Pub Date : 2024-08-07DOI: 10.1007/s12205-024-0189-2
Yang Bai, Yapeng Li, Lei Li
In recent years, more and more river-crossing and sea-crossing underwater tunnels have become the first choice for the construction of large channels in regions with developed river system. Relying on its superior pressure control mode and high security, Slurry Pressure Balance shield (SPB) is widely used in the construction of underwater tunnels with large cross-sections. The filter cake is an important medium to guarantee the stability of the excavation in SPB tunnelling. However, the mechanism of cutter on soil and filter cake (the interaction of “cutter-soil”) are still unclear. In this study, a self-made test apparatus based on the interaction of “cutter-soil” is presented. The experiment results revealed that “cutter-soil” interaction, compared to cases without the interaction, reduced the impermeability and effective stress conversion rate of filter cake, which is unfavorable to guarantee the stability of the tunnel face. To overcome this problem, two methods were proposed: continuous injection of slurry with different densities and increasing the coarse particles of slurry. It is shown that the methods have improved filter the impermeability of cake formation, which contributes to the stability of the shield excavation face.
{"title":"Experimental Study on Characteristics of Filter Cake Formation in Slurry Shield Tunnelling Based on “Cutter-Soil” Interaction","authors":"Yang Bai, Yapeng Li, Lei Li","doi":"10.1007/s12205-024-0189-2","DOIUrl":"https://doi.org/10.1007/s12205-024-0189-2","url":null,"abstract":"<p>In recent years, more and more river-crossing and sea-crossing underwater tunnels have become the first choice for the construction of large channels in regions with developed river system. Relying on its superior pressure control mode and high security, Slurry Pressure Balance shield (SPB) is widely used in the construction of underwater tunnels with large cross-sections. The filter cake is an important medium to guarantee the stability of the excavation in SPB tunnelling. However, the mechanism of cutter on soil and filter cake (the interaction of “cutter-soil”) are still unclear. In this study, a self-made test apparatus based on the interaction of “cutter-soil” is presented. The experiment results revealed that “cutter-soil” interaction, compared to cases without the interaction, reduced the impermeability and effective stress conversion rate of filter cake, which is unfavorable to guarantee the stability of the tunnel face. To overcome this problem, two methods were proposed: continuous injection of slurry with different densities and increasing the coarse particles of slurry. It is shown that the methods have improved filter the impermeability of cake formation, which contributes to the stability of the shield excavation face.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"4 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938999","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}
Pub Date : 2024-08-07DOI: 10.1007/s12205-024-0605-7
Byeong-Soo Yoo, Jin-Tae Han, Eomzi Yang
Geotechnical survey data is essential for the construction of civil engineering and architectural structures, with high utilization rates. However, variations in the forms used across different entities such as host organizations, contractors, and structures necessitate manual input tasks during the database creation process, leading to significant consumption of human and time resources. To address this challenge, both standard and distributed boring logs were collected and subjected to comprehensive feature analysis. Based on this analysis, an algorithm capable of automatically extracting the desired geotechnical information from boring logs was developed. This algorithm is versatile, applicable across various formats, and has demonstrated a staggering improvement in information processing speed compared to manual input.
{"title":"Automated Geotechnical Information Extraction from Construction Boring Logs Using Keyword Groups","authors":"Byeong-Soo Yoo, Jin-Tae Han, Eomzi Yang","doi":"10.1007/s12205-024-0605-7","DOIUrl":"https://doi.org/10.1007/s12205-024-0605-7","url":null,"abstract":"<p>Geotechnical survey data is essential for the construction of civil engineering and architectural structures, with high utilization rates. However, variations in the forms used across different entities such as host organizations, contractors, and structures necessitate manual input tasks during the database creation process, leading to significant consumption of human and time resources. To address this challenge, both standard and distributed boring logs were collected and subjected to comprehensive feature analysis. Based on this analysis, an algorithm capable of automatically extracting the desired geotechnical information from boring logs was developed. This algorithm is versatile, applicable across various formats, and has demonstrated a staggering improvement in information processing speed compared to manual input.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"58 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939000","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}
Pub Date : 2024-08-07DOI: 10.1007/s12205-024-0454-4
Changwon Chae, Soobean Park, Sang-Gyu Yoon, Jinsung An
Exposure to fluorine (F) in soil increases the risks of dental and skeletal fluorosis and osteoporosis. Therefore, it is important to accurately determine the soil F concentration, and quantitatively evaluate the factors that affect the human health risk of soil F. Differences in soil F concentrations were investigated based on source type (anthropogenically contaminated or naturally enriched) and determination method (perchloric acid extraction-distillation (PAED) or alkali fusion-filtration). A soil sample without contamination history (background F concentration = 208 mg·kg−1) was collected and injected with sodium fluoride (NaF) to prepare anthropogenically F-contaminated soil. Mica gravel (> 2 mm) was ground and mixed with quartz powder to mimic soil components of natural F origin. The F concentration in anthropogenically contaminated soil did not significantly differ between methods (slope = 0.959, p > 0.05). The concentration in the naturally F-enriched soil analyzed using alkali fusion-filtration was approximately twice that of the sample analyzed using PAED (slope = 0.548, p < 0.05). This significant difference was ascribed to the abundance of chemically stable F. Non-carcinogenic hazard quotients for children differed between methods in naturally F-enriched soil, at 1.335 (alkali fusion-filtration) and 0.641 (PAED). These findings offer valuable insights for assessing, managing, and remediating soils contaminated or enriched with F.
接触土壤中的氟(F)会增加罹患氟斑牙、氟骨症和骨质疏松症的风险。因此,准确测定土壤中氟的浓度并定量评估影响土壤氟对人体健康风险的因素非常重要。研究人员根据来源类型(人为污染或天然富集)和测定方法(高氯酸萃取-蒸馏(PAED)或碱熔-过滤)调查了土壤中氟浓度的差异。采集无污染历史的土壤样本(本底 F 浓度 = 208 mg-kg-1)并注入氟化钠 (NaF),制备人为 F 污染土壤。云母砾石(> 2 毫米)经研磨后与石英粉混合,以模拟天然氟来源的土壤成分。人为污染土壤中的 F 浓度在不同方法之间没有显著差异(斜率 = 0.959,p > 0.05)。采用碱熔过滤法分析的天然富钙质土壤中的钙浓度约为采用 PAED 分析的样本的两倍(斜率 = 0.548,p <0.05)。在富含膳食纤维的天然土壤中,不同方法得出的儿童非致癌危害商数也不同,分别为 1.335(碱熔过滤法)和 0.641(PAED)。这些发现为评估、管理和修复受 F 污染或富集的土壤提供了宝贵的见解。
{"title":"Effect of Origin on Chemical Extractability of Fluorine in Soil and Its Consequence on Human Health Risk","authors":"Changwon Chae, Soobean Park, Sang-Gyu Yoon, Jinsung An","doi":"10.1007/s12205-024-0454-4","DOIUrl":"https://doi.org/10.1007/s12205-024-0454-4","url":null,"abstract":"<p>Exposure to fluorine (F) in soil increases the risks of dental and skeletal fluorosis and osteoporosis. Therefore, it is important to accurately determine the soil F concentration, and quantitatively evaluate the factors that affect the human health risk of soil F. Differences in soil F concentrations were investigated based on source type (anthropogenically contaminated or naturally enriched) and determination method (perchloric acid extraction-distillation (PAED) or alkali fusion-filtration). A soil sample without contamination history (background F concentration = 208 mg·kg<sup>−1</sup>) was collected and injected with sodium fluoride (NaF) to prepare anthropogenically F-contaminated soil. Mica gravel (> 2 mm) was ground and mixed with quartz powder to mimic soil components of natural F origin. The F concentration in anthropogenically contaminated soil did not significantly differ between methods (slope = 0.959, <i>p</i> > 0.05). The concentration in the naturally F-enriched soil analyzed using alkali fusion-filtration was approximately twice that of the sample analyzed using PAED (slope = 0.548, <i>p</i> < 0.05). This significant difference was ascribed to the abundance of chemically stable F. Non-carcinogenic hazard quotients for children differed between methods in naturally F-enriched soil, at 1.335 (alkali fusion-filtration) and 0.641 (PAED). These findings offer valuable insights for assessing, managing, and remediating soils contaminated or enriched with F.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"32 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938995","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}
To address limitations in conventional static load tests for composite foundations, a method utilizing an elastic cushion layer is proposed to accurately simulate subgrade behavior, focusing on a highway project in Guangdong Province. Initial finite element calculations justify the elastic cushion layer introduction. Functional correlations are established between the stab deformation of the piles and the thickness, modulus and the pile-soil stress ratio. The reasonable value of the elastic modulus is taken as 4–10 MPa when the elastic cushion layer thickness is 60 mm. Lab and field tests of cement fly-ash gravel (CFG) pile composite foundations assess settlement variations and pile-soil stress ratios from the proposed improvements. Results reveal the superior performance of the elastic cushion layer over the sand cushion layer, effectively mimicking embankment subgrade layers and reducing rigid constraints on the loading plate. The elastic cushion layer exhibits a significant stress-regulating effect, allowing the transition from the original “100–150 mm sand cushion layer + loading plate” to “less than 100 mm sand cushion layer + 60 mm elastic cushion layer (8 MPa) + loading plate”. This adjustment enhances the practical role of the subgrade in the composite foundation, improving the accuracy and feasibility of static load testing methods.
{"title":"Static Load Testing with Elastic Cushion Layer: A Case Study in Foshan Highway Project","authors":"Yunlong Yao, Xin Liu, Fenqiang Xu, Zhiwei Shao, Guisen Wang, Baoning Hong","doi":"10.1007/s12205-024-0159-8","DOIUrl":"https://doi.org/10.1007/s12205-024-0159-8","url":null,"abstract":"<p>To address limitations in conventional static load tests for composite foundations, a method utilizing an elastic cushion layer is proposed to accurately simulate subgrade behavior, focusing on a highway project in Guangdong Province. Initial finite element calculations justify the elastic cushion layer introduction. Functional correlations are established between the stab deformation of the piles and the thickness, modulus and the pile-soil stress ratio. The reasonable value of the elastic modulus is taken as 4–10 MPa when the elastic cushion layer thickness is 60 mm. Lab and field tests of cement fly-ash gravel (CFG) pile composite foundations assess settlement variations and pile-soil stress ratios from the proposed improvements. Results reveal the superior performance of the elastic cushion layer over the sand cushion layer, effectively mimicking embankment subgrade layers and reducing rigid constraints on the loading plate. The elastic cushion layer exhibits a significant stress-regulating effect, allowing the transition from the original “100–150 mm sand cushion layer + loading plate” to “less than 100 mm sand cushion layer + 60 mm elastic cushion layer (8 MPa) + loading plate”. This adjustment enhances the practical role of the subgrade in the composite foundation, improving the accuracy and feasibility of static load testing methods.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"133 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938997","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 hydrological drought occurs due to a decrease in water storage, there is no choice but to supply limited water. Because this has a devastating impact on the community, it is necessary to identify causes and make predictions for emergency planning. The state of change in dam inflow can be used to confirm hydrological drought conditions using the Standardized Runoff Index (SRI), and meteorological drought and climate variability are used to identify causal relationships. Multiple Linear Regression (MLR) and Generalized Additive Model (GAM) models are developed to predict accumulated hydrological drought for 6, 12, and 24 months in the Boryeong Dam basin, and the Nash-Sutcliffe model efficiency coefficient (NSE) exceeded 0.4, satisfying the suitability criteria. The estimation ability is highest when predicting a 12-month annual drought, and reliability can be further increased by reflecting some climate fluctuations in a non-linear form. The droughts of 6 month and 24 month cumulative scales are significantly influenced by the Western Hemisphere Warm Pool (WHWP) extending from the eastern North Pacific to the North Atlantic and by the Nino 3.4 region in the tropical Pacific. Furthermore, it is anticipated that the drought conditions of the inflow volume to the Boryeong Dam will worsen with increasing sea surface temperatures in both regions.
{"title":"Predicting Hydrological Drought Conditions of Boryeong Dam Inflow Using Climate Variability in South Korea","authors":"Seonhui Noh, Micah Lourdes Felix, Seungchan Oh, Kwansue Jung","doi":"10.1007/s12205-024-0160-2","DOIUrl":"https://doi.org/10.1007/s12205-024-0160-2","url":null,"abstract":"<p>When a hydrological drought occurs due to a decrease in water storage, there is no choice but to supply limited water. Because this has a devastating impact on the community, it is necessary to identify causes and make predictions for emergency planning. The state of change in dam inflow can be used to confirm hydrological drought conditions using the Standardized Runoff Index (SRI), and meteorological drought and climate variability are used to identify causal relationships. Multiple Linear Regression (MLR) and Generalized Additive Model (GAM) models are developed to predict accumulated hydrological drought for 6, 12, and 24 months in the Boryeong Dam basin, and the Nash-Sutcliffe model efficiency coefficient (NSE) exceeded 0.4, satisfying the suitability criteria. The estimation ability is highest when predicting a 12-month annual drought, and reliability can be further increased by reflecting some climate fluctuations in a non-linear form. The droughts of 6 month and 24 month cumulative scales are significantly influenced by the Western Hemisphere Warm Pool (WHWP) extending from the eastern North Pacific to the North Atlantic and by the Nino 3.4 region in the tropical Pacific. Furthermore, it is anticipated that the drought conditions of the inflow volume to the Boryeong Dam will worsen with increasing sea surface temperatures in both regions.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"89 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938996","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}
To study the breaking differences between CS hob and BT hob under hard rock (rust rock) and soft rock (red sandstone), and reveal their adaptability in the two rock formations, the vertical breaking experiments of two hobs are conducted. Then, the rock breaking load, rock breaking difficulty coefficient, and rock breaking efficiency of the two hobs in different hob spacings are analyzed and discussed. The result denotes that the CS hob has a greater rock breaking load and rock breaking difficulty compared to the BT hob. Meanwhile, when the breaking object changes from hard rock (rust rock) to soft rock (red sandstone), both types of hobs’ rock breaking loads decrease, but the CS hob’s decrease is significantly greater than the BT hob’s. Meanwhile, the optimal hob spacing for the CS hob increases from 40 mm to 50 mm, whereas for the BT hob, it remains at 30 mm. Considering the rock breaking load and rock breaking efficiency of the hobs together, the CS hob is found to be more suitable for soft rock formation, while the BT hob is more suitable for hard rock formation.
{"title":"Research on Adaptability of CS and BT Hobs to Break Soft and Hard Rock","authors":"Xuhui Zhang, Kang Long, TaoTan, Yashi Liao, Jianfang Li, Jingping Liao","doi":"10.1007/s12205-024-2753-1","DOIUrl":"https://doi.org/10.1007/s12205-024-2753-1","url":null,"abstract":"<p>To study the breaking differences between CS hob and BT hob under hard rock (rust rock) and soft rock (red sandstone), and reveal their adaptability in the two rock formations, the vertical breaking experiments of two hobs are conducted. Then, the rock breaking load, rock breaking difficulty coefficient, and rock breaking efficiency of the two hobs in different hob spacings are analyzed and discussed. The result denotes that the CS hob has a greater rock breaking load and rock breaking difficulty compared to the BT hob. Meanwhile, when the breaking object changes from hard rock (rust rock) to soft rock (red sandstone), both types of hobs’ rock breaking loads decrease, but the CS hob’s decrease is significantly greater than the BT hob’s. Meanwhile, the optimal hob spacing for the CS hob increases from 40 mm to 50 mm, whereas for the BT hob, it remains at 30 mm. Considering the rock breaking load and rock breaking efficiency of the hobs together, the CS hob is found to be more suitable for soft rock formation, while the BT hob is more suitable for hard rock formation.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"21 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938933","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}
Pub Date : 2024-08-06DOI: 10.1007/s12205-024-1717-9
Guanfeng Yan, Yanjie Li, Mingnian Wang, Tao Yan
Few studies focus on exploring the relationship between psychological factors and drivers’ violation intention in the tunnel sections which feature several adverse characteristics like poor lighting and a monotonous driving environment. In this study, hierarchical multiple regression is adopted to test the predictive effect of the demographic parameters, standard theory of planned behavior (TPB) constructs, and three additional constructs of moral norms, past behavior, and perceived stress to account for intentions to violate traffic rules while driving through road tunnels. In this study, three typical violations while driving inside tunnels including changing the lane, overtaking, and speeding are selected. A sample of drivers (N = 384; 50.3% are men and 49.7% women) were surveyed through a self-report questionnaire. Hierarchical multiple regression analyses show that age appears to be the only significant predictor of violation intention among demographic parameters, and theory of planned behavior (TPB) components account for the majority of the variance in violation intention. In addition, moral norms show a negative significant relationship with violation intention while perceived stress is positively associated with violation intention. The findings could provide an important reference for the development of corresponding interventions.
{"title":"Why Do Drivers Decide to Violate Traffic Rules while Driving Through Road Tunnels? An Application of the Theory of Planned Behavior","authors":"Guanfeng Yan, Yanjie Li, Mingnian Wang, Tao Yan","doi":"10.1007/s12205-024-1717-9","DOIUrl":"https://doi.org/10.1007/s12205-024-1717-9","url":null,"abstract":"<p>Few studies focus on exploring the relationship between psychological factors and drivers’ violation intention in the tunnel sections which feature several adverse characteristics like poor lighting and a monotonous driving environment. In this study, hierarchical multiple regression is adopted to test the predictive effect of the demographic parameters, standard theory of planned behavior (TPB) constructs, and three additional constructs of moral norms, past behavior, and perceived stress to account for intentions to violate traffic rules while driving through road tunnels. In this study, three typical violations while driving inside tunnels including changing the lane, overtaking, and speeding are selected. A sample of drivers (N = 384; 50.3% are men and 49.7% women) were surveyed through a self-report questionnaire. Hierarchical multiple regression analyses show that age appears to be the only significant predictor of violation intention among demographic parameters, and theory of planned behavior (TPB) components account for the majority of the variance in violation intention. In addition, moral norms show a negative significant relationship with violation intention while perceived stress is positively associated with violation intention. The findings could provide an important reference for the development of corresponding interventions.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"32 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938938","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}
Pub Date : 2024-08-06DOI: 10.1007/s12205-024-2082-4
XiangYan Fan, FangWen Wu, LaiJun Liu, Meng Du, LiGuo Zhao, JinCheng Cao, Song Lei
In this study, the failure mode and mechanism of single-box two-compartment segmental box girders under flexural shear coupling were experimentally studied. Loading tests were conducted on five scaled girders, and the effects of the design parameters on the shear performance were analyzed. The test variables included the loading methods, ratio of internal to external prestressing tendons, and key joint types (vertical and horizontal keys). The test results indicated that different loading methods produce different stress characteristics and damage modes; however, the difference in the ultimate load capacity was negligible. The greater the number of internal prestressing tendons, the greater the bearing capacity. The stress increment of the internal bottom prestress reinforcement was great than the external prestressing tendons. Monolithic box girders could maintain approximately 1.8 times as much pressure as segmental box girders. With the increase of shear span ratio, the load carrying capacity of the segmental beam decreases. Vertical key teeth had a slightly higher bearing capacity than horizontal key teeth. Vertical keys are recommended for segmental box girders owing to their excellent structural properties and ease of construction. and the structure. AASHTO can better predict the shear capacity of segmental beams, while the Chinese code is applicable to segmental beams with appropriate hoop ratio.
{"title":"Experimental and Theoretical Study on the Shear Performance of Single-Box Double-Compartment Segmental Box Girder","authors":"XiangYan Fan, FangWen Wu, LaiJun Liu, Meng Du, LiGuo Zhao, JinCheng Cao, Song Lei","doi":"10.1007/s12205-024-2082-4","DOIUrl":"https://doi.org/10.1007/s12205-024-2082-4","url":null,"abstract":"<p>In this study, the failure mode and mechanism of single-box two-compartment segmental box girders under flexural shear coupling were experimentally studied. Loading tests were conducted on five scaled girders, and the effects of the design parameters on the shear performance were analyzed. The test variables included the loading methods, ratio of internal to external prestressing tendons, and key joint types (vertical and horizontal keys). The test results indicated that different loading methods produce different stress characteristics and damage modes; however, the difference in the ultimate load capacity was negligible. The greater the number of internal prestressing tendons, the greater the bearing capacity. The stress increment of the internal bottom prestress reinforcement was great than the external prestressing tendons. Monolithic box girders could maintain approximately 1.8 times as much pressure as segmental box girders. With the increase of shear span ratio, the load carrying capacity of the segmental beam decreases. Vertical key teeth had a slightly higher bearing capacity than horizontal key teeth. Vertical keys are recommended for segmental box girders owing to their excellent structural properties and ease of construction. and the structure. AASHTO can better predict the shear capacity of segmental beams, while the Chinese code is applicable to segmental beams with appropriate hoop ratio.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"89 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938939","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}
Pub Date : 2024-08-06DOI: 10.1007/s12205-024-1975-6
Shuming Zhou, Donghuang Yan, Yu He
Existing reinforced concrete (RC) bridges are subjected to environmental erosion and vehicle loads. It is becoming an urgent problem to evaluate the safety condition of bridge structures combining inspection data with artificial intelligence methods. This paper proposes a data-driven capacity assessment framework for existing RC bridges. The load capacity limit state (LCLS) and serviceability limit state (SLS) prediction model are established based on the proposed information fusion machine learning model. The genetic algorithm (GA) optimized support vector machine (SVM) learner is established to capture the relationship between the feature variables and the LSLS or SLS. Forty-five samples are obtained by static and dynamic simulation of the ANSYS models. Five-dimensional parameters are adopted as the key input parameters of the model, including the maximum dynamic deflection, crack opening ratio, and crack normal damage ratio at midspan, 1/4 span, and 3/4 span. The Shapley additive explanations method is proposed to conduct parameters sensitivity analysis. The results show that the GA-SVM regression algorithm in LCLS and SLS reduction factor prediction is better than the artificial neural network (ANN) model. The crack opening ratio is the most critical parameter that can considerably affect the outcomes of the LCLS and SLS prediction.
{"title":"Interpretable Capacity Prediction of RC Bridges Based on Genetic Algorithm-enhanced Support Vector Machine Learning","authors":"Shuming Zhou, Donghuang Yan, Yu He","doi":"10.1007/s12205-024-1975-6","DOIUrl":"https://doi.org/10.1007/s12205-024-1975-6","url":null,"abstract":"<p>Existing reinforced concrete (RC) bridges are subjected to environmental erosion and vehicle loads. It is becoming an urgent problem to evaluate the safety condition of bridge structures combining inspection data with artificial intelligence methods. This paper proposes a data-driven capacity assessment framework for existing RC bridges. The load capacity limit state (LCLS) and serviceability limit state (SLS) prediction model are established based on the proposed information fusion machine learning model. The genetic algorithm (GA) optimized support vector machine (SVM) learner is established to capture the relationship between the feature variables and the LSLS or SLS. Forty-five samples are obtained by static and dynamic simulation of the ANSYS models. Five-dimensional parameters are adopted as the key input parameters of the model, including the maximum dynamic deflection, crack opening ratio, and crack normal damage ratio at midspan, 1/4 span, and 3/4 span. The Shapley additive explanations method is proposed to conduct parameters sensitivity analysis. The results show that the GA-SVM regression algorithm in LCLS and SLS reduction factor prediction is better than the artificial neural network (ANN) model. The crack opening ratio is the most critical parameter that can considerably affect the outcomes of the LCLS and SLS prediction.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"22 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938946","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}
Pub Date : 2024-08-06DOI: 10.1007/s12205-024-0055-2
Weiyi Kong, Chuanguo Fu, Zhen Wang
RC structures are usually large, and it is arduous to use test methods to accurately analyse the redistribution of internal forces and development of plastic hinges during fires. This paper proposes a method for judging the formation and development of plastic hinges in the cross-sections of reinforced concrete structures under thermo-mechanical coupling effects. Using this method, the damage patterns of reinforced concrete structures under high temperatures are preliminarily studied. For reinforced concrete structures, the most severely damaged components during a fire may not necessarily be those on the floors exposed to the fire. For structural components on other floors, even if they remain at ambient temperature during the fire, the internal forces within them may undergo drastic changes due to the redistribution of internal forces throughout the structure. This can lead to reaching the yield limit or even the ultimate limit state, severely impacting the overall structural safety.
{"title":"A Method to Analyze the Formation of Plastic Hinges in RC Structures under Fire Conditions","authors":"Weiyi Kong, Chuanguo Fu, Zhen Wang","doi":"10.1007/s12205-024-0055-2","DOIUrl":"https://doi.org/10.1007/s12205-024-0055-2","url":null,"abstract":"<p>RC structures are usually large, and it is arduous to use test methods to accurately analyse the redistribution of internal forces and development of plastic hinges during fires. This paper proposes a method for judging the formation and development of plastic hinges in the cross-sections of reinforced concrete structures under thermo-mechanical coupling effects. Using this method, the damage patterns of reinforced concrete structures under high temperatures are preliminarily studied. For reinforced concrete structures, the most severely damaged components during a fire may not necessarily be those on the floors exposed to the fire. For structural components on other floors, even if they remain at ambient temperature during the fire, the internal forces within them may undergo drastic changes due to the redistribution of internal forces throughout the structure. This can lead to reaching the yield limit or even the ultimate limit state, severely impacting the overall structural safety.</p>","PeriodicalId":17897,"journal":{"name":"KSCE Journal of Civil Engineering","volume":"94 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938942","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}