variable quantity. This model could essentially explain the effects of various factors on chloride ion transport and has good consistency with the test results. Finally, the flexural bearing capacity of the corroded beams is tested, and the failure characteristics, crack characteristics, ultimate bearing capacity, load-displacement relationship and strain distribution of the corroded beams under different corrosion conditions were researched. The results show that the flexural capacity of the corroded beams suffered the coupling effects of multiple corrosion factors degrades, and the bearing capacity decreases with the increase of the corrosion degree of carbonation-freezing thawing cycles;The continuous tensile stress applied to the test beams in t

关键词： Bearing capacity

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Spatial Correlation of Intensity Measures of Mainshock-Aftershock Ground Motion Sequence Pairs

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SSRN 2024年

作者： Ding, Jiawei Lu, Dagang Cao, Zheng-Gang School of Civil Engineering Harbin Institute of Technology Harbin China Key Lab of Structural Dynamic Behaviors and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Laboratory of Earthquake Disaster Mitigation The Ministry of Emergency Management Harbin Institute of Technology Harbin150090 China

This manuscript examines spatial correlations among ground motion intensity measures (IMs) for mainshock and aftershock, including spectral acceleration (Sa), peak ground acceleration (PGA), peak ground velocity (PGV), cumulative absolute velocity (CAV), Arias intensity (Ia), significant duration parameters (Ds5-75, Ds5-95), using a suite of 662 mainshock-aftershock ground motion sequence pairs from 13 earthquake sequences in the NGA-West2 ground motion database based on geostatistical tools. Univariate and multivariate normality of intraevent residuals of IMs for the mainshock and aftershock are verified. We proposed Adaptive Weighted Particle Swarm Optimization Algorithm—Inverse Distance Weighting (AWPSO-IDW) fitting method and use the exponential semivariogram model to fit the empirical semivariogram. An improved Monte Carlo random simulation procedure is used to evaluate the stability of the estimation and several fitting methods used in past research. The results show AWPSO-IDW fitting method is more stable and reliable than other methods, and the results show that the spatial correlation range between the mainshock-aftershock ground motions sequence pairs at different periods of spectral acceleration has a similar trend, only have differences in individual spectral acceleration periods, and the model proposed by Jayaram and Baker (2009) has been improved. Finally, this manuscript employs the spatial correlation range between the mainshock and the aftershock to generate an independent regional spatial correlation influence field. It further constructs the conditional generation of the aftershock spatial correlation influence field, considering the known mainshock spatial correlation influence field. This is achieved by adopting multivariate conditional normal characteristics between intensity measures (IMs) for both mainshocks and aftershocks. © 2024, The Authors. All rights reserved.

关键词： Monte Carlo methods

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Pretreated Lightweight Aggregates for Self-Healing Concrete Exposed to Calcium Hydroxide-Rich Sewage

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SSRN 2022年

作者： Li, Jinglu Guan, Xinchun Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Wastewater concrete pipes are prone to cracking, causing deterioration in durability. As an acidic effluent treatment agent, calcium hydroxide is widely applied in sewage pipes. Based on the above background, this study investigated the self-healing behavior of the mortar containing pretreated lightweight aggregates in calcium hydroxide-rich sewage. Ceramsites were previously treated by impregnating with sodium silicate and encapsulating. Then, the mortar mixed with pretreated ceramsites was pre-cracked and exposed to water, Ca(OH)2 solution and Ca(OH)2 solution/dry cycles. The healing efficiency was evaluated by mechanical test, water absorption and crack visual observation. Results showed that the mortar exposed to Ca(OH)2 solution/dry cycles exhibited the most dominant healing efficiency. After healing for 30 days, the recovery rate of strength and reduction rate of sorptivity coefficient were 65% and 68%, respectively. The closure rate of the crack of 0-250 μm in width exceeded 80%. The area healing rates of the crack with an initial width of 200 μm reached up to 100%, 89% and 78%, respectively. Moreover, SEM and EDS indicated that healing products were mainly C-S-H gel and calcite. The accumulation and filling of products made crack self-healing, thereby improving the durability of the cracked mortar. © 2022, The Authors. All rights reserved.

关键词： Sewage

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