War, terrorist attacks, explosions, progressive collapse and other unforeseen circumstances have damaged many structures, including buildings and bridges in war- torn countries such as Iraq. Most of the damaged structural members, for example, beams, columns and slabs, have not totally collapsed and can be repaired. Nowadays, carbon fibre reinforced polymer (CFRP) is widely used in strengthening and retrofitting structural members. CFRP can restore the load- carrying capacity of damaged structural members to make them serviceable. The effect of using CFRP to repair the damaged beams has not been not properly addressed in the literature. This research has the aim of providing a better understanding of the behaviour of reinforced concrete beams strengthened or repaired with CFRP strip under impact loading. Experimental and analytical work were conducted in this research to investigate the performance of RC beams strengthened or repaired using CFRP. To study the impact behaviour of the CFRP reinforced concrete beams, a new heavy drop weight impact test machine has been designed and manufactured to conduct the experimental work. Twelve RC beams were tested experimentally under impact load. The experimental work was divided into two stages; stage 1 (strengthened) and stage 2 (repair). At stage 1, three pairs of beams were tested under impact loading. External bonded reinforcement (EBR) and near surface mounted (NSM) techniques were used to strengthen the RC beams to find the most effective technique. Three pairs of beams were tested in stage 2 (repair). Different degrees of damages were induced using different impact energies. NSM technique was used to repair the damaged beams using CFRP strip. Stiffness degradation method was used to assess the degree of damage in beams due to impact. The study investigated the stiffness, bending load, impact energy, deflection and mode of failure of CFRP strengthened or repaired beams under impact loading. The distribution of the stresses, strains, accelerations, inertia forces, and cracks in the beam under impact loading was also investigated in this study. Empirical equations were proposed in this research to predict the bending load and maximum deflection of the damaged and repaired beams under impact loading. For validation purposes, finite element analysis was used with the LUSAS package. The FEA results were compared with the experimental load-deflection curves and ultimate failure load results. In this research, to simulate a real situation, different models were used to simulate the bonding between the CFRP and concrete and also between steel bars and concrete. In these FEA models, the bonding between the concrete and the CFRP was modelled using the Drucker-Prager model. To simulate the bonding between steel and concrete, a joint element was used with spring constants to model the bond between steel bars and surrounding concrete. The analytical results were compared with the experimental results. In most previous research, FEA has been used to simulate the RC beams under impact loading without any damage. In this thesis, a new 3D FEA model was proposed to simulate and analyse the damaged RC beams under impact loading with different degrees of damage. The effect of the damage on concrete stiffness and the bonding between the steel bars and the concrete were investigated in FEA model. The damage was modelled by reducing the mechanical properties of the concrete and the bonding between steel bars and concrete. This thesis has contributed to improving knowledge of the behaviour of damaged beams repaired with CFRP, and the experimental work conducted, together with the numerical analysis, have provided essential data in the process of preparing a universal standard of CFRP design and construction. In the FEA model, the damage to the beams due to impact loading was successfully modelled by reducing the beam stiffness.

Yes / Tests results of three flanged and two rectangular cross-section concrete beams reinforced with carbon fibre reinforced polymer (CFRP) bars are reported. In addition, a companion concrete flanged beam reinforced with steel bars is tested for comparison purposes. The amount of CFRP reinforcement used and flange thickness were the main parameters investigated in the test specimens. One CFRP reinforced concrete rectangular beam exhibited concrete crushing failure mode, whereas the other four CFRP reinforced concrete beams failed due to tensile rupture of CFRP bars. The ACI 440 design guide for FRP reinforced concrete members underestimated the moment capacity of beams failed due to CFRP tensile rupture and reasonably predicted deflections of the beams tested. A simplified theoretical analysis for estimating the moment capacity of concrete flanged beams reinforced with FRP bars was developed. The experimental moment capacity of the CFRP reinforced concrete beams tested compared favourably with that predicted by the theoretical analysis developed.

An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS-M03-07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440-1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment-curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.

An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS¿M03¿07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440¿1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment¿curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.

Fibre reinforced polymer (FRP) composites have been used for strengthening concrete structures since early 1990s. More recently, FRP has been used for retrofitting concrete structures for high energy events such as impact and blast. Debonding at the FRP-to-concrete interface is one of the predominant failure modes for both static and dynamic loading. Although extensive research has been conducted on the static bond behaviour, the bond-slip mechanics under high strain rates is not well understood yet. This thesis is mainly concerned with the FRP-to-concrete bond behaviour under dynamic loading. Because debonding mostly occurs in the concrete adjacent to the FRP, the behaviour of concrete is of crucial importance for the FRP-to-concrete bond behaviour. The early emphasis of this thesis is thus on the meso-scale concrete modelling of concrete with appropriate consideration of static and dynamic properties. Issues related to FE modelling of tensile and compressive localization of concrete are first investigated in detail under static condition using the K&C concrete damage model in LS-DYNA. It is discovered for the first time that dilation of concrete plays an important role in the FRP-to-concrete bond behaviour. This has led to the development of a model relating the shear dilation factor to the concrete strength based on the modelling of a large number of static FRP-to-concrete shear tests, forming the basis for dynamic modelling. Concrete dynamic increasing factor (DIF) has been a subject of extensive investigation and debate for many years, but it is for the first time discovered in this study that mesh objectivity cannot be achieved in meso-scale modelling of concrete under high strain rate deformation. This has led to the development of a mesh and strain rate dependent concrete tension DIF model. This DIF model shall have wide applications in meso-scale modelling of concrete, not limited to the topic in this thesis. Based on a detailed numerical investigation of the FRP-to-concrete bond shear test under different loading rates, taking on the above issues into careful consideration, a slip rate dependent FRP-to-concrete dynamic bond-slip model is finally proposed for the first time. The FE predictions deploring this proposed bond-slip model are compaed with test results of a set of FRP-to-concrete bonded specimens under impact loading, and a FRP plated slab under blast loading, validating the model.

In this study, a total of twelve beams continuous over two spans of 2,800 mm each were constructed and tested to failure. The beams were divided into two series. Series 1 included six T-beams under symmetrical loading, while Series 2 dealt with six rectangular beams under unsymmetrical loading conditions. In Series 1, the test variables included material type, assumed percentage of moment redistribution, spacing of lateral reinforcement in flange, arrangement of shear reinforcement, and serviceability requirements. In Series 2, three different loading cases were considered, I) loading both spans equally, II) loading both spans maintaining a load ratio of 1.5 and III) loading one span only. Under the loading case II, the parameters of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements were investigated. The test results of both series showed that moment redistribution from the hogging to the sagging moment region took place in GFRP-RC beams which were designed for an assumed percentage of moment redistribution. In Series 1, the decrease of the stirrups spacing from 0.24d to 0.18d enhanced the moment redistribution percentage. Also, decreasing the spacing of lateral reinforcement in the flange from 450 to 150 mm improved the moment redistribution through enhancing the stiffness of the sagging moment region. In Series 2, the unsymmetrical loading conditions (loading case II and III) reduced the moment redistribution by reducing flexural stiffness in the heavily loaded span due to extensive cracking. Regarding serviceability in both series, the GFRP-RC beam designed for the same service moment calculated from the reference steel-RC beam, was able to meet the serviceability requirements for most types of the structural applications. / February 2017

Thesis. (M.Tech. (Dept. of Civil Engineering and Building, Faculty of Engineering and Technology)) -- Vaal University of Technology, 2011. / This research focused on the structural performance of Fibre Reinforced Polymer (FRP) re-bars in structural foundation compared to steel reinforcement re-bars. The corrosion of steel re-bars is the main reason of deterioration of reinforced concrete. However, use of FRP re-bars as alternative reinforcement will address the deterioration of reinforced concrete. Carbon and Glass Fibre Reinforced Polymer re-bars were used as reinforcing bars and traditional steel reinforced concrete was used as the reference. Thirty six specimens of reinforced concrete bases were tested for flexural capacity at different ages. The simulation of Soil Bearing Pressure of this study was derived from the model of beam finite length on elastic foundation. The foundation base was treated as a beam while the soil was modelled as series of timber elements acting as springs. The mathematical model to reflect the model was as documented by Timoshenko (1976:18) and Den Hartog (1952:160). Results showed that stress in the steel re-bars of reinforced concrete was higher than that of Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) re-bars by 227 MPa (5.99 percent) and 284 MPa (7.61 percent), respectively. The stress in CFRP re-bars was 57 MPa or 1.53 percent higher compared to GFRP re-bars of FRP reinforced concrete. Furthermore, the experimental ultimate moments of CFRP and GFRP reinforced concrete foundation – bases on the 28th day were 23.917 kNm (79.0 percent) and 23.529 kNm (77.7 percent) higher than the theoretical ultimate moments, respectively. However, steel reinforced concrete foundation – bases had the higher calculated deflection than FRP reinforced concrete. With high resistance to corrosion as a property, FRP re-bars appeared to be a better alternative reinforcement to steel in corrosion in an aggressive environment. / Vaal University of Technology

There are approximately 6000 Gulfport-type wood structures used to support 1600 km of 230 kV electrical transmission lines in Ontario. An unexpected structural failure caused by wood deterioration has been recognized as a major risk to the safety of these transmission lines. Since the reliability of the electricity transmission and distribution lines is extremely important to the electrical industry and other users of electricity, failure of these structures can result in devastating incidents. Due to the remote location of the transmission network and the requirement to keep the power lines in continuous service, replacement of the Gulfport structures has proved to be very difficult and expensive. This research program investigated the use of Glass Fibre Reinforced Polymer (GFRP) wrap as a light weight and durable strengthening system that can be applied to the existing structures without any interruptions in the functionality of the transmission lines. A total of three control specimens and three strengthened samples were tested in Phase I of the experimental program, which was designed as a feasibility study. It was concluded that the average strength of strengthened samples was 42% higher than the average strength of the control samples, and was greater than the end of life (EOL) threshold of 30 MPa for the cross arms. Therefore, the proposed strengthening system was concluded to be an effective solution for strengthening the deteriorated cross arms of the Gulfport structures. Taguchi methods and Analysis of Variation (ANOVA) were employed in Phase II to optimize the proposed strengthening system. The optimal configuration was determined to be the application of the filler material, non-sanded surface, and the shorter width of wrap (width of 0.6 m). The mean strength of the optimal configuration was estimated to be 52 MPa with a 95% confidence interval of: 38.7 MPa < True Mean < 65.3 MPa. Phase III confirmed the estimated mean and the confidence interval for the optimal configuration in Phase II. The strengthening system changed the failure mode from combined shear-flexure failure to pure flexure and resulted in more consistent strength and stiffness values. The strain values of the GFRP wrap showed that a single layer of wrap was sufficient for the confinement purposes.

There are approximately 6000 Gulfport-type wood structures used to support 1600 km of 230 kV electrical transmission lines in Ontario. An unexpected structural failure caused by wood deterioration has been recognized as a major risk to the safety of these transmission lines. Since the reliability of the electricity transmission and distribution lines is extremely important to the electrical industry and other users of electricity, failure of these structures can result in devastating incidents. Due to the remote location of the transmission network and the requirement to keep the power lines in continuous service, replacement of the Gulfport structures has proved to be very difficult and expensive. This research program investigated the use of Glass Fibre Reinforced Polymer (GFRP) wrap as a light weight and durable strengthening system that can be applied to the existing structures without any interruptions in the functionality of the transmission lines. A total of three control specimens and three strengthened samples were tested in Phase I of the experimental program, which was designed as a feasibility study. It was concluded that the average strength of strengthened samples was 42% higher than the average strength of the control samples, and was greater than the end of life (EOL) threshold of 30 MPa for the cross arms. Therefore, the proposed strengthening system was concluded to be an effective solution for strengthening the deteriorated cross arms of the Gulfport structures. Taguchi methods and Analysis of Variation (ANOVA) were employed in Phase II to optimize the proposed strengthening system. The optimal configuration was determined to be the application of the filler material, non-sanded surface, and the shorter width of wrap (width of 0.6 m). The mean strength of the optimal configuration was estimated to be 52 MPa with a 95% confidence interval of: 38.7 MPa < True Mean < 65.3 MPa. Phase III confirmed the estimated mean and the confidence interval for the optimal configuration in Phase II. The strengthening system changed the failure mode from combined shear-flexure failure to pure flexure and resulted in more consistent strength and stiffness values. The strain values of the GFRP wrap showed that a single layer of wrap was sufficient for the confinement purposes.

Increased demand for reliable public transit is motivating new and innovative transportation solutions. Monorail trains are quickly being established as transportation solutions for dense urban areas, due to their unobtrusive infrastructure. To obtain maximum value from investments made, the infrastructure is required to last longer than typical reinforced concrete. This thesis will explore the use of glass-fibre reinforced polymer (GFRP) bars as reinforcement in concrete guideway beams as a means of avoiding the deterioration problems that plague steel-reinforced concrete. This thesis includes a two part investigation: a full-scale field application of a GFRP-reinforced concrete guideway beam (690 mm x 1,500 mm x 11,600 mm), compared to a typical steel-reinforced beam (both installed on a 1.86 km long monorail test track); and a laboratory study of a scaled-down version of the GFRP-reinforced beam to better predict behaviour beyond typical service load levels. A total of 450 test passes of a two-car monorail train were observed over the two instrumented beams on the track. These passes were performed at vehicle loads ranging from fully unloaded for the first testing phase, up to the maximum allowable design service load. At each stage of testing, vehicle speeds ranged from as low as 5 km/h to as high as 90 km/h, allowing for the dynamic behaviour of the guideway to be observed and quantified. Deflections, strains, and cracks were recorded and compared with code/guideline limitations as well as to numerical predictions to determine which design tools were most effective and could predict behaviour accurately. In the laboratory, the half-scale GFRP-reinforced beam was tested statically to failure, and the behaviour was compared to the same modelling tools used in the field study. Based on the testing performed, the GFRP-reinforced concrete beams performed satisfactorily and met all serviceability requirements, but did not perform as well as the steel-reinforced beam (as a result of the reduced stiffness of GFRP). The use of non-prestressed GFRP-reinforced beams should be limited to applications where spans are of comparable length to the field study. To maintain satisfactory performance, guideway spans significantly longer will need to continue to be design as prestressed beams. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-01-31 15:15:31.307