Saudi Arabia leads the Gulf Cooperation Council countries in the construction industry, with 63% of the region’s future projects and $1.4 trillion in building and transportation projects. Previous studies have shown that 60% of construction projects are behind the schedule. One of the reasons behind this delay is the inappropriate selection of contractors for construction projects; therefore, the development of a contractor performance assessment model is needed for construction projects in Saudi Arabia. The proposed model includes the major key performance indicators (KPIs) used to measure contractors’ performance in construction projects. Afterward, a questionnaire is conducted with construction professionals to recommend the important KPIs to consider while developing the model. The analytic hierarchy process decision-making technique is applied for assessing relative priorities among the identified KPIs based on expert or decision-maker consensus. The results show that the time category is the most important in selecting the best contractor, emphasizing the significance of timely project completion.
{"title":"Development of a Performance Assessment Model for Contractors in Saudi Arabian Construction Projects","authors":"Ghasan Alfalah, Saad Aldajani, Nehal Elshaboury, Abobakr Al-Sakkaf, Othman Alshamrani","doi":"10.1155/2024/8780539","DOIUrl":"https://doi.org/10.1155/2024/8780539","url":null,"abstract":"Saudi Arabia leads the Gulf Cooperation Council countries in the construction industry, with 63% of the region’s future projects and $1.4 trillion in building and transportation projects. Previous studies have shown that 60% of construction projects are behind the schedule. One of the reasons behind this delay is the inappropriate selection of contractors for construction projects; therefore, the development of a contractor performance assessment model is needed for construction projects in Saudi Arabia. The proposed model includes the major key performance indicators (KPIs) used to measure contractors’ performance in construction projects. Afterward, a questionnaire is conducted with construction professionals to recommend the important KPIs to consider while developing the model. The analytic hierarchy process decision-making technique is applied for assessing relative priorities among the identified KPIs based on expert or decision-maker consensus. The results show that the time category is the most important in selecting the best contractor, emphasizing the significance of timely project completion.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140169400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spherical steel bearings play an important role in the normal longitudinal expansion of the main girders of long-span bridges. With the increase in service time, the wear damage will deteriorate the longitudinal slip performance of spherical steel bearings. In this research, a method of real-time quantitative evaluation on longitudinal slip performance is proposed through monitoring data analysis, correlation analysis, damage evaluation analysis, and experiment data analysis. Monitoring data analysis shows that the temperature field has a good linear relationship with longitudinal displacement. Correlation analysis shows that this relationship is well described by a time-varying multiple linear regression model. Furthermore, bearing friction is used as an index for real-time quantitative evaluation, and a large value of bearing friction indicates serious damage. An evaluation model considering the influence of temperature field and bearing frictions is proposed. The time-varying values of bearing frictions are calculated through Kalman filtering analysis. Experimental results show that the maximum evaluation error of this method is less than 5%, verifying that the proposed method is feasible for real-time quantitative evaluation on the longitudinal slip performance of bridge bearings.
{"title":"Real-Time Quantitative Evaluation on the Longitudinal Slip Performance of Spherical Steel Bearings of Long-Span Bridges","authors":"Shiyang Xu, Xin Zhou, Gaoxin Wang, Youliang Ding","doi":"10.1155/2024/6461381","DOIUrl":"https://doi.org/10.1155/2024/6461381","url":null,"abstract":"Spherical steel bearings play an important role in the normal longitudinal expansion of the main girders of long-span bridges. With the increase in service time, the wear damage will deteriorate the longitudinal slip performance of spherical steel bearings. In this research, a method of real-time quantitative evaluation on longitudinal slip performance is proposed through monitoring data analysis, correlation analysis, damage evaluation analysis, and experiment data analysis. Monitoring data analysis shows that the temperature field has a good linear relationship with longitudinal displacement. Correlation analysis shows that this relationship is well described by a time-varying multiple linear regression model. Furthermore, bearing friction is used as an index for real-time quantitative evaluation, and a large value of bearing friction indicates serious damage. An evaluation model considering the influence of temperature field and bearing frictions is proposed. The time-varying values of bearing frictions are calculated through Kalman filtering analysis. Experimental results show that the maximum evaluation error of this method is less than 5%, verifying that the proposed method is feasible for real-time quantitative evaluation on the longitudinal slip performance of bridge bearings.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140150001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wang Yao, Zhang Hao, Zhang Feng, Li Yang, Li Dong, Bao Min
For medium and small-scale steel structure stadiums, in order to minimize the impact of the construction process on the structural state, a prestressing construction process tailored to medium and small stadiums is proposed, taking full advantage of the inherent elastic deformation range of steel structures. The main steps of the process involve the construction of the main truss first. After the main truss construction is completed, it is lowered to a certain position within its elastic range using cables. The roof grid is then connected to the main truss. Once all connections are completed, the cable tension is gradually released. After the cable tension is released, the main truss exhibits a certain degree of rebound. During the rebound process, the roof grid forms a prestressed structure, ensuring stability and integrity between the main truss and the roof. Through numerical simulation, process analysis is conducted on this construction process, and the optimal construction scheme is proposed.
{"title":"Construction Method and Process Optimization of Prestress Reverse Tensioning for Large-Span Bidirectional Suspension Steel Roof Structures","authors":"Wang Yao, Zhang Hao, Zhang Feng, Li Yang, Li Dong, Bao Min","doi":"10.1155/2024/1668290","DOIUrl":"https://doi.org/10.1155/2024/1668290","url":null,"abstract":"For medium and small-scale steel structure stadiums, in order to minimize the impact of the construction process on the structural state, a prestressing construction process tailored to medium and small stadiums is proposed, taking full advantage of the inherent elastic deformation range of steel structures. The main steps of the process involve the construction of the main truss first. After the main truss construction is completed, it is lowered to a certain position within its elastic range using cables. The roof grid is then connected to the main truss. Once all connections are completed, the cable tension is gradually released. After the cable tension is released, the main truss exhibits a certain degree of rebound. During the rebound process, the roof grid forms a prestressed structure, ensuring stability and integrity between the main truss and the roof. Through numerical simulation, process analysis is conducted on this construction process, and the optimal construction scheme is proposed.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The 3D morphology of the joint surface significantly influences the shear behavior of the jointrock. Constant normal load (CNL) direct shear tests with different shear displacement were conducted to understand the shear stress changing with joint roughness and damage degree during shear. The rough joint specimens were prepared using 3D scanning and printing techniques, and shear tests with different normal stresses and shear displacements were performed. Four different parameters and the damaged area quantitatively described by the image binarization and box dimension were calculated and compared to study the roughness evolution of joint surfaces. The experimental results demonstrated that the roughness parameter and shear stress decrease and approach constant values with increasing shear displacement. A JRC degradation model was presented based on regression analyses to evaluate the JRC values of rock joints under various displacements to replace it in the JRC–JCS model. Additionally, a new postshear behavior modeling was proposed for rock joints based on surface degradation characteristics under various initial joint roughness coefficients (JRC0) and normal stress. The stress–displacement curves resulting from the proposed modified model work well in predicting the postpeak stress–displacement curve, which can prove the effectiveness of the postpeak shear behavior modeling.
{"title":"Study on Mechanical Model for Postpeak Shear Behavior of Rock Joints Based on Degradation Characteristics of the 3D Morphology","authors":"Juan Liu, Feng Gao, Yan Xing, Xianghe Gao","doi":"10.1155/2024/6632239","DOIUrl":"https://doi.org/10.1155/2024/6632239","url":null,"abstract":"The 3D morphology of the joint surface significantly influences the shear behavior of the jointrock. Constant normal load (CNL) direct shear tests with different shear displacement were conducted to understand the shear stress changing with joint roughness and damage degree during shear. The rough joint specimens were prepared using 3D scanning and printing techniques, and shear tests with different normal stresses and shear displacements were performed. Four different parameters and the damaged area quantitatively described by the image binarization and box dimension were calculated and compared to study the roughness evolution of joint surfaces. The experimental results demonstrated that the roughness parameter and shear stress decrease and approach constant values with increasing shear displacement. A JRC degradation model was presented based on regression analyses to evaluate the JRC values of rock joints under various displacements to replace it in the JRC–JCS model. Additionally, a new postshear behavior modeling was proposed for rock joints based on surface degradation characteristics under various initial joint roughness coefficients (JRC<sub>0</sub>) and normal stress. The stress–displacement curves resulting from the proposed modified model work well in predicting the postpeak stress–displacement curve, which can prove the effectiveness of the postpeak shear behavior modeling.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140106780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structural stability of engineering rock mass under dynamic disturbance is directly associated with the fracture mechanics properties in engineering practice. Fully understanding the rock’s fracture mechanical behavior and crack evolution caused by stress concentration at the crack tip in engineering rock mass under dynamic load can offer useful insight into the rock’s dynamic fracture mechanism. A dynamic test using split-Hopkinson pressure bar (SHPB) test system was performed on a single prefabricated fissure sandstone centrally cracked Brazilian disk (CCBD) specimens. Based on the theory of fracture mechanics and one-dimensional stress wave theory, the dynamic crack initiation criterion of CCBD specimen is proposed, and the regression model of sandstone’s dynamic fracture toughness under the coupling effect of fissure angle and strain rate is established by using response surface methodology (RSM). The influence of strain rate and fissure angle on stress wave characteristics, dynamic tensile mechanical behavior, and fracture mechanics characteristic was investigated in this study. The findings demonstrate that: (1) The fissure angle plays a pivotal role in determining the failure mode of sandstone. As the fissure angle increases, three distinct failure modes emerge in the sandstone specimens, while variations in strain rate have minimal impact on the fracture mode of these specimens. (2) Alterations in the fissure angle result in changes to the waveform of transmitted waves. When the fissure angle is below 30°, the transmitted wave exhibits “double peak” characteristics; when it exceeds 30°, a “single peak” waveform is observed. This phenomenon can be attributed to diffraction principles governing incident waves. (3) When the impact pressure is 0.2 MPa, the peak load initially exhibits an increase followed by a decrease, with the peak load reaching its maximum at a fracture angle of 60°; when the impact pressures are 0.3 and 0.5 MPa, there exists a negative correlation between the peak load and the fissure angle. (4) The influence of strain rate on sandstone’s fracture resistance is predominant, with alterations in fissure angle exerting an auxiliary effect on this property. The research results can provide a theoretical and experimental basis for dynamic disaster prevention in urban underground space.
{"title":"Experimental Study on Dynamic Tensile Mechanical Behavior and Fracture Mechanical Characteristics of Sandstone with a Single Prefabricated Fissure","authors":"Jie-hao Wu, Yu-xiang Du, Chang-bai Wang, Qi Zong","doi":"10.1155/2024/5501703","DOIUrl":"https://doi.org/10.1155/2024/5501703","url":null,"abstract":"The structural stability of engineering rock mass under dynamic disturbance is directly associated with the fracture mechanics properties in engineering practice. Fully understanding the rock’s fracture mechanical behavior and crack evolution caused by stress concentration at the crack tip in engineering rock mass under dynamic load can offer useful insight into the rock’s dynamic fracture mechanism. A dynamic test using split-Hopkinson pressure bar (SHPB) test system was performed on a single prefabricated fissure sandstone centrally cracked Brazilian disk (CCBD) specimens. Based on the theory of fracture mechanics and one-dimensional stress wave theory, the dynamic crack initiation criterion of CCBD specimen is proposed, and the regression model of sandstone’s dynamic fracture toughness under the coupling effect of fissure angle and strain rate is established by using response surface methodology (RSM). The influence of strain rate and fissure angle on stress wave characteristics, dynamic tensile mechanical behavior, and fracture mechanics characteristic was investigated in this study. The findings demonstrate that: (1) The fissure angle plays a pivotal role in determining the failure mode of sandstone. As the fissure angle increases, three distinct failure modes emerge in the sandstone specimens, while variations in strain rate have minimal impact on the fracture mode of these specimens. (2) Alterations in the fissure angle result in changes to the waveform of transmitted waves. When the fissure angle is below 30°, the transmitted wave exhibits “double peak” characteristics; when it exceeds 30°, a “single peak” waveform is observed. This phenomenon can be attributed to diffraction principles governing incident waves. (3) When the impact pressure is 0.2 MPa, the peak load initially exhibits an increase followed by a decrease, with the peak load reaching its maximum at a fracture angle of 60°; when the impact pressures are 0.3 and 0.5 MPa, there exists a negative correlation between the peak load and the fissure angle. (4) The influence of strain rate on sandstone’s fracture resistance is predominant, with alterations in fissure angle exerting an auxiliary effect on this property. The research results can provide a theoretical and experimental basis for dynamic disaster prevention in urban underground space.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140107041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When a super-large diameter shield tunnel passes through a strongly karst-developed area, in order to ensure the stability of the tunnel and economy of karst reinforcement, the reasonable treatment range for a huge number of karst caves needs to be researched. Based on a karst treatment project of a shield tunnel with a diameter of 14.5 m, this paper studies the influence of intrusive fully filled karst caves on the stability of the lining and excavation face by using theoretical calculation. In addition, the safe distance between the tunnel and karst caves outside the tunnel is proposed through numerical simulation, and the corresponding treatment range is obtained. The results show that the bearing capacity of the lining has a certain reserve when the intrusive cave is smaller than a certain size, and the caves filled with plastic or hard plastic clay have sufficient antifracturing ability. Therefore, some small fully filled caves inside the tunnel profile can be left unreinforced. On the other side, the critical safe distance is only 1–2 m for the caves with a size of 3 m, so the outside caves with a size less than 3 m can be left unreinforced in the treatment range farther away from the tunnel. The proposed treatment range is close to similar projects that have been built, indicating that analysis results are reasonable.
{"title":"Reasonable Treatment Range of Karst Cave Encountered by Super-Large Diameter Shield Tunnel in Strongly Karst-Developed Area","authors":"Jiang Wang, Jinwen Yang, Xianglin Yan","doi":"10.1155/2024/9994801","DOIUrl":"https://doi.org/10.1155/2024/9994801","url":null,"abstract":"When a super-large diameter shield tunnel passes through a strongly karst-developed area, in order to ensure the stability of the tunnel and economy of karst reinforcement, the reasonable treatment range for a huge number of karst caves needs to be researched. Based on a karst treatment project of a shield tunnel with a diameter of 14.5 m, this paper studies the influence of intrusive fully filled karst caves on the stability of the lining and excavation face by using theoretical calculation. In addition, the safe distance between the tunnel and karst caves outside the tunnel is proposed through numerical simulation, and the corresponding treatment range is obtained. The results show that the bearing capacity of the lining has a certain reserve when the intrusive cave is smaller than a certain size, and the caves filled with plastic or hard plastic clay have sufficient antifracturing ability. Therefore, some small fully filled caves inside the tunnel profile can be left unreinforced. On the other side, the critical safe distance is only 1–2 m for the caves with a size of 3 m, so the outside caves with a size less than 3 m can be left unreinforced in the treatment range farther away from the tunnel. The proposed treatment range is close to similar projects that have been built, indicating that analysis results are reasonable.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140099735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinsong Liao, Fuhai Li, Jing Gong, Lei Zhao, Xi Tong, Xinxin Li
The utilization of recycled aggregate can significantly mitigate the extraction of natural sand and gravel. However, the practical application of recycled aggregate in engineering is impeded by its inherent characteristics, encompassing high water absorption, high crushing, and low apparent density. This study employed a soaking and air-drying method to enhance the strength of three types of aggregates with varying initial strengths by utilizing permeated crystalline materials. The durability of recycled aggregate concrete (RAC) was studied with three different aggregate replacement rates (0%, 50%, and 100%). The test results demonstrate that the slump, compressive strength, freeze resistance, and carbonation resistance of RAC exhibit a decreasing trend as the aggregate replacement rate increases. The freeze resistance and carbonation resistance of RAC are notably enhanced after incorporating permeated crystalline material. This study contributes to a sustainable and efficient solution for the treatment of construction waste, thereby enhancing the utilization rate of recycled concrete.
{"title":"Durability of Recycled Concrete after Reinforcing the Aggregates with Permeable Crystalline Materials","authors":"Jinsong Liao, Fuhai Li, Jing Gong, Lei Zhao, Xi Tong, Xinxin Li","doi":"10.1155/2024/9978563","DOIUrl":"https://doi.org/10.1155/2024/9978563","url":null,"abstract":"The utilization of recycled aggregate can significantly mitigate the extraction of natural sand and gravel. However, the practical application of recycled aggregate in engineering is impeded by its inherent characteristics, encompassing high water absorption, high crushing, and low apparent density. This study employed a soaking and air-drying method to enhance the strength of three types of aggregates with varying initial strengths by utilizing permeated crystalline materials. The durability of recycled aggregate concrete (RAC) was studied with three different aggregate replacement rates (0%, 50%, and 100%). The test results demonstrate that the slump, compressive strength, freeze resistance, and carbonation resistance of RAC exhibit a decreasing trend as the aggregate replacement rate increases. The freeze resistance and carbonation resistance of RAC are notably enhanced after incorporating permeated crystalline material. This study contributes to a sustainable and efficient solution for the treatment of construction waste, thereby enhancing the utilization rate of recycled concrete.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140055433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gas extraction is a major technique for regional gas regulation and coal and gas comining in China. Assuring effective gas extraction operations is a crucial step in ensuring the supply of energy. The effect range of extraction drilling, pressure relief degree, and standard period of gas extraction are all constrained because of the geological constraints affecting coal gas permeability and occurrence. Combined with the advantages of directional drilling and high-efficiency pumping technology and antireflection enhanced pumping technology of hydraulic fracturing, directional long-drilling hydraulic fracturing can effectively improve the efficiency of gas control and expand the scale of gas control. The present study focuses on the exploration of directional long-hole hydraulic fracturing technique in thick coal seams with high gas content using Dafosi Mine as a case study. The research findings demonstrate that hydraulic fracturing contributes to the enlargement of pore size, pore density, and pore connectivity in coal seams. In-depth research was conducted on the expansion of coal seam fractures during the hydraulic fracturing process using the RFPA3D-flow numerical simulation program. Additionally, a comprehensive analysis of stress distribution around the fractures under the flow-solid coupling condition was performed. To further improve the effectiveness of hydraulic fracturing technique, the research team optimized the fracturing tools and construction processes in the four coal seams of Dafosi Mine. The impact of segmented hydraulic fracturing in coal seam bare hole drilling was also studied. Furthermore, an investigation method specific to the coal seam bare hole segmented hydraulic fracturing effects applicable to Dafosi Mine was developed. The maximum fracture extension pressure, minimum fracture closure pressure, and fracture morphology change characteristics during drilling and fracturing were measured, and the fracturing influence radius of coal seam was determined to be 46−58 m, the gas extraction concentration after fracturing increased by 2.20–4.22 times, and the 100-m extraction flow increased by 4.93–11.03 times. It gives other mines technical assistance so they can keep advocating and utilizing the horizontal directional long-drilling stage hydraulic fracturing technique.
{"title":"Research on Hydraulic Fracturing Technology of Long Boreholes along Strata of High Vast Thick Coal Seam","authors":"Chenyang Wang, Shugang Li, Li Liu, Le Liu","doi":"10.1155/2024/6305640","DOIUrl":"https://doi.org/10.1155/2024/6305640","url":null,"abstract":"Gas extraction is a major technique for regional gas regulation and coal and gas comining in China. Assuring effective gas extraction operations is a crucial step in ensuring the supply of energy. The effect range of extraction drilling, pressure relief degree, and standard period of gas extraction are all constrained because of the geological constraints affecting coal gas permeability and occurrence. Combined with the advantages of directional drilling and high-efficiency pumping technology and antireflection enhanced pumping technology of hydraulic fracturing, directional long-drilling hydraulic fracturing can effectively improve the efficiency of gas control and expand the scale of gas control. The present study focuses on the exploration of directional long-hole hydraulic fracturing technique in thick coal seams with high gas content using Dafosi Mine as a case study. The research findings demonstrate that hydraulic fracturing contributes to the enlargement of pore size, pore density, and pore connectivity in coal seams. In-depth research was conducted on the expansion of coal seam fractures during the hydraulic fracturing process using the RFPA3D-flow numerical simulation program. Additionally, a comprehensive analysis of stress distribution around the fractures under the flow-solid coupling condition was performed. To further improve the effectiveness of hydraulic fracturing technique, the research team optimized the fracturing tools and construction processes in the four coal seams of Dafosi Mine. The impact of segmented hydraulic fracturing in coal seam bare hole drilling was also studied. Furthermore, an investigation method specific to the coal seam bare hole segmented hydraulic fracturing effects applicable to Dafosi Mine was developed. The maximum fracture extension pressure, minimum fracture closure pressure, and fracture morphology change characteristics during drilling and fracturing were measured, and the fracturing influence radius of coal seam was determined to be 46−58 m, the gas extraction concentration after fracturing increased by 2.20–4.22 times, and the 100-m extraction flow increased by 4.93–11.03 times. It gives other mines technical assistance so they can keep advocating and utilizing the horizontal directional long-drilling stage hydraulic fracturing technique.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140044525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarmed Wahab, Nasim Shakouri Mahmoudabadi, Sarmad Waqas, Nouman Herl, Muhammad Iqbal, Khurshid Alam, Afaq Ahmad
This research focuses on a comprehensive comparative analysis of shear strength prediction in slab–column connections, integrating machine learning, design codes, and finite element analysis (FEA). The existing empirical models lack the influencing parameters that decrease their prediction accuracy. In this paper, current design codes of American Concrete Institute 318-19 (ACI 318-19) and Eurocode 2 (EC2), as well as innovative approaches like the compressive force path method and machine learning models are employed to predict the punching shear strength using a comprehensive database of 610 samples. The database consists of seven key parameters including slab depth (ds), column dimension (cs), shear span ratio (av/d), yield strength of longitudinal steel (fy), longitudinal reinforcement ratio (ρl), ultimate load-carrying capacity (Vu), and concrete compressive strength (fc). Compared with the design codes and other machine learning models, the particle swarm optimization-based feedforward neural network (PSOFNN) performed the best predictions. PSOFNN predicted the punching shear of flat slab with maximum accuracy with R2 value of 99.37% and least MSE and MAE values of 0.0275% and 1.214%, respectively. The findings of the study are validated through FEA of slabs to confirm experimental results and machine learning predictions that showed excellent agreement with PSOFNN predictions. The research also provides insight into the application of metaheuristic models along with ANN, revealing that not all metaheuristic models can outperform ANN as usually perceived. The study also highlights superior predictive capabilities of EC2 over ACI 318-19 for punching shear values.
{"title":"Comparative Analysis of Shear Strength Prediction Models for Reinforced Concrete Slab–Column Connections","authors":"Sarmed Wahab, Nasim Shakouri Mahmoudabadi, Sarmad Waqas, Nouman Herl, Muhammad Iqbal, Khurshid Alam, Afaq Ahmad","doi":"10.1155/2024/1784088","DOIUrl":"https://doi.org/10.1155/2024/1784088","url":null,"abstract":"This research focuses on a comprehensive comparative analysis of shear strength prediction in slab–column connections, integrating machine learning, design codes, and finite element analysis (FEA). The existing empirical models lack the influencing parameters that decrease their prediction accuracy. In this paper, current design codes of American Concrete Institute 318-19 (ACI 318-19) and Eurocode 2 (EC2), as well as innovative approaches like the compressive force path method and machine learning models are employed to predict the punching shear strength using a comprehensive database of 610 samples. The database consists of seven key parameters including slab depth (<i>d</i><sub><i>s</i></sub>), column dimension (<i>c</i><sub><i>s</i></sub>), shear span ratio (<i>a</i><sub><i>v</i></sub>/<i>d</i>), yield strength of longitudinal steel (<i>f</i><sub><i>y</i></sub>), longitudinal reinforcement ratio (<i>ρ</i><sub><i>l</i></sub>), ultimate load-carrying capacity (<i>V</i><sub><i>u</i></sub>), and concrete compressive strength (<i>f</i><sub><i>c</i></sub>). Compared with the design codes and other machine learning models, the particle swarm optimization-based feedforward neural network (PSOFNN) performed the best predictions. PSOFNN predicted the punching shear of flat slab with maximum accuracy with <i>R</i><sup>2</sup> value of 99.37% and least MSE and MAE values of 0.0275% and 1.214%, respectively. The findings of the study are validated through FEA of slabs to confirm experimental results and machine learning predictions that showed excellent agreement with PSOFNN predictions. The research also provides insight into the application of metaheuristic models along with ANN, revealing that not all metaheuristic models can outperform ANN as usually perceived. The study also highlights superior predictive capabilities of EC2 over ACI 318-19 for punching shear values.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140047861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The goals and benefits of implementing building information modeling (BIM) in different facilities are comparable, although there are variations in the employed technologies. Nevertheless, when considering the practical aspects of BIM, the specific variations in implementing BIM across different facilities lack clarity. This study investigated the variations in viewpoints among participants in the architecture, engineering, and construction (AEC) industry regarding the adoption of BIM. The objective was to assess the necessity of developing diverse BIM application strategies based on the specific needs of AEC facilities. The following outlines the investigative process: (1) The survey questions were structured as items that necessitate prior investigation and consultation of BIM execution plans from prominent countries. (2) Appropriate statistical tests were chosen to analyze the correlation between respondents’ information and the questions. (3) The findings of the analysis conducted on the group of respondents were deliberated. The survey revealed that strategic variations are essential for the implementation of space for meetings in a technical setting, the formulation of data standards and BIM team for a cooperative environment, and the assessment of subjects based on the type of facility. Specifically, client-specified common data environments exhibited variations in the responsibilities of participants, while the assignment of BIM coordinators also displayed differences in participant roles, depending on the type of facilities involved. Nevertheless, all participants were in complete agreement regarding the collaborative environment, technical environment, organizational structure, implementation guide, and the necessity for evaluation. Surveys of the perceptions of these AEC participants help identify factors that may hinder collaboration in advance and assist in adjusting communication and collaboration strategies. The BIM implementation strategy, which considers variations depending on the type of facility and the role of participants, facilitates seamless collaboration throughout the project and helps establish forward-thinking guidelines for BIM operations from the standpoint of the client and governance.
{"title":"Analyzing the Variances in Perspectives on BIM Implementation among Korea AEC Participants","authors":"Min Ho Shin, Seong-Ah Kim","doi":"10.1155/2024/4809957","DOIUrl":"https://doi.org/10.1155/2024/4809957","url":null,"abstract":"The goals and benefits of implementing building information modeling (BIM) in different facilities are comparable, although there are variations in the employed technologies. Nevertheless, when considering the practical aspects of BIM, the specific variations in implementing BIM across different facilities lack clarity. This study investigated the variations in viewpoints among participants in the architecture, engineering, and construction (AEC) industry regarding the adoption of BIM. The objective was to assess the necessity of developing diverse BIM application strategies based on the specific needs of AEC facilities. The following outlines the investigative process: (1) The survey questions were structured as items that necessitate prior investigation and consultation of BIM execution plans from prominent countries. (2) Appropriate statistical tests were chosen to analyze the correlation between respondents’ information and the questions. (3) The findings of the analysis conducted on the group of respondents were deliberated. The survey revealed that strategic variations are essential for the implementation of space for meetings in a technical setting, the formulation of data standards and BIM team for a cooperative environment, and the assessment of subjects based on the type of facility. Specifically, client-specified common data environments exhibited variations in the responsibilities of participants, while the assignment of BIM coordinators also displayed differences in participant roles, depending on the type of facilities involved. Nevertheless, all participants were in complete agreement regarding the collaborative environment, technical environment, organizational structure, implementation guide, and the necessity for evaluation. Surveys of the perceptions of these AEC participants help identify factors that may hinder collaboration in advance and assist in adjusting communication and collaboration strategies. The BIM implementation strategy, which considers variations depending on the type of facility and the role of participants, facilitates seamless collaboration throughout the project and helps establish forward-thinking guidelines for BIM operations from the standpoint of the client and governance.","PeriodicalId":7242,"journal":{"name":"Advances in Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140036998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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