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11th International Symposium on Project Management, ISPM 2023

作者： Jiang, Pinglin Liao, Qiulin Wang, Ren Liu, Zhongxian Zou, Jinglong Wu, Di Beijing Urban Construction Design & Development Group Co. Limited Beijing100037 China School of Mechanics and Civil Engineering China University of Mining & Technology Beijing100083 China Beijing Urban Construction Rail Transit Construction Engineering Co. Ltd. Beijing102600 China School of Civil Engineering Tianjin Chengjian University Tianjin300384 China Chongqing Branch of China Railway Eryuan Engineering Group Co. Ltd. Chongqing401120 China

ISBN: (纸本)9781713877134

Utilizing the response acceleration method, forced response displacement method, and integral response displacement method respectively, the aseismic analyses of a circular lined tunnel were performed and by adopting the software ANSYS the dynamic numerical analysis was also carried out. Taking the internal force calculation results of lined tunnels under different radii and burial depths as reference values, the influence laws obtained by various calculation methods were analyzed. The results show that the above analysis methods can reflect the structural mechanical characteristics of the underground structure at different burial depths, and the error range of the response acceleration method and forced displacement method is large at different burial depths, while the error of integral response deformation method is always less than 10%, which has good accuracy and wider applicability. In the analysis of tunnel internal forces for different tunnel radii, the variation patterns are the same, but the numerical errors are more obvious. Among them, the response acceleration method is more applicable to the calculation of large diameter tunnels. The results have certain guiding significance for the comparison and selection of seismic design methods for underground structures.. © 11th International Symposium on Project Management, ISPM 2023. All rights reserved.

关键词： Numerical methods

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Durability properties of metakaolin based geopolymer polypropylene fibre reinforced concrete

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Materials Today: Proceedings 2023年 93卷 227-233页

作者： Prafful Prasad S.P. Singh Civil Engineering (Structural and Construction Engineering) at Dr B R Ambedkar National Institute of Technology Jalandhar India Civil Engineering at Dr B R Ambedkar National Institute of Technology Jalandhar India

As the modernization is taking place these days, adaption to the new innovations are going on, which is also true for the civil construction sector. Conventional concrete i.e. Oridinary Portland Cement (OPC) has a very high carbon dioxide (CO 2 ) emission nearly from 5%−7% in its production, leading to the major by-product pollution as greenhouse gases. Due to these back falls, need of eco-friendly and sustainable material like Geopolymer (GP) comes into place, however, even geopolymer exhibits low tensile strength and quasi-brittle behaviour which needs to be improved by adding or replacing certain components such as Meta Kaolin (MK) and Polypropylene Fibres (PPF). Also it consumes less energy and is cost effective and also helps in low emission of greenhouse gases. The durability properties of the Meta kaolin-based geopolymer (MKG) with the inclusion of polypropylene Fibres (PP) are elaborately discussed in this research paper. This Geopolymer Fibre Reinforced Concrete (GPFR) offers myriad of advantages. Sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) are used as the alkali activator solution in this for geopolymerization process. With the inclusion of polypropylene fibres, drying shrinkage decreases and various other factors like chloride penetration and temperature resistance increases. Nevertheless, in all these years only limited study has been done in this particular area. Various tests are to be investigated like Ultrasonic Pulse Velocity test (UPV), water absorption test etc for finding its different aspects in different environmental conditions.

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Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

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Journal of Central South University 2024年第7期31卷 2431-2445页

作者： ZHENG Ke-yue SHI Cheng-hua ZHAO Qian-jin LEI Ming-feng JIA Chao-jun PENG Zhu National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China School of Civil Engineering Central South UniversityChangsha 410075China China Railway Group Co. Ltd.Beijing 100039China

Due to the long-term plate tectonic movements in southwestern China,the in-situ stress field in deep formations is *** passing through deep soft-rock mass under non-hydrostatic high in-situ stress field,tunnels will suffer serious asymmetric *** is no available support design method for tunnels under such a situation in existing studies to clarify the support time and support *** study first analyzed the mechanical behavior of tunnels in non-hydrostatic in-situ stress field and derived the theoretical equations of the ground squeezing curve(GSC)and ground loosening curve(GLC).Then,based on the convergence confinement theory,the support design method of deep soft-rock tunnels under non-hydrostatic high in-situ stress field was established considering both squeezing and loosening *** addition,this method can provide the clear support time and support stiffness of the second layer of initial *** proposed design method was applied to the Wanhe tunnel of the China-Laos railway in *** data indicated that the optimal support scheme had a good effect on controlling the tunnel deformation in non-hydrostatic high in-situ stress *** applications showed that the secondary lining could be constructed properly.

关键词： non-hydrostatic stress field high in-situ stress deep soft-rock tunnel squeezing pressure loosening pressure support design method

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Study on the simplified evaluation method of the remaining load-carrying capacity of a corroded steel I-girder end using FEA

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Journal of constructional Steel Research 2023年第1期210卷

作者： Chiu, Chien-Kuo Liao, I-Hsiang Yamaguchi, Eiki Lee, Yi-Chia Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan Department of Civil Engineering Kyushu Institute of Technology Kitakyushu Japan

In a steel I-bridge, corrosion often occurs severely at the I-girder end rather than at other parts. Therefore, this work mainly discusses the corrosion at the I-girder end as a bearing problem and shear capacity of the end plate. A finite element model (FEM) of a corroded steel I-girder end is developed considering commonly occurring corrosion at first. For the initial imperfection of a steel I-girder end, the initial deformation and residual stress are considered in the model which are simulated by elastic buckling analysis (eigenvalue analysis) and thermal stress, respectively. To investigate the effect of the corrosion pattern on the strength development, the single-area corrosion (flange, stiffener, web) and multi-area corrosion are included in the case study. Finally, the simulation results from the case study using finite element analysis (FEA) are used to formulate the simplified equations for evaluating the remaining load-carrying capacity of a corroded steel I-girder end with the specified corrosion patterns. Furthermore, for the engineering design and preliminary assessment of a corroded steel I-girder end, the simplified equations for evaluating the remaining yield strength ratio are also provided based on the remaining load-carrying capacity. © 2023

关键词： Finite element method

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Numerical simulation of porous phenolic engineering composites under impact load

Numerical simulation of porous phenolic engineering composit...

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2022 International Conference on Optoelectronic Information and Functional Materials, OIFM 2022

作者： Zhu, Zhigang Zhang, Qiang School of Municipal and Transportation of Guangdong Construction Vocational Technology Institute China School of Civil Engineering of Guangdong Construction Vocational Technology Institute Guangzhou Guangdong510440 China

ISBN: (数字)9781510655126

ISBN: (纸本)9781510655119

Based on the experiment of porous phenolic engineering materials, based on the phenomenological theory and using the finite element analysis software, this paper numerically simulates the impact experiment of porous phenolic materials, gives some basic mechanical parameters of the impact experiment of porous phenolic materials, provides a full series of pictures for the impact experiment process, and vividly describes the whole process of the experiment. On the basis of the experiment, we give the particle velocity time history curve of the free surface behind the target plate, and compare it with the experimental curve. The results show that the two agree well. At the same time, the axial stress is compared with the experimental data. The calculated results are in good agreement with the experiment, which shows that the established model and constitutive relationship are reasonable, It can provide some reference support for the practical application of this material in protection engineering. © 2022 SPIE.

关键词： Numerical models

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Thermally insulating and fire-retardant bio-mimic structural composites with a negative Poisson's ratio for battery protection

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Carbon Energy 2023年第12期5卷 83-96页

作者： Fengyin Du Zuquan Jin Ruizhe Yang Menglong Hao Jiawei Wang Gang Xu Wenqiang Zuo Zifan Geng Hao Pan Tian Li Wei Zhang Wei She Jiangsu Key Laboratory of Construction Materials School of Materials Science and EngineeringSoutheast UniversityNanjingPeople's Republic of China School of Mechanical Engineering Purdue UniversityWest LafayetteIndianaUSA State Key Laboratory of High-Performance Civil Engineering Materials Jiangsu Sobute New Materials Co.Ltd.NanjingPeople's Republic of China School of Civil Engineering Qingdao University of TechnologyQingdaoPeople's Republic of China Department of Mechanical and Aerospace Engineering University at BuffaloThe State University of New YorkBuffaloNew YorkUSA School of Energy and Environment Southeast UniversityNanjingPeople's Republic of China Jiangsu Key Laboratory of Advanced Metallic Materials School of Materials Science and EngineeringSoutheast UniversityNanjingPeople's Republic of China

Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric *** battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal ***,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic ***,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery *** work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.

关键词： battery protection negative Poisson's ratio thermal insulation toughness wood-inspired materials

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An Intelligent and Dynamic Pricing IoT Model to Stimulate the Use of Shared Economies in Smart Cities

An Intelligent and Dynamic Pricing IoT Model to Stimulate th...

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construction Research Congress 2024, CRC 2024

作者： Mohammadi, Mohsen Assaad, Rayan H. Chang, Aichih Jasmine John A. Reif Jr. Dept. of Civil and Environmental Engineering New Jersey Institute of Technology NewarkNJ United States Smart Construction and Intelligent Infrastructure Systems Lab Dept. of Civil and Environmental Engineering New Jersey Institute of Technology NewarkNJ United States Martin Tuchman School of Management New Jersey Institute of Technology NewarkNJ United States

ISBN: (数字)9780784485262

ISBN: (纸本)9780784485262

There has been an increasing interest in smart cities and digital technology/information to enhance the quality of services, while reducing costs and resource consumption. Hence, the "shared economies" notion was introduced accordingly, which is a modern business concept highlighting people's preference to share/rent goods and services (e.g., space, transportation, utilities) rather than to buy and/or own them. Smart cities enabled by peer-to-peer internet capabilities - e.g., IoT technology and devices - can fuel the growth of shared economies by improving information transparency, rationalizing resource allocation, and reducing waste. This paper proposes a dynamic pricing model developed from an innovative renter reliability index, which is measured and created by IoT-enabled and real-time data. The proposed intelligent dynamic IoT model was used and tested in a real-world long-term shared economy environment (i.e., a rental space) of a smart city in New Jersey, USA. The results showed that the proposed model can significantly enhance the transparency and legitimacy of rental pricing in a shared. This paper contributes to the literature by improving the efficiency of the shared products/services, the allocation of resources, and the pricing rationalization, which ultimately stimulates the shared economy concept in smart cities. The proposed model is useful for both the providers and users of shared economy systems, particularly those of shared properties (i.e., rental spaces). © 2024 ASCE.

关键词： Internet of things

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Suggestions on Promoting the High-Quality Development of Chinese Real Estate Industry

Suggestions on Promoting the High-Quality Development of Chi...

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2023 International Conference on construction and Real Estate Management: The Human-Centered construction Transformation, ICCREM 2023

作者： Liu, Jian Zhang, Shixuan Song, Botong Key Laboratory for Resilient Infrastructures of Coastal Cities Ministry of Education and Ecological Technology Institute of Construction Engineering Shenzhen Univ. Shenzhen China College of Civil and Transportation Engineering Shenzhen Univ. Shenzhen China

ISBN: (数字)9780784485217

ISBN: (纸本)9780784485217

Recently, China's real estate industry, as a pillar industry of the national economy, has been mentioned by the central government. This depends on the continuous willingness of urban residents and migrant workers to buy houses and the central government's policy on real estate development. The real estate industry involves the development of many industries such as building materials industry, construction industry, and financial industry, therefore, promoting the high-quality development of real estate industry will have important systemic impact on China's economic and financial stability. This paper analyzes the difficulties and problems faced by the real estate industry, and puts forward improvement measures and suggestions to promote the high-quality development of China's real estate industry. The difficulties and problems include: (1) insufficient disposable funds for real estate projects, (2) real estate sales profit declined, (3) the government's macro-control policy having led to the frequent bankruptcy of some real estate enterprises, (4) the enrollment of civil engineering majors in colleges and universities nationwide ranking the last, and the employment rate of graduates being only 60%, (5) the real estate tax increasing the collapse of the real estate industry, and (6) green buildings two-star and three-star buildings are rare. The improvement measures and suggestions include (1) formulating policies to limit real estate speculation and exploring new development models of real estate industry, (2) improving the financial system to ensure the reasonable profits of real estate enterprises, (3) adjusting the real estate land policy, and strengthening the supervision function of the government on the real estate market, (4) reducing or cancelling the enrollment of civil engineering majors and developing into intelligent construction majors, (5) suspending the imposition of real estate tax, and (6) increasing the proportion of high-star green buildings. ©

关键词： construction industry

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A review of Obayashi’s fleet management system using a Robotics Evaluation Framework

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construction Robotics 2024年第2期8卷 1-15页

作者： Portocarrero Rodriguez, Cesar Augusto Diaz Salgado, Daniel Nishimoto, Takuo Brosque, Cynthia Fischer, Martin Department of Civil and Environmental Engineering Stanford University Stanford USA Department of Construction Technology Obayashi Corporation Tokyo Japan

This case study examines Obayashi Corporation’s fleet management system (FMS), an advanced remote, and semi-automatic operation system for construction equipment. The FMS integrates robotics and autonomous technology to enhance efficiency, safety, and productivity in construction operations during excavation. Through a Robotics Evaluation Framework (REF), product, organization, and process data as well as four variables: safety, quality, schedule, and cost were used to compare the FMS’s performance to its manual counterpart. The analysis reveals that the FMS reduces unergonomic periods by 68% and cuts labor expenses by 31% per zone, and by 18% in the total test volume. The FMS, however, faces considerable challenges in terms of schedule, with a 145% increase in total duration compared to the conventional method. Assuming all four variables in the REF are of equal importance to the contractor, the sensitivity analysis indicates the FMS is superior to human operation, even considering the system’s setbacks. Overall, the study highlights the potential benefits of reduced human error, labor savings, improved safety, repeatability, and modular technology. This analysis provides insights for innovators in the construction industry seeking to introduce digital and automation technologies. Future work should analyze this technology’s performance in other locations to assess its adaptability and the robustness of the results obtained.

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Mechanical Properties of Sleeve Grouting Connection Based on Water-Binder Ratio Variable 9

Mechanical Properties of Sleeve Grouting Connection Based on...

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9th International Technical Conference on Frontiers of Hydraulic and civil engineering technology, HCET 2024

作者： Xie, Yannan Liu, Wenchao Zhang, Kesheng Ren, Baoshuang Qiao, Qiyun CCCC Construction Group CO. LTD Beijing100022 China Research and Development Center of Green Building Technology CCCC Beijing100022 China College of Architecture and Civil Engineering Beijing University of Technology Beijing100124 China

ISBN: (纸本)9781643685595

Grout is sensitive to water content, and to investigate the effect of different water-cement ratios of grout on the mechanical performance of grout sleeve connections, eight conditions were designed comprising a total of 48 specimens with 12 mm diameter steel bars subjected to uniaxial tensile tests. Complemented by compressive strength adjustments of grout specimens, finite element software was employed to simulate unit fracture criteria, and finite element simulations were conducted on selected specimens. Finally, based on the current research findings, a preliminary derivation of the compressive strength of grout and the calculation process of sleeve tensile strength was achieved. The study indicates: (1) specimens primarily fail due to steel bar pullout when the water-cement ratio exceeds 0.2;failures due to steel bar or thread rupture are predominant when the ratio is below 0.2;(2) the failure mode and load-displacement curves in numerical simulations correspond to experimental trends;(3) there exists a quantitative relationship between calculated load and theoretical steel bar load, with the critical compressive strength of grout during experiments being 63.07 MPa and the critical water-cement ratio being 0.23. © 2024 The Authors.

关键词： Grouting

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