amer farouk | University of Baghdad (original) (raw)

Papers by amer farouk

Research paper thumbnail of Retrofit of Shear Critical R.C. Beams with Carbon Fiber Reinforced Polymers (CFRP)

Maǧallaẗ al-handasaẗ wa-al-tiknūlūǧiyā, Aug 31, 2009

Research paper thumbnail of Finite element modeling of post fire RC rafters with openings of different sizes and shapes

Nucleation and Atmospheric Aerosols, 2023

This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite... more This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite element computer application to examine the performance and residual strength of 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with 8 circular openings). Rising the burning temperature causes degradation in those beams with comparable shape, as shown in their increasing mid-span deflection during the fire exposure period and their residual deflection after cooling, while the existing openings condition was exacerbated. The main objective of this article are to provide a numerical model for simulating nonlinear behavior of such beams, which includes a trustworthy finite element model approach and constitutive material models. By means of load-deflection and cracking patterns, comparisons between computational and experimental models are provided, and a reasonable fit is demonstrated. The average ratio of numerical model ultimate loads and deflection to experimentally examined rafters were 1.033 and 0.96, respectively. As a result, finite element analysis may be regarded as a preferred and trustworthy approach for simulating the non-linear behavior of burned RC rafters (solid or perforated) in terms of complexity, difficulty, time savings, human effort, and money.

Research paper thumbnail of Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature

Zenodo (CERN European Organization for Nuclear Research), Oct 13, 2019

The main objective of this study is to characterize the main factors which may affect the behavio... more The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM-E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experimental results. These included the prestress effect, load-deflection relation under applied load, and load at failure of the reference beam and the beams after the exposure to fire.

Research paper thumbnail of Optimal Bedding Selection with the Specific Soil Type According to the Thrust Forces Generated in the Water Distribution Networks Using the Restraining Joint System

Research paper thumbnail of Performance of Reinforced Concrete Gable Beam with Quadrilateral Openings of Different Side Inclinations

E3S Web of Conferences

The existence of openings in a gable beam would have numerous advantages, the most important of w... more The existence of openings in a gable beam would have numerous advantages, the most important of which would be a reduction in the overall weight. These advantages include geometric flexibility, ease of handling when erected, and more. This study aims to investigate the flexural behavior of reinforced concrete gable beams with quadrilateral openings of different side inclinations; this goal has been specified with beam stiffness, the maximum load-carrying capacity, and strains of the beams. Beams are identical in their dimensions and reinforcement. The experimental program involved casting and testing four simply supported beams: a solid beam (reference beam) and others with quadrilateral openings. They were 3000mm long, 100mm wide, and 400 mm deep in the middle, tapering to 250 mm on both ends, concentrically loaded. The results demonstrate the load-carrying capacity is reduced by 6.1–12.9%, and the mid-span deflection is increased by 13–52% when openings exist compared to the solid...

Research paper thumbnail of Finite element modeling of post fire RC rafters with openings of different sizes and shapes

8TH ENGINEERING AND 2ND INTERNATIONAL CONFERENCE FOR COLLEGE OF ENGINEERING – UNIVERSITY OF BAGHDAD: COEC8-2021 Proceedings

This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite... more This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite element computer application to examine the performance and residual strength of 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with 8 circular openings). Rising the burning temperature causes degradation in those beams with comparable shape, as shown in their increasing mid-span deflection during the fire exposure period and their residual deflection after cooling, while the existing openings condition was exacerbated. The main objective of this article are to provide a numerical model for simulating nonlinear behavior of such beams, which includes a trustworthy finite element model approach and constitutive material models. By means of load-deflection and cracking patterns, comparisons between computational and experimental models are provided, and a reasonable fit is demonstrated. The average ratio of numerical model ultimate loads and deflection to experimentally examined rafters were 1.033 and 0.96, respectively. As a result, finite element analysis may be regarded as a preferred and trustworthy approach for simulating the non-linear behavior of burned RC rafters (solid or perforated) in terms of complexity, difficulty, time savings, human effort, and money.

Research paper thumbnail of Performance of quadrilateral perforated prestressed concrete rafters

Maǧallaẗ al-abḥāṯ al-handasiyyaẗ, Nov 3, 2021

This study focuses on the behavior of simply supported perforated prestressed concrete rafters (P... more This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages of performance of the prestressed concrete rafter. On the other hand, decreasing the depth of the upper and lower chords by 25% for PPCRs with the same number of openings led to a reduction in the failure load by (36, 29.5, and 24.5%) for rafters with 6, 8, and 10 openings, respectively.

Research paper thumbnail of Effect of posts inclination on the behavior of prestressed quadrilateral perforated concrete rafter

8TH ENGINEERING AND 2ND INTERNATIONAL CONFERENCE FOR COLLEGE OF ENGINEERING – UNIVERSITY OF BAGHDAD: COEC8-2021 Proceedings

The present study focuses on the performance of simply supported prestressed perforated concrete ... more The present study focuses on the performance of simply supported prestressed perforated concrete rafters (PPCRs) system having inclined or vertical posts with different numbers of quadrilateral openings. The advantages of (PPCRs) are easy erection and handling, geometrical flexibility, and most importantly the overall weight would be reduced. Therefore (PPCRs) chose as an alternative preferred option from steel to support roofs for long-spanned roof rafters. The experimental work includes investigation of seven rafters tested under monotonic static load until failure. The first rafter was the reference rafter (non-perforated), and the remaining six rafters were perforated with quadrilateral openings. The findings show that the presence of openings in PPCR decreases the ultimate load capacity by (3.5 ~ 10.9) % and increases the mid-span deflection at the ultimate load range of (7.9 ~ 24.7) % for PPCRs compared to the non-perforated one (PGB). For rafters having the same configuration extended over the same distance, when the number of openings increased (increasing posts number), the load carrying capacity increases. Whilst its companion deflection decreases for all loading stages. Also an increase in the ultimate load carrying capacity by (7, 4.5, and 3.5) % was noticed when inclined posts are used rather than vertical ones for rafters with 6, 8, and 10 openings, respectively, accompanied with a decreasing in midspan deflection at all loading stages.

Research paper thumbnail of Comparative Study between the Behavior of the Concrete Thrust Block and the Restraint Joint in a Water Distribution System; Review

Journal of Engineering

Thrust blocks and restraint joints are the two most popular methods of counteracting the thrust f... more Thrust blocks and restraint joints are the two most popular methods of counteracting the thrust force that generated at pipe fittings (bends, Tee, wye, reducers, dead ends, etc…). Both systems perform the same function, which is to prevent the joints from separating from the pipes. The aim of the study is to review previous studies and scientific theories related to the study and design of thrust blocks and restraint joints to study the behavior of both systems under thrust force and to study the factors and variables that affect the behavior of these systems. The behavior of both systems must be studied because they cannot be abandoned, as each system has conditions whose use is more feasible, scientific, and economical. The use of thrust blocks is usually more economical. Still, in many cases, its use is not appropriate, as it is required to wait for the result of the compressive strength test of the concrete. It is required to close the pipe trench as soon as possible; thus, this...

Research paper thumbnail of Static Shear Strength of a Non-Prismatic Beam with Transverse Openings

Engineering, Technology & Applied Science Research

In this study, a predicated formula is been proposed to find the shear strength of non-prismatic ... more In this study, a predicated formula is been proposed to find the shear strength of non-prismatic beams with or without openings. It depends on the contributions of concrete shear strength considering the beam depth variation and existing openings, shear steel reinforcements and defines the critical shear section, the effect of diagonal shear reinforcement, the effect of inclined tensile steel reinforcement, and the compression chord influence. The verification of the proposed formula has been conducted on the experimental test results of 26 non-prismatic beams with or without openings at the same loading conditions. The results reflect that the predicted formula finds the shear capacity of non-prismatic beams with openings, it is conservative and can be used for designing without the strength reduction factor.

Research paper thumbnail of Performance of concrete thrust block at several burial conditions under the influence of thrust forces generated in the water distribution networks

Journal of the Mechanical Behavior of Materials

This study was prepared to investigate the performance and behavior of concrete thrust blocks sup... more This study was prepared to investigate the performance and behavior of concrete thrust blocks supporting pipe fittings. In the water distribution networks, it is always necessary to change the path of the pipes at different degrees or to create new branches. In these regions, an unbalanced force called the thrust force is generated. In order to counter this force, these regions are supported with concrete blocks. In this article, the system components (soil, pipe with its bend and thrust blocks) have been numerically modeled and simulated by the ABAQUS CAE/2019 software program in order to study the behavior and stability of the thrust block with different burial conditions (several burial depths) by the soil under the influence of the thrust force. Accordingly, 45° bend angles were studied with a specified pipe diameter placed on soil with known properties under the influence of internal hydrostatic test pressure. The obtained results that were relied upon to describe the behavior ...

Research paper thumbnail of Performance of Prestressed Concrete Hunched Beams with Multi-Quadrilaterals Openings

Civil and Environmental Engineering

A long-span Prestressed Concrete Hunched Beam with Multi-Quadrilateral Opening has been developed... more A long-span Prestressed Concrete Hunched Beam with Multi-Quadrilateral Opening has been developed as an alternative to steel structural elements. An experimental program was created and evaluated utilizing a single mid-span monotonic static load on simply supported beams, which included six beams with openings and the solid control beam without openings, to investigate the performance of such beams. The number and height of the quadrilateral openings are the variables to consider. According to test results, the presence of openings in the prestressed concrete hunched beam with multi-quadrilateral opening did not considerably affect their ultimate load capacity with respect to a control beam (solid); the diminishing ratio of maximum strength capacity varied from 4.22 % to 13.5 %.

Research paper thumbnail of Performance of reinforced concrete non-prismatic beams having multiple openings configurations

Journal of the Mechanical Behavior of Materials

This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several n... more This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several number of openings (six and eight) and posts’ inclination, aimed to find the strength reduction in this type of beam. The major results found are: for the openings extending over similar beam length it is better to increase the number of posts (openings), i.e., increasing opening number led to decrease in opening area, which allows us to transmit stresses and act as lever arms between the upper and the lower chords. Also, findings revealed that the inclined posts have larger loading at the mid-point relative to vertical ones. For gables with vertical posts having six and eight openings, the ultimate strength reduction was 31.5 and 25.6%, whereas it was 29 and 17.3% for those with inclined posts, respectively.

Research paper thumbnail of Deformability of non-prismatic prestressed concrete beams with multiple openings of different configurations

Journal of the Mechanical Behavior of Materials

This work presents experimental research using draped prestressed steel strands to improve the lo... more This work presents experimental research using draped prestressed steel strands to improve the load-carrying capacity of prestressed concrete non-prismatic beams with multiple openings of various designs. The short-term deflection of non-prismatic prestressed concrete beams (NPCBs) flexural members under static loading were used to evaluate this improvement. Six simply supported (NPCBs) beams, five beams with openings, and one solid specimen used as a reference beam were all tested as part of the experiment. All of the beams were subjected to a monotonic midpoint load test. The configuration of the opening (quadrilateral or circular), as well as the depth of the chords, were the variables studied in this study. In comparison to a solid beam, experimental results show that beams with openings have a lower load-carrying capacity not exceeding (2.3–10.6%) and higher mid-span deflection through all loading stages of elastic, service, and ultimate loads (14–73%), (19–44%), and (31–55%), ...

Research paper thumbnail of Prestress Losses in Concrete Rafters with Openings

Engineering, Technology & Applied Science Research, 2020

In this paper, experimental work was conducted to evaluate the losses in prestressing force of 13... more In this paper, experimental work was conducted to evaluate the losses in prestressing force of 13 (12 perforated and 1 solid) simply supported prestressed concrete rafters. All beams had the same dimensions and reinforcements. The tested beams were divided into four main groups and three additional subgroups were driven. These groups were classified according to size, number, and configuration of the openings, and the orientation of the posts (vertical or inclined). Regarding the prestress losses that have been affected by the cross-section properties, the provision of the codes is applicable only to prismatic solid beams, so non-prismatic or moreover perforated beams also need to be studied. This paper aims to propose a method based on the same code provisions but taking into consideration the cross-section variation along the beam length. The proposed method divides the overall length of the rafter into a number of assumed prismatic segments with heights measured at centers. Then,...

Research paper thumbnail of Experimental and Numerical Comparison of Reinforced Concrete Gable Roof Beams with Openings of Different Configurations

Engineering, Technology & Applied Science Research, 2019

This paper demonstrates an experimental and numerical study aimed at comparing the influence of o... more This paper demonstrates an experimental and numerical study aimed at comparing the influence of openings of different configurations on the flexural behavior of reinforced concrete gable roof beams. The experimental program consisted of testing six simply supported gable beams subjected to mid-point concentrated load. The variable which has been investigated in this work was opening's configuration (quadrilateral or circular) with the same upper and lower chords depth. The results indicate improvement in the beams’ flexural behavior when circular openings were used compared with that of quadrilateral openings, represented by an increase in ultimate load capacity and a decrease in deflection at the service limit. Also, there was an enhancement in the ductility and rigidity of the beams. The results of the tested beams were verified by a nonlinear finite element program, ABAQUS (2018). Comparisons are presented and good agreement is shown between the predictions of the finite elem...

Research paper thumbnail of Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature

Engineering, Technology & Applied Science Research, 2019

The main objective of this study is to characterize the main factors which may affect the behavio... more The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM–E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experime...

Research paper thumbnail of Experimental and Numerical Comparison of Prestressed Perforated Concrete Rafters of Different Configurations

IOP Conference Series: Materials Science and Engineering, 2020

This paper demonstrates an experimental and numerical study aimed to compare the influence of ope... more This paper demonstrates an experimental and numerical study aimed to compare the influence of openings of different configurations on the flexural behavior of prestressed concrete rafters. The experimental program consisted of testing six simply supported prestressed concrete rafters; 5 rafters are perforated, and the other one is solid as a reference. All rafters were tested under monotonic midpoint load. The variable which has been investigated in this work was the opening’s configuration (quadrilateral or circular) with the same upper and lower chords depths. The results indicate improvement in the beam flexural behavior using the circular openings compared to the quadrilateral openings, represented by increase the ultimate load capacity and decrease in deflection at the service limit. The experimental results of the tested rafters were confirmed by the non-linear finite element software (ABAQUS13.6.1). Comparisons are offered and the good agreement appears between the experiment...

Research paper thumbnail of Post-Fire Behavior of Non-Prismatic Beams with Multiple Rectangular Openings Monotonically Loaded

Engineering, Technology & Applied Science Research, 2021

The main objective of this paper is to study the behavior of Non-Prismatic Reinforced Concrete (N... more The main objective of this paper is to study the behavior of Non-Prismatic Reinforced Concrete (NPRC) beams with and without rectangular openings either when exposed to fire or not. The experimental program involves casting and testing 9 NPRC beams divided into 3 main groups. These groups were categorized according to heating temperature (ambient temperature, 400°C, and 700°C), with each group containing 3 NPRC beams (solid beams and beams with 6 and 8 trapezoidal openings). For beams with similar geometry, increasing the burning temperature results in their deterioration as reflected in their increasing mid-span deflection throughout the fire exposure period and their residual deflection after cooling. Meanwhile, the existing openings situation was compounded. The burned NPRC beams were left to gradually cool down under ambient laboratory conditions, and afterward, they were loaded until failure. The influence of temperature on the residual ultimate load-carrying capacity of each b...

Research paper thumbnail of Serviceability of Reinforced Concrete Gable Roof Beams with Openings under Static Loads

Engineering, Technology & Applied Science Research, 2019

This paper presents an analytical study on the serviceability of reinforced concrete gable roof b... more This paper presents an analytical study on the serviceability of reinforced concrete gable roof beams with openings of different sizes, based on an experimental study which includes 13 concrete gable roof beams with openings under static loading. For deflection and crack widths under static loading at service stage, a developed unified calculation procedure has been submitted, which includes prismatic beams with one opening subjected to flexure concentrated force. The deflection has been calculated with two methods: the first method calculated deflections via relevant equations and the second was Direct Stiffness Method in which the beam is treated as a structural member with several segments constituting the portions with solid sections and those with sections crossed by the opening. The crack width was calculated with the ACI code’s equation with a proposed magnification factor equal to 1.125. The analytical results were compared with the experimental ones and a good agreement was...

Research paper thumbnail of Retrofit of Shear Critical R.C. Beams with Carbon Fiber Reinforced Polymers (CFRP)

Maǧallaẗ al-handasaẗ wa-al-tiknūlūǧiyā, Aug 31, 2009

Research paper thumbnail of Finite element modeling of post fire RC rafters with openings of different sizes and shapes

Nucleation and Atmospheric Aerosols, 2023

This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite... more This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite element computer application to examine the performance and residual strength of 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with 8 circular openings). Rising the burning temperature causes degradation in those beams with comparable shape, as shown in their increasing mid-span deflection during the fire exposure period and their residual deflection after cooling, while the existing openings condition was exacerbated. The main objective of this article are to provide a numerical model for simulating nonlinear behavior of such beams, which includes a trustworthy finite element model approach and constitutive material models. By means of load-deflection and cracking patterns, comparisons between computational and experimental models are provided, and a reasonable fit is demonstrated. The average ratio of numerical model ultimate loads and deflection to experimentally examined rafters were 1.033 and 0.96, respectively. As a result, finite element analysis may be regarded as a preferred and trustworthy approach for simulating the non-linear behavior of burned RC rafters (solid or perforated) in terms of complexity, difficulty, time savings, human effort, and money.

Research paper thumbnail of Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature

Zenodo (CERN European Organization for Nuclear Research), Oct 13, 2019

The main objective of this study is to characterize the main factors which may affect the behavio... more The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM-E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experimental results. These included the prestress effect, load-deflection relation under applied load, and load at failure of the reference beam and the beams after the exposure to fire.

Research paper thumbnail of Optimal Bedding Selection with the Specific Soil Type According to the Thrust Forces Generated in the Water Distribution Networks Using the Restraining Joint System

Research paper thumbnail of Performance of Reinforced Concrete Gable Beam with Quadrilateral Openings of Different Side Inclinations

E3S Web of Conferences

The existence of openings in a gable beam would have numerous advantages, the most important of w... more The existence of openings in a gable beam would have numerous advantages, the most important of which would be a reduction in the overall weight. These advantages include geometric flexibility, ease of handling when erected, and more. This study aims to investigate the flexural behavior of reinforced concrete gable beams with quadrilateral openings of different side inclinations; this goal has been specified with beam stiffness, the maximum load-carrying capacity, and strains of the beams. Beams are identical in their dimensions and reinforcement. The experimental program involved casting and testing four simply supported beams: a solid beam (reference beam) and others with quadrilateral openings. They were 3000mm long, 100mm wide, and 400 mm deep in the middle, tapering to 250 mm on both ends, concentrically loaded. The results demonstrate the load-carrying capacity is reduced by 6.1–12.9%, and the mid-span deflection is increased by 13–52% when openings exist compared to the solid...

Research paper thumbnail of Finite element modeling of post fire RC rafters with openings of different sizes and shapes

8TH ENGINEERING AND 2ND INTERNATIONAL CONFERENCE FOR COLLEGE OF ENGINEERING – UNIVERSITY OF BAGHDAD: COEC8-2021 Proceedings

This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite... more This study offers numerical simulation results from the use of the ABAQUS/CAE version 2019 finite element computer application to examine the performance and residual strength of 12 post-fire non-prismatic reinforced concrete beams (solid and perforated). Three groups were formed based on heating temperature (room temperature, 400 °C, and 700 °C), each group consisting four rafters (solid, rafters with 6 and 8 trapezoidal openings, and rafter with 8 circular openings). Rising the burning temperature causes degradation in those beams with comparable shape, as shown in their increasing mid-span deflection during the fire exposure period and their residual deflection after cooling, while the existing openings condition was exacerbated. The main objective of this article are to provide a numerical model for simulating nonlinear behavior of such beams, which includes a trustworthy finite element model approach and constitutive material models. By means of load-deflection and cracking patterns, comparisons between computational and experimental models are provided, and a reasonable fit is demonstrated. The average ratio of numerical model ultimate loads and deflection to experimentally examined rafters were 1.033 and 0.96, respectively. As a result, finite element analysis may be regarded as a preferred and trustworthy approach for simulating the non-linear behavior of burned RC rafters (solid or perforated) in terms of complexity, difficulty, time savings, human effort, and money.

Research paper thumbnail of Performance of quadrilateral perforated prestressed concrete rafters

Maǧallaẗ al-abḥāṯ al-handasiyyaẗ, Nov 3, 2021

This study focuses on the behavior of simply supported perforated prestressed concrete rafters (P... more This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages of performance of the prestressed concrete rafter. On the other hand, decreasing the depth of the upper and lower chords by 25% for PPCRs with the same number of openings led to a reduction in the failure load by (36, 29.5, and 24.5%) for rafters with 6, 8, and 10 openings, respectively.

Research paper thumbnail of Effect of posts inclination on the behavior of prestressed quadrilateral perforated concrete rafter

8TH ENGINEERING AND 2ND INTERNATIONAL CONFERENCE FOR COLLEGE OF ENGINEERING – UNIVERSITY OF BAGHDAD: COEC8-2021 Proceedings

The present study focuses on the performance of simply supported prestressed perforated concrete ... more The present study focuses on the performance of simply supported prestressed perforated concrete rafters (PPCRs) system having inclined or vertical posts with different numbers of quadrilateral openings. The advantages of (PPCRs) are easy erection and handling, geometrical flexibility, and most importantly the overall weight would be reduced. Therefore (PPCRs) chose as an alternative preferred option from steel to support roofs for long-spanned roof rafters. The experimental work includes investigation of seven rafters tested under monotonic static load until failure. The first rafter was the reference rafter (non-perforated), and the remaining six rafters were perforated with quadrilateral openings. The findings show that the presence of openings in PPCR decreases the ultimate load capacity by (3.5 ~ 10.9) % and increases the mid-span deflection at the ultimate load range of (7.9 ~ 24.7) % for PPCRs compared to the non-perforated one (PGB). For rafters having the same configuration extended over the same distance, when the number of openings increased (increasing posts number), the load carrying capacity increases. Whilst its companion deflection decreases for all loading stages. Also an increase in the ultimate load carrying capacity by (7, 4.5, and 3.5) % was noticed when inclined posts are used rather than vertical ones for rafters with 6, 8, and 10 openings, respectively, accompanied with a decreasing in midspan deflection at all loading stages.

Research paper thumbnail of Comparative Study between the Behavior of the Concrete Thrust Block and the Restraint Joint in a Water Distribution System; Review

Journal of Engineering

Thrust blocks and restraint joints are the two most popular methods of counteracting the thrust f... more Thrust blocks and restraint joints are the two most popular methods of counteracting the thrust force that generated at pipe fittings (bends, Tee, wye, reducers, dead ends, etc…). Both systems perform the same function, which is to prevent the joints from separating from the pipes. The aim of the study is to review previous studies and scientific theories related to the study and design of thrust blocks and restraint joints to study the behavior of both systems under thrust force and to study the factors and variables that affect the behavior of these systems. The behavior of both systems must be studied because they cannot be abandoned, as each system has conditions whose use is more feasible, scientific, and economical. The use of thrust blocks is usually more economical. Still, in many cases, its use is not appropriate, as it is required to wait for the result of the compressive strength test of the concrete. It is required to close the pipe trench as soon as possible; thus, this...

Research paper thumbnail of Static Shear Strength of a Non-Prismatic Beam with Transverse Openings

Engineering, Technology & Applied Science Research

In this study, a predicated formula is been proposed to find the shear strength of non-prismatic ... more In this study, a predicated formula is been proposed to find the shear strength of non-prismatic beams with or without openings. It depends on the contributions of concrete shear strength considering the beam depth variation and existing openings, shear steel reinforcements and defines the critical shear section, the effect of diagonal shear reinforcement, the effect of inclined tensile steel reinforcement, and the compression chord influence. The verification of the proposed formula has been conducted on the experimental test results of 26 non-prismatic beams with or without openings at the same loading conditions. The results reflect that the predicted formula finds the shear capacity of non-prismatic beams with openings, it is conservative and can be used for designing without the strength reduction factor.

Research paper thumbnail of Performance of concrete thrust block at several burial conditions under the influence of thrust forces generated in the water distribution networks

Journal of the Mechanical Behavior of Materials

This study was prepared to investigate the performance and behavior of concrete thrust blocks sup... more This study was prepared to investigate the performance and behavior of concrete thrust blocks supporting pipe fittings. In the water distribution networks, it is always necessary to change the path of the pipes at different degrees or to create new branches. In these regions, an unbalanced force called the thrust force is generated. In order to counter this force, these regions are supported with concrete blocks. In this article, the system components (soil, pipe with its bend and thrust blocks) have been numerically modeled and simulated by the ABAQUS CAE/2019 software program in order to study the behavior and stability of the thrust block with different burial conditions (several burial depths) by the soil under the influence of the thrust force. Accordingly, 45° bend angles were studied with a specified pipe diameter placed on soil with known properties under the influence of internal hydrostatic test pressure. The obtained results that were relied upon to describe the behavior ...

Research paper thumbnail of Performance of Prestressed Concrete Hunched Beams with Multi-Quadrilaterals Openings

Civil and Environmental Engineering

A long-span Prestressed Concrete Hunched Beam with Multi-Quadrilateral Opening has been developed... more A long-span Prestressed Concrete Hunched Beam with Multi-Quadrilateral Opening has been developed as an alternative to steel structural elements. An experimental program was created and evaluated utilizing a single mid-span monotonic static load on simply supported beams, which included six beams with openings and the solid control beam without openings, to investigate the performance of such beams. The number and height of the quadrilateral openings are the variables to consider. According to test results, the presence of openings in the prestressed concrete hunched beam with multi-quadrilateral opening did not considerably affect their ultimate load capacity with respect to a control beam (solid); the diminishing ratio of maximum strength capacity varied from 4.22 % to 13.5 %.

Research paper thumbnail of Performance of reinforced concrete non-prismatic beams having multiple openings configurations

Journal of the Mechanical Behavior of Materials

This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several n... more This experimental study demonstrates the gable-reinforced concrete beams’ behavior with several number of openings (six and eight) and posts’ inclination, aimed to find the strength reduction in this type of beam. The major results found are: for the openings extending over similar beam length it is better to increase the number of posts (openings), i.e., increasing opening number led to decrease in opening area, which allows us to transmit stresses and act as lever arms between the upper and the lower chords. Also, findings revealed that the inclined posts have larger loading at the mid-point relative to vertical ones. For gables with vertical posts having six and eight openings, the ultimate strength reduction was 31.5 and 25.6%, whereas it was 29 and 17.3% for those with inclined posts, respectively.

Research paper thumbnail of Deformability of non-prismatic prestressed concrete beams with multiple openings of different configurations

Journal of the Mechanical Behavior of Materials

This work presents experimental research using draped prestressed steel strands to improve the lo... more This work presents experimental research using draped prestressed steel strands to improve the load-carrying capacity of prestressed concrete non-prismatic beams with multiple openings of various designs. The short-term deflection of non-prismatic prestressed concrete beams (NPCBs) flexural members under static loading were used to evaluate this improvement. Six simply supported (NPCBs) beams, five beams with openings, and one solid specimen used as a reference beam were all tested as part of the experiment. All of the beams were subjected to a monotonic midpoint load test. The configuration of the opening (quadrilateral or circular), as well as the depth of the chords, were the variables studied in this study. In comparison to a solid beam, experimental results show that beams with openings have a lower load-carrying capacity not exceeding (2.3–10.6%) and higher mid-span deflection through all loading stages of elastic, service, and ultimate loads (14–73%), (19–44%), and (31–55%), ...

Research paper thumbnail of Prestress Losses in Concrete Rafters with Openings

Engineering, Technology & Applied Science Research, 2020

In this paper, experimental work was conducted to evaluate the losses in prestressing force of 13... more In this paper, experimental work was conducted to evaluate the losses in prestressing force of 13 (12 perforated and 1 solid) simply supported prestressed concrete rafters. All beams had the same dimensions and reinforcements. The tested beams were divided into four main groups and three additional subgroups were driven. These groups were classified according to size, number, and configuration of the openings, and the orientation of the posts (vertical or inclined). Regarding the prestress losses that have been affected by the cross-section properties, the provision of the codes is applicable only to prismatic solid beams, so non-prismatic or moreover perforated beams also need to be studied. This paper aims to propose a method based on the same code provisions but taking into consideration the cross-section variation along the beam length. The proposed method divides the overall length of the rafter into a number of assumed prismatic segments with heights measured at centers. Then,...

Research paper thumbnail of Experimental and Numerical Comparison of Reinforced Concrete Gable Roof Beams with Openings of Different Configurations

Engineering, Technology & Applied Science Research, 2019

This paper demonstrates an experimental and numerical study aimed at comparing the influence of o... more This paper demonstrates an experimental and numerical study aimed at comparing the influence of openings of different configurations on the flexural behavior of reinforced concrete gable roof beams. The experimental program consisted of testing six simply supported gable beams subjected to mid-point concentrated load. The variable which has been investigated in this work was opening's configuration (quadrilateral or circular) with the same upper and lower chords depth. The results indicate improvement in the beams’ flexural behavior when circular openings were used compared with that of quadrilateral openings, represented by an increase in ultimate load capacity and a decrease in deflection at the service limit. Also, there was an enhancement in the ductility and rigidity of the beams. The results of the tested beams were verified by a nonlinear finite element program, ABAQUS (2018). Comparisons are presented and good agreement is shown between the predictions of the finite elem...

Research paper thumbnail of Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature

Engineering, Technology & Applied Science Research, 2019

The main objective of this study is to characterize the main factors which may affect the behavio... more The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM–E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experime...

Research paper thumbnail of Experimental and Numerical Comparison of Prestressed Perforated Concrete Rafters of Different Configurations

IOP Conference Series: Materials Science and Engineering, 2020

This paper demonstrates an experimental and numerical study aimed to compare the influence of ope... more This paper demonstrates an experimental and numerical study aimed to compare the influence of openings of different configurations on the flexural behavior of prestressed concrete rafters. The experimental program consisted of testing six simply supported prestressed concrete rafters; 5 rafters are perforated, and the other one is solid as a reference. All rafters were tested under monotonic midpoint load. The variable which has been investigated in this work was the opening’s configuration (quadrilateral or circular) with the same upper and lower chords depths. The results indicate improvement in the beam flexural behavior using the circular openings compared to the quadrilateral openings, represented by increase the ultimate load capacity and decrease in deflection at the service limit. The experimental results of the tested rafters were confirmed by the non-linear finite element software (ABAQUS13.6.1). Comparisons are offered and the good agreement appears between the experiment...

Research paper thumbnail of Post-Fire Behavior of Non-Prismatic Beams with Multiple Rectangular Openings Monotonically Loaded

Engineering, Technology & Applied Science Research, 2021

The main objective of this paper is to study the behavior of Non-Prismatic Reinforced Concrete (N... more The main objective of this paper is to study the behavior of Non-Prismatic Reinforced Concrete (NPRC) beams with and without rectangular openings either when exposed to fire or not. The experimental program involves casting and testing 9 NPRC beams divided into 3 main groups. These groups were categorized according to heating temperature (ambient temperature, 400°C, and 700°C), with each group containing 3 NPRC beams (solid beams and beams with 6 and 8 trapezoidal openings). For beams with similar geometry, increasing the burning temperature results in their deterioration as reflected in their increasing mid-span deflection throughout the fire exposure period and their residual deflection after cooling. Meanwhile, the existing openings situation was compounded. The burned NPRC beams were left to gradually cool down under ambient laboratory conditions, and afterward, they were loaded until failure. The influence of temperature on the residual ultimate load-carrying capacity of each b...

Research paper thumbnail of Serviceability of Reinforced Concrete Gable Roof Beams with Openings under Static Loads

Engineering, Technology & Applied Science Research, 2019

This paper presents an analytical study on the serviceability of reinforced concrete gable roof b... more This paper presents an analytical study on the serviceability of reinforced concrete gable roof beams with openings of different sizes, based on an experimental study which includes 13 concrete gable roof beams with openings under static loading. For deflection and crack widths under static loading at service stage, a developed unified calculation procedure has been submitted, which includes prismatic beams with one opening subjected to flexure concentrated force. The deflection has been calculated with two methods: the first method calculated deflections via relevant equations and the second was Direct Stiffness Method in which the beam is treated as a structural member with several segments constituting the portions with solid sections and those with sections crossed by the opening. The crack width was calculated with the ACI code’s equation with a proposed magnification factor equal to 1.125. The analytical results were compared with the experimental ones and a good agreement was...