This research investigated the utilization of palm oil waste as a source material for developing an alkaliactivated binder with alumina-silicate properties. The geopolymer synthesis involved a combination of palm oil fuel ash (POFA) and fly ash (FA), as well as sodium silicate and sodium hydroxide as alkali activator solutions. The study assessed the physical, mechanical, water-transport and thermal performances of the binder, including the influence of oxide ratios on its strength-gain characteristic. The highest strength achieved was 54.7 MPa for a blend of POFA-FA in a ratio of 20:50 with a molarity of NaOH at 12M. The experimental results revealed good water-transport performance due to the dense nature of the binder that restricted water movement. However, the material's insulation performance did not produce significant results with the lowest thermal conductivity value of 0.59 W/mK. Overall, the developed binder has potential industrial applications, as it performed well in the technical aspects studied. KEYWORDS: Palm oil fuel ash, Alkali-activated binder, Waste, Sustainability, Water-transport performance.
{"title":"Using Palm Oil Fuel Ash as a Source Material for Alumina Silicate","authors":"Rehaman Dudekula","doi":"10.14525/jjce.v18i1.09","DOIUrl":"https://doi.org/10.14525/jjce.v18i1.09","url":null,"abstract":"This research investigated the utilization of palm oil waste as a source material for developing an alkaliactivated binder with alumina-silicate properties. The geopolymer synthesis involved a combination of palm oil fuel ash (POFA) and fly ash (FA), as well as sodium silicate and sodium hydroxide as alkali activator solutions. The study assessed the physical, mechanical, water-transport and thermal performances of the binder, including the influence of oxide ratios on its strength-gain characteristic. The highest strength achieved was 54.7 MPa for a blend of POFA-FA in a ratio of 20:50 with a molarity of NaOH at 12M. The experimental results revealed good water-transport performance due to the dense nature of the binder that restricted water movement. However, the material's insulation performance did not produce significant results with the lowest thermal conductivity value of 0.59 W/mK. Overall, the developed binder has potential industrial applications, as it performed well in the technical aspects studied. KEYWORDS: Palm oil fuel ash, Alkali-activated binder, Waste, Sustainability, Water-transport performance.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the challenges in using Manning’s equation lies in accurately determining Manning’s roughness coefficient, especially due to sediment transport. The condition of sediment transport within a specific section of a river can be in equilibrium, meaning that the amount of sediment entering and exiting the segment is balanced or it can be in non-equilibrium, where there is an imbalance between the sediment entering and leaving the segment. Experiments were carried out in the laboratory to simulate both transport conditions, one involving sediment feeding (equilibrium condition) and the other without sediment feeding (non-equilibrium condition). A total of 180 mean velocity profiles were measured using an acoustic doppler velocimeter (ADV) in fixed and movable bed flows. The present experiment was combined with theoretical approaches to evaluate Manning’s coefficient in open channels under sediment transport-flow conditions and reach conclusive results. The shape of the velocity profile, u/U, for flows over a movable bed with sediment feeding is “slender” compared to those without sediment feeding. The presence of sediment transport affects the shape of the velocity profile, especially in the inner region, influencing Manning's roughness coefficient. This coefficient can be determined from two-point velocity measurements at z/H = 0.1 and 0.2 for fixed and movable bed flows with and without sediment feeding, respectively. On average, sediment feeding increases the coefficient by 19% compared to the non-sediment feeding case. KEYWORDS: Manning’s roughness coefficient, Velocity profile, Equilibrium and non-equilibrium, Sediment transport, Open-channel flow
{"title":"Evaluating Manning's Roughness Coefficient for Flows with Equilibrium and Non-equilibrium Sediment Transport","authors":"Miskar Maini","doi":"10.14525/jjce.v18i1.06","DOIUrl":"https://doi.org/10.14525/jjce.v18i1.06","url":null,"abstract":"One of the challenges in using Manning’s equation lies in accurately determining Manning’s roughness coefficient, especially due to sediment transport. The condition of sediment transport within a specific section of a river can be in equilibrium, meaning that the amount of sediment entering and exiting the segment is balanced or it can be in non-equilibrium, where there is an imbalance between the sediment entering and leaving the segment. Experiments were carried out in the laboratory to simulate both transport conditions, one involving sediment feeding (equilibrium condition) and the other without sediment feeding (non-equilibrium condition). A total of 180 mean velocity profiles were measured using an acoustic doppler velocimeter (ADV) in fixed and movable bed flows. The present experiment was combined with theoretical approaches to evaluate Manning’s coefficient in open channels under sediment transport-flow conditions and reach conclusive results. The shape of the velocity profile, u/U, for flows over a movable bed with sediment feeding is “slender” compared to those without sediment feeding. The presence of sediment transport affects the shape of the velocity profile, especially in the inner region, influencing Manning's roughness coefficient. This coefficient can be determined from two-point velocity measurements at z/H = 0.1 and 0.2 for fixed and movable bed flows with and without sediment feeding, respectively. On average, sediment feeding increases the coefficient by 19% compared to the non-sediment feeding case. KEYWORDS: Manning’s roughness coefficient, Velocity profile, Equilibrium and non-equilibrium, Sediment transport, Open-channel flow","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The behaviour of two-way reinforced-concrete slabs exposed to direct fire was investigated in this study. The slabs were exposed to fire for one hour in a gas furnace and the flame-spread area was varied by increasing the number of fire sources from three to six. The slabs were cooled in two different ways: gradual cooling and sudden cooling. The results showed that the flame-spread area had a significant effect on the load-carrying capacity and deflection of the slabs. The load-carrying capacity decreased by 20.68% with gradual cooling and by 33.78% with sudden cooling when the flame-spread area was increased. The deflection at failure increased by 26.3% with gradual cooling and by 33.78% with sudden cooling when the flame-spread area was increased. The ductility factor showed an increase of 12.6% to 50.3 % for gradually-cooled slabs and of 50.3% to 59.6% for suddenly-cooled slabs with an increasing flame-spread area, compared to reference slabs. KEYWORDS: Reinforced solid concrete slabs, Direct fire flame, Thermal flame, Cooling method.
{"title":"Fire Performance of Reinforced Concrete Slabs: Direct Flame Effects","authors":"Raneen Aldarf","doi":"10.14525/jjce.v18i1.08","DOIUrl":"https://doi.org/10.14525/jjce.v18i1.08","url":null,"abstract":"The behaviour of two-way reinforced-concrete slabs exposed to direct fire was investigated in this study. The slabs were exposed to fire for one hour in a gas furnace and the flame-spread area was varied by increasing the number of fire sources from three to six. The slabs were cooled in two different ways: gradual cooling and sudden cooling. The results showed that the flame-spread area had a significant effect on the load-carrying capacity and deflection of the slabs. The load-carrying capacity decreased by 20.68% with gradual cooling and by 33.78% with sudden cooling when the flame-spread area was increased. The deflection at failure increased by 26.3% with gradual cooling and by 33.78% with sudden cooling when the flame-spread area was increased. The ductility factor showed an increase of 12.6% to 50.3 % for gradually-cooled slabs and of 50.3% to 59.6% for suddenly-cooled slabs with an increasing flame-spread area, compared to reference slabs. KEYWORDS: Reinforced solid concrete slabs, Direct fire flame, Thermal flame, Cooling method.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An unlined rock-blast tunnel constructed by the drill and blast method is susceptible to frequent deterioration, including sagging beds, water ingress and loose rock masses. Thus, assessing potential damages above the roadway that may impact the safety of tunnel users is of utmost importance. While tapping, a conventional nondestructive method, is typically used to predict sub-surface delamination, water ingress can be identified with the naked eye. In this research, we utilized a modern-technology approach called passive thermography, together with a high-resolution digital camera and tapping. The study encountered two primary challenges; namely, the absence of direct solar radiation during the inspection and the groove-exposed surface of the unlined tunnel. The results demonstrated that passive thermography was able to detect delaminated areas and water infiltration on the tunnel's walls and ceiling, even without direct sunlight. Large delaminated areas can be detected with just a 2°C change in atmospheric temperature twelve hours before testing. Additionally, the results of image post-processing significantly contributed to enhancing the results of passive thermography. The thermal image was processed into a grayscale image prior to HE processing, which enhances contrast by over 50%. The combination of tapping, digital camera and passive thermography was proven to be effective in periodically inspecting unlined rock tunnels, while significantly reducing time and cost. KEYWORDS: Tunnel safety, Passive thermography, Old rock-cut tunnel, Hammer sounding, Non-destructive evaluation, Image post-processing.
采用钻爆法建造的无衬砌岩石爆破隧道容易经常出现老化问题，包括路基下陷、进水和岩块松动。因此，评估巷道上方可能影响隧道使用者安全的潜在损坏至关重要。传统的非破坏性方法--敲击法通常用于预测地表下的分层，而进水则可以用肉眼识别。在这项研究中，我们采用了一种名为被动热成像的现代技术方法，同时还使用了高分辨率数码相机和拍击法。这项研究遇到了两个主要挑战：一是检查期间没有太阳直射，二是无衬砌隧道的沟槽表面裸露在外。结果表明，即使没有阳光直射，被动热成像技术也能检测到隧道墙壁和天花板上的脱层区域和渗水情况。在测试前 12 小时，大气温度仅有 2°C 的变化，就能检测到大面积分层区域。此外，图像后处理的结果也大大提高了被动热成像的效果。在 HE 处理之前，热图像被处理成灰度图像，对比度提高了 50% 以上。事实证明，在对无衬砌岩石隧道进行定期检查时，攻丝机、数码相机和被动热成像技术的组合非常有效，同时还大大减少了时间和成本。关键词： 隧道安全、被动热成像仪、旧岩石切割隧道、锤击探测、无损评估、图像后处理。
{"title":"Detection of Sub-surface Delamination and Moisture Penetration in Unlined Rock Tunnels Using Passive Thermography and Tapping","authors":"Jungwon Huh","doi":"10.14525/jjce.v18i1.01","DOIUrl":"https://doi.org/10.14525/jjce.v18i1.01","url":null,"abstract":"An unlined rock-blast tunnel constructed by the drill and blast method is susceptible to frequent deterioration, including sagging beds, water ingress and loose rock masses. Thus, assessing potential damages above the roadway that may impact the safety of tunnel users is of utmost importance. While tapping, a conventional nondestructive method, is typically used to predict sub-surface delamination, water ingress can be identified with the naked eye. In this research, we utilized a modern-technology approach called passive thermography, together with a high-resolution digital camera and tapping. The study encountered two primary challenges; namely, the absence of direct solar radiation during the inspection and the groove-exposed surface of the unlined tunnel. The results demonstrated that passive thermography was able to detect delaminated areas and water infiltration on the tunnel's walls and ceiling, even without direct sunlight. Large delaminated areas can be detected with just a 2°C change in atmospheric temperature twelve hours before testing. Additionally, the results of image post-processing significantly contributed to enhancing the results of passive thermography. The thermal image was processed into a grayscale image prior to HE processing, which enhances contrast by over 50%. The combination of tapping, digital camera and passive thermography was proven to be effective in periodically inspecting unlined rock tunnels, while significantly reducing time and cost. KEYWORDS: Tunnel safety, Passive thermography, Old rock-cut tunnel, Hammer sounding, Non-destructive evaluation, Image post-processing.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139392802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
his study was conducted to investigate the effect of strengthening with ferro-cement on the flexural behavior of two-way RC slabs after exposure to direct fire. Twelve reinforced-concrete slabs were exposed to direct fire for one hour and cooled with air and water. They were then rehabilitated with a layer of ferro-cement using different bonding patterns (surface roughening, SBR material and screws). The effect of these variables was studied on the load-deflection relationship, ultimate load capacity, stiffness, energy absorption, ductility factor and strains of the compressed zone. The results showed a significant improvement in all the investigated parameters, demonstrating the efficiency of ferro-cement strengthening in improving the behavior of the slabs. It contributed to increasing the ultimate load capacity and initial stiffness of the slabs and to preventing and arresting crack propagation after cracking and even after reaching collapse. The effectiveness of SBR material in ensuring the bonding between the surface of the damaged slabs and the reinforcement layer was also revealed. KEYWORDS: Solid slab, Direct fire flame, Ferro-cement, Rehabilitation, SBR (styrene-butadiene rubber), Roughing.
{"title":"Rehabilitation of Fire-damaged Reinforced-concrete Slabs Using Ferro-cement","authors":"Raneen Aldarf","doi":"10.14525/jjce.v18i1.10","DOIUrl":"https://doi.org/10.14525/jjce.v18i1.10","url":null,"abstract":"his study was conducted to investigate the effect of strengthening with ferro-cement on the flexural behavior of two-way RC slabs after exposure to direct fire. Twelve reinforced-concrete slabs were exposed to direct fire for one hour and cooled with air and water. They were then rehabilitated with a layer of ferro-cement using different bonding patterns (surface roughening, SBR material and screws). The effect of these variables was studied on the load-deflection relationship, ultimate load capacity, stiffness, energy absorption, ductility factor and strains of the compressed zone. The results showed a significant improvement in all the investigated parameters, demonstrating the efficiency of ferro-cement strengthening in improving the behavior of the slabs. It contributed to increasing the ultimate load capacity and initial stiffness of the slabs and to preventing and arresting crack propagation after cracking and even after reaching collapse. The effectiveness of SBR material in ensuring the bonding between the surface of the damaged slabs and the reinforcement layer was also revealed. KEYWORDS: Solid slab, Direct fire flame, Ferro-cement, Rehabilitation, SBR (styrene-butadiene rubber), Roughing.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurately identifying the vehicle load on the bridge plays a vital role in structural-stress analysis and safety evaluation. Also, extracting the spatiotemporal information of the vehicle’s is crucial for identifying the vehicle load. This study aimed to propose a vehicle spatiotemporal information-identification method based on machine-vision technology. First, digital video surveillance cameras were installed in the front and on the side of the monitoring section to capture real-time videos of vehicles passing through the monitoring section. The background-difference method was used to detect vehicles based on the frontal video. Subsequently, the transverse position was evaluated according to the distance between the vehicle’s license plate and the lane line. Other vehicle parameters, including the vehicle’s speed, the number of axles and the wheelbase, were identified based on the lateral video and the auxiliary lines with a known distance. Second, a laboratory model experiment and multiple field tests under different scenes were carried out to validate the efficiency and accuracy of the proposed method. The results indicated that the average identification errors of wheelbase for the model experiment and the field tests were all 1.12% and those of the vehicle’s speed were 1.25% and 1.35, respectively. Also, the average deviations of the lateral position were 2.57 mm and 2.69 cm, respectively. The variances of the identified error of the three parameters for the field tests were 0.78%, 1.83 cm and 0.54%, respectively. This verified that the proposed method has high accuracy, reliability and good anti-noise performance. KEYWORDS: Machine vision, Spatiotemporal information, Load identification, Orthotropic deck, Bridge engineering.
{"title":"Machine Vision Based The Spatiotemporal Information Identification of The Vehicle","authors":"Chao Wang","doi":"10.14525/jjce.v17i4.14","DOIUrl":"https://doi.org/10.14525/jjce.v17i4.14","url":null,"abstract":"Accurately identifying the vehicle load on the bridge plays a vital role in structural-stress analysis and safety evaluation. Also, extracting the spatiotemporal information of the vehicle’s is crucial for identifying the vehicle load. This study aimed to propose a vehicle spatiotemporal information-identification method based on machine-vision technology. First, digital video surveillance cameras were installed in the front and on the side of the monitoring section to capture real-time videos of vehicles passing through the monitoring section. The background-difference method was used to detect vehicles based on the frontal video. Subsequently, the transverse position was evaluated according to the distance between the vehicle’s license plate and the lane line. Other vehicle parameters, including the vehicle’s speed, the number of axles and the wheelbase, were identified based on the lateral video and the auxiliary lines with a known distance. Second, a laboratory model experiment and multiple field tests under different scenes were carried out to validate the efficiency and accuracy of the proposed method. The results indicated that the average identification errors of wheelbase for the model experiment and the field tests were all 1.12% and those of the vehicle’s speed were 1.25% and 1.35, respectively. Also, the average deviations of the lateral position were 2.57 mm and 2.69 cm, respectively. The variances of the identified error of the three parameters for the field tests were 0.78%, 1.83 cm and 0.54%, respectively. This verified that the proposed method has high accuracy, reliability and good anti-noise performance. KEYWORDS: Machine vision, Spatiotemporal information, Load identification, Orthotropic deck, Bridge engineering.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135406761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the significant advancement in deep-learning methods and their feature representation, deep-learning methods are more prevalent in solving change-detection tasks. The prime purpose of change detection is to detect the changes on the surface of the earth. In this work, an end-to-end encoder-decoder architecture is used to detect the changes in the land cover. The proposed method uses residual U-Net to find land-cover image changes. The UNet structure is used as the backbone of the network. The effectiveness of the proposed method has been experimented through LEVIR-CD datasets. The results showed that the proposed method outperforms the state-of-the-art techniques and gives reliable results. These techniques can be used to examine changes in the earth's crest due to natural events, such as landslides, earthquakes, erosion and geo-hazards or human activity, like mining and development. KEYWORDS: Change detection, Remote sensing, Residual UNet, Deep learning, Land cover, Climate.
{"title":"Deep Learning-based Land-cover Change Detection in Remote-sensing Imagery","authors":"A. Diana Andrushia","doi":"10.14525/jjce.v17i4.06","DOIUrl":"https://doi.org/10.14525/jjce.v17i4.06","url":null,"abstract":"With the significant advancement in deep-learning methods and their feature representation, deep-learning methods are more prevalent in solving change-detection tasks. The prime purpose of change detection is to detect the changes on the surface of the earth. In this work, an end-to-end encoder-decoder architecture is used to detect the changes in the land cover. The proposed method uses residual U-Net to find land-cover image changes. The UNet structure is used as the backbone of the network. The effectiveness of the proposed method has been experimented through LEVIR-CD datasets. The results showed that the proposed method outperforms the state-of-the-art techniques and gives reliable results. These techniques can be used to examine changes in the earth's crest due to natural events, such as landslides, earthquakes, erosion and geo-hazards or human activity, like mining and development. KEYWORDS: Change detection, Remote sensing, Residual UNet, Deep learning, Land cover, Climate.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135407246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-strength jute fibre-reinforced polymer (JFRP) laminates have recently been introduced to strengthen RC beams against shear. In contrast to synthetic-based composites, JFRP laminates would be more ductile, compatible with steel shear rebar and effective in reducing debonding due to their lower modulus of elasticity. The prime objective of this research was providing an optimal solution to strengthen a severely deficient RC beam against shear using an externally bonded JFRP laminate with anchor. Fabrication of the JFRP laminate was carried out with the maximum fibre content of 37.5% to obtain high tensile strength. Five full-scale RC beam specimens were cast. Shear strengthening was done by an externally bonded JFRP laminate with double connector, multiple connector and embedded-bar anchor systems. The dimensions of JFRP laminate were obtained based on proposed guidelines. Based on the experimental test, the average tensile strength of the fabricated JFRP laminate was found to be 162 MPa. Results also showed that the JFRP laminate with multiconnector anchor increased the maximum shear capacity of deficient RC beams by 89% and the beams had failed by the fracture of laminate. Beams strengthened with embedded-bar anchor had shown flexural ductile failure. Both beams failed after yielding of flexural bar. The proposed guidelines could be used for shear strengthening of severely deficient beams to enhance the maximum shear capacity using full strength of JFRP laminate with anchor. KEYWORDS: RC beam, Shear strengthening, JFRP laminate, Anchor, Optimal design
{"title":"Optimal Shear Strengthening of Severely Deficient RC Beam Using JFRP Laminate with Anchor","authors":"Md Ashraful Alam","doi":"10.14525/jjce.v17i4.13","DOIUrl":"https://doi.org/10.14525/jjce.v17i4.13","url":null,"abstract":"High-strength jute fibre-reinforced polymer (JFRP) laminates have recently been introduced to strengthen RC beams against shear. In contrast to synthetic-based composites, JFRP laminates would be more ductile, compatible with steel shear rebar and effective in reducing debonding due to their lower modulus of elasticity. The prime objective of this research was providing an optimal solution to strengthen a severely deficient RC beam against shear using an externally bonded JFRP laminate with anchor. Fabrication of the JFRP laminate was carried out with the maximum fibre content of 37.5% to obtain high tensile strength. Five full-scale RC beam specimens were cast. Shear strengthening was done by an externally bonded JFRP laminate with double connector, multiple connector and embedded-bar anchor systems. The dimensions of JFRP laminate were obtained based on proposed guidelines. Based on the experimental test, the average tensile strength of the fabricated JFRP laminate was found to be 162 MPa. Results also showed that the JFRP laminate with multiconnector anchor increased the maximum shear capacity of deficient RC beams by 89% and the beams had failed by the fracture of laminate. Beams strengthened with embedded-bar anchor had shown flexural ductile failure. Both beams failed after yielding of flexural bar. The proposed guidelines could be used for shear strengthening of severely deficient beams to enhance the maximum shear capacity using full strength of JFRP laminate with anchor. KEYWORDS: RC beam, Shear strengthening, JFRP laminate, Anchor, Optimal design","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135406756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recycled aggregates have been increasingly considered in recent years, owing to the limited supply of natural aggregates coupled with the corresponding carbon footprint. Recycled aggregates are aggregates prepared from construction and demolition waste. Their use aims to reduce energy consumption and contributes to reducing waste harmful to the environment. This study is based on a number of numerical tests using the finite element method of PLAXIS 3D software with the elastic-perfectly plastic behavior model and the Mohr flow criterion for all materials. A unit cell model of soft soil treated with three types of granular columns was loaded to failure: ordinary stone columns (OSCs), sand-fiber mix (SFM) and recycled aggregate porous concrete pile (RAPP). An extensive parametric study was conducted to investigate the effect of column type, friction angle, elasticity modulus, column length and geotextile effective stiffness on the behavior of soft soils. The results of numerical tests indicated that the bearing capacity of the recycled aggregate columns is three times greater than that of columns of natural aggregates. The findings of this research are given in the form of load-settlement graphs, which made it possible to release recommendations to carry out works using this technique. KEYWORDS: Soft soil, Granular column, Numerical analysis, Unit cell, Bearing capacity, PLAXIS 3D software
{"title":"Numerical Analysis of a 3D Unit Cell Model for Soft Soil Reinforced with Different Granular Columns","authors":"Yousfi Amin","doi":"10.14525/jjce.v17i4.05","DOIUrl":"https://doi.org/10.14525/jjce.v17i4.05","url":null,"abstract":"Recycled aggregates have been increasingly considered in recent years, owing to the limited supply of natural aggregates coupled with the corresponding carbon footprint. Recycled aggregates are aggregates prepared from construction and demolition waste. Their use aims to reduce energy consumption and contributes to reducing waste harmful to the environment. This study is based on a number of numerical tests using the finite element method of PLAXIS 3D software with the elastic-perfectly plastic behavior model and the Mohr flow criterion for all materials. A unit cell model of soft soil treated with three types of granular columns was loaded to failure: ordinary stone columns (OSCs), sand-fiber mix (SFM) and recycled aggregate porous concrete pile (RAPP). An extensive parametric study was conducted to investigate the effect of column type, friction angle, elasticity modulus, column length and geotextile effective stiffness on the behavior of soft soils. The results of numerical tests indicated that the bearing capacity of the recycled aggregate columns is three times greater than that of columns of natural aggregates. The findings of this research are given in the form of load-settlement graphs, which made it possible to release recommendations to carry out works using this technique. KEYWORDS: Soft soil, Granular column, Numerical analysis, Unit cell, Bearing capacity, PLAXIS 3D software","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135407253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Advancing tunnel boring machine (TBM) during tunnel construction induces a surface settlement, affecting adjacent buildings and facilities. A three-dimensional finite-element model (Plaxis 3D) was used to simulate and analyze this process. A comparison between the numerical model and field measurements of the Greater Cairo Metro (Line 3) was made to validate the obtained results. A sensitivity analysis was conducted to determine how changes in some parameters, such as constitutive models, pile position relative to the tunnel axis and pile spacing, affect the results of the finite-element model. Three constitutive models: hardening soil small (HSS), hardening soil (HS) and the Mohr-Coulomb (MC) models, were used to evaluate the effect of the constitutive models on the results. From the numerical analysis, it is clear that the numerical results are in good agreement with field measurements. The results of the HSS model are more realistic and closer to field measurements than those of the HS and MC models. Furthermore, the effect of the tunnel construction on the settlement of adjacent piles is virtually null at a distance of 2 D (where D is the tunnel diameter). Finally, increasing the pile spacing decreases the effect of tunnel excavation on adjacent pile foundations. KEYWORDS: Tunneling, Numerical models, Constitutive models, Pile foundation, Pile spacing
{"title":"Three-dimensional Finite-element Analysis of the Influence of Tunneling on Pile Foundations","authors":"Moamen Abd El Raouf","doi":"10.14525/jjce.v17i4.04","DOIUrl":"https://doi.org/10.14525/jjce.v17i4.04","url":null,"abstract":"Advancing tunnel boring machine (TBM) during tunnel construction induces a surface settlement, affecting adjacent buildings and facilities. A three-dimensional finite-element model (Plaxis 3D) was used to simulate and analyze this process. A comparison between the numerical model and field measurements of the Greater Cairo Metro (Line 3) was made to validate the obtained results. A sensitivity analysis was conducted to determine how changes in some parameters, such as constitutive models, pile position relative to the tunnel axis and pile spacing, affect the results of the finite-element model. Three constitutive models: hardening soil small (HSS), hardening soil (HS) and the Mohr-Coulomb (MC) models, were used to evaluate the effect of the constitutive models on the results. From the numerical analysis, it is clear that the numerical results are in good agreement with field measurements. The results of the HSS model are more realistic and closer to field measurements than those of the HS and MC models. Furthermore, the effect of the tunnel construction on the settlement of adjacent piles is virtually null at a distance of 2 D (where D is the tunnel diameter). Finally, increasing the pile spacing decreases the effect of tunnel excavation on adjacent pile foundations. KEYWORDS: Tunneling, Numerical models, Constitutive models, Pile foundation, Pile spacing","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135406992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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