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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

A 4D Digital Recovery of the Morphological Evolvement During Pitting Corrosion in Austenitic Grain Structure

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SSRN 2023年

作者： Wang, Mingzhi Yang, Xu Wang, Zhenbo Wang, Wei School of Civil Engineering Harbin Institute of Technology Harbin150090 China 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 FAW GROUP Changchun130011 China

Pitting corrosion is one fatal phenomenon in metallic material deterioration. A comprehensive understanding of mesoscale corrosion morphology aids the material design for macroscale resilience. This paper presents a confluence between numerical grain structure reconstruction and multiphase corrosion kinetics. A cellular automaton algorithm is proposed to digitally recover the austenite grain structure through nucleation. Image-based input technique is adopted to perform a grain size distribution comparison between digital and practical austenite grain mesostructure. The morphological evolvement during a nanoscale Lattice Boltzmann corrosion is quantitatively characterized by surface area and surface roundness factor. Single pitting results show that the heterogeneous phase distribution contributed up to 7% of the surface roughness of a single pit in the designed environment. The surface roughness development of single pit corrosion is independent of the damage depth under the designed environment. A damage depth threshold exists to trigger the verticle corrosion pit development towards non-spherical morphology. Multiple pitting results show that grain boundary percolation is crucial to maintain mesostructure integrity. This work suggests that manufactured metallic material with high grain boundary resistivity provides a mesoscale skeleton, providing structural resistance in an environment with anti-corrosion requirement. © 2023, The Authors. All rights reserved.

关键词： Surface roughness

A Two-Stage Mitigation Method for Optical Turbulence-Induced Errors in Vision-Based Structural Displacement Measurement

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SSRN 2024年

作者： Zhang, Xiulin Zhou, Wensong Chen, Xize Wang, Yonghuan Wu, Qi 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 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 Central Research Institute of Building and Construction Co. Ltd MCC Group Beijing100088 China

Vision-based structural displacement measurement techniques have been widely applied. However, the visual sensors used for remote monitoring of structures in high-temperature weather are easily affected by optical turbulence, which introduces errors in displacement measurement. Therefore, this paper proposes a two-stage optical turbulence-induced error alleviation method. In the first stage, the steerable pyramid method is used to decompose the monitoring video, and the phase of each position is independently temporal filtered at different spatial scales and directions to reconstruct the video. To further reduce errors with spatial randomness, a feature point matching method considering the weighted distance is used to track the displacement of multiple measurement points on the target structure in the reconstructed video, and the results are spatially filtered in the second stage. The effectiveness of the proposed method was verified through static and dynamic target experiments using a heater to simulate optical turbulence in the lab.ratory. © 2024, The Authors. All rights reserved.

关键词： Errors

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

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

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

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

Effects of cooking oil on the shrinkage-reducing of high-strength concrete

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Results in Materials

Results in Materials 2024年 23卷

作者： Huo, Yanlin Dong, Xinhong Gao, Yang Xu, Xiaodong Zeng, Liang Wu, Yuanchao Zhao, Yunhui Yang, Yingzi Su, Qunshan Huang, Jinguang Lu, Dong School of Civil Engineering Harbin Institute of Technology Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Postdoctor Workstation Henan D.R. Construction Group Research and Development Center Henan Qingshui Construction Technology Co. Ltd.

Autogenous shrinkage is a serious problem for high-strength concrete, which may lead to early-age cracking. Shrinkage-reducing agents are typically used to mitigate the autogenous shrinkage of concrete. However, some negative effects, such as unstable workability and the reduction of compressive strength, will be caused. In this study, emulsified or plain cooking oil is used as a shrinkage-reducing agent in low water-binder ratio concrete. Deformational behaviours of concrete with cooking oil and normal commercially availab.e shrinkage-reducing agent are investigated. Experimental results show that the utilization of cooking oil could significantly reduce the autogenous shrinkage of high-strength concrete due to the reduction of surface tension. Additionally, emulsified cooking oil is better than normal shrinkage-reducing agents and plain cooking oil in many aspects of the concrete. Micro-structure of the concrete with different shrinkage-reducing agents is also observed. Emulsified cooking oil is considered a promising admixture for the mitigation of autogenous shrinkage of high-strength concrete. © 2024 The Authors

关键词： Autogenous shrinkage Cooking oil High strength concrete Shrinkage reducing agent

The Deformation of C–S–H Gel and its Link with Length Change of Cement Pastes on Drying and Resaturation

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SSRN 2023年

作者： Zhang, Xiaoyu Qiao, Jing Feng, Jingjing Xu, Shilang Zhou, Chunsheng Zeng, Qiang Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China College of Water Conservancy and Civil Engineering Shandong Agricultural University Taian271018 China College of Civil Engineering and Architecture Zhejiang University Hangzhou310058 China

Drying shrinkage of cement pastes (CPs) facilitating superficial cracking deserves primary concern when handling durability performance. In order to further clarify shrinkage mechanism, the changes of mass, length and pore water allocation of two mature CPs were monitored principally through non-destructive low-field NMR relaxation technique. Experimental results revealed that, heat treatment under hot water slightly coarsens the pore structure of CPs through modifying the morphology of C-S-H gel, but reduces shrinkage during first drying remarkably. During drying at 80% RH, although both interlayer and gel pores are saturated, they loss their water progressively at reducing rates. At the expense of reducing interlayer space, the contraction of gel pores is partly and even entirely compensated. When drying at lower 43% RH, interlayer pores still saturated are compacted more significantly with reducing size and volume. The compaction of interlayer pores is at the micro-structural origin and dominates drying shrinkage of CPs. © 2023, The Authors. All rights reserved.

关键词： Drying