Proceedings of the Institution of Civil Engineers - Structures and Buildings
Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinfo... more Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinforcing steel bars, especially for severely exposed structures such as bridges. This paper reports on an experimental study on the bond characteristics of both sand-coated and ribbed-surface glass-fibre-reinforced polymer bars embedded in high-strength concrete (HSC). A total of 145 pull-out tests were conducted to examine the effect of varying parameters on the bond characteristics, namely embedment length, bar diameter, surface treatment and concrete cover. In addition, 45 pull-out tests were conducted to investigate the effect of providing headed-end anchorage for the sand-coated bars. The experimental results showed that the sand-coated bars exhibited better bond strength than the ribbed-surface bars, which entailed lower development lengths. Thus, based on the experimental results, expressions for the development length of both sand-coated and ribbed-surface bars embedded in HSC were ...
A reinforced concrete beam with a recess is an example of a non-prismatic beam, which develops st... more A reinforced concrete beam with a recess is an example of a non-prismatic beam, which develops stress concentrations at the corner of the recess owing to the abrupt change in its depth. This entail...
Abstract This paper presents an experimental study on the bond characteristics of both sand-coate... more Abstract This paper presents an experimental study on the bond characteristics of both sand-coated and ribbed-surface glass fiber reinforced polymer (GFRP) bars embedded in high-performance concrete (HPC). A total of 145 pullout tests were conducted in order to examine the effect of varying parameters on the bond characteristics, namely: embedment length, bar diameter, surface treatment, concrete cover and bond stress-slip relationships. The experimental results showed that the sand-coated bars exhibited better bond strength than that developed by the ribbed-surface GFRP bars, which entails lower development lengths. Besides, it was found that the increase in bar diameter was accompanied by a decrease in the bond strength. Furthermore, experimental results displayed a slight increase in the bond strength as the concrete cover increased from 40 to 60 mm. Finally, based on the material properties of the used GFRP bars and concrete patch, using HPC surrounding both sand-coated and ribbed surface GFRP bars resulted in unfavorable modes of failure. That is because in most cases GFRP bars failed by either shearing of the ribs of the ribbed-surface bars or peeling of the sand-coating layer out of the core diameter for the sand-coated bars.
Abstract The current paper presents an experimental study in order to verify the flexural perform... more Abstract The current paper presents an experimental study in order to verify the flexural performance of a new developed perforated beam system. This system facilitates passing the pipes of utility services through its perforations as well as it has a good-looking appearance. Three main factors were studied; namely, the percentage of mass loss (14% 19% and 26%) due to the provided perforations, the reinforcement configurations around the perforations (orthogonal reinforcement, circular stirrups, and cross-bars) and the perforations shape (circular and oval). Therefore, three perforations sizes were studied having perforation diameter to the beam total depth ratio (D/t) of 0.38, 0.50, and 0.62. Accordingly, six perforated beams along with one solid reference beam were prepared and configured then tested under repeated loading till complete collapse. It could be concluded that the perforated beams of 200 mm perforations diameter (D/t = 0.5) reinforced by circular stirrups and cross-bars showed approximately the same flexural capacity as that of the solid beam but cross-bars stirrups enabled the perforated beam to develop approximately the same ductility as that of the solid beam. While, the beam with circular perforations (D/t = 0.5) provided by orthogonal reinforcement manifested increased flexural capacity by about 31% compared to that of the solid beam, while the developed ductility was lower than that of the solid beam by about 55%. In addition, the ductility could be outperformed by about 21% keeping the same ultimate capacity compared to those of solid beam provided that the mass loss of 14% was achieved as showed by the perforated beam with 150 mm perforations diameter (D/t = 0.38).
This article presents the results of an experimental study conducted in order to investigate the ... more This article presents the results of an experimental study conducted in order to investigate the behavior of Type-I beam–column joints, where the beam was subjected to shear stresses due to combined effect of shear force and torsional moment (beam eccentric loading). Eight beam–column joint specimens were constructed and tested up to failure in order to better understand the complicated behavior due to combined loading transmitted from the beam to the column. The studied parameters were the eccentricity of beam load (torsional-moment-to-shear-force ratio Mt/ Q), the configuration of beam side and compression reinforcing steel, the existence of the joint reinforcing stirrups, and the beam rigidity. Generally, the shear failure at the beam zone or at the joint panel was noticed to be the governing mode of failure for all tested specimens. The test results highlighted the importance of the configuration of both longitudinal side and compression reinforcing steel of the beam, where the ...
ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the te... more ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the tension cover zone of one-way reinforced concrete (RC) slabs beside the main steel reinforcement. Using pre-cast and cured ECC mitigates issues associated with volumetric changes associated with the ECC material. In order to assess the structural performance enhancement of the new hybrid system, four point bending tests were performed on two different sizes of RC slabs. The tested slabs were geometrically similar in thickness but and differed in their width and span. Small, 300 mm wide × 900 mm long, slabs were strengthened using one 150 × 500 × 20 mm ECC strip. Larger, 300 × 2000 mm slabs were strengthened with two 150 × 1600 × 20 mm ECC strips. A small amount of conventional reinforcing steel was provided inside the ECC strips in order to enhance the strain hardening behavior of the ECC strengthening strip, and thereby increase its efficiency. The structural evaluation of the slabs considered crack width and spacing, deflection at the service load level, and ultimate capacity and ductility. Test results showed that the ECC strips enhanced the structural performance of the slabs at both service and ultimate limit states. Providing additional internal reinforcement by a reinforcing ratio of 1.88% exhibited outstanding performance in terms of decreased crack width, better crack distribution, and improved capacity and ductility compared to control slabs without internal ECC strips.
The most simple equivalent frame system with reduced degrees of freedom is proposed for handling ... more The most simple equivalent frame system with reduced degrees of freedom is proposed for handling multi-story multi-bay infilled frames. The system is composed of homogenized continuum for the reinforced concrete members braced with unilateral diagonal struts for each bay, ...
This paper presents the results of both experimental and numerical investigations on the overall ... more This paper presents the results of both experimental and numerical investigations on the overall structural performance of two-equal-span reinforced concrete perforated (castellated) beams subjecte...
ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the te... more ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the tension cover zone of one-way reinforced concrete (RC) slabs beside the main steel reinforcement. Using pre-cast and cured ECC mitigates issues associated with volumetric changes associated with the ECC material. In order to assess the structural performance enhancement of the new hybrid system, four point bending tests were performed on two different sizes of RC slabs. The tested slabs were geometrically similar in thickness but and differed in their width and span. Small, 300 mm wide × 900 mm long, slabs were strengthened using one 150 × 500 × 20 mm ECC strip. Larger, 300 × 2000 mm slabs were strengthened with two 150 × 1600 × 20 mm ECC strips. A small amount of conventional reinforcing steel was provided inside the ECC strips in order to enhance the strain hardening behavior of the ECC strengthening strip, and thereby increase its efficiency. The structural evaluation of the slabs considered crack width and spacing, deflection at the service load level, and ultimate capacity and ductility. Test results showed that the ECC strips enhanced the structural performance of the slabs at both service and ultimate limit states. Providing additional internal reinforcement by a reinforcing ratio of 1.88% exhibited outstanding performance in terms of decreased crack width, better crack distribution, and improved capacity and ductility compared to control slabs without internal ECC strips.
Proceedings of the Institution of Civil Engineers - Structures and Buildings
Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinfo... more Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinforcing steel bars, especially for severely exposed structures such as bridges. This paper reports on an experimental study on the bond characteristics of both sand-coated and ribbed-surface glass-fibre-reinforced polymer bars embedded in high-strength concrete (HSC). A total of 145 pull-out tests were conducted to examine the effect of varying parameters on the bond characteristics, namely embedment length, bar diameter, surface treatment and concrete cover. In addition, 45 pull-out tests were conducted to investigate the effect of providing headed-end anchorage for the sand-coated bars. The experimental results showed that the sand-coated bars exhibited better bond strength than the ribbed-surface bars, which entailed lower development lengths. Thus, based on the experimental results, expressions for the development length of both sand-coated and ribbed-surface bars embedded in HSC were ...
A reinforced concrete beam with a recess is an example of a non-prismatic beam, which develops st... more A reinforced concrete beam with a recess is an example of a non-prismatic beam, which develops stress concentrations at the corner of the recess owing to the abrupt change in its depth. This entail...
Abstract This paper presents an experimental study on the bond characteristics of both sand-coate... more Abstract This paper presents an experimental study on the bond characteristics of both sand-coated and ribbed-surface glass fiber reinforced polymer (GFRP) bars embedded in high-performance concrete (HPC). A total of 145 pullout tests were conducted in order to examine the effect of varying parameters on the bond characteristics, namely: embedment length, bar diameter, surface treatment, concrete cover and bond stress-slip relationships. The experimental results showed that the sand-coated bars exhibited better bond strength than that developed by the ribbed-surface GFRP bars, which entails lower development lengths. Besides, it was found that the increase in bar diameter was accompanied by a decrease in the bond strength. Furthermore, experimental results displayed a slight increase in the bond strength as the concrete cover increased from 40 to 60 mm. Finally, based on the material properties of the used GFRP bars and concrete patch, using HPC surrounding both sand-coated and ribbed surface GFRP bars resulted in unfavorable modes of failure. That is because in most cases GFRP bars failed by either shearing of the ribs of the ribbed-surface bars or peeling of the sand-coating layer out of the core diameter for the sand-coated bars.
Abstract The current paper presents an experimental study in order to verify the flexural perform... more Abstract The current paper presents an experimental study in order to verify the flexural performance of a new developed perforated beam system. This system facilitates passing the pipes of utility services through its perforations as well as it has a good-looking appearance. Three main factors were studied; namely, the percentage of mass loss (14% 19% and 26%) due to the provided perforations, the reinforcement configurations around the perforations (orthogonal reinforcement, circular stirrups, and cross-bars) and the perforations shape (circular and oval). Therefore, three perforations sizes were studied having perforation diameter to the beam total depth ratio (D/t) of 0.38, 0.50, and 0.62. Accordingly, six perforated beams along with one solid reference beam were prepared and configured then tested under repeated loading till complete collapse. It could be concluded that the perforated beams of 200 mm perforations diameter (D/t = 0.5) reinforced by circular stirrups and cross-bars showed approximately the same flexural capacity as that of the solid beam but cross-bars stirrups enabled the perforated beam to develop approximately the same ductility as that of the solid beam. While, the beam with circular perforations (D/t = 0.5) provided by orthogonal reinforcement manifested increased flexural capacity by about 31% compared to that of the solid beam, while the developed ductility was lower than that of the solid beam by about 55%. In addition, the ductility could be outperformed by about 21% keeping the same ultimate capacity compared to those of solid beam provided that the mass loss of 14% was achieved as showed by the perforated beam with 150 mm perforations diameter (D/t = 0.38).
This article presents the results of an experimental study conducted in order to investigate the ... more This article presents the results of an experimental study conducted in order to investigate the behavior of Type-I beam–column joints, where the beam was subjected to shear stresses due to combined effect of shear force and torsional moment (beam eccentric loading). Eight beam–column joint specimens were constructed and tested up to failure in order to better understand the complicated behavior due to combined loading transmitted from the beam to the column. The studied parameters were the eccentricity of beam load (torsional-moment-to-shear-force ratio Mt/ Q), the configuration of beam side and compression reinforcing steel, the existence of the joint reinforcing stirrups, and the beam rigidity. Generally, the shear failure at the beam zone or at the joint panel was noticed to be the governing mode of failure for all tested specimens. The test results highlighted the importance of the configuration of both longitudinal side and compression reinforcing steel of the beam, where the ...
ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the te... more ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the tension cover zone of one-way reinforced concrete (RC) slabs beside the main steel reinforcement. Using pre-cast and cured ECC mitigates issues associated with volumetric changes associated with the ECC material. In order to assess the structural performance enhancement of the new hybrid system, four point bending tests were performed on two different sizes of RC slabs. The tested slabs were geometrically similar in thickness but and differed in their width and span. Small, 300 mm wide × 900 mm long, slabs were strengthened using one 150 × 500 × 20 mm ECC strip. Larger, 300 × 2000 mm slabs were strengthened with two 150 × 1600 × 20 mm ECC strips. A small amount of conventional reinforcing steel was provided inside the ECC strips in order to enhance the strain hardening behavior of the ECC strengthening strip, and thereby increase its efficiency. The structural evaluation of the slabs considered crack width and spacing, deflection at the service load level, and ultimate capacity and ductility. Test results showed that the ECC strips enhanced the structural performance of the slabs at both service and ultimate limit states. Providing additional internal reinforcement by a reinforcing ratio of 1.88% exhibited outstanding performance in terms of decreased crack width, better crack distribution, and improved capacity and ductility compared to control slabs without internal ECC strips.
The most simple equivalent frame system with reduced degrees of freedom is proposed for handling ... more The most simple equivalent frame system with reduced degrees of freedom is proposed for handling multi-story multi-bay infilled frames. The system is composed of homogenized continuum for the reinforced concrete members braced with unilateral diagonal struts for each bay, ...
This paper presents the results of both experimental and numerical investigations on the overall ... more This paper presents the results of both experimental and numerical investigations on the overall structural performance of two-equal-span reinforced concrete perforated (castellated) beams subjecte...
ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the te... more ABSTRACT Pre-cast and cured Engineered Cementitious Composites (ECC) strips were placed in the tension cover zone of one-way reinforced concrete (RC) slabs beside the main steel reinforcement. Using pre-cast and cured ECC mitigates issues associated with volumetric changes associated with the ECC material. In order to assess the structural performance enhancement of the new hybrid system, four point bending tests were performed on two different sizes of RC slabs. The tested slabs were geometrically similar in thickness but and differed in their width and span. Small, 300 mm wide × 900 mm long, slabs were strengthened using one 150 × 500 × 20 mm ECC strip. Larger, 300 × 2000 mm slabs were strengthened with two 150 × 1600 × 20 mm ECC strips. A small amount of conventional reinforcing steel was provided inside the ECC strips in order to enhance the strain hardening behavior of the ECC strengthening strip, and thereby increase its efficiency. The structural evaluation of the slabs considered crack width and spacing, deflection at the service load level, and ultimate capacity and ductility. Test results showed that the ECC strips enhanced the structural performance of the slabs at both service and ultimate limit states. Providing additional internal reinforcement by a reinforcing ratio of 1.88% exhibited outstanding performance in terms of decreased crack width, better crack distribution, and improved capacity and ductility compared to control slabs without internal ECC strips.
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