1.
Joko Purnomo; Aylie Han; Rito Yamakawa; Buntara S. Gan
Systematic calibration procedure for CFRP sheets and rods strengthened RC T-beams by using RBSM Journal Article
In: Mechanics of Advanced Materials and Structures , 2022.
@article{nokey,
title = {Systematic calibration procedure for CFRP sheets and rods strengthened RC T-beams by using RBSM},
author = {Joko Purnomo and Aylie Han and Rito Yamakawa and Buntara S. Gan},
url = {https://www.tandfonline.com/doi/full/10.1080/15376494.2022.2111483},
doi = {https://doi.org/10.1080/15376494.2022.2111483},
year = {2022},
date = {2022-08-22},
urldate = {2022-08-22},
journal = {Mechanics of Advanced Materials and Structures },
abstract = {In this study, a nonlinear 2D rigid body spring model (RBSM) was developed to verify the experimental works of Carbon Fiber Reinforced Polymer (CFRP) sheets and rods strengthened reinforced concrete (RC) T-shape beam (RC T-beam) section under a combination of bending and shearing loads. Modified Mohr–Coulomb criteria were adopted for modeling the plastic damage of concrete material. The orthotropic smeared layers representing the steel and CFRP materials were laminated on the concrete surface to model the reinforcing steel bars, stirrup steel, and CFRP sheets and rods. A mechanical behavior-based approach to fit the experimental results was discussed using the numerical results at each calibration stage. This study shows how the gradient of compressive and ultimate tensile strength of concrete affects the initial flexure behavior of the load-displacement curve of an RC T-beam. In contrast with finite element modeling, the RBSM can exhibit the crack propagation processes of element separation during the simulation. The calibrations showed the agreement of the models used in predicting the flexural behavior, ultimate load, and strengthening effects of the CFRP sheets and rods to the RC T-beam under bending loads. A systematic calibration procedure combined with the recommended use of energy-based criteria to evaluate the results of calibrated load-displacement curve was proposed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this study, a nonlinear 2D rigid body spring model (RBSM) was developed to verify the experimental works of Carbon Fiber Reinforced Polymer (CFRP) sheets and rods strengthened reinforced concrete (RC) T-shape beam (RC T-beam) section under a combination of bending and shearing loads. Modified Mohr–Coulomb criteria were adopted for modeling the plastic damage of concrete material. The orthotropic smeared layers representing the steel and CFRP materials were laminated on the concrete surface to model the reinforcing steel bars, stirrup steel, and CFRP sheets and rods. A mechanical behavior-based approach to fit the experimental results was discussed using the numerical results at each calibration stage. This study shows how the gradient of compressive and ultimate tensile strength of concrete affects the initial flexure behavior of the load-displacement curve of an RC T-beam. In contrast with finite element modeling, the RBSM can exhibit the crack propagation processes of element separation during the simulation. The calibrations showed the agreement of the models used in predicting the flexural behavior, ultimate load, and strengthening effects of the CFRP sheets and rods to the RC T-beam under bending loads. A systematic calibration procedure combined with the recommended use of energy-based criteria to evaluate the results of calibrated load-displacement curve was proposed.
2.
Ay Lie Han; Hsuan-Teh Hu; Buntara S. Gan; Fu-Pei Hsiao; Yanuar Haryanto
Carbon Fiber-Reinforced Polymer Rod Embedment Depth Influence on Concrete Strengthening Journal Article
In: Arabian Journal for Science and Engineering, 2022.
@article{nokey,
title = {Carbon Fiber-Reinforced Polymer Rod Embedment Depth Influence on Concrete Strengthening},
author = {Ay Lie Han and Hsuan-Teh Hu and Buntara S. Gan and Fu-Pei Hsiao and Yanuar Haryanto},
url = {https://link.springer.com/article/10.1007/s13369-022-06601-2},
doi = {https://doi.org/10.1007/s13369-022-06601-2},
year = {2022},
date = {2022-02-04},
journal = {Arabian Journal for Science and Engineering},
abstract = {The use of carbon fiber-reinforced polymer (CFRP) rods offers a good solution for external strengthening of flexural reinforced concrete (RC) members. Limited data are available on the behavior of beams externally reinforced with CFRP rods under a loading–unloading protocol, which is of great importance for structural components subjected to vehicle loading. The embedment depth mandated by the majority of standards cannot always be acquired due to concrete cover limitations; the influence of embedment depth under this loading–unloading sequence needs to be investigated. This research studied the effects of rod embedment depth by comparing fully-embedded rods with half-embedded rods under a loading–unloading protocol and comparing the results with monotonic responses. An identical specimen without CFRP reinforcement functioned as the controlling element. The near-surface mounted technique (NSM) was used to integrate the rods with the concrete. The results show that CFRP rods positively affect the load-carrying capacity under a loading–unloading condition. The rods reduce the member’s ductility under monotonic loading but have no negative impact under loading–unloading. Whereas the difference in embedment depth configuration slightly affected the enhancement under monotonic loading, the half-embedded rods drastically reduced the capacity improvement under the loading–unloading sequence. An embedment depth deviating from the advised depth, should not be implemented for members subjected to a loading–unloading condition. The CFRP placement method had an impact on the failure behavior of the elements. The half-embedded rod failed by debonding between the rod and the epoxy resin, while the fully-embedded members were characterized by concrete spalling.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The use of carbon fiber-reinforced polymer (CFRP) rods offers a good solution for external strengthening of flexural reinforced concrete (RC) members. Limited data are available on the behavior of beams externally reinforced with CFRP rods under a loading–unloading protocol, which is of great importance for structural components subjected to vehicle loading. The embedment depth mandated by the majority of standards cannot always be acquired due to concrete cover limitations; the influence of embedment depth under this loading–unloading sequence needs to be investigated. This research studied the effects of rod embedment depth by comparing fully-embedded rods with half-embedded rods under a loading–unloading protocol and comparing the results with monotonic responses. An identical specimen without CFRP reinforcement functioned as the controlling element. The near-surface mounted technique (NSM) was used to integrate the rods with the concrete. The results show that CFRP rods positively affect the load-carrying capacity under a loading–unloading condition. The rods reduce the member’s ductility under monotonic loading but have no negative impact under loading–unloading. Whereas the difference in embedment depth configuration slightly affected the enhancement under monotonic loading, the half-embedded rods drastically reduced the capacity improvement under the loading–unloading sequence. An embedment depth deviating from the advised depth, should not be implemented for members subjected to a loading–unloading condition. The CFRP placement method had an impact on the failure behavior of the elements. The half-embedded rod failed by debonding between the rod and the epoxy resin, while the fully-embedded members were characterized by concrete spalling.
3.
Purwanto; Januarti Jaya Ekaputri; Nuroji; Bobby Rio Indriyantho; Aylie Han; Buntara Sthenly Gan
Shear-bond behavior of self-compacting geopolymer concrete to conventional concrete Journal Article
In: Construction and Building Materials, vol. 321, no. 126167, pp. 1-10, 2022.
@article{nokey,
title = {Shear-bond behavior of self-compacting geopolymer concrete to conventional concrete},
author = {Purwanto and Januarti Jaya Ekaputri and Nuroji and Bobby Rio Indriyantho and Aylie Han and Buntara Sthenly Gan},
url = {https://www.sciencedirect.com/science/article/abs/pii/S0950061821038988},
doi = {https://doi.org/10.1016/j.conbuildmat.2021.126167},
year = {2022},
date = {2022-01-15},
journal = {Construction and Building Materials},
volume = {321},
number = {126167},
pages = {1-10},
abstract = {The shear-bond behavior of two mechanically different concretes is fundamental when conducting external reinforcement, retrofitting, or repair. The two components are designed to possess full strain compatibility in sustaining the stress transfer between the two parts throughout the loading sequence. This work investigated the shear-bond behavior between conventional and self-compacting geopolymer concrete based on the push-off method. The influence of surface roughness on the bond behavior was studied, and a finite element model was constructed and validated to the experimental data. Surprisingly, the chemical bond characteristics of geopolymer concrete have little effect on the bond strength as compared to conventional concrete having the same compression strengths, but significantly influences the load-slip pattern of the interface. As expected, the bond strength was positively influenced by the interface roughness. All failure modes were unmistakably brittle. The strain deformation pattern generated from the finite element model underlined that large strains and stresses were present at the far ends in the interface, where initial cracking was detected in these regions. The study concluded that self-compacting geopolymer concrete is a perfect solution for older structure’s external strengthening or retrofitting. This material has a better sustainable and a more environmentally friendly character.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The shear-bond behavior of two mechanically different concretes is fundamental when conducting external reinforcement, retrofitting, or repair. The two components are designed to possess full strain compatibility in sustaining the stress transfer between the two parts throughout the loading sequence. This work investigated the shear-bond behavior between conventional and self-compacting geopolymer concrete based on the push-off method. The influence of surface roughness on the bond behavior was studied, and a finite element model was constructed and validated to the experimental data. Surprisingly, the chemical bond characteristics of geopolymer concrete have little effect on the bond strength as compared to conventional concrete having the same compression strengths, but significantly influences the load-slip pattern of the interface. As expected, the bond strength was positively influenced by the interface roughness. All failure modes were unmistakably brittle. The strain deformation pattern generated from the finite element model underlined that large strains and stresses were present at the far ends in the interface, where initial cracking was detected in these regions. The study concluded that self-compacting geopolymer concrete is a perfect solution for older structure’s external strengthening or retrofitting. This material has a better sustainable and a more environmentally friendly character.
4.
Junaedi Utomo; Muhammad Nur Khusyeni; Windu Partono; Ay Lie Han; Buntara S. Gan
Experimental Investigation on the Failure Behavior of Carbon Fiber Reinforced Polymer (CFRP) Strengthened Reinforced Concrete T-beams Journal Article
In: Civil Engineering Dimension, vol. 23, no. 2, pp. 115-122, 2021, ISSN: 1979-570X.
@article{nokey,
title = {Experimental Investigation on the Failure Behavior of Carbon Fiber Reinforced Polymer (CFRP) Strengthened Reinforced Concrete T-beams},
author = {Junaedi Utomo and Muhammad Nur Khusyeni and Windu Partono and Ay Lie Han and Buntara S. Gan},
url = {https://ced.petra.ac.id/index.php/civ/article/view/23978},
doi = {https://doi.org/10.9744/ced.23.2.115-122},
issn = {1979-570X},
year = {2021},
date = {2021-10-05},
journal = {Civil Engineering Dimension},
volume = {23},
number = {2},
pages = {115-122},
abstract = {Carbon Fiber Reinforced Polymers (CFRP) are widely used as external concrete reinforcement. The behavior of T-beams strengthened in shear and flexure using CFRP sheets and plates was studied to analyze the load carrying capacity and failure mode as compared to conventional concrete members. The bonding response of the plate-to-concrete was investigated by comparing a specimen with a plate anchored at the far ends, one without anchoring. The sheets were in situ wet lay-up, the plate was pre-impregnated and pultruded during manufacturing. The test result suggested that this integrated strengthening method notably improved the load-carrying capacity, it was also demonstrated that anchoring had a positive but insignificant effect on the moment capacity and deformation. The influence of anchoring was noteworthy from the point of view that it shifted the failure mode from debonding to CFRP plate rupture. The most important factors influencing the behavior of CFRP strengthened beams are outlined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Carbon Fiber Reinforced Polymers (CFRP) are widely used as external concrete reinforcement. The behavior of T-beams strengthened in shear and flexure using CFRP sheets and plates was studied to analyze the load carrying capacity and failure mode as compared to conventional concrete members. The bonding response of the plate-to-concrete was investigated by comparing a specimen with a plate anchored at the far ends, one without anchoring. The sheets were in situ wet lay-up, the plate was pre-impregnated and pultruded during manufacturing. The test result suggested that this integrated strengthening method notably improved the load-carrying capacity, it was also demonstrated that anchoring had a positive but insignificant effect on the moment capacity and deformation. The influence of anchoring was noteworthy from the point of view that it shifted the failure mode from debonding to CFRP plate rupture. The most important factors influencing the behavior of CFRP strengthened beams are outlined.
5.
Junaedi Utomo; Nauval Rabbani; Sri Tudjono; Ay Lie Han; Sukamta
The Influence of External CFRP String Reinforcement on The Behavior of Flexural RC Elements Journal Article
In: JGEET (Journal of Geoscience, Engineering, Environment, and Technology), vol. 6, no. 3, pp. 141 - 146, 2021, ISSN: 2541-5794.
@article{nokey,
title = {The Influence of External CFRP String Reinforcement on The Behavior of Flexural RC Elements},
author = {Junaedi Utomo and Nauval Rabbani and Sri Tudjono and Ay Lie Han and Sukamta},
url = {https://journal.uir.ac.id/index.php/JGEET/article/view/5685},
issn = {2541-5794},
year = {2021},
date = {2021-09-17},
urldate = {2021-09-17},
journal = {JGEET (Journal of Geoscience, Engineering, Environment, and Technology)},
volume = {6},
number = {3},
pages = {141 - 146},
abstract = {External reinforcement is an excellent method for improving the load carrying capacity and ductility behaviour of reinforced concrete members in flexure. Enhancement becomes a necessity when current standards mandate a higher performance compared to older codes. External reinforcement is an environmentally friendly and sustainable solution, since demolition and re-building could be postponed, and the building can be used while work in conducted on the members. Carbon Fiber Reinforced Polymers (CFRP), having a low weight-to-volume ratio and an excellent resistance to corrosion, can be used as external reinforcement to effectively increase the flexural and shear strength of a member. To evaluate the effectiveness of CFRP strings, two types of reinforced concrete T-beams were tested. The specimens consist of a strengthened member in both shear and flexure using CFRP wraps and CFRP strings, and a conventional reinforced concrete beam. The specimens were subjected to a one-point-loading system to simulate high shear stresses in combination with a maximum bending moment at mid-point. The installation of CFRP strings was conducted using the Near Surface Mounted (NSM) method, while the sheets were Externally Bonded Reinforcement (EBR). The strings and sheets were impregnated and pultruded on side. The test results showed that the strings and wraps substantially increased the ultimate load carrying capacity and ductility of the member. The ultimate load enhancement was found to be 32% from 117kN to 154kN, and the vertical deformation improved 25% from 16 mm to 20 mm. The failure mode was characterized by initial debonding of the strings in the interface between the strings and the epoxy, followed by string-rupture. The two strings ruptured concurrently, due to stress re-distribution within the member.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
External reinforcement is an excellent method for improving the load carrying capacity and ductility behaviour of reinforced concrete members in flexure. Enhancement becomes a necessity when current standards mandate a higher performance compared to older codes. External reinforcement is an environmentally friendly and sustainable solution, since demolition and re-building could be postponed, and the building can be used while work in conducted on the members. Carbon Fiber Reinforced Polymers (CFRP), having a low weight-to-volume ratio and an excellent resistance to corrosion, can be used as external reinforcement to effectively increase the flexural and shear strength of a member. To evaluate the effectiveness of CFRP strings, two types of reinforced concrete T-beams were tested. The specimens consist of a strengthened member in both shear and flexure using CFRP wraps and CFRP strings, and a conventional reinforced concrete beam. The specimens were subjected to a one-point-loading system to simulate high shear stresses in combination with a maximum bending moment at mid-point. The installation of CFRP strings was conducted using the Near Surface Mounted (NSM) method, while the sheets were Externally Bonded Reinforcement (EBR). The strings and sheets were impregnated and pultruded on side. The test results showed that the strings and wraps substantially increased the ultimate load carrying capacity and ductility of the member. The ultimate load enhancement was found to be 32% from 117kN to 154kN, and the vertical deformation improved 25% from 16 mm to 20 mm. The failure mode was characterized by initial debonding of the strings in the interface between the strings and the epoxy, followed by string-rupture. The two strings ruptured concurrently, due to stress re-distribution within the member.
6.
Yanuar Haryanto; Hsuan-Teh Hu; Ay L. Han; Fu-Pei Hsiao; Chrang-Jen Teng; Banu A. Hidayat; Laurencius Nugroho
Numerical investigation on RC T-beams strengthened in the negative moment region using NSM FRP rods at various depth of embedment Journal Article
In: Computers and Concrete, vol. 28, no. 4, pp. 347-360, 2021.
@article{nokey,
title = {Numerical investigation on RC T-beams strengthened in the negative moment region using NSM FRP rods at various depth of embedment },
author = {Yanuar Haryanto and Hsuan-Teh Hu and Ay L. Han and Fu-Pei Hsiao and Chrang-Jen Teng and Banu A. Hidayat and Laurencius Nugroho},
url = {http://www.techno-press.org/content/?page=article&journal=cac&volume=28&num=4&ordernum=1},
doi = {https://doi.org/10.12989/cac.2021.28.4.347},
year = {2021},
date = {2021-09-14},
journal = {Computers and Concrete},
volume = {28},
number = {4},
pages = {347-360},
abstract = {The application of Near Surface Mounted (NSM) method to strengthen reinforced concrete (RC) members in flexure through the use of Fiber Reinforced Polymer (FRP) rods has become a subject of interest to designers and researchers over the past few years. This technique has been extensively applied, and there is still a need for more experiments, analytical, and numerical studies to determine the effects of their parameters on the flexural performance of RC members. Therefore, a detailed 3D nonlinear finite element (FE) numerical model was developed in this study to predict the load-carrying capacity and the response of RC T-beams strengthened in the negative moment region accurately through the use of NSM FRP rods at different depth of embedment which are placed under three-point bending loading. The model was, however, designed with due consideration for the nonlinear constitutive material properties of concrete, yielding of steel reinforcement, NSM rods, and cohesive behaviors to simulate the contact between two neighboring materials. Moreover, the findings of the numerical simulations were compared with those from the experiments by other investigators which involve two specimens strengthened with NSM FRP rods added to one unstrengthened control specimen. The results, however, showed that the mid-span deflection responses of the predicted FE were in line with the corresponding data from the experiment for all the flexural loading stages. This was followed by the use of the validated FE models to analyze the effect of several properties of the FRP materials to provide more information than the limited experimental data available. It was discovered that the FE model developed is appropriate to be applied practically and economically with more focus on the parametric studies based on design to precisely model and analyze flexural negative moment strengthening for the RC members through the use of NSM FRP rods.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The application of Near Surface Mounted (NSM) method to strengthen reinforced concrete (RC) members in flexure through the use of Fiber Reinforced Polymer (FRP) rods has become a subject of interest to designers and researchers over the past few years. This technique has been extensively applied, and there is still a need for more experiments, analytical, and numerical studies to determine the effects of their parameters on the flexural performance of RC members. Therefore, a detailed 3D nonlinear finite element (FE) numerical model was developed in this study to predict the load-carrying capacity and the response of RC T-beams strengthened in the negative moment region accurately through the use of NSM FRP rods at different depth of embedment which are placed under three-point bending loading. The model was, however, designed with due consideration for the nonlinear constitutive material properties of concrete, yielding of steel reinforcement, NSM rods, and cohesive behaviors to simulate the contact between two neighboring materials. Moreover, the findings of the numerical simulations were compared with those from the experiments by other investigators which involve two specimens strengthened with NSM FRP rods added to one unstrengthened control specimen. The results, however, showed that the mid-span deflection responses of the predicted FE were in line with the corresponding data from the experiment for all the flexural loading stages. This was followed by the use of the validated FE models to analyze the effect of several properties of the FRP materials to provide more information than the limited experimental data available. It was discovered that the FE model developed is appropriate to be applied practically and economically with more focus on the parametric studies based on design to precisely model and analyze flexural negative moment strengthening for the RC members through the use of NSM FRP rods.
7.
Nuroji; Mhd. Rony Asshidiqie; Sukamta; Han Ay Lie
The development of A Simulation Tool for Numerical Modelling of High Flexure and High Shear Reinforced Concrete Elements Journal Article
In: Jurnal Ilmiah Bidang Ilmu Kerekayasaan, vol. 42, no. 2, pp. 106 - 116, 2021, ISSN: 2460-9919.
@article{nokey,
title = {The development of A Simulation Tool for Numerical Modelling of High Flexure and High Shear Reinforced Concrete Elements},
author = {Nuroji and Mhd. Rony Asshidiqie and Sukamta and Han Ay Lie
},
url = {https://ejournal.undip.ac.id/index.php/teknik/article/view/32683},
doi = {https://doi.org/10.14710/teknik.v42i2.32683},
issn = {2460-9919},
year = {2021},
date = {2021-08-31},
urldate = {2021-08-31},
journal = {Jurnal Ilmiah Bidang Ilmu Kerekayasaan},
volume = {42},
number = {2},
pages = {106 - 116},
abstract = {The weakness of full-scale testing of reinforced concrete elements in a laboratory is the long period, both to prepare and test specimens and the high-cost, resulting in a limited number of specimens. The heavy specimen creates another difficulty during set-up. Data accuracy depends on apparatus precision, laboratory conditions, and the technicians' expertise in experimenting. A finite element model was constructed to simulate a reinforced concrete element subject to high flexure and shear stresses induced by vertical and horizontal forces to overcome these constraints. The model can further be utilized to evaluate the effects of independent variables on the behavior of the member. The model was validated both numerically and experimentally to ensure accuracy and precision. The numerical validation was conducted through a sensitivity analyses process on the finesses of meshing and loading incrementation. At the same time, the load-deformation data and the crack propagation of identical laboratory-tested elements were utilized for validation of the experimental data. It was proven that the developed model predicts the behavior of the beam to a high degree of correctness. The model can further be used as a tool for analyses in the field.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The weakness of full-scale testing of reinforced concrete elements in a laboratory is the long period, both to prepare and test specimens and the high-cost, resulting in a limited number of specimens. The heavy specimen creates another difficulty during set-up. Data accuracy depends on apparatus precision, laboratory conditions, and the technicians' expertise in experimenting. A finite element model was constructed to simulate a reinforced concrete element subject to high flexure and shear stresses induced by vertical and horizontal forces to overcome these constraints. The model can further be utilized to evaluate the effects of independent variables on the behavior of the member. The model was validated both numerically and experimentally to ensure accuracy and precision. The numerical validation was conducted through a sensitivity analyses process on the finesses of meshing and loading incrementation. At the same time, the load-deformation data and the crack propagation of identical laboratory-tested elements were utilized for validation of the experimental data. It was proven that the developed model predicts the behavior of the beam to a high degree of correctness. The model can further be used as a tool for analyses in the field.
8.
Yanuar Haryanto And Hsuan-teh Hu And Ay L. Han And Fu-pei Hsiao And Nanang G. Wariyatno And Banu A. Hidayat
Numerical parametric study on the flexural capacity of reinforced concrete beams strengthened with non-metallic materials Journal Article
In: Journal of Engineering Science and Technology (JESTEC), vol. 16, no. 4, pp. 3295 - 3311, 2021.
@article{95,
title = {Numerical parametric study on the flexural capacity of reinforced concrete beams strengthened with non-metallic materials},
author = {Yanuar Haryanto And Hsuan-teh Hu And Ay L. Han And Fu-pei Hsiao And Nanang G. Wariyatno And Banu A. Hidayat},
url = {https://hanaylie.id/wp-content/uploads/2021/08/16_4_37.pdf
http://jestec.taylors.edu.my/V16Issue4.htm},
year = {2021},
date = {2021-08-01},
journal = {Journal of Engineering Science and Technology (JESTEC)},
volume = {16},
number = {4},
pages = {3295 - 3311},
abstract = {A modified compression field theory and models developed with Response-2000 using the theory were applied to the prediction of the flexural capacity of reinforced concrete beams strengthened with the assistance of non-metallic material such as bamboo. Data were retrieved from earlier studies conducted in 2017 and two RC beams were used as specimens with one designed as the control beam (BC) while the other was strengthened through a near-surface mounted technique using four bamboo strips (BB). The study showed the accuracy of the models developed in predicting the responses of load-deflection up to the peak load, but underestimated figures were generally obtained from the predictions of beam ductility with an average of 34.41% difference. The models also provided conservative predictions of the flexural capacity for the beams with the ratios of 1.16 and 1.04 for BC and BB respectively. Moreover, the model developed was observed to be efficient in making quick and accurate predictions on the flexural strength based on a normalized mean square error (NMSE) of 0.006 and also has the ability to determine the conditions with the potential to cause the collapse of the reinforced concrete beams. Furthermore, the validated model was later used
to study the impact of bamboo diameter, concrete compressive strength, and steel reinforcement ratio on strengthened beams behaviour.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A modified compression field theory and models developed with Response-2000 using the theory were applied to the prediction of the flexural capacity of reinforced concrete beams strengthened with the assistance of non-metallic material such as bamboo. Data were retrieved from earlier studies conducted in 2017 and two RC beams were used as specimens with one designed as the control beam (BC) while the other was strengthened through a near-surface mounted technique using four bamboo strips (BB). The study showed the accuracy of the models developed in predicting the responses of load-deflection up to the peak load, but underestimated figures were generally obtained from the predictions of beam ductility with an average of 34.41% difference. The models also provided conservative predictions of the flexural capacity for the beams with the ratios of 1.16 and 1.04 for BC and BB respectively. Moreover, the model developed was observed to be efficient in making quick and accurate predictions on the flexural strength based on a normalized mean square error (NMSE) of 0.006 and also has the ability to determine the conditions with the potential to cause the collapse of the reinforced concrete beams. Furthermore, the validated model was later used
to study the impact of bamboo diameter, concrete compressive strength, and steel reinforcement ratio on strengthened beams behaviour.
to study the impact of bamboo diameter, concrete compressive strength, and steel reinforcement ratio on strengthened beams behaviour.
9.
Purwanto; Aylie Han; Januarti J. Ekaputri; Nuroji; Blinka H. Prasetya
Self-Compacting-Geopolymer-Concrete (SCGC) Retrofitted Haunch Journal Article
In: Interantional Journal on Engineering Applications (IREA), vol. 9, no. 4, 2021.
@article{nokey,
title = {Self-Compacting-Geopolymer-Concrete (SCGC) Retrofitted Haunch},
author = {Purwanto and Aylie Han and Januarti J. Ekaputri and Nuroji and Blinka H. Prasetya},
url = {https://www.praiseworthyprize.org/jsm/index.php?journal=irea&page=article&op=view&path%5B%5D=25717},
doi = {https://doi.org/10.15866/irea.v9i4.20652},
year = {2021},
date = {2021-07-01},
journal = {Interantional Journal on Engineering Applications (IREA)},
volume = {9},
number = {4},
abstract = {Retrofitting methods are widely used to reinforce existing concrete structures and frames. Strengthening becomes necessary when building codes mandate a higher load carrying capacity originated from, for example, changes in earthquake zone mapping. A haunch conclusively relocates the formation of plastic hinges away from the beam-column-joint. Geopolymer concrete is an environmentally friendly material, based on fly ash. Utilizing a haunch with this material is effectual and sustainable. The low workability of geopolymer concrete was in this study improved by adding a superplasticizer, which effectiveness was trigger by the presence of low volume Portland cement and water creating a Self-Compacting-Geopolymer-Concrete (SCGC). This SCGC ensured easy fabrication in the field, and improved the compaction and homogeneousness of the haunch. A full-scale experiment based on water-loading was conducted on an existing building to analyze the behavior of a SCGC haunch. The research concluded that the SCGC resulted in a high-performance haunch with good compatibility to the structure, the integrity of the haunch and the structure was maintained up to working-loading conditions. The load carrying capacity and the serviceability greatly improved. Analytical comparison to the prismatic section showed that the SCGC haunch reduced the deflection at mid-span to 77%.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Retrofitting methods are widely used to reinforce existing concrete structures and frames. Strengthening becomes necessary when building codes mandate a higher load carrying capacity originated from, for example, changes in earthquake zone mapping. A haunch conclusively relocates the formation of plastic hinges away from the beam-column-joint. Geopolymer concrete is an environmentally friendly material, based on fly ash. Utilizing a haunch with this material is effectual and sustainable. The low workability of geopolymer concrete was in this study improved by adding a superplasticizer, which effectiveness was trigger by the presence of low volume Portland cement and water creating a Self-Compacting-Geopolymer-Concrete (SCGC). This SCGC ensured easy fabrication in the field, and improved the compaction and homogeneousness of the haunch. A full-scale experiment based on water-loading was conducted on an existing building to analyze the behavior of a SCGC haunch. The research concluded that the SCGC resulted in a high-performance haunch with good compatibility to the structure, the integrity of the haunch and the structure was maintained up to working-loading conditions. The load carrying capacity and the serviceability greatly improved. Analytical comparison to the prismatic section showed that the SCGC haunch reduced the deflection at mid-span to 77%.
10.
Yanuar Haryanto; Hsuan-Teh Hu; Ay Lie Han; Fu-Pei Hsiao,Charng-Jen Teng; Banu Ardi Hidayat; Nanang Gunawan Wariyatno
Negative moment region flexural strengthening system of RC T-beams with half-embedded NSM FRP rods: a parametric analytical approach Journal Article
In: Journal of the Chinese Institute of Engineers , 2021, ISSN: 2158-7299.
@article{86,
title = {Negative moment region flexural strengthening system of RC T-beams with half-embedded NSM FRP rods: a parametric analytical approach},
author = {Yanuar Haryanto and Hsuan-Teh Hu and Ay Lie Han and Fu-Pei Hsiao,Charng-Jen Teng and Banu Ardi Hidayat and Nanang Gunawan Wariyatno},
url = {https://www.tandfonline.com/doi/full/10.1080/02533839.2021.1936646},
doi = {https://doi.org/10.1080/02533839.2021.1936646},
issn = {2158-7299},
year = {2021},
date = {2021-06-21},
journal = {Journal of the Chinese Institute of Engineers },
abstract = {Fiber Reinforced Polymer (FRP) rods are considered to be the most effective in retrofitting to increase the strength of reinforced concrete (RC) structures through Near-Surface Mounted (NSM) technique. There are, however, frequent cases encountered by engineers where the embedment depth mandated by ACI 440.2 R-08 code is not achievable in the field implementation. It has also been discovered that it is more challenging to strengthen the negative moment region of concrete members in comparison with the positive region. This research was conducted to determine the behavior of RC T-beams strengthened in the negative moment region using half-embedded NSM FRP rods. The findings were associated with the Modified Compression Field Theory (MCFT) which was applied in the analytical models. The model proposed was validated through a comparison with previous experimental study that showed half-embedded NSM FRP was effective as another method in comparison with the conventional soffit strengthening systems in retrofitting RC T-beams in the negative moment region, and good agreement was obtained. After that, a parametric analysis was initiated to determine the influence of FRP rod diameters, the compressive strength of concretes, the ratio of steel reinforcement as well as the materials used for the FRP on the flexural behavior of strengthened beams.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fiber Reinforced Polymer (FRP) rods are considered to be the most effective in retrofitting to increase the strength of reinforced concrete (RC) structures through Near-Surface Mounted (NSM) technique. There are, however, frequent cases encountered by engineers where the embedment depth mandated by ACI 440.2 R-08 code is not achievable in the field implementation. It has also been discovered that it is more challenging to strengthen the negative moment region of concrete members in comparison with the positive region. This research was conducted to determine the behavior of RC T-beams strengthened in the negative moment region using half-embedded NSM FRP rods. The findings were associated with the Modified Compression Field Theory (MCFT) which was applied in the analytical models. The model proposed was validated through a comparison with previous experimental study that showed half-embedded NSM FRP was effective as another method in comparison with the conventional soffit strengthening systems in retrofitting RC T-beams in the negative moment region, and good agreement was obtained. After that, a parametric analysis was initiated to determine the influence of FRP rod diameters, the compressive strength of concretes, the ratio of steel reinforcement as well as the materials used for the FRP on the flexural behavior of strengthened beams.