Construction Engineering and Management Commons^™

Study On Optimal Layout Of Cross ⁃Diaphragm In Oblique Small Box Girder, Mai Xinhao

Journal of China & Foreign Highway

In order to determine the optimal layout of the cross⁃diaphragms in the oblique small box girder, a prestressed concrete small box girder bridge with a 50 m span was taken as the research object, and its internal force under the load of the moving beam was numerically simulated and measured. First, the model was modified according to the measured stress data, and the maximum distance between the cross⁃diaphragms was determined by using the warping-limited normal stress. Then, the height and thickness of the middle cross⁃diaphragms were determined according to the deflection difference coefficient of the bridge span. Finally, according to …

Non⁃Gaussian Features Of Fluctuating Wind Pressures Under Combined Axle Condition, Chen Zhiqiang

Journal of China & Foreign Highway

In view of the non-Gaussian characteristics of wind pressure on the train surface of a typical high-speed railway train and bridge system, the Gaussian variable was expressed as a Hermite polynomial considering non-Gaussian variables by using Hermite series expansion method, and the probability density curve and peak factor of train surface were analyzed. The results show that the Davenport peak factor based on Gaussian distribution obviously underestimates the non-Gaussian peak factor, and its probability density curve deviates from the actual curve of the measuring point. The Hermite series peak factor method based on the modified method takes into account the …

Application Of 3d Reconstruction Model In Inspection Of Bridge Apparent Defects, Xu Guangli, Li Shaoyong, Tang Jun, Liu Shuqi, Zhou Yin

Journal of China & Foreign Highway

In view of problems such as low efficiency, poor accuracy, and imprecise three-dimensional (3D) location of defects in apparent defect inspection of bridges, this paper proposed a method for apparent defect inspection of bridges based on a 3D reconstruction model. By taking the indoor rectangular beam as the object, a three-dimensional bridge model was established, and its accuracy was verified. Then, based on the point cloud data derived from the model, a program was written in Python to realize the identification, measurement, and parameter derivation of apparent defects of bridges. Dade Bridge in Kunming, Yunnan Province was set as the …

Design And Construction Of Steel Caisson For Inclined Pilecap Of Beitstadsund Bridge In Norway, Yang Dingjun

Journal of China & Foreign Highway

At present, the underwater bridge foundation construction technology in China and abroad has been relatively mature, but the different geographical environments, hydrogeological conditions, the form of basic structure, and the available construction equipment lead to different construction schemes and technologies. The Beitstadsund Bridge in Norway is located near the Arctic Circle in central Norway and across the strait. In the design and construction of the deep-water steel cofferdam of the inclined steel pile cap for the bridge, the overall installation of the steel cofferdam was realized by setting the cofferdam support on the inclined steel pipe group, the overall positioning …

Study On Correction Method Of Cable Length Error In Construction Control Of Cable ⁃Stayed Bridges, Huang Gen, Chen Changsong

Journal of China & Foreign Highway

In order to effectively correct the stay cable length error during the construction of the cable-stayed bridge, this paper proposed a correction method with the exposure of the sockets as the error control index and analyzed the influence of the elastic modulus, temperature effect, and anchor point coordinates of the cable on the cable length error from the perspective of construction control. Then, error correction was achieved by adjusting the position of the manufacturing cable length and the nut at the anchor end. The results of application in Jiayu Yangtze River Highway Bridge show that this method can improve the …

Analysis Of Mechanical And Deformation Characteristics Of Karst Tunnel Structure And Research On Treatment Technology, Huang Haifeng, Chang Zhenchao, Luo Junhui, Zhou Xiang, Ceng Fuquan, Tian Fapai

Journal of China & Foreign Highway

Combined with the construction process of Nongmo Karst Tunnel on Du’an–Bama Expressway, this paper used Midas-GTS finite element calculation software to conduct numerical simulation research on the stability of surrounding rock and treatment structure of tunnel with karst caves on either side, analyzed the influence of tunnel excavation on the stress and deformation characteristics of surrounding rock and supporting structure, and probed into the treatment effect of biased wall and root pile on the treatment of karst tunnel. The results show that the surrounding rock at the bottom of the tunnel, the top of the composite foundation, and the top …

Influence Of Proximity Construction Of A New Pile Foundation On Adjacent Metro Tunnel, Jin Shengji, Mu Anxin, Bi Bo, Xu Chao, Yu He

Journal of China & Foreign Highway

The construction of a bridge pile foundation and cap not only causes disturbance to its foundation and surrounding soil but also has a certain influence on adjacent existing structures. In order to study the influence of new pile foundation proximity construction on tunnels adjacent to subway sections, this paper took the pile foundation construction process of auxiliary bridge extension on both sides of Shenyang Changqing Bridge as the research object and adopted Midas/GTS finite element numerical simulation and construction monitoring methods to study the influence of new pile foundation proximity construction on tunnels adjacent to subway sections. The results show …

Research On Crack And Permeability Characteristics Of Cement ⁃Modified Expansive Soil Under Dry ⁃Wet Cycles, Bao Guiyong, Xu Yangshaojun, Jiang Zhijie, Rong Hongliu, Wang Jinlong

Journal of China & Foreign Highway

In order to study the engineering permeability characteristics of cement-modified expansive soil under dry and wet cycles, the mix ratio of cement-modified expansive soil was designed, and the orthogonal design test method was adopted. Image analysis software PACS, unconfined compressive strength test, and laboratory permeability test were used to study the crack development, strength attenuation characteristics, and permeability changes of cement-modified expansive soil under dry and wet cycle conditions. The results show that soil permeability and strength are greatly affected by the number of dry and wet cycles. Under the condition of dry and wet cycles, the moisture content of …

Study On Influence Of Freeze ⁃Thaw Cycles On Shear Properties Of Fly Ash Modified Saline Soil, Cheng Zhuo, Cui Gaohang, Gao Zening, Hou Zhao, Gang Haohang

Journal of China & Foreign Highway

In order to explore the shear strength of fly ash-modified saline soil subgrade under the freeze-thaw cycle, saline soil samples from Suihua–Daqing Expressway were selected for direct shear test under different fly ash contents. The results show that the cohesive force and internal friction angle of the saline soil decrease after several freeze-thaw cycles. With the increase in fly ash content, the internal friction angle, cohesive force, and shear strength of the improved saline soil increase first and then decrease. When the fly ash content is 15%, the cohesive force, internal friction angle, and other mechanical indexes of the saline …

Effect Of Temperature And Light On Characteristics Of Asphalt Emissions, Zhu Xuwei, Tian Bo

Journal of China & Foreign Highway

In order to study the effects of temperature and light on the characteristics of asphalt emissions, atmospheric pressure chemical ionization–time-of-flight mass spectrometer (APCI‑TOF MS) and electron impact ionization mass spectrometry (EI‑MS) were used to quantitatively characterize the composition information of PG 62-22 asphalt emissions at different temperatures (40–200 °C). The effects of different temperatures and light on total emission factor, SOA conversion factor, intermediate volatile organic compound (IVOC)/semi-volatile organic compound (SVOC) volume fraction, and aromatics volume fraction of asphalt emissions were studied. The results show that the components of asphalt emissions change with temperature, and the components are complex and …

Study On Triaxial Mechanical Properties Of Glass Fiber Reinforced Cement Soil In Short Age, Wang Wei, Dai Mengdan, Yu Wenjie

Journal of China & Foreign Highway

In order to evaluate the improvement effect of fiber on the brittle damage of cement soil, a triaxial unconsolidated undrained (UU) test was carried out on glass fiber cement soil (GCS) with a curing age of 7 d and a mass fraction of glass fiber (GF) of 0, 2‰, 4‰, 6‰, and 8‰, respectively. The results show that: ① GCS retains the original strain softening characteristics of cement soil; ② For the same mass fraction of GF, the peak stress, peak strain, and residual strength of GCS samples increase gradually with the increase in confining pressure, but the brittleness index …

Study On Experimental Application Of Xinjiang Steel Slag In Cement Stabilized Base, Chen Wei, Yu Haiming, Li Qian, Huang Yong, Si Yi

Journal of China & Foreign Highway

Based on the experimental study of Xinjiang steel slag in cement-stabilized base, the physical and chemical characteristics of steel slag were analyzed, and the unconfined compressive strength, splitting strength, and dry shrinkage performance of cement-stabilized steel slag and gravel mixture with different cement dosages (4% and 5%) and steel slag contents (30%, 40%, and 60%) were analyzed. The test results show that steel slag can be used as a good engineering aggregate in a cement-stabilized base, and with the addition of steel slag, the unconfined compressive strength and splitting strength of steel slag and gravel mixture are increased to varying …

Research On Cyclic Accumulative Strain Characteristics Of Structured Soft Clay, Ding Zhi, Yu Jiangang, Sun Miaomiao, Wang Jiawei, Ye Ke

Journal of China & Foreign Highway

Due to its structural properties, natural soft clay is prone to produce large cumulative deformation under cyclic loads such as traffic, which has a great impact on engineering. In order to solve the deformation problem caused by structural failure of soft clay under dynamic action, dynamic characteristics of undisturbed soft clay near a highway in Hangzhou were tested by the dynamic triaxial device under cyclic loading, and the dynamic characteristics of saturated undisturbed soft clay under different effective consolidation confining pressures, vibration frequencies, and dynamic stress ratios under K0 (static earth pressure coefficient) consolidation conditions were studied. The results show …

Effect Of Activator On Compressive Strength Of Steel Slag Powder Cement Soil, Chen Fei, Wang Yanchun, Du Sujun

Journal of China & Foreign Highway

In order to reasonably solve the environmental pollution caused by steel slag, steel slag powder was used to improve cement soil. The optimal mix ratio was determined by a laboratory unconfined compressive strength test to prepare steel slag powder cement soil. In view of of low activity and limited compressive strength enhancement effect of steel slag powder, three kinds of activators including sodium hydroxide, silica fume, and calcium chloride were selected to be added to steel slag powder cement soil, so as to study the strength variation rule. The results show that the strength of cement soil can be improved …

Experimental Study On Time ⁃Varying Characteristics Of Saturated Water Content Of Granite Residual Soil In Acid⁃Etched Environment, Zhang Maolin, Xie Qingzhong, Fu Helin, Zhang Meng, Li Qinglong, Dong Hui

Journal of China & Foreign Highway

In order to clarify the correlation between saturated water content variability and slope stability, characteristic tests on saturated water content of granite residual soil affected by acid were carried out. Direct shear tests were carried out to test the variation rule of saturated water content and its characteristic value under the influence of vertical loading and acidification time, and the internal causes of variation were deduced based on the structural characteristics obtained by microscope electron microscopy. The results show that: ① The vertical pressure σ = 300 kPa is the turning point of the linear and nonlinear relationship, and under …

Mechanical Properties And Micro Analysis Of Cement Stabilized Steel Slag Macadam Base, Wan Tianbao

Journal of China & Foreign Highway

With steel slag as coarse aggregate, cement-stabilized steel slag macadam base material was designed and prepared by selecting three kinds of cement dosage and three kinds of steel slag content. The mechanical properties of cement-stabilized steel slag macadam base were studied through compaction and unconfined compressive strength tests, and XRD and SEM microscopic tests were carried out to analyze the mineral composition and microscopic morphology of steel slag and mixture and clarify the internal mechanism of hydration product formation and microstructure and strength formation. The results show that the maximum dry density and optimum moisture content of cement-stabilized steel slag …

Analysis Of Influence Of Moisture Content ⁃Temperature Dual Factor On Mechanical Properties Of Red Clay, Wang Jiangtao, Bao Temenbaiyila, Yang Weiguang, Zhou Qi, Fu Helin

Journal of China & Foreign Highway

Under the new climatic environment and engineering construction requirements, engineering problems involving red clay are becoming more and more prominent, and it is urgent to deeply grasp the mechanical and engineering properties of residual slope red clay. The typical red clay in Hunan Province was studied in this paper. Based on the unconsolidated undrained direct shear test, this paper studied the mechanical properties of residual slope red clay under the influence of moisture content and temperature, focusing on the most unfavorable conditions affecting the mechanical properties of red clay. The results show that: ① The shear strength of red clay …

Influence Of Steel Fiber And Polymer Emulsion On Mechanical Properties And Microstructure Of Concrete, Guo Guanglei, Sun Shiqiang, Li Ying, Zheng Yiwei, Mei Yingjun

Journal of China & Foreign Highway

The microstructure and mechanical properties of concrete were improved by adding steel fiber and polymer emulsion. The working properties and mechanical properties of steel fiber concrete, polymer emulsion-modified concrete, and steel fiber polymer concrete were tested at 3 d, 28 d, and 90 d. Nitrogen adsorption test, mercury injection test, and density method were used to obtain the total pore volume, median pore size, and closed porosity of concrete. The influence of steel fiber and polymer emulsion on the microstructure and mechanical properties of concrete was analyzed. The results show that the compressive strength of concrete after adding steel fiber …

Effect Of Nano ⁃Metakaolin On Frost Resistance Of Concrete, Li Zhenfa

Journal of China & Foreign Highway

The denudation per unit area, relative dynamic elastic modulus, mechanical strength, and fracture characteristics of concrete with different nano-metakaolin contents before and after freezing and thawing were studied. The results show that nano-metakaolin can significantly improve the freezing resistance of concrete, and the denudation per unit area and relative dynamic elastic modulus loss rate of modified concrete are significantly improved compared with the reference group. The mechanical strength and fracture properties of nano-mekaolin-modified concrete before and after freezing and thawing are higher than those of the control group, and the mechanical strength, fracture toughness, and fracture energy loss rate are …

Traffic Conflict Analysis Of Multila Neexpressway Based On Simulation, Ceng Yuekai, Zhou Tao, Chen Yazhen

Journal of China & Foreign Highway

In order to prevent traffic accidents on multi-lane expressways, the VISSIM traffic simulation model was established based on three types of multi-lane traffic conflicts: mixed passenger and cargo type, separated passenger and cargo type, and separated main and auxiliary type. SSAM software was used to obtain traffic conflict data, and the form, quantity, and location of the conflicts were analyzed. The results show that traffic conflicts are the most under the mixed passenger and cargo type, which are mainly distributed in the upper 100 m range of the innermost lane, outermost lane, and deceleration lane. The traffic conflicts under the …

Risk Analysis Of Highway Nighttime Maintenance Operation Based On Sem, Fan Jinhua, Zou Leping, Qi Shaoren, Tian Zhen

Journal of China & Foreign Highway

In order to analyze the factors affecting the risk of nighttime expressway maintenance operation and quantitatively assess the degree of influence of various factors on the risk of nighttime maintenance operation, this paper extracted five first-level indicators and 36 second-level indicators that affect the risk of operation through literature review, accident data, and questionnaire survey and built an evaluation system. The first-order and second-order confirmatory factor analysis models were constructed by using a structural equation model (SEM) based on 343 questionnaires of the nighttime maintenance operation risks. The results show that the driver factor has the greatest effect on the …

Construction And Management Practice Of Green Highways In Qinling Mountains, Gao Shuohan, Zhang Lei, Zhao Fuqiang, Wang Dong, Li Gang, Liu Xuexin, Yao Jialin

Journal of China & Foreign Highway

In order to practice the concept of green development and promote the transformation and upgrading of highways in Qinling Mountain areas, the paper took Taibai–Fengxian Expressway, a typical demonstration project of green highway in Shaanxi Province as the basis to explore the practical experience of green highway construction suitable for Qinling Mountain areas. The project is located in the hinterland of the Qinling Mountains, with a sensitive water environment, important ecological functions, and rich tourism resources. In addition, it adopts EPC mode. Through the all-round and whole-process implementation of the green concept, the project was planned and launched from the …

Digital Challenges And Opportunities Of Addressing On-Site Productivity And Safety On Construction Job Sites: An International Perspective, Ahmed Hassan, Ankur Mitra, Mark Mulville, Alan Hore

Conference papers

The slow pace of digital transformation in construction remains an impediment to the industry’s evolution. Despite rapid developments in digital technologies, the vast bulk of data generated on construction job sites remains underutilised due to the limited use of real-time data capture. The diffusion of digital solutions in construction depends on successfully capturing critical real-time data that can inform and contribute to more productive work patterns and safer job sites. Nevertheless, the construction industry’s fragmented nature has segregated the digital solutions offered by technology providers from the volatile challenges facing on-site construction practitioners.

This paper will present the early development …

Residential Building Flood Risk Assessment And The Benefits Of Home Elevation, Ayat Al Assi

LSU Doctoral Dissertations

Evaluating flood risk is an essential component of understanding and increasing community resilience. A robust approach for quantifying flood risk in terms of average annual loss (AAL) in dollars is needed to provide valuable information for stakeholder decision-making inside and outside the special flood hazard area (SFHA, which corresponds to the 100-year floodplain). To further inform flood mitigation strategies, quantifying flood risk reduction with home elevation above an initial first-floor height (FFH₀) and the cost effectiveness of federal mitigation assistance for elevation are important steps to enhance awareness of the effect of elevation in reducing flood risk. …

Public Sector Bim Adoption: Development And Evaluation Of Government Policy Interventions: A Systematic Literature Review, Shiyao Kuang, Alan Hore, Ahmed Hassan, Barry Mcauley, Roger West

Conference Papers

Rapid technological advancements in the Architecture, Engineering and Construction (AEC) sector have provided a significant opportunity for improving the industry's efficiency, performance and sustainability. Building Information Modelling (BIM) is an innovative approach to information management in construction that provides a structured methodology for storing and analysing building information exchanged between project stakeholders. However, successful interventions and supports introduced by the public sector in accelerating BIM adoption can be seen through BIM mandates, promotion of information management ISO standards, guidance, funding and procurement integration. In this study, a systematic literature review is adopted to identify BIM policy interventions. The study aims …

Development Of Reduced Cementitious Materials Concrete (Rcmc) Mixtures For Bridge Decks And Rails, Soumitra Das

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Right after construction, drying shrinkage of restrained concrete bridge decks and rails causes early-age cracking that eventually leads to delamination and spalling of concrete due to insertion of water and chemicals, and corrosion of reinforcing steel. The main objective of this research is to control early-age shrinkage cracking by reducing cementitious material content in the bridge deck and rail concrete mixtures. Several reduced cementitious materials concrete (RCMC) mixtures were developed by optimizing aggregate particle packing and conducting overall performance evaluation. This evaluation was carried out in three phases: The first phase investigated the feasibility of new RCMC mixtures by testing …

Construction Semantics And Generative Pre-Trained Transformer (Gpt) Language Models, Ankur Mitra, Ahmed Hassan, Mark Mulville

Articles

The article explores the impact of ChatGPT, a powerful language model developed by OpenAI, on the construction industry. ChatGPT, with its ability to provide contextually accurate responses to a wide range of queries, has the potential to enhance safety, scheduling, and knowledge dissemination in construction. While it shows promise in tasks like hazard recognition and project scheduling, the article emphasizes the need for cautious optimism and human oversight. The construction industry could benefit from ChatGPT's digital assistance to boost productivity and address skills shortages, but it is essential to recognize the value of human expertise alongside AI advancements.

Building Services Engineering July/August 2023

Building Services Engineering

No abstract provided.

Mechanical And Durability Properties Of Fly Ash Geopolymer Concrete – A Review, Ali Shebli, Jamal Khatib, Adel Elkordi

BAU Journal - Science and Technology

Geopolymers have emerged as a promising alternative for Ordinary portland cement (OPC) in construction industry, due to their potential to minimize the emissions of carbon dioxide (CO₂) and improve the efficiency of waste recycling. This paper aims to study the fresh and hardened properties of fly ash geopolymer concrete (GPC), as well as to review the raw materials used in the production of geopolymers. Several factors impact the mechanical and durability properties of fly ash GPC, including the specific type of fly ash utilized, the curing temperature, the alkaline activator (AA) concentration, and the type of AA used. …

Construction And Preliminary Application Of The Carbon-Based Spatial Governance Performance Evaluation System ——Taking Zhejiang Province As An Example, Lin Qu, Ganlin Xia, Cunkuan Bao Prof.

CSID Journal of Infrastructure Development

Carbon is generated through human socio-economic activities, with territorial space serving as the medium for these activities. Variations in spatial governance result in differences in the scale, intensity and efficiency of social and economic activities, as well as energy and resource consumption and carbon emissions across diverse functional spaces. Consequently, spatial governance performance should be evaluated using carbon-related indicators. This study initially established a theoretical model for assessing spatial governance performance based on carbon and an evaluation method encompassing three dimensions or indices "level-progress-gap". Zhejiang Province and its 11 prefecture-level cities were selected as the research area for preliminary application …