检索结果-内蒙古大学图书馆

Experiment and Analysis on Flexural behavior of Uhpc Encased Steel Beams

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Wang, Kun Wang, Jiahui Omar, Ahmed Ahmad Luo, Huihui Yang, Yang Chen, Zaixian Tao, Qiyu College of Civil Science and Engineering Yangzhou University Yangzhou225127 China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Heilongjiang Harbin150090 China Guangling College Yangzhou University Yangzhou225127 China Key Lab of Civil Engineering Structure and Disaster Prevention in Universities of Shandong Harbin Institute of Technology at Weihai Shandong Weihai264209 China

To improve the normal section design approach for ultra-high-performance concrete (UHPC) encased steel beams, this paper first conducted a flexural experiment on eight simply supported UHPC encased steel beams, where the test parameters included the longitudinal reinforcement ratio in tension, the width and thickness of H-shaped steel flanges, the strength grade of H-shaped steel, and the location of H-shaped steel. Then, the calculation method of the flexural capacity of the UHPC encased steel beams was proposed based on the position of the neutralization axis. The short-term stiffness before and after cracking, as well as the average crack width, were established by considering the effect of the steel fibers. Finally, a finite element model of the UHPC encased steel beam was constructed using reasonable material relations and compared with the test results for validation. The results showed that the longitudinal steel bars and the lower flanges of the UHPC encased steel beams first reached a yielding state, and then the upper UHPC was crushed, exhibiting an under-reinforced damage pattern. Increasing the longitudinal reinforcement ratio, the width and thickness of the H-shaped steel flange, the strength grade of the steel, and offsetting the H-shaped steel downward can effectively increase the vertical load-carrying capacity. Due to the high compression strength of the UHPC and the small depth of the compression zone, the upper flanges of the H-shaped steels for some UHPC encased steel beams did not reach yield. Concerning the presence of the H-shaped steel, after the upper UHPC in the span was crushed, the falling branches of the vertical load-deflection curves flattened, showing good ductility. The equivalent stress coefficient k in tension is suggested to be 0.7 when calculating the flexural capacity. For predicting the post-crack stiffness and the average crack width, the fiber influence coefficients B and w are recommended to be 0.2 and 0.3, respectively. The

关键词： Stiffness

An experimental study on early age compression and shear strength properties of mixed clay soil

学校读者我要写书评

暂无评论

Arabian Journal of Geosciences 2024年第2期17卷 1-14页

作者： Abbas, Azhar Akbar, Muhammad Huali, Pan Zar, Ali Ramzan, Samar Hussain, Zahoor Department of Geotechnical Engineering Tongji University Shanghai China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Sir Syed University of Engineering & Technology Karachi Pakistan Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin China Department of Civil Engineering University of Engineering and Technology Lahore Lahore Pakistan Zhengzhou University Zhengzhou China

Clay mixed soil is a combination of clay and soil components that may be used as the core of earth dams and the foundation for building and road construction. Up until now, significant research work has been carried out to design cement-based clay materials; however, only a couple of studies have been reported in the literature on earth-based materials. The methodology portion provides an overview of the different materials, tools, and protocols used during work to develop ways to earth-based materials and study their early age compression strength along with their shear strength. Finally, it summarizes all the results and the outcome of the experimental work done. The probability of producing an object using earth-based material was examined. Improvement in the compressive strength in the early age of strength by adding additives like bentonite and rice husk was assessed in this study. Three clayey soil samples were investigated. The undrained shear strength based on an unconfined compression test (UCT) over those samples was measured by varying the moisture content (MC). After performing all these tests, a relationship was developed between the UCT and vane shear test (VST) undrained shear strengths of the selected soil samples. Clay samples with different mix designs were investigated, and building components were printed out to check the early age shear strength development and printable properties of different mix designs. This study will lay the foundation for further research on different aspects relating to the emerging technology of 3D clay printing in Pakistan.

关键词：

General Effect of Internal Span of U-shaped Stud on UHPC-NC Interfacial Failure Load 9th

学校读者我要写书评

暂无评论

General Effect of Internal Span of U-shaped Stud on UHPC-NC ...

9th International Conference on Civil Engineering and Materials Science, ICCEMS 2024

作者： Wu, Zhongchong Liu, Dayong Wu, Xiangguo Zhang, Yun Wu, Chengen Lin, Lanri Zhong, Jing Zhu, Hongbing Zhou, Ruiquan You, Xianhui CGN New Energy Holdings Co. Ltd. Beijing China Fujian Provincial Key Laboratory of Multi-Disasters Prevention and Mitigation in Civil Engineering College of Civil Engineering Fuzhou University Fuzhou350108 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of the Industry and Information Technology Harbin Institute of Technology Harbin150090 China College of Civil Engineering Fuzhou University Fuzhou350108 China Sinovel Wind Group Co. Ltd Beijing100086 China Shanghai Electric Wind Power Group Co. Ltd Shanghai200233 China Wind Power Hybrid Tower Co. Ltd Fulaerji161042 China China Power Engineering Consulting Group CO. LTD Beijing100120 China

ISBN: (纸本)9789819615735

To improve the durability design level of the foundation bearing platform for offshore fixed wind power, Ultra-high performance concrete (UHPC) is used as a non-demolding membrane shell system, and a high-performance composite concrete bearing platform structure is formed with on-site pouring of core concrete. The interface performance between the prefabricated UHPC membrane shell and the post cast core concrete has become an important aspect of the overall integrity of the high-performance composite concrete bearing platform. The use of interface shear key design to improve interface integrity is necessary for improving the overall stress of the bearing platform structure. The objective of this study is to assess the effect of the internal span on the shear behavior at the junction of UHPC and normal concrete (NC). © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Ultra-high performance concrete

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

学校读者我要写书评

暂无评论

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

Optimized Repairment Properties Of Wer-Cement Composite Material: An Experimental and Simulation Study

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Li, Cong Xiao, Huigang Min, Liu Wang, Wei Xu, Fan School of Civil Engineering Harbin Institute of Technology Heilongjiang China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Heilongjiang Construction Group Co. Ltd Heilongjiang China

The demand for high-performance repair materials has significantly increased in modern society after the completion of infrastructure construction. However, current research on epoxy resin cement mortar composite lacks theoretical investigation of the proportion of epoxy resin and hardener to prepare a composite material with optimal performance, as it often relies on empirical and previous studies. To address this issue, this study employed E44 and D230 raw materials and determined through theoretical calculations that the optimal ratio for the composite material is 4:1. The best ratio and content were validated by various testing techniques, such as workability, mechanical properties, self-developed shear bond strength test, and impermeability performance. These analyses showed that the composite material's epoxy resin and hardener ratio should be 4:1, with a content of 30%. Additionally, the microstructure of the composite material was analyzed using various testing techniques, including SEM, SEM-EDS, XRD, FTIR, and MIP, to investigate its influence on the ITZ, composition, and pore structure. Furthermore, molecular dynamics simulation was conducted to analyze the mechanical properties, adsorption energy, MSD, and RDF of C-S-H and epoxy resin molecules (cross-linked structures) composite, explaining the effect of water molecules on the composite material from an atomic scale perspective. By combining experimentation and simulation, this study proposed a computationally based ratio design method, which could provide new ideas for research and development of WER-cement composite while created a simple shear bond strength testing method for repair materials. © 2023, The Authors. All rights reserved.

关键词： Epoxy resins

Real-Time Seismic Damage Simulation for Urban Building Portfolio Based on Basic Building Information and Machine Learning

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Li, Shuang Li, Changqing Huang, Yuwen Zhai, Changhai 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 of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Beijing Glory PKPM Technology Co. Ltd Beijing100013 China

Timely and accurate simulation of seismic damage of the urban building portfolio is important for pre-earthquake planning and post-earthquake rescue. This study proposes a real-time seismic damage simulation method for the urban building portfolio based on the multiple degree-of-freedom (MDOF) shear model and flexural-shear model established by basic building information and the machine learning. The formulas for predicting periods of six types of structures are proposed and the surrogate model-Ⅰ for predicting the key inter-story hysteretic parameters are established to optimize the MDOF models. The surrogate model-Ⅱ is established to rapidly predict the engineering demand parameters and damage states of structures under earthquakes. In terms of the generalization capability, an incremental learning strategy is advised to guarantee the accuracy of the surrogate model-Ⅱ in predicting the seismic damage of other urban building portfolios. The results in two city-scale cases show that the proposed method can achieve real-time seismic damage simulation of urban building portfolio with acceptable accuracy, and it’s not necessary to retrain or only needs minor additional training on the existing surrogate model when applied to other urban building portfolios. © 2023, The Authors. All rights reserved.

关键词： Machine learning

A Study On Properties of Pu-Cement Composites Repairing Material for Seepage control and Plugging

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Li, Cong Bai, Jinrong Jiang, Ying Xiao, Huigang Wang, Wei Xu, Fan School of Civil Engineering Harbin Institution of Technology Heilongjiang China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Heilongjiang Construction Group Co. Ltd Heilongjiang China

Composite grouting materials are increasingly becoming the focus of seepage control and plugging research, and in order to improve its mechanical properties and delayed hydration repairment effect without compromising its workability, PU-cement composites grouting materials, in which cement are not the main component, still, requiring a finer particle size and good shape. In this study, the ball-milled cement are prepared to combine with WPU and OPU, creating a new PU-cement composites grouting *** particle size distribution, early strength, and micro-structure of ball-milled cement were analyzed, then the best preparation process was determined as 120min ball-milling time and 0.03% grinding aid doping. The viscosity, swelling rate, bond strength, FTIR, XRD and micro-structure of the composites with different ratios of polymer/cement and OPU/WPU were then examined, especially, based on moisture distribution, a new method to evaluate the impermeability of repair materials is proposed, and the function of ball-milled cement in composites and the interaction mechanism between ball-milled cement and PU were discussed. The results showed that the best performance was achieved with the P/C ratio of 3:1 and 4:1, and the OPU/WPU ratio of 2:1 or 3:1, indicating that PU-cement grouting material can be an ideal choice for underground structure seepage control and plugging. © 2023, The Authors. All rights reserved.

关键词： Cements

An invariance constrained deep learning network for PDE discovery

学校读者我要写书评

暂无评论

arXiv

arXiv 2024年

作者： Chen, Chao Li, Hui Jin, Xiaowei 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 Dynamics Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Shenzhen518055 China

The discovery of partial differential equations (PDEs) from datasets has attracted increased attention. However, the discovery of governing equations from sparse data with high noise is still very challenging due to the difficulty of derivatives computation and the disturbance of noise. Moreover, the selection principles for the candidate library to meet physical laws need to be further studied. The invariance is one of the fundamental laws for governing equations. In this study, we propose an invariance constrained deep learning network (ICNet) for the discovery of PDEs. Considering that temporal and spatial translation invariance (Galilean invariance) is a fundamental property of physical laws, we filter the candidates that cannot meet the requirement of the Galilean transformations. Subsequently, we embedded the fixed and possible terms into the loss function of neural network, significantly countering the effect of sparse data with high noise. Then, by filtering out redundant terms without fixing learnable parameters during the training process, the governing equations discovered by the ICNet method can effectively approximate the real governing equations. We select the 2D Burgers equation, the equation of 2D channel flow over an obstacle, and the equation of 3D intracranial aneurysm as examples to verify the superiority of the ICNet for fluid mechanics. Furthermore, we extend similar invariance methods to the discovery of wave equation (Lorentz Invariance) and verify it through Single and Coupled Klein-Gordon equation. The results show that the ICNet method with physical constraints exhibits excellent performance in governing equations discovery from sparse and noisy data. © 2024, CC BY-NC-ND.

关键词： Equations of motion

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

学校读者我要写书评

暂无评论

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