The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two altern...The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two alternative solutions for the pier cap on one of the bridge crossings over IH-35E in the IH-635 project were analyzed in this case study, a cast-in-place post-tensioned concrete cap and an innovative prefabricated steel-concrete com- posite cap. The approach was to use an estimation of direct costs for material and labor and consideration of con- struction time schedules. A supplementary numerical modeling confirmed that both alternatives behave elasti- cally under imposed loads. The direct cost of material and labor for the two alternatives were close. However, the composite alternative required 13 days less construction time, resulting in substantial cost savings from traffic closing in the very busy traffic corridor. Traffic closing costs were substantially higher than the direct costs, especially for the post-tensioned cap. The quantification of the benefits allows more confidence in the utilization of the composites caps, leading to faster completion of bridge projects and substantial economic savings.展开更多
Static load tests and bearing capacity analyses are carried out for two outer-plated steel-concrete continuous composite beams. The load-deflection curve and the load-strain curve of specimens are obtained and analyze...Static load tests and bearing capacity analyses are carried out for two outer-plated steel-concrete continuous composite beams. The load-deflection curve and the load-strain curve of specimens are obtained and analyzed. The test results indicate that effective cooperation can be achieved by the shearresistant connection between the reinforcement in the negative moment area and the outer-plated steel beam, and the overall working performance of the composite beams is favorable. At the load-bearing limiting state, the plastic strain on the maximum negative and positive moment section becomes fully developed so as to form relatively ideal plastic hinges. With the increase in the reinforcement ratio, the moment-carrying capacity of the composite beams improves significantly, but the ductility of the beams and the rotation ability of the plastic hinges decrease. The formulae for calculating the limit bending capacity in the negative moment area of outer-plated steel-concrete composite beams are proposed based on the test data. The calculated results agree well with the test results.展开更多
Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in s...Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in service is a recurring problem due to the immediate or overtime appearance of cracks. The objective of this work was therefore to assess the damage phenomena of the steel-concrete interface in order to assess the performance of an RC structure. Samples of approximately 30 cm of reinforcement attacked by rust were taken from broken reinforced concrete columns and beams in order to determine the impact of corrosion on high adhesion steel (HA) and therefore on its ability to resist. The experimental results have shown that the corrosion degradation rates of reinforcing bars of different diameters increase as the diameter of the reinforcing bars decreases: 5% for HA12;23.75% for HA8 and 50% for HA6. Using the approach proposed by Mangat and Elgalf on the bearing capacity as a function of the progress of the corrosion phenomenon, these rates made it possible to assess the new fracture limits of corroded HA steels. For HA6 respectively HA8 and HA12, their initial limit resistances will decrease by 4/4, 3/4 and 1/4. Based on the results of this study and in order to guarantee their durability, an RC structure can be dimensioned by taking into account the effects of reinforcement corrosion.展开更多
Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis t...Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis to be assessed. Fibroscan measures both elasticity correlated with hepatic fibrosis and CAP correlated with steatosis. The aim of this study was to evaluate hepatic fibrosis and steatosis using pulse elastometry (Fibroscan/CAP). Methods: This was a descriptive and analytical cross-sectional study in which 170 patients were included. It was conducted from October 1 2021 to December 31 2023, i.e. 27 months, in an outpatient clinic in the hepato-gastroenterology department of the Donka national hospital of the CHU Conakry. Results: Of the 170 patients identified, 87 were male (51%) and 83 female (49%), giving a M/F sex ratio of 1.04. The average age of our patients was 40. The 30 - 50 age group was the most affected, with a frequency of 58.23% (n = 99), followed by the 50 age group with a frequency of 29.41% (n = 50). Hepatomegaly, steatotic liver on ultrasonography, transaminase elevation and obesity were the main indications, respectively: (21.76%), (17.65%), (14.71%), and (13.53%). The examinations were requested by hepatogastroenterologists (47.06%), diabetologists (35.88%) and general practitioners (29%). Of the 170 patients, 100 patients (58.82%) had no significant fibrosis F0F1, 39 (22.94%) had moderate fibrosis F2, 20 patients (11.76%) had severe fibrosis F3 and 11 patients (6.47%) had fibrosis F4. Hepatic steatosis: 62 patients (36.47%) had no S0 steatosis;29.41% had S1 steatosis, 20% had S2 steatosis and 24 patients (14.11%) had S3 steatosis. Abdominal ultrasound revealed a normal liver in 67.05% of patients, hepatic steatosis in 29.41% and non-decompensated cirrhosis in 6 cases. Thus, 108 patients had the parameters required to calculate the Fatty Liver Index (FLI), steatosis was present in 20% of our patients, while 29.41% had an undetermined status and 24 14.11% had a normal FLI. Conclusion: Identifying subjects at risk of metabolic steatopathy, diagnosing and managing these patients is a public health issue and one of the future challenges of hepato-gastroenterology. Fibroscan is an increasingly popular screening tool for hepatic fibrosis and steatosis. The fight against obesity must be a priority.展开更多
The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the...The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.展开更多
Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast...Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.展开更多
基金herein for allowing the use of various data from the LBJ Project in the development of this paper
文摘The complexity of the IH-635 Managed Lanes Project, located in Dallas County, Texas, posed several technical and constructive challenges, leading to the adoption of solutions different from the traditional. Two alternative solutions for the pier cap on one of the bridge crossings over IH-35E in the IH-635 project were analyzed in this case study, a cast-in-place post-tensioned concrete cap and an innovative prefabricated steel-concrete com- posite cap. The approach was to use an estimation of direct costs for material and labor and consideration of con- struction time schedules. A supplementary numerical modeling confirmed that both alternatives behave elasti- cally under imposed loads. The direct cost of material and labor for the two alternatives were close. However, the composite alternative required 13 days less construction time, resulting in substantial cost savings from traffic closing in the very busy traffic corridor. Traffic closing costs were substantially higher than the direct costs, especially for the post-tensioned cap. The quantification of the benefits allows more confidence in the utilization of the composites caps, leading to faster completion of bridge projects and substantial economic savings.
文摘Static load tests and bearing capacity analyses are carried out for two outer-plated steel-concrete continuous composite beams. The load-deflection curve and the load-strain curve of specimens are obtained and analyzed. The test results indicate that effective cooperation can be achieved by the shearresistant connection between the reinforcement in the negative moment area and the outer-plated steel beam, and the overall working performance of the composite beams is favorable. At the load-bearing limiting state, the plastic strain on the maximum negative and positive moment section becomes fully developed so as to form relatively ideal plastic hinges. With the increase in the reinforcement ratio, the moment-carrying capacity of the composite beams improves significantly, but the ductility of the beams and the rotation ability of the plastic hinges decrease. The formulae for calculating the limit bending capacity in the negative moment area of outer-plated steel-concrete composite beams are proposed based on the test data. The calculated results agree well with the test results.
文摘Reinforced concrete (RC) constructions are the innovation of sustainable constructions replacing masonry constructions. Despite this, the use of concrete and steel to improve the performance of structural members in service is a recurring problem due to the immediate or overtime appearance of cracks. The objective of this work was therefore to assess the damage phenomena of the steel-concrete interface in order to assess the performance of an RC structure. Samples of approximately 30 cm of reinforcement attacked by rust were taken from broken reinforced concrete columns and beams in order to determine the impact of corrosion on high adhesion steel (HA) and therefore on its ability to resist. The experimental results have shown that the corrosion degradation rates of reinforcing bars of different diameters increase as the diameter of the reinforcing bars decreases: 5% for HA12;23.75% for HA8 and 50% for HA6. Using the approach proposed by Mangat and Elgalf on the bearing capacity as a function of the progress of the corrosion phenomenon, these rates made it possible to assess the new fracture limits of corroded HA steels. For HA6 respectively HA8 and HA12, their initial limit resistances will decrease by 4/4, 3/4 and 1/4. Based on the results of this study and in order to guarantee their durability, an RC structure can be dimensioned by taking into account the effects of reinforcement corrosion.
文摘Introduction: Fibroscan is a recent, non-invasive and non-irradiating diagnostic method. It is based on the principle of ultrasound, which enables liver tissue elasticity to be quantified using a probe, and fibrosis to be assessed. Fibroscan measures both elasticity correlated with hepatic fibrosis and CAP correlated with steatosis. The aim of this study was to evaluate hepatic fibrosis and steatosis using pulse elastometry (Fibroscan/CAP). Methods: This was a descriptive and analytical cross-sectional study in which 170 patients were included. It was conducted from October 1 2021 to December 31 2023, i.e. 27 months, in an outpatient clinic in the hepato-gastroenterology department of the Donka national hospital of the CHU Conakry. Results: Of the 170 patients identified, 87 were male (51%) and 83 female (49%), giving a M/F sex ratio of 1.04. The average age of our patients was 40. The 30 - 50 age group was the most affected, with a frequency of 58.23% (n = 99), followed by the 50 age group with a frequency of 29.41% (n = 50). Hepatomegaly, steatotic liver on ultrasonography, transaminase elevation and obesity were the main indications, respectively: (21.76%), (17.65%), (14.71%), and (13.53%). The examinations were requested by hepatogastroenterologists (47.06%), diabetologists (35.88%) and general practitioners (29%). Of the 170 patients, 100 patients (58.82%) had no significant fibrosis F0F1, 39 (22.94%) had moderate fibrosis F2, 20 patients (11.76%) had severe fibrosis F3 and 11 patients (6.47%) had fibrosis F4. Hepatic steatosis: 62 patients (36.47%) had no S0 steatosis;29.41% had S1 steatosis, 20% had S2 steatosis and 24 patients (14.11%) had S3 steatosis. Abdominal ultrasound revealed a normal liver in 67.05% of patients, hepatic steatosis in 29.41% and non-decompensated cirrhosis in 6 cases. Thus, 108 patients had the parameters required to calculate the Fatty Liver Index (FLI), steatosis was present in 20% of our patients, while 29.41% had an undetermined status and 24 14.11% had a normal FLI. Conclusion: Identifying subjects at risk of metabolic steatopathy, diagnosing and managing these patients is a public health issue and one of the future challenges of hepato-gastroenterology. Fibroscan is an increasingly popular screening tool for hepatic fibrosis and steatosis. The fight against obesity must be a priority.
文摘The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey bees (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey bees exhibit the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our laboratory have explored whether the concept of expectancy can account for honey bee performance and have all failed to support the cognitive interpretation. The first experiment examined if bees could differentiate between the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference by presenting bees with a choice between the two caps. The third and fourth experiments tested the bee’s ability to expect reward or punishment based on cap weight. Results revealed that bees were found to have a strong preference for the light cap and therefore were not able to expect reward or punishment based on cap weight. These experiments contribute to the debate on whether bees have “cognitive” representations and continue to support the behaviorist interpretation.
基金the support provided by the Laboratory of Applied Research in Engineering Geology, Geotechnics, Water Sciences, and Environment, Setif 1 University, Algeria
文摘Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.
