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Jamal A. Abdalla

American University of Sharjah, Department of Civil Engineering, Faculty Member

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I received my bachelor’s degree in civil engineering from the University of Khartoum, earned my master's from Purdue University, West Lafayette, USA and my Ph.D. degree from the University of California at Berkeley, USA, that was followed by Postdoctoral Research studies at the Civil Engineering Department of Stanford University, USA. I am currently a professor of civil engineering (structural engineering) at the American University of Sharjah (AUS), United Arab Emirates (UAE). Prior to that, I taught at Qatar University and at the University of Khartoum. My teaching interest spans a wide range of structural engineering topics including structural dynamics, structural analysis and steel and concrete design. My research interest covers computing and machine learning in civil engineering, seismic hazard assessment, earthquake engineering, strengthening/retrofitting of structures and sustainable building materials. During my academic career, I have delivered keynote presentations, gave seminars, organized conferences and workshops and served on numerous conferences' technical committees.

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Papers by Jamal A. Abdalla

CFRP U-Wraps and Spike Anchors for Enhancing the Flexural Performance of CFRP-Plated RC Beams

Polymers

Deterioration of infrastructure is a major challenge in the civil engineering industry. One of th... more Deterioration of infrastructure is a major challenge in the civil engineering industry. One of the methods that has been deemed effective in upgrading reinforced concrete (RC) structures is using externally bonded fiber-reinforced polymer (FRP) composites. However, the efficacy of this retrofitting technique is limited by the premature debonding failure of the FRP at the concrete-FRP interface; thus, the full capacity of the FRP is rarely utilized. Anchorage systems were proposed as a feasible solution to suppress or delay debonding failure. This paper presents an experimental investigation on the use of end U-wraps and carbon FRP (CFRP) spike anchors to anchor CFRP plates bonded to flexure-deficient RC beams. The experimental program consisted of seven RC beams with the length of the CFRP plate, type of anchorage, and the number of anchors as experimental variables. Test results indicated a remarkable enhancement in the ultimate load-carrying capacity when longer CFRP plates were u...

Bond Stress-Slip Models and Behavior of Aluminum Alloy (Aa) Plates to Concrete Interface

SSRN Electronic Journal

Using bore-epoxy anchorage to delay debonding of CFRP plates strengthened concrete beams

2018 Advances in Science and Engineering Technology International Conferences (ASET)

Repairing of deteriorating structures has been done using different methods and techniques. Shear... more Repairing of deteriorating structures has been done using different methods and techniques. Shear strengthening of Reinforced Concrete (RC) elements with externally bonded carbon fiber reinforced polymer (CFRP) plates and sheets have been widely used and accepted. It has been observed that de-bonding of the CFRP laminate and other strengthening materials is the most common type of failure. To address this issue many anchorage systems and methods have been developed. In this paper the use of bore-epoxy anchorage (Boring) system has been investigated. A total of five shear deficient RC beams were strengthened with carbon (CFRP) plates using bore-epoxy anchorage with bores of different diameters. The specimens were tested under four points bending. The results showed that the bore-epoxy anchorage delayed the CFRP de-bonding considerably and increased the shear capacity of the tested specimens by up to 48 % compared to the control beam.

Evaluation on the effect of anchor embedment depth on the flexural capacity of concrete prisms

Procedia Structural Integrity

Finite Element Modeling of Engineered Cementitious Composite (ECC) Prisms and Beams

2022 Advances in Science and Engineering Technology International Conferences (ASET), 2022

In this study, 3-dimensional Finite Element (FE) models of prisms and beams subjected to 4 point-... more In this study, 3-dimensional Finite Element (FE) models of prisms and beams subjected to 4 point-loading setup were developed. The objective is to investigate the flexural behavior of Engineered Cementitious Composite (ECC) prisms exposed to different temperatures and to verify the effectiveness of the corresponding FE predictions. Two ECC prism models were analyzed; one model was for an ECC prism tested at room temperature, while the second was for an ECC prism tested after exposure to a temperature of 200° C. Moreover, analysis was conducted and the results were compared for Reinforced Ultra-High-Performance Engineered Cementitious Composite (UHP-ECC) beams and traditional Reinforced Concrete (RC) beams. The impact of two different reinforcement ratios was analyzed for both (UHP-ECC) and RC beams. Comparison between FE models for prisms and beams confirmed that the models provide reasonable predictions of experimental results.

Finite element modelling of aluminum alloy plated reinforced concrete beams

Computers and Concrete, 2021

This study presents a nonlinear finite element (FE) model development of reinforced concrete (RC)... more This study presents a nonlinear finite element (FE) model development of reinforced concrete (RC) beams externally strengthened with aluminum alloy (AA) plates. The aim of this numerical study was to elucidate the effects of different anchorage schemes on the capacity, ductility, and failure mode of AA plate strengthened beams reported in a published test. Three FE models were developed; namely, a reference RC beam, a beam externally bonded (EB) with an AA plate, and a beam EB with an AA plate with carbon fiber reinforced polymers (CFRP) U-wraps at the plate's end. Validation of the developed FE models was carried out by comparing their load-deflection plots, maximum attained loads, deflections at failure, and failure modes with those reported during the test. The results of each FE model yielded an absolute percentage error less than 5%. Moreover, premature failure modes like end-plate and intermediate crack debonding were simulated and closely agreed with those observed during...

Shear Behavior of RC Beams Cast with LAVA Lightweight Aggregates

2019 Advances in Science and Engineering Technology International Conferences (ASET), 2019

The objective of this paper is to study the shear behavior of reinforced concrete (RC) beams cast... more The objective of this paper is to study the shear behavior of reinforced concrete (RC) beams cast with lava light weight aggregate (LWA). Six shear deficient beams were designed, constructed and cast with Normal weight concrete (NWC) and lightweight concrete (LWC). All the normal weight concrete (NWC) and light weight concrete (LWC) beam specimens were tested under one point loading, however LWC specimens were tested after 28 and 56 days. Load versus mid-span deflection response along with the failure modes was recorded until the failure of the specimens. The experimental results shows that all beam failed due diagonal crack and the specimens tested at 56 days achieved comparable shear strength to that of NWC beams. In-addition, the shear strength reduction factor was in the range of 0.78-0.94.

A semi-automated method for integrating textural and material data into as-built BIM using TIS

Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle... more Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle for various applications, such as design, construction, facility management, and maintenance. For existing buildings, the geometry of as-built BIM is often constructed using dense, three dimensional (3D) point clouds data obtained with laser scanners. Traditionally, as-built BIM systems do not contain the material and textural information of the buildings' elements. This paper presents a semi-automatic method for generation of material and texture rich as-built BIM. The method captures and integrates material and textural information of building elements into as-built BIM using thermal infrared sensing (TIS). The proposed method uses TIS to capture thermal images of the interior walls of an existing building. These images are then processed to extract the interior walls using a segmentation algorithm. The digital numbers in the resulted images are then transformed into radiance valu...

Bond behavior of Galvanized Steel Mesh to concrete

2018 Advances in Science and Engineering Technology International Conferences (ASET), 2018

This paper presents the results of an experimental investigation conducted to study the bond stre... more This paper presents the results of an experimental investigation conducted to study the bond strength between Galvanized Steel Mesh (GSM) sheets and concrete surfaces via mortar and epoxy adhesives. Epoxy and cement mortar adhesives are used to externally bond the GSM sheets to concrete prisms. The GSM sheets bonded length was chosen to be 200 mm in length which represents 40% of the prism's length. Three-point bending tests are conducted on the tested specimens and load-deflection response are recorded along the with associated capacity and failure modes. Epoxy and cement mortar bonded specimens failed in cohesive and adhesive modes, respectively. The strengthened specimen bonded with cement mortar was 40% less effective as compared to that bonded with epoxy adhesives. The ductility and strength of the epoxy bonded specimen was significantly higher than the specimens bonded with cement mortar.

Nonlinear finite element models of reinforced concrete beams strengthened in bending with mechanically fastened aluminum alloy plates

Computers & Structures, 2021

Abstract This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) b... more Abstract This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) beams externally strengthened with mechanically fastened (MF) and externally bonded (EB) aluminum alloy (AA) plates. The measured and observed parameters of each specimen were obtained from an experiment conducted by the authors of this study. Each FE model adopted accurate material constitutive laws and appropriate element definitions to approximate the mechanical behavior observed during testing. A total of ten models were constructed based on the diameter, embedment depth, and arrangement of the expansion anchor bolt (EAB) as well as the presence or absence of epoxy. Results like the load-carrying capacity of the tested specimens as well as the failure modes like end-plate debonding (ED), local-plate debonding (LD), and plate rupture (PR) were accurately predicted. Additionally, Stress and strain contour plots were generated to investigate the FE models’ mechanical behaviors. Finally, a parametric study was conducted to illustrate the effects of the flexural steel reinforcement ratio and AA plate grades on the models’ structural response. It was concluded that the FE models could serve as a valid predictive platform for simulating the flexural behavior of RC beams strengthened with MF and EB AA plates.

Prediction of shear strength and behavior of RC beams strengthened with externally bonded FRP sheets using machine learning techniques

Composite Structures, 2019

Abstract This paper presents the use Machine Learning (ML) techniques to study the behavior of sh... more Abstract This paper presents the use Machine Learning (ML) techniques to study the behavior of shear-deficient reinforced concrete (RC) beams strengthened in shear with side-bonded and U-wrapped fiber-reinforced polymers (FRP) laminates. An extensive database consisting of 120 tested specimen and 15 parameters was collected. The resilient back-propagating neural network (RBPNN) was used as a regression tool and the recursive feature elimination (RFE) algorithm and neural interpretation diagram (NID) were employed within the validated RBPNN to identify the parameters that greatly influence the prediction of FRP shear capacity. The results indicated that the RBPNN with the selected parameters was capable of predicting the FRP shear capacity more accurately (r2 = 0.885; RMSE = 8.1 kN) than that of the RBPNN with the original 15 parameters (r2 = 0.668; RMSE = 16.6 kN). The model also outperformed previously established standard predictions of ACI 440.R-17, fib14 and CNRDT200. A comprehensive parametric study was conducted and it concluded that the implementation of RBPNN with RFE and NID, separately, is a viable tool for assessing the strength and behavior of FRP in shear strengthened beams.

Performance of hybrid carbon and basalt FRP sheets in strengthening concrete beams in flexure

Composite Structures, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Modeling of nonlinear response of R/C shear deficient t-beam subjected to cyclic loading

Computers & concrete, 2012

This paper presents a finite element (FE) model for predicting the nonlinear response and behavio... more This paper presents a finite element (FE) model for predicting the nonlinear response and behavior of a reinforced concrete T-beam deficient in shear under cyclic loading. Cracking loads, failure loads, response hysteresis envelopes and crack patterns were used as bench mark for comparison between experimental and FE results. A parametric study was carried out to predict the optimum combination of the open and close crack shear transfer coefficients ( and ) of the constitutive material model for concrete. It is concluded that when both shear transfer coefficients are equal to 0.2 the FE results gave the best correlation with the experimental results. The results were also verified on a rectangular shear deficient beam (R-beam) tested under cyclic loading and it is concluded that the variation of section geometry has no effect on the optimum choice of the values of shear transfer coefficients of 0.2. In addition, a parametric study based on the variation of concrete compressive strength, was carried out on the T-beam and it is observed that the variation of concrete compressive strength has little effect on the deflection. Further conclusions and observations were also drawn.

Models for predicting elastic modulus and tensile strength of carbon, basalt and hybrid carbon-basalt FRP laminates at elevated temperatures

Construction and Building Materials, 2016

h i g h l i g h t s Mechanical properties of basalt and carbon FRP laminates with temperature. Ca... more h i g h l i g h t s Mechanical properties of basalt and carbon FRP laminates with temperature. Carbon, basalt and carbon-basalt sheets were used. The elastic modulus and tensile strength were significantly reduced. Analytical models were developed to predict the mechanical properties as a function of temperature.

Finite element analysis of strengthened RC beams in shear with aluminum plates

Computers & Structures, 2015

This paper presents the development of a 3D nonlinear finite element (FE) model to capture and pr... more This paper presents the development of a 3D nonlinear finite element (FE) model to capture and predict the response of shear deficient simply supported reinforced concrete (RC) beams strengthened externally with aluminum alloy plates. Five FE models were developed based on experimental tests conducted by the authors in a previous investigation. The experimental program included four RC beams strengthened in shear with externally bonded structural aluminum alloy plates of grade 5083-0 and tested under fourpoint loading to failure. The use of this material instead of the conventional fiber reinforced polymer (FRP) materials seemed to be very promising in enhancing both the strength and ductility of the strengthened specimens. The beams were designed to fail in shear and then strengthened with aluminum alloy plates with different strip spacing and orientation. The developed FE models have exact geometry, nonlinear material properties and boundary conditions to that of the experimental specimens. The FE models employed material constitutive laws for the concrete in tension and compression, yielding of the aluminum plates and flexural steel reinforcement. The developed FE models also incorporated the interfacial bond behavior at the aluminum concrete interface. The predicted FE results for the load-midspan deflection are compared to the measured experimental data. Close agreement was found between the predicted and measured results at all stages of loading for the tested specimens. For the maximum load and maximum mid-span deflection, it is observed that the Mean Absolute Percent Error (MAPE) of the prediction for the five specimens is 1.19% and 4.31% and the Normalized Mean Square Error (NMSE) is 0.0005 and 0.004, respectively. It could be concluded that the developed FE model could be used in future investigations to predict the performance of shear deficient RC beams externally strengthened with aluminum alloy plates with different configurations and orientations.

Modeling Phosphorus Removal Process Using Artificial Neural Network

4th International BALWOIS Conference on Water Observation and Information System for Decision Support, Ohrid, Republic of Macedonia, May, May 25, 2010

Phosphorus pollution is one of the most important causes of surface water pollution. Effective ph... more Phosphorus pollution is one of the most important causes of surface water pollution. Effective phosphorus removal was observed using dried alum residual. The use of waste residuals as a treatment media is very new. For this reason, a model to predict phosphorus removal using alum residual is novel. Experimental results were obtained from a fixed bed column tests conducted in a control environment. Six input variables were used to tests the efficiency of phosphorus removal at different times. In this study Artificial Neural Networks ( ...

Bond behavior of CFRP cured laminates: Experimental and numerical investigation

Journal of Engineering Materials and Technology, Transactions of the ASME, 2012

Bond Behavior of CFRP Cured Laminates: Expérimentai and Numericai investigation The use of extern... more Bond Behavior of CFRP Cured Laminates: Expérimentai and Numericai investigation The use of externally bonded carbon flber-reinforced polymers (CFRPs) as strengthening systems to improve the condition and overall capacity of existing reinforced concrete structural members is found to be a promising scheme, Thisfleld has drawn the attention of many researchers in the past two decades through the implementation of much theoretical work as well as experimental studies. It was evident through many experimental investigations conducted by a number of researchers that the bond action between fiberreinforced polymers and reinforced concrete members is considered one of the main factors affecting the performance and reliability of external strengthening systems and warrants further investigation, Debonding failure is a brittle mode of failure that may occur prematurely before strengthened members develop their full composite and expected capacities. This paper aims to investigate the bond behavior between the CFRP-concrete interface via experimental work andflnite element (FE) simulations. The experimental study consisted in testing nine concrete prisms with different bonded lengths of the CFRP plates that vary between 25% (60 mm), 50% (120 mm), and 75% (180 mm) of the total length of the concrete prisms and instrumented with strain gauges, A FE simulation model was created and validated using the experimental results of the tested specimens, and a parametric study was carried out to investigate the effect of several parameters on the bond behavior between CFRP and concrete surfaces. The trend of the FE simulation results shows a good agreement with the experimental results and those available in the literature. It was observed that the optimum length of the CFRP plate is in the range between 150 mm and 160 mm when bonded to concrete surfaces. Other conclusions and observations were drawn based on the experimental and numerical results,

Seismic Microzonation of Central Khartoum, Sudan

University of Khartuom, 2001

A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital... more A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. The Central Khartoum with its high rise buildings is the center of governmental and business activities and is located on strip adjacent to the Blue Nile. Geological and geotechnical data indicated that the subsoil conditions at Central Khartoum are characterized by alluvial deposits underlain by Nubian Sandstone below a depth of 20 m. The alluvial deposits locally known as Gezira formations , consist of clays grading into silt and sand with depth. Macro seismic zonation of Sudan and its vicinities, developed by the authors, gave the ground acceleration at the bed rock surface. The effect of alluvial deposits at Central Khartoum on propagation of seismic motion parameters to the ground surface is investigated in this study. Correlations are proposed for pertinent cyclic soil properties such as shear modulus, damping, and shear wave velocity. The classical shear beam model developed by Idriss and Seed is used to study the effect of local soil conditions on ground motion parameters. In absence of strong motion records, artificial time histories of ground motion parameters are used. Plots showing the time histories of ground motion parameters at the ground surface are obtained. The results indicated amplification of ground acceleration of up to 1.15. Because of the presence of saturated loose to medium dense sand at some locations within Central Khartoum, the risk of earthquake-induced liquefaction is evaluated. The susceplity of subsoils in Central Khartoum to liguefaction is evaluated probabilistically by modifying the classical method developed by Seed and Idriss. The risk of earthquake-induced liquefaction is computed by combining the seismic hazard and the conditional probability of liquefaction. The study showed that the risk of liquefaction is low.

Tensile and compressive strength of polyethylene engineered cementitious composite (PE-ECC) at elevated temperature

by Fardin Mahmoudi and Jamal A. Abdalla

Materials Today: Proceedings, 2022

The fire performance of engineered cementitious composites (ECC) made with polyethylene (PE) fibe... more The fire performance of engineered cementitious composites (ECC) made with polyethylene (PE) fibers has not been addressed extensively in the literature. Therefore, this study’s main objective is to investigate the residual compressive and tensile properties of PE-ECC specimens after high-temperature exposures. The compression cube samples were heated up to 400 C, and the tensile specimens were exposed to sub-elevated temperatures up to 120 C. After the samples were heated, they were allowed to cool down naturally to room temperature. During the heating process, no explosive spalling was observed. Cube specimens exposed to the temperature of 200 C, maintained almost all the compressive strength of unheated specimens. The compressive strength of the samples heated to the temperature of 400 C, was almost 60% of that of the control ones. All the tensile dogbone specimens at different temperature exposures showed strain-hardening and multiple cracking behaviors. At 80 C, the tensile strength of dogbone specimens was increased by 13% and then decreased by 10% at 120 C compared to the control unheated specimens.

Finite Element Modeling and Prediction of Tensile Behavior of PE-ECC Dogbones

by Fardin Mahmoudi and Jamal A. Abdalla

2022 Advances in Science and Engineering Technology International Conferences (ASET), Feb 21, 2022

CFRP U-Wraps and Spike Anchors for Enhancing the Flexural Performance of CFRP-Plated RC Beams

Polymers

Deterioration of infrastructure is a major challenge in the civil engineering industry. One of th... more Deterioration of infrastructure is a major challenge in the civil engineering industry. One of the methods that has been deemed effective in upgrading reinforced concrete (RC) structures is using externally bonded fiber-reinforced polymer (FRP) composites. However, the efficacy of this retrofitting technique is limited by the premature debonding failure of the FRP at the concrete-FRP interface; thus, the full capacity of the FRP is rarely utilized. Anchorage systems were proposed as a feasible solution to suppress or delay debonding failure. This paper presents an experimental investigation on the use of end U-wraps and carbon FRP (CFRP) spike anchors to anchor CFRP plates bonded to flexure-deficient RC beams. The experimental program consisted of seven RC beams with the length of the CFRP plate, type of anchorage, and the number of anchors as experimental variables. Test results indicated a remarkable enhancement in the ultimate load-carrying capacity when longer CFRP plates were u...

Bond Stress-Slip Models and Behavior of Aluminum Alloy (Aa) Plates to Concrete Interface

SSRN Electronic Journal

Using bore-epoxy anchorage to delay debonding of CFRP plates strengthened concrete beams

2018 Advances in Science and Engineering Technology International Conferences (ASET)

Repairing of deteriorating structures has been done using different methods and techniques. Shear... more Repairing of deteriorating structures has been done using different methods and techniques. Shear strengthening of Reinforced Concrete (RC) elements with externally bonded carbon fiber reinforced polymer (CFRP) plates and sheets have been widely used and accepted. It has been observed that de-bonding of the CFRP laminate and other strengthening materials is the most common type of failure. To address this issue many anchorage systems and methods have been developed. In this paper the use of bore-epoxy anchorage (Boring) system has been investigated. A total of five shear deficient RC beams were strengthened with carbon (CFRP) plates using bore-epoxy anchorage with bores of different diameters. The specimens were tested under four points bending. The results showed that the bore-epoxy anchorage delayed the CFRP de-bonding considerably and increased the shear capacity of the tested specimens by up to 48 % compared to the control beam.

Evaluation on the effect of anchor embedment depth on the flexural capacity of concrete prisms

Procedia Structural Integrity

Finite Element Modeling of Engineered Cementitious Composite (ECC) Prisms and Beams

2022 Advances in Science and Engineering Technology International Conferences (ASET), 2022

In this study, 3-dimensional Finite Element (FE) models of prisms and beams subjected to 4 point-... more In this study, 3-dimensional Finite Element (FE) models of prisms and beams subjected to 4 point-loading setup were developed. The objective is to investigate the flexural behavior of Engineered Cementitious Composite (ECC) prisms exposed to different temperatures and to verify the effectiveness of the corresponding FE predictions. Two ECC prism models were analyzed; one model was for an ECC prism tested at room temperature, while the second was for an ECC prism tested after exposure to a temperature of 200° C. Moreover, analysis was conducted and the results were compared for Reinforced Ultra-High-Performance Engineered Cementitious Composite (UHP-ECC) beams and traditional Reinforced Concrete (RC) beams. The impact of two different reinforcement ratios was analyzed for both (UHP-ECC) and RC beams. Comparison between FE models for prisms and beams confirmed that the models provide reasonable predictions of experimental results.

Finite element modelling of aluminum alloy plated reinforced concrete beams

Computers and Concrete, 2021

This study presents a nonlinear finite element (FE) model development of reinforced concrete (RC)... more This study presents a nonlinear finite element (FE) model development of reinforced concrete (RC) beams externally strengthened with aluminum alloy (AA) plates. The aim of this numerical study was to elucidate the effects of different anchorage schemes on the capacity, ductility, and failure mode of AA plate strengthened beams reported in a published test. Three FE models were developed; namely, a reference RC beam, a beam externally bonded (EB) with an AA plate, and a beam EB with an AA plate with carbon fiber reinforced polymers (CFRP) U-wraps at the plate's end. Validation of the developed FE models was carried out by comparing their load-deflection plots, maximum attained loads, deflections at failure, and failure modes with those reported during the test. The results of each FE model yielded an absolute percentage error less than 5%. Moreover, premature failure modes like end-plate and intermediate crack debonding were simulated and closely agreed with those observed during...

Shear Behavior of RC Beams Cast with LAVA Lightweight Aggregates

2019 Advances in Science and Engineering Technology International Conferences (ASET), 2019

The objective of this paper is to study the shear behavior of reinforced concrete (RC) beams cast... more The objective of this paper is to study the shear behavior of reinforced concrete (RC) beams cast with lava light weight aggregate (LWA). Six shear deficient beams were designed, constructed and cast with Normal weight concrete (NWC) and lightweight concrete (LWC). All the normal weight concrete (NWC) and light weight concrete (LWC) beam specimens were tested under one point loading, however LWC specimens were tested after 28 and 56 days. Load versus mid-span deflection response along with the failure modes was recorded until the failure of the specimens. The experimental results shows that all beam failed due diagonal crack and the specimens tested at 56 days achieved comparable shear strength to that of NWC beams. In-addition, the shear strength reduction factor was in the range of 0.78-0.94.

A semi-automated method for integrating textural and material data into as-built BIM using TIS

Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle... more Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle for various applications, such as design, construction, facility management, and maintenance. For existing buildings, the geometry of as-built BIM is often constructed using dense, three dimensional (3D) point clouds data obtained with laser scanners. Traditionally, as-built BIM systems do not contain the material and textural information of the buildings' elements. This paper presents a semi-automatic method for generation of material and texture rich as-built BIM. The method captures and integrates material and textural information of building elements into as-built BIM using thermal infrared sensing (TIS). The proposed method uses TIS to capture thermal images of the interior walls of an existing building. These images are then processed to extract the interior walls using a segmentation algorithm. The digital numbers in the resulted images are then transformed into radiance valu...

Bond behavior of Galvanized Steel Mesh to concrete

2018 Advances in Science and Engineering Technology International Conferences (ASET), 2018

This paper presents the results of an experimental investigation conducted to study the bond stre... more This paper presents the results of an experimental investigation conducted to study the bond strength between Galvanized Steel Mesh (GSM) sheets and concrete surfaces via mortar and epoxy adhesives. Epoxy and cement mortar adhesives are used to externally bond the GSM sheets to concrete prisms. The GSM sheets bonded length was chosen to be 200 mm in length which represents 40% of the prism's length. Three-point bending tests are conducted on the tested specimens and load-deflection response are recorded along the with associated capacity and failure modes. Epoxy and cement mortar bonded specimens failed in cohesive and adhesive modes, respectively. The strengthened specimen bonded with cement mortar was 40% less effective as compared to that bonded with epoxy adhesives. The ductility and strength of the epoxy bonded specimen was significantly higher than the specimens bonded with cement mortar.

Nonlinear finite element models of reinforced concrete beams strengthened in bending with mechanically fastened aluminum alloy plates

Computers & Structures, 2021

Abstract This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) b... more Abstract This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) beams externally strengthened with mechanically fastened (MF) and externally bonded (EB) aluminum alloy (AA) plates. The measured and observed parameters of each specimen were obtained from an experiment conducted by the authors of this study. Each FE model adopted accurate material constitutive laws and appropriate element definitions to approximate the mechanical behavior observed during testing. A total of ten models were constructed based on the diameter, embedment depth, and arrangement of the expansion anchor bolt (EAB) as well as the presence or absence of epoxy. Results like the load-carrying capacity of the tested specimens as well as the failure modes like end-plate debonding (ED), local-plate debonding (LD), and plate rupture (PR) were accurately predicted. Additionally, Stress and strain contour plots were generated to investigate the FE models’ mechanical behaviors. Finally, a parametric study was conducted to illustrate the effects of the flexural steel reinforcement ratio and AA plate grades on the models’ structural response. It was concluded that the FE models could serve as a valid predictive platform for simulating the flexural behavior of RC beams strengthened with MF and EB AA plates.

Prediction of shear strength and behavior of RC beams strengthened with externally bonded FRP sheets using machine learning techniques

Composite Structures, 2019

Abstract This paper presents the use Machine Learning (ML) techniques to study the behavior of sh... more Abstract This paper presents the use Machine Learning (ML) techniques to study the behavior of shear-deficient reinforced concrete (RC) beams strengthened in shear with side-bonded and U-wrapped fiber-reinforced polymers (FRP) laminates. An extensive database consisting of 120 tested specimen and 15 parameters was collected. The resilient back-propagating neural network (RBPNN) was used as a regression tool and the recursive feature elimination (RFE) algorithm and neural interpretation diagram (NID) were employed within the validated RBPNN to identify the parameters that greatly influence the prediction of FRP shear capacity. The results indicated that the RBPNN with the selected parameters was capable of predicting the FRP shear capacity more accurately (r2 = 0.885; RMSE = 8.1 kN) than that of the RBPNN with the original 15 parameters (r2 = 0.668; RMSE = 16.6 kN). The model also outperformed previously established standard predictions of ACI 440.R-17, fib14 and CNRDT200. A comprehensive parametric study was conducted and it concluded that the implementation of RBPNN with RFE and NID, separately, is a viable tool for assessing the strength and behavior of FRP in shear strengthened beams.

Performance of hybrid carbon and basalt FRP sheets in strengthening concrete beams in flexure

Composite Structures, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Modeling of nonlinear response of R/C shear deficient t-beam subjected to cyclic loading

Computers & concrete, 2012

This paper presents a finite element (FE) model for predicting the nonlinear response and behavio... more This paper presents a finite element (FE) model for predicting the nonlinear response and behavior of a reinforced concrete T-beam deficient in shear under cyclic loading. Cracking loads, failure loads, response hysteresis envelopes and crack patterns were used as bench mark for comparison between experimental and FE results. A parametric study was carried out to predict the optimum combination of the open and close crack shear transfer coefficients ( and ) of the constitutive material model for concrete. It is concluded that when both shear transfer coefficients are equal to 0.2 the FE results gave the best correlation with the experimental results. The results were also verified on a rectangular shear deficient beam (R-beam) tested under cyclic loading and it is concluded that the variation of section geometry has no effect on the optimum choice of the values of shear transfer coefficients of 0.2. In addition, a parametric study based on the variation of concrete compressive strength, was carried out on the T-beam and it is observed that the variation of concrete compressive strength has little effect on the deflection. Further conclusions and observations were also drawn.

Models for predicting elastic modulus and tensile strength of carbon, basalt and hybrid carbon-basalt FRP laminates at elevated temperatures

Construction and Building Materials, 2016

h i g h l i g h t s Mechanical properties of basalt and carbon FRP laminates with temperature. Ca... more h i g h l i g h t s Mechanical properties of basalt and carbon FRP laminates with temperature. Carbon, basalt and carbon-basalt sheets were used. The elastic modulus and tensile strength were significantly reduced. Analytical models were developed to predict the mechanical properties as a function of temperature.

Finite element analysis of strengthened RC beams in shear with aluminum plates

Computers & Structures, 2015

This paper presents the development of a 3D nonlinear finite element (FE) model to capture and pr... more This paper presents the development of a 3D nonlinear finite element (FE) model to capture and predict the response of shear deficient simply supported reinforced concrete (RC) beams strengthened externally with aluminum alloy plates. Five FE models were developed based on experimental tests conducted by the authors in a previous investigation. The experimental program included four RC beams strengthened in shear with externally bonded structural aluminum alloy plates of grade 5083-0 and tested under fourpoint loading to failure. The use of this material instead of the conventional fiber reinforced polymer (FRP) materials seemed to be very promising in enhancing both the strength and ductility of the strengthened specimens. The beams were designed to fail in shear and then strengthened with aluminum alloy plates with different strip spacing and orientation. The developed FE models have exact geometry, nonlinear material properties and boundary conditions to that of the experimental specimens. The FE models employed material constitutive laws for the concrete in tension and compression, yielding of the aluminum plates and flexural steel reinforcement. The developed FE models also incorporated the interfacial bond behavior at the aluminum concrete interface. The predicted FE results for the load-midspan deflection are compared to the measured experimental data. Close agreement was found between the predicted and measured results at all stages of loading for the tested specimens. For the maximum load and maximum mid-span deflection, it is observed that the Mean Absolute Percent Error (MAPE) of the prediction for the five specimens is 1.19% and 4.31% and the Normalized Mean Square Error (NMSE) is 0.0005 and 0.004, respectively. It could be concluded that the developed FE model could be used in future investigations to predict the performance of shear deficient RC beams externally strengthened with aluminum alloy plates with different configurations and orientations.

Modeling Phosphorus Removal Process Using Artificial Neural Network

4th International BALWOIS Conference on Water Observation and Information System for Decision Support, Ohrid, Republic of Macedonia, May, May 25, 2010

Phosphorus pollution is one of the most important causes of surface water pollution. Effective ph... more Phosphorus pollution is one of the most important causes of surface water pollution. Effective phosphorus removal was observed using dried alum residual. The use of waste residuals as a treatment media is very new. For this reason, a model to predict phosphorus removal using alum residual is novel. Experimental results were obtained from a fixed bed column tests conducted in a control environment. Six input variables were used to tests the efficiency of phosphorus removal at different times. In this study Artificial Neural Networks ( ...

Bond behavior of CFRP cured laminates: Experimental and numerical investigation

Journal of Engineering Materials and Technology, Transactions of the ASME, 2012

Bond Behavior of CFRP Cured Laminates: Expérimentai and Numericai investigation The use of extern... more Bond Behavior of CFRP Cured Laminates: Expérimentai and Numericai investigation The use of externally bonded carbon flber-reinforced polymers (CFRPs) as strengthening systems to improve the condition and overall capacity of existing reinforced concrete structural members is found to be a promising scheme, Thisfleld has drawn the attention of many researchers in the past two decades through the implementation of much theoretical work as well as experimental studies. It was evident through many experimental investigations conducted by a number of researchers that the bond action between fiberreinforced polymers and reinforced concrete members is considered one of the main factors affecting the performance and reliability of external strengthening systems and warrants further investigation, Debonding failure is a brittle mode of failure that may occur prematurely before strengthened members develop their full composite and expected capacities. This paper aims to investigate the bond behavior between the CFRP-concrete interface via experimental work andflnite element (FE) simulations. The experimental study consisted in testing nine concrete prisms with different bonded lengths of the CFRP plates that vary between 25% (60 mm), 50% (120 mm), and 75% (180 mm) of the total length of the concrete prisms and instrumented with strain gauges, A FE simulation model was created and validated using the experimental results of the tested specimens, and a parametric study was carried out to investigate the effect of several parameters on the bond behavior between CFRP and concrete surfaces. The trend of the FE simulation results shows a good agreement with the experimental results and those available in the literature. It was observed that the optimum length of the CFRP plate is in the range between 150 mm and 160 mm when bonded to concrete surfaces. Other conclusions and observations were drawn based on the experimental and numerical results,

Seismic Microzonation of Central Khartoum, Sudan

University of Khartuom, 2001

A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital... more A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. The Central Khartoum with its high rise buildings is the center of governmental and business activities and is located on strip adjacent to the Blue Nile. Geological and geotechnical data indicated that the subsoil conditions at Central Khartoum are characterized by alluvial deposits underlain by Nubian Sandstone below a depth of 20 m. The alluvial deposits locally known as Gezira formations , consist of clays grading into silt and sand with depth. Macro seismic zonation of Sudan and its vicinities, developed by the authors, gave the ground acceleration at the bed rock surface. The effect of alluvial deposits at Central Khartoum on propagation of seismic motion parameters to the ground surface is investigated in this study. Correlations are proposed for pertinent cyclic soil properties such as shear modulus, damping, and shear wave velocity. The classical shear beam model developed by Idriss and Seed is used to study the effect of local soil conditions on ground motion parameters. In absence of strong motion records, artificial time histories of ground motion parameters are used. Plots showing the time histories of ground motion parameters at the ground surface are obtained. The results indicated amplification of ground acceleration of up to 1.15. Because of the presence of saturated loose to medium dense sand at some locations within Central Khartoum, the risk of earthquake-induced liquefaction is evaluated. The susceplity of subsoils in Central Khartoum to liguefaction is evaluated probabilistically by modifying the classical method developed by Seed and Idriss. The risk of earthquake-induced liquefaction is computed by combining the seismic hazard and the conditional probability of liquefaction. The study showed that the risk of liquefaction is low.

Tensile and compressive strength of polyethylene engineered cementitious composite (PE-ECC) at elevated temperature

by Fardin Mahmoudi and Jamal A. Abdalla

Materials Today: Proceedings, 2022

The fire performance of engineered cementitious composites (ECC) made with polyethylene (PE) fibe... more The fire performance of engineered cementitious composites (ECC) made with polyethylene (PE) fibers has not been addressed extensively in the literature. Therefore, this study’s main objective is to investigate the residual compressive and tensile properties of PE-ECC specimens after high-temperature exposures. The compression cube samples were heated up to 400 C, and the tensile specimens were exposed to sub-elevated temperatures up to 120 C. After the samples were heated, they were allowed to cool down naturally to room temperature. During the heating process, no explosive spalling was observed. Cube specimens exposed to the temperature of 200 C, maintained almost all the compressive strength of unheated specimens. The compressive strength of the samples heated to the temperature of 400 C, was almost 60% of that of the control ones. All the tensile dogbone specimens at different temperature exposures showed strain-hardening and multiple cracking behaviors. At 80 C, the tensile strength of dogbone specimens was increased by 13% and then decreased by 10% at 120 C compared to the control unheated specimens.

Finite Element Modeling and Prediction of Tensile Behavior of PE-ECC Dogbones

by Fardin Mahmoudi and Jamal A. Abdalla

2022 Advances in Science and Engineering Technology International Conferences (ASET), Feb 21, 2022