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Analysis of flexural fatigue damage and micro-mechanisms of nano-SiO2 modified recycled aggregate concrete

construction and Building Materials 2025年 487卷

作者： Zhang, Xianggang Wang, Liuyang Shen, Youchuan Liu, Jianfei Fan, Yuhui School of Intelligent Construction Wuchang University of Technology Wuhan430223 China School of Civil Engineering Henan Polytechnic University Jiaozuo454003 China

Converting demolition waste into recycled coarse aggregate (RCA) for recycled aggregate concrete (RAC) is an effective, sustainable method. However, the engineering application of RCA is substantially restricted owing to its high porosity and water absorption. This study proposes a nano-SiO₂ immersion method to enhance RCA fatigue performance and microstructure. Based on varying parameters including RCA replacement ratios (0 %, 50 %, 100 %), nano-SiO2 solution concentrations (0 %, 0.5 %, 1 %), immersion durations (24 h, 48 h), and stress levels (0.60, 0.65, 0.70), specimens were prepared for comprehensive flexural fatigue testing and microstructural mechanism analysis. This research focused on analyzing the characteristic variations of flexural fatigue strain and fatigue modulus in nano-SiO2 modified RAC subjected to multiple stress levels. The progression patterns of fatigue damage were thoroughly analyzed, and a corresponding damage evolution model was developed. The experimental results revealed that nano-SiO₂ immersion treatment (optimal: 1 %, 48 h) significantly enhances RAC performance. Nano-SiO₂ modified RAC's flexural fatigue strain and modulus show a three-stage evolution. A fatigue damage model using flexural fatigue modulus as the variable can predict damage. The damage progression was significantly influenced by stress levels and replacement ratios, showing accelerated deterioration with their increase. Conversely, higher nano-SiO2 solution concentrations and extended immersion durations effectively mitigated damage development. Nano-SiO₂ modifies mortar's chemical composition, reduces CH content and optimizes ITZ. Specimen R-100–0.5–48 has a 14.62 % porosity reduction. The findings are anticipated to provide fundamental insights and technical support for advancing both theoretical understanding and practical applications of nano-SiO2 modified RAC in engineering structures. © 2025 Elsevier Ltd

关键词： Fatigue damage

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Operational Modal Analysis and Finite Element Model Updating of a 53-Story Building 39th

Operational Modal Analysis and Finite Element Model Updating...

引用

39th IMAC, A Conference and Exposition on Structural Dynamics, 2021

作者： Avci, Onur Alkhamis, Khalid Abdeljaber, Osama Hussein, Mohammed Civil Construction and Environmental Engineering Iowa State University AmesIA United States Department of Civil and Architectural Engineering Qatar University Doha Qatar Department of Building Technology Linnaeus University Växjö Sweden

ISBN: (纸本)9783030771423

This paper presents Operational Modal Analysis (OMA) and Finite Element (FE) model updating of a tall structure. Located in the West Bay area of Doha (Qatar), the structure was constructed between 2012 and 2016. It is a reinforced concrete building with shear wall cores located towards the center of the building plan. With 53 stories above the ground and 2 stories below ground, the 230 m (755 ft) tall building is being used for residential and hotel purposes. The material presented here is arguably the first published work on large-scale dynamic testing of a civil structure in Qatar. The wireless sensors used for testing are state-of-the-art equipment that can capture very low frequencies, something that cannot be accomplished with most of the conventional accelerometers available in the market. © 2022, The Society for Experimental Mechanics, Inc.

关键词： Structural dynamics

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Analytical Solution of Seepage Field in Infinite Different Strata Grouting Models

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Science technology and engineering 2024年第29期24卷 12723-12733页

作者： Wei, Fu-Cheng Wang, Zhen Zhou, Feng-Xi School of Civil Engineering Lanzhou University of Technology Lanzhou730050 China The Fifth Engineering Co. Ltd. China Communication Construction Co. Ltd. First Highway Engineering Company Beijing101200 China

Based on groundwater dynamics, the tunnel grouting process was analogized with the movement of groundwater towards a complete well, and a seepage model was established under layered geological conditions. By using the conformal transformation method, the problem was transformed from a planar radial flow to a planar uniform flow, and the analytical solution of the seepage field under layered geological conditions was solved. On this basis, the tunnel grouting model was simplified into three layers of strata, and analytical solutions were obtained for the tunnel seepage flow rate, external water pressure of the grouting ring, and external water pressure of the lining. To verify the effectiveness of the solution, the equivalent area method was used and numerical simulations were conducted against the background of the unity tunnel. The results show that with an increase in the thickness of the grouting circle and a decrease in the permeability coefficient of the grouting circle and lining, the water inflow and external water pressure of the tunnel will decrease, while the water blocking rate and external water pressure of the grouting circle will increase. Through error analysis, it was found that compared with the analytical solution, the error of the concentric circular section decreases with the increase of the thickness error of the grouting ring, while the error of the six centered circular section decreases. The simulation solution show that the water inflow of the two sections is close to 59%. As the permeability coefficient of the grouting ring decreases, the relative error between the simulated and analytical solutions for water inflow is relatively large. As the permeability coefficient of the lining decreases, the simulated solutions for water inflow and external water pressure of the lining are greater than the analytical solutions. © 2024 Beijing Kexue Jishu yu Gongcheng Zazhishe. All rights reserved.

关键词： Conformal mapping

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Small-strain shear modulus of fine-grained gassysoil under different gas content and initial pore water pressure

Results in Engineering

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Results in engineering 2025年 26卷

作者： Liang, Xu Pan, Daoming Wu, Tingyu Hangzhou Urban Infrastructure Construction Management Center Hangzhou311103 China College of Civil Engineering Zhejiang University of Technology Hangzhou310023 China

The fine-grained gassy soils are prevalent in coastal regions worldwide. The inadequate knownledge of their mechanics, leads to engineering geological issues such as seabed landslides, amid marine and offshore advancements. Through a series of triaxial tests combined with bender elements, this study investigated the stress-strain behavior of fine-grained gassy soil with varying initial gas contents and pore water pressures, along with the variations in the small-strain shear modulus during shearing, thereby facilitating a better understanding of gassy soils mechanics in situ exploration. Our findings show the gassy soils at initial pore water pressure of 150 kPa resemble saturated soils in the stress-strain behaviors, but differ in small-strain moduli. A distinctive inflection point at 5% strain signifies peak pore pressure and valley shear modulus, precedes strength and strain peaks. Additionally, there is an unique power relationship between the small-strain modulus and the secant shear modulus during shearing. © 2025

关键词： Pore pressure

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A co-simulation method for the train-track-bridge interaction analysis under earthquake using Simpack and OpenSees

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Journal of Central South University 2022年第8期29卷 2791-2806页

作者： TANG Jian-yuan GUO Wei WANG Yang LI Jun-long ZENG Zhe-feng School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China

Under high-level earthquakes,bridge piers and bearings are prone to be damaged and the elastoplastic state of bridge structural components is easily accessible in the train-track-bridge interaction(TTBI)*** the complexity and structural non-linearity of the TTBI system under earthquakes,a single software is not adequate for the coupling ***,in this paper,an interactive method for the TTBI system is proposed by combining the multi-body dynamics software Simpack and the seismic simulation software OpenSees based on the Client-Server architecture,which takes full advantages of the powerful wheel-track contact analysis capabilities of Simpack and the sophisticated nonlinear analysis capabilities of *** on the proposed Simpack and OpenSees co-simulating train-track-bridge(SOTTB)method,a single-span bridge analysis under the earthquake was conducted and the accuracy of co-simulation method was verified by comparing it with results of the finite element ***,the TTBI model is built utilizing the SOTTB method to further discuss the running safety of HST on multi-span simply supported bridges under *** results show that the SOTTB method has the advantages of usability,high versatility and accuracy which can be further used to study the running safety of HST under earthquakes with high intensities.

关键词： train-track-bridge system co-simulation SOTTB client-server running safety

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Novel dynamic test system for simulating high-speed train moving on bridge under earthquake excitation

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Journal of Central South University 2022年第8期29卷 2485-2501页

作者： LIU Han-yun YU Zhi-wu GUO Wei JIANG Li-zhong School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-Speed Railway Construction Technology Changsha 410075China

China’s high-speed railways are always facing the potential damage risk induced by strong *** the route design concept of“using bridge instead of embankment”has also greatly increased the probability of high speed trains moving on bridges when a strong earthquake *** the past decades,a bunch of theoretical and numerical studies have been conducted in the seismic dynamic field of high-speed ***,the effective dynamic test system for verifying the given method and theoretical results is still ***,a novel dynamic test system(DTS)consisting of a shaking table array and a train-pass-bridge reduced-scale model is proposed in this *** some crucial technical problems discussion,the effectiveness of similar design scheme and the feasibility of reduced-scale DTS are elaborated,and then the detailed DTS structures are given and displayed as *** this basis,the demonstration tests are conducted and compared with the numerical *** results show that the proposed DTS is accurate and ***,the DTS can provide a new physical simulation approach to study the high-speed train’s running safety on bridges under earthquakes and can also provide a reference for the construction of related systems.

关键词： strong earthquake high-speed train shaking table test dynamic test system similar design bridge

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Damage-Controlling Seismic Design of Low- and Mid-Rise RC Buildings Considering Mainshock-Aftershock Sequences

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Structures 2023年 57卷

作者： Nugroho, Lorddy Zefanya Chiu, Chien-Kuo Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei City10607 Taiwan

Recently, the modified equivalent linearization method (MELM) is used to estimate the maximum deformation response for a structure under a near-fault or far-fault earthquake. However, most works in which the equivalent linearization method is used consider only one earthquake event. When a reinforced concrete (RC) building structure is damaged by a mainshock, which is the main seismic event of an earthquake, its stiffness and strength are reduced by concrete cracking and rebar yielding and then its period is longer in the sequent seismic events or so-called aftershock. Therefore, for seismic design of low- and mid-rise RC building structures, this work is aim to propose a simplified method that can be used to quantify the damage that is subjected to an MSAS sequence in a near-fault or far-fault earthquake using MELM. Additionally, a formula that can be used to do the damage-controlling seismic design considering an MSAS sequence is also suggested. © 2023 Institution of Structural Engineers

关键词： Reinforced concrete

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Optimization Model of Maintenance Scheduling Problem for Heritage Buildings with Constraint Programming

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Buildings 2023年第7期13卷 1867页

作者： Liu, Shu-Shun Utami, Putri Budiwirawan, Agung Arifin, Muhammad Faizal Ardhiansyah Perdana, Fernanda Sarwatatwadhika Department of Civil and Construction Engineering National Yunlin University of Science & Technology Yunlin 640 Taiwan Department of Civil Engineering Universitas Negeri Semarang Semarang50229 Indonesia

The preservation and maintenance of ancient buildings, particularly heritage buildings, is a complex process that requires careful consideration of several aspects, including maintenance plans and budget availability. An effective long-term maintenance plan is crucial for preserving the historical value and condition of these buildings. The primary purpose of such a plan is to limit building deterioration, maintain optimal building performance, minimize operational costs and ensure budget constraints are met. This study introduces an innovative methodology to optimize maintenance strategies for heritage buildings in various scenarios, including normal conditions and the aftermath of possible catastrophic events. The proposed methodology compares different parameters, such as building conditions, building service life and various types of maintenance interventions. However, budget availability poses a significant challenge in many case studies, and addressing budgetary constraints is notoriously difficult. Limited budgets may hinder the implementation of desired maintenance activities, necessitating optimization of the maintenance plan to overcome these issues. To address these challenges, this study utilizes constraint programming (CP) as an optimization tool. Constraint programming is a powerful optimization methodology that addresses combinatorial problems by formulating them as mathematical models and handling the associated constraints. By representing the problem as one or more instances of the Constraint Satisfaction Problem (CSP), constraint programming enables efficient and effective problem solving. The proposed CP model proves to be a valuable tool in solving maintenance scheduling problems for heritage buildings. The results of this study are intended to assist decision makers in developing long-term maintenance plans for heritage building preservation. © 2023 by the authors.

关键词： Budget control

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Performance analysis and improvement of air-cooled chiller system with enhanced heat rejection control 3

Performance analysis and improvement of air-cooled chiller s...

引用

3rd International Conference on Energy, Power and Electrical technology, ICEPET 2024

作者： Yang, Jia Shen, Changliang Fu, Ling Liu, Zhaoyong Chongqing University of Science and Technology School of Civil Engineering and Architecture Chongqing401331 China Chongqing Normal University Capital Construction Management Office Chongqing401331 China Chongqing Earthquake Agency Chongqing401147 China Chongqing College of Architecture and Technology Chongqing401331 China

ISBN: (纸本)9798350352658

The chiller system accounts for a significant proportion of a building's energy consumption. To improve the performance of air-cooled chillers, more energy-efficient condenser features were investigated in this study, including the variable speed condenser fans (VSCF) and the variable condensing temperature control (VCTC). The thermodynamic models by TRNSYS were developed for an air-cooled chiller with different heat rejection control, and the chiller performance with each heat rejection control was determined. In comparison with the conventional head pressure control (HPC), the chiller COP could be improved by 17.9% with VSCF under HPC, and it could be improved further by up to 51.8% with VSCF under VCTC. The chiller models were applied to determine how the different heat rejection control affected the energy consumption of air-cooled chillers serving an office building. The annual energy saving of the chillers with VSCF under VCTC was 7.7%, indicating the significant energy saving potential by using VSCF and VCTC for air-cooled chillers. © 2024 IEEE.

关键词： Energy efficiency

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Digitalization Paths for Aerial Building Machine construction technology

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Science technology and engineering 2025年第9期25卷 3840-3850页

作者： Guo, Feng-Yi Liu, Shi-Ping Fu, Shuang Xu, Jian Sun, Jun National Innovation Center for Digital Construction Technology Huazhong University of Science and Technology Wuhan430074 China School of Civil and Hydraulic Engineering Huazhong University of Science and Technology Wuhan430074 China School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan430074 China

The emergence of aerial building machines has greatly improved the environment and efficiency of high-rise building operations, while also facing challenges such as increased difficulty in construction operations and complex construction processes. With the continuous deepening of digital transformation in the construction industry, the digital expression of building machine construction processes has emerged as an intuitive and clear solution. It significantly enhances the transparency of the construction process, optimizes resource allocation, and strengthens decision support for project management. An effective pathway for the digital expression of building machine construction processes was established, aimed at advancing high-rise construction towards intelligent management. Through theoretical foundations and field research analysis, the needs for the digital expression of building machine construction processes were identified, leading to the design of a framework for implementing digital expression of building machine construction processes. This research not only provides theoretical guidance for the digital transformation of building machine construction processes but also expands new perspectives on the application of knowledge graphs, interactive electronic technical manuals, model-based definition (MBD) techniques, and augmented reality(AR) technology in the construction field. © 2025 Beijing Kexue Jishu yu Gongcheng Zazhishe. All rights reserved.

关键词： Project management

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