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2023 | Buch

8th International Conference on Advanced Composite Materials in Bridges and Structures

Volume 2


Über dieses Buch

This book comprises the proceedings of the 8th International Conference on Advanced Composite Materials in Bridges and Structures (ACMBS) 2021. The contents of this volume focus on recent technological advances in the field of material behavior, seismic performance, fire resistance, structural health monitoring, sustainability, rehabilitation of structures, etc. The contents cover latest advances especially in applications in reinforced concrete, wood, masonry and steel structures, field application, bond development and splice length of FRB bars, structural shapes and fully composite bars, etc. This volume will prove a valuable resource for those in academia and industry.


Axial Capacity of Concrete Filled GFRP Tubes with Simulated Tube Damage
Concrete-filled fiber-reinforced polymer (FRP) tube (CFFT) systems have attracted much attention over the past several decades due to their superior features including ease and speed of construction, strength, ductility, and durability. This study aims at understanding the effect of tube damage on the axial behavior and strength of CFFTs. A test program was conducted on two types of tubes, namely, a near cross-ply and an angle-ply glass-FRP (GFRP) tubes. The damage was simulated as a vertical cut of different lengths throughout the full thickness of the tubes. A comparison with undamaged CFFTs and plain concrete specimens was included. The undamaged CFFTs had an axial strength double that of the plain concrete core because of the confinement effect and some axial load sharing of the tube. For damaged CFFTs, test results demonstrated a correlation between the reduced axial strength and length of cut. For example, vertical cut lengths equal to 9% and 19% of the perimeter resulted in 27% and 40% reductions in axial strength, respectively.
Osvaldo Taveras, Abdeldayem Hadhood, Amir Fam, Bhum Keun Song
Durability Performance of Various Corrosion Resistant Reinforcing Materials Under Severe Environmental Exposure
Durability of reinforced concrete structures may significantly affect not only the lifespan of a structure but also the cost associated with maintenance and rehabilitation. The conducted research focused on durability testing of concrete beams reinforced with various types of corrosion-resistant reinforcing bars. The beams represented a bridge parapet, i.e. a component loaded structurally, yet located in a splash zone. While the number of studies reported in the literature testing performance of specific bar type has been done, direct comparison of multiple materials exposed to identical conditions is rare. Therefore, in our research, four different reinforcing bars were tested. Fibre Reinforced Polymers (FRP) bars included fibres of two types of Glass, Carbon and novel Basalt fibres. The test specimens were designed to resist the same flexural load. Twelve reinforced concrete beams out of the total sixteen beams tested were placed into a climate chamber and exposed to identical controlled environmental conditions. The exposure regime applied cycles of freezing and thawing combined with relative humidity and spraying of saltwater to generate severe accelerated exposure, comparable with real-time environmental conditions. After the exposure, the beams were tested for ultimate flexural capacity, and their performance was evaluated in relevance to control beams left outside of the climate chamber. Performance categories such as cracking patterns at service and ultimate loads, load–deflection behaviour, and ductility of the beams were analysed and compared. A summary matrix was assembled as a guideline to serve owners and asset managers in the planning stage of a project, considering the structural performance of various rebars and their unique attributes and applicability.
Raafat El-Hacha, Mouhammad Amiri, Martin Hudecek, Kip Skabar
Dynamic Response Calibration of Hybrid Floating Bridge System Using Rayleigh Damping
Floating bridges are efficient and rapid solutions in crossing water gaps when the conditions are not suitable or economic for the construction of other conventional bridge systems. Using floating bridges is promoted to be a good solution in various applications such as rapid disaster relief, military gap crossing operations, and connecting lifelines of cross-shore territories. However, design and analysis of floating bridges are challenging engineering tasks where various factors have to be considered such as water structure interaction, wind, and different traffic loading cases. Moreover, inherit structural damping is another concern to simulate the structural energy dissipation and capture to a considerable limit the bridge dynamic behavior. In this study, the Rayleigh damping method is used to calibrate the dynamic structural behavior of a ribbon floating bridge system. The floating bridge is composed of the assembly of three different floating bridge structures: The Heavy Communication Bridge (HCB), the assault floating bridge (PMM71), and both are connected using a pontoon unit named New Connection Pontoon (NCP). The NCP is fully manufactured of steel sheets and sections and developed to integrate a traffic line through connecting the HCB and PMM71. The whole bridge assembly is subjected to tracked tank load of Military Loading Class of 70 tons (MLC70). Due to the request for rapid and reduced assembly time, a Hybrid NCP (HNCP) is redesigned of FRP composite laminated sheets and a steel skeleton to minimize weight. A 3D numerical model is developed of the full floating bridge system solution PMM71, HNCP, and HCB using ANSYS FE Package. The dynamic structural response is captured at two tracked passing vehicle speeds, 8 km/h and 16 km/h. A modal analysis is performed to quantify the cumulative bridge mass participation, mass, and stiffness Rayleigh factors based on the cyclic frequency values. The baseline steel NCP dynamic structural draft values are calibrated using the Rayleigh method and validated with experimental results. Furthermore, the structural response of the full-bridge system involving the HNCP is investigated. The obtained results showed the difference in draft values between the steel NCP and the experimental values are minimized to reach 3.88% and 4.8% for 8 km/h and 16 km/h vehicle speeds, respectively. A comparison between draft values obtained for the baseline steel NCP and HNCP is performed. The results showed an improvement of the draft values by 3.8% and 3.69% for 8 km/h and 16 km/h vehicle speeds, respectively. The numerical model is concluded as a promising model for studying the structural behavior of a fully composite laminated floating bridge system.
Ahmed S. Elareshy, M. M. Abdel Wahab, Sherif A. Mazek, Ashraf Osman
Numerical Modeling of Hybrid Steel/GFRP Reinforced Concrete Bridges Piers
This paper suggests hybrid (steel/glass fiber-reinforced polymer (GFRP) composites) bars as primary reinforcement for modern reinforced concrete (RC) bridge piers. A detailed two-dimensional finite element model (2D FEM), that considers material and geometric nonlinearity and the bond behavior of steel and glass FRP (GFRP) reinforcement, was created and validated against the available experimental results. The built model predicted the experimentally obtained results representing in failure mode and deformation response with good accuracy. Different configurations of steel/GFRP combination were studied. The results patently showed that hybrid reinforced bridge piers can undergo large displacement with minimal damage. This, however, can be guaranteed through carefully selection of reinforcement arrangement.
Ahmed Arafa, Brahim Benmokrane
Field Investigation of CFRP Bond on RC Bridges
This paper presents results of a non-destructive test conducted October 2019, on CFRP systems applied to RC (reinforced concrete) highway bridges in North Macedonia and one bridge in Slovenia. The goal was to determine CFRP-concrete bond condition, i.e., bonded or de-bonded. The field investigation tested 12 of the 17 CFRP-retrofitted bridges in northeastern Macedonia. Over a distance of 55 km, six slab and six girder bridges were tested in five hours over two days. Test results indicated all CFRP plates are still bonded to the bridge concrete 18 years after installation. Several small areas of de-bonding on four bridges were identified where the concrete has sustained water damage. The bridge section tested in Slovenia found all CFRP plates fully bonded 21 years after installation. Using the impact-echo method the machine hammer produced unique frequencies and sinusoidal waveforms indicating bond condition. Signal analysis of the recorded data showed consistent frequencies and decaying sinusoidal waveforms for bonded CFRP plates. De-bonded CFRP plates had lower frequencies with faster decaying waveforms. Test data shows the impact acoustic emission frequencies and waveform damping ratios are valid indicators of changes in CFRP-bond structure on retrofitted concrete bridges. This investigation confirmed CFRP systems applied in 2001 remain fully bonded to the bridge concrete.
Kenneth C. Crawford
Examining the Effect of Load Type and History Using Reliability on Optimizing the Design of FRP-Strengthened RC Members in Flexure
There is an increasing need for optimizing the design of fiber reinforced polymer (FRP) flexural strengthening of deficient concrete beams. Optimizing the design is crucial for enhancing the competitiveness of FRP material as compared with conventional environmentally unfriendly materials like concrete and steel. Practicing engineers in Canada are often faced with design challenges when applying the current codes and standards (NBCC 2015; CSA S806-17) to strengthen existing buildings, including the high amount of FRP material required to strengthen existing deficient members. These challenges often result in practicing engineers selecting more financially viable conventional retrofit options, like shortening existing spans with steel posts. In this study, a simple reliability-based method is used to generate user-friendly design charts, to optimize the amount of FRP layers required to strengthen concrete beams, deficient in flexure. These charts are derived to be compatible with the Canadian building codes (NBCC 2015; CSA S806-17). A database of experimentally tested strengthened beams is collected, applied along with the statistics for unstrengthened beams and loads, used to calibrate the NBCC and ACI 318 codes, respectively, to run the reliability analysis. Results show that the code generally prescribes an over-conservative amount of FRP for a given target safety and that when accounting for load type and history, the reliability method can meet the same target reliability index with less material.
Connor Petrie, Fadi Oudah
Design and Performance of GFRP Reinforced Bridge Decks in NOVA SCOTIA—Preliminary Analysis
The use of glass fibre-reinforced polymer (GFRP) reinforcement in bridge decks has gained popularity due to its corrosion resistance. With the adverse effects of frequent freeze–thaw cycles and the ingress of de-icing agents in concrete bridge decks, GFRP is proving to be an ideal solution for reinforcing material in Canada. The Canadian Highway Bridge Design Code (CSA S6-19) provides general design requirements for GFRP-reinforced bridge decks. However, there is some variability in the durability design requirements in Canada due to climatic differences across the country. There are variations in design methods (flexural design approach versus empirical design approach), as well as variations in the choice of concrete material specifications and geometric parameters such as overall deck thickness and concrete cover. In addition, limited research has been completed to assess the long-term durability performance of GFRP bars in concrete decks and any impact on remaining capacity and reliability. The primary objectives of this research programme are to 1) provide a review of the design methods for GFRP-reinforced bridge decks in Nova Scotia and 2) recommend regional specific durability-based design criteria for GFRP-reinforced bridge decks. This paper presents parts of the two phases of the research programme. Phase I consists of evaluating the design of existing GFRP-reinforced bridge decks in Nova Scotia and performing statistical analysis. Phase II consists of developing a framework to assess the structural reliability of bridge deck design options subjected to the province’s specific environmental exposure. Analyses performed in Phase I show that all considered bridge decks meet the flexural strength requirements of CSA S6-19 and that the parts of the deck subjected to transverse negative moments are the most critical zone for the serviceability crack width criteria in the flexural design method. In Phase II, the analysis of Weight-In-Motion (WIM) data from a highway in Nova Scotia shows that the third axle of Class 13 (7 or more axles) vehicles has the highest mean loads of all vehicle classes. The proposed design criteria provided at the end of this research programme will serve as a design aid for bridge engineers in Atlantic Canada to evaluate existing GFRP-reinforced bridge decks and optimize the design of new ones.
David Idemudia, John Newhook, Fadi Oudah
Three-Dimensional CT Imaging Analysis of Concrete: Effects of Water and Sand Contents on Pore Characteristics
Understanding the impact of concrete composition on its pore properties is essential for determining the appropriate mixing proportions for different loadings and environmental conditions. This paper conducted a qualitative and quantitative analysis to investigate the effect of water-to-cement (W/C) and sand-to-cement (S/C) ratios on the pore properties of small concrete specimens using a non-destructive micro-computed tomography (µCT). It was observed that altering the W/C and S/C ratios substantially affected the concrete porosity and the quality of its pore structure represented by the volume ratio of small and large voids. It was also found that the W/C and S/C ratios have contrary effects on the pore structure of concrete. A high W/C ratio (e.g., W/C = 0.9) or low S/C ratio (e.g., S/C = 0.5) produced low-quality specimens with increased concrete porosity and volume ratio of large voids. In contrast, a low W/C ratio (e.g., W/C = 0.4) or high S/C ratio (e.g., S/C = 3) degraded its workability and created specimens with higher porosity with a lower volume ratio of large voids. In other words, decreasing the W/C ratio or increasing the S/C ratio can produce stronger concrete specimens by minimizing the percentage of large voids, which matched well with the reported findings in the literature. Based on the aforementioned results, it was concluded that utilizing the appropriate W/C and S/C ratios of 0.6 and 1, respectively, can enhance the performance of concrete by reducing its porosity and large void content.
Mustafa Alhusain, Adil Al-Mayah
An Innovative Wedge Anchorage for CFRP Plates: Finite Element Modeling and Experimental Verification
The corrosion-resistant carbon fiber reinforced polymer (CFRP) has been proven to be a good candidate for repairing and strengthening concrete structures attributed of its lightweight and high tensile strength. Prestressing CFRP strengthening materials such as plates will have a high impact on improving the performance of the strengthened structures while utilizing the high strength of the CFRP. However, the process is hindered by the lack of a suitable anchorage system to grip the CFRP due to the sensitivity of the CFRP to the lateral gripping stress. The proposed mechanical wedge anchorage system for gripping CFRP plates was made of two soft copper sleeves, two steel wedges, and a steel barrel. Developing an accurate finite element (FE) model of the anchorage is crucial to thoroughly understand the stress distribution within the anchorage and the interactions between its components and the gripped CFRP plate. In this paper, a three-dimensional FE model was developed and verified. The symmetric model consisted of a CFRP plate, a copper sleeve, a steel wedge, and a steel barrel. Different experimentally verified contact conditions were applied at the CFRP-sleeve, sleeve-wedge, and wedge-barrel interfaces to accurately simulate the presetting and tensile loading processes of the wedge anchorage. The accuracy of the FEM model was illustrated by the notable agreement between its results and experimental results.
Mustafa Alhusain, Adil Al-Mayah
Effects of Load Level on the Structural Fire Behaviour of GFRP-Reinforced Concrete Beams with Straight-End bar Lap Splices
Over the past two decades, glass fiber-reinforced polymer (GFRP) has been utilized as an alternative reinforcing material to steel in concrete structures. Due to the superior corrosion resistance and high strength-to-weight ratio of GFRP they are considered as economical alternatives to reinforce various concrete structural elements. However, fire safety consideration often limits the utilization of GFRP bars as reinforcement in concrete structures. This paper presents the results of an experimental investigation on the effects of applied load level on the structural behaviour of GFRP-reinforced concrete beams when exposed to standard fire. The study involved two 2750-mm long concrete beams of 300 mm × 350 mm cross-sectional dimensions. Both beams had straight-end bar lap splices located at the beam midspan. Beams were designed as per CSA-S806 standard, and the fire tests were conducted in compliance with CAN/ULC S101 standard. Each beam was subjected to 85% of the beam ultimate design load. The experimental results and time to failure of the two beams when subjected to standard fire exposure were compared to those of identical beams subjected to only 40% of the beam ultimate design load in a prior related experimental study. Unpredictably, experimental results show that increasing the applied load level from 40% to 85% did not affect the fire resistance time of the GFRP-reinforced beams with straight-end bar lap splices.
Sobita Gurung, Osama Salem
Durability Assessment of Fiber-Reinforced Polymer Composites Externally Bonded to a Concrete Bridge After 26-Year Exposure
The effectiveness of externally bonded carbon fiber reinforced polymer (CFRP) composites for structural rehabilitation depends on their long-term performance. Current durability testing of CFRP composites involves accelerating conditioning to ensure that they maintain their mechanical properties during service life. However, without field data, relating accelerated conditioning test data to real-time outdoor exposure cannot be reliable. This paper study provides information on the durability of CFRP composites installed on the Foulk Road concrete bridge in Wilmington, Delaware (USA)—one of the oldest CFRP repairs of a publicly-owned bridge in the US. Field assessment of CFRP repairs included visual inspection of the bridge and pull-off tests to assess bond strength. Material samples collected from the bridge were characterized by Differential Scanning Calorimetry to determine thermal properties. Scanning electron microscope was used to observe the microstructure of the repairs. The results indicate that after 26-year long service life, the condition of CFRP repairs considerably deteriorated.
Sandra Milev, Jovan Tatar
Experimental Testing of GFRP-Reinforced Concrete Beams with Mid-Span Lap Splices Utilizing Straight- and Hooked-End Bars
Four large-scale concrete beams reinforced with glass fiber-reinforced polymers (GFRP) bars were experimentally tested to investigate the bond strength between the reinforcing bars and concrete. Two beam specimens were designed using 550 mm long lap splices that utilized straight-end bars, while the other two specimens were designed with hooked-end bar lap splices. Beams were designed in accordance with CSA-S806-12 (CSA 2012) design standard and were tested under four-point flexure bending until failure. Test results show that the two beams with straight-end bar lap splices achieved the theoretical design moment resistance, and both specimens failed due to slippage of the bars. On the other hand, the experimental results of the two beams designed with hooked-end bar lap splices failed due to concrete crushing within the hooks at about 50% greater moment capacity than their theoretical design value. Outcomes of this experimental study on large-scale GFRP-reinforced concrete beams show that hooked-end bars would provide excellent bar anchorage compared to that provided in case of straight-end bars.
Omar Nour, Osama Salem, Ahmed Mostafa
Bond Behaviour of FRP Shear Reinforcement on I-Sections
Although external fibre reinforced polymer (FRP) reinforcements are easy to manipulate around any shape, their behaviour varies with respect to the geometry of the strengthened cross sections. This is, in particular, the case for shear strengthening of I-sections, such as prestressed concrete girders. The externally bonded (EB) FRP shear reinforcement is susceptible to early debonding around the internal angles at the web–flange interface. Due to this early debonding, strength of the FRP is not utilized efficiently. This paper demonstrates a newly developed test configuration to study bond behaviour and debonding mechanism of externally bonded FRP shear reinforcement around the web–flange interface in I-shaped specimens. FRP spike anchors were used to protect the early debonding at the web–flange interface that increased 35% of the ultimate shear load. Further, the obtained results in terms of bond capacity, failure aspect and anchorage behaviour are discussed in comparison to the standard FRP shear design and prediction models.
Muhammad Arslan Yaqub, Stijn Matthys, Christoph Czaderski
A Review on Properties of Carbon Nanofibre Infused Ultra-High-Performance Fibre Reinforced Concrete
Ultra-High-Performance Fibre Reinforced Concrete (UHPFRC) is a special purpose material characterized by outstanding structural performance. On the other hand, Carbon Nano Fibres (CNF) are nanomaterials with high tensile strength, high conductivity, and good cement modification effect. CNF infused UHPFRC is marketed as a new generation of UHPFRC that is strong and durable. However, it has been subjected to very few investigations. Nevertheless, these studies demonstrate the abovementioned hypothesis. A review of these investigations is presented herein, followed by a discussion. It is inferred that the hybrid reinforcement, which includes the inherent UHPFRC micro steel fibres along with CNF, enhances the material’s mechanical and durability properties further. CNF densifies the UHPFRC matrix more, preventing the ingress of harmful materials and extending the service life of the structure. Strength-wise, it increases the material’s tensile strength throughout delaying the cracking onset and retaining its ductility. Correspondingly, it increases the material’s tensile hardening ratio, energy dissipation, and energy absorption capacity. However, this is conditioned to incorporating the adequate CNF amount. Providing CNF in excess of the matrix’s capacity will force the nanomaterials to agglomerate in some regions, leaving little or no CNF for other regions. Similarly, ensuring the nanomaterial’s uniform dispersion in the cementitious matrix is a key to their efficient enhancement.
Marwa Ibrahim, Raafat El-Hacha
A Review on Seismic Performance of Reinforced Concrete Columns Strengthened with Smart and Composite Materials
Over the past decades, research studies related to earthquake engineering have been active because some earthquakes caused significant damage to bridge-reinforced concrete (RC) columns which eventually triggered the collapse of the whole bridge. Therefore, this motivated researchers to carry out extensive investigations to know the reason behind it. After that, researchers concluded that engineering codes set before 1971 included inadequate engineering considerations in the reinforcement design and detailing of RC columns, thus, making the columns deficient in resisting earthquakes. As a result, they were highly susceptible to collapse because they did not have adequate ductility to absorb the seismic energy. Moreover, other causes of deficiencies include exposure to higher load demands (gravity loads, wind loads, earthquakes), exposure to environmental deterioration (corrosion, freeze-thaw cycles, high temperatures), or being subjected to localized damages. All the mentioned deficiencies require strengthening and repairing systems to increase the column’s capacity or restore the latter’s original capacity. Therefore, this paper aims to present a review of various strengthening and repairing systems applied to deficient RC columns by many researchers. The scope of the presented review will be limited to RC columns that were strengthened with Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC), Shape Memory Alloys (SMAs), and Fibre-Reinforced Polymers (FRPs). This paper will also present the authors’ discussion on some research works and will identify the potential research gaps that direct the future of research in the field of strengthening and repairing deficient RC columns.
Adel Al Ekkawi, Raafat El-Hacha
Flexural Strengthening of Reinforced Concrete Structures Using Iron-Based Shape Memory Alloys: Case Studies
Our world relies heavily on our infrastructure. Reinforced concrete (RC) is the most widely used material, and any efficiencies developed in RC structures will have a substantial cost and environmental benefits. However, when infrastructure deteriorates, and if a deficiency is observed, a structural intervention can be carried out. However, if a deficiency is not detected, it can result in a catastrophic failure causing significant loss of life and property damage. Current active strengthening techniques have inherent challenges, such as requiring heavy jacking equipment to prestress the material or removal of original material to provide proper anchorage for prestressing. These challenges are addressed by a novel strengthening material, iron-based shape memory alloy (Fe-SMA). Fe-SMA is an emerging material capable of changing shape on demand by recovering large deformations when heated and then cooled. When prestrained Fe-SMA is prevented from recovering the strains, recovery stress develops, which prestresses the structure to which it is attached without the need for heavy jacking equipment or removal of original material to provide suitable anchorage. The material offers also a very strong advantage in terms of circular economy, as the alloy is fully recyclable and can be, upon deconstruction, fully re-introduced into the steel casting cycle. Fe-SMA has great potential to replace conventional strengthening materials but awareness is limited. The motivation of this article is to increase awareness of this novel strengthening technique within the research community and advocate for additional experiments to improve the effectiveness of using Fe-SMA for the flexural strengthening of RC structures. There are over 50 projects in the world demonstrating this technology being implemented in the field. A brief history of the development of Fe-SMA is presented, along with an overview of the mechanism of the shape recovery. An overview of the strengthening process of the latest case studies is presented, along with a discussion on their merit and new ideas for prestress strengthening of RC structures.
Benjamin Forrest, Raafat El-Hacha, Julien Michels
GFRP Reinforced Precast Concrete Tunnel Lining Segments Under Flexural Cyclic Loading
The strength and behavior of precast segmental tunnel linings reinforced internally with fiber-reinforced-polymer (FRP) bars is one area in which limited experimental research results are available in practice. This paper reports on an investigation of the behavior of precast concrete tunnel segments reinforced with glass FRP (GFRP) bars under cyclic flexural loading. The study comprised testing of two full-scale precast concrete tunnel segments up to failure. The length and width of the segments are 3100 mm and 1500 mm, respectively, while the thickness is 250 mm. Segments are skewed at their ends rather than straight edges. Steel and GFRP bars were used in the experimental program. Test results show that the nominal flexural strength of the specimen reinforced with GFRP bars was higher than that of the steel counterpart specimen when the reinforcement ratios were similar. The experimental results were presented in terms of the general behavior of the tested specimens, flexural capacity, and mode of failure. The results of the current study show the feasibility and efficiency of using GFRP bars instead of steel bars for precast segmental tunnel linings.
Basil Ibrahim, Salaheldin Mousa, Hamdy M. Mohamed, Brahim Benmokrane
Durability of GFRP-RC Square Columns in Severe Marine Environment
This paper reports on an investigation of the axial compression behavior of glass fiber reinforced polymer (GFRP)-reinforced concrete (RC) square columns after immersing in simulated severe marine environments. Four laboratory-scale GFRP-RC square columns (300 mm width and 1000 mm height) were reinforced longitudinally with GFRP bars and transversely with GFRP square spirals. Two columns (set as conditioned specimens) were continuously immersed in a simulated marine environment (saline solution) at high temperature (heat waves—60 °C) for 365 days before testing under concentric loading. The remaining two columns were kept at room temperature (set as unconditioned specimens). The results revealed that due to conditioning, the concrete gained strength, causing an enhancement in the axial capacity of tested columns by about 23.5% compared to their control counterparts, on average. Moreover, the GFRP bars and spirals did not show any degradation in their material, as illustrated in SEM images. The optical microscopy (OM) results showed that no debonding between concrete and bars was observed. The effect of increasing the longitudinal reinforcement ratio on the axial carrying capacity was limited, and almost neglected; however, its effect on post-peak response was significantly pronounced.
Ahmed Elhamaymy, Hamdy M. Mohamed, Brahim Benmokrane
Behavior of Concentrically Loaded GFRP-RC Circular Hollow Columns with Varying Transverse Reinforcement Ratios
Limited experimental studies have been implemented to examine the performance of hollow concrete columns (HCCs) reinforced with glass fiber-reinforced polymers (GFRP) reinforcements. This study investigated the performance of four large-scale HCCs that were tested under concentric load. These columns were reinforced in the longitudinal direction with eight GFRP bars No.5 and with different transverse reinforcement ratios (nil, 0.75, 1.10, and 2.20%), which were achieved by changing the spiral’s pitch (no transverse reinforcement, 120, 80, and 40 mm). The 305/113 mm outer/inner diameter columns were designed according to Canadian design code requirements. The objective of the study was to investigate the effect of the transverse reinforcement ratio (in terms of the spiral’s spacing). The test results indicated that the GFRP-RC hollow columns exhibited a compression failure in terms of concrete cover spalling, and the GFRP reinforcement remained undamaged up to the failure. The GFRP longitudinal reinforcement significantly contributed to resisting the peak loads in all tested columns, on average 11% of the ultimate carrying load. It also was found that increasing the transverse reinforcement ratio from 0.75 to 2.20% increases 8–14% in the peak and 1.60–1.90 in the confinement efficiency.
Mohammed Gamal Gouda, Hamdy M. Mohamed, Allan C. Manalo, Brahim Benmokrane
Torsional Behavior of Concrete Box Girders Reinforced with Longitudinal GFRP Bars and Without Stirrups
So far, the torsional strength and behavior of reinforced concrete (RC) box girders reinforced with glass-fiber-reinforced polymer (GFRP) bars have not yet been discussed. This paper reports on an investigation of the torsional behavior of large-scale RC box girders reinforced with GFRP and steel reinforcement. All box girders had the same dimensions with 4,000 mm long, 380 mm wide, 380 mm deep, and 100 mm wall thickness and were examined under pure torsion moment. The test specimens included one box girder reinforced with longitudinal GFRP bars and one box girder reinforced with longitudinal steel bars. All specimens have the same longitudinal reinforcement ratio with different reinforcement types and without any transverse torsional reinforcement to study the influence of the longitudinal reinforcement only on the torsional behavior. The test results pointed out that the GFRP RC box girder experienced cracking torsional strength slightly higher than the steel one. All girders did not achieve post-cracking torsional strength owing to the absence of the transverse reinforcement. The ultimate torsional strength for these specimens coincided with the cracking torsional strength. In addition, the ACI-318-19 cracking torsional strength design equation underestimated the cracking torque by an average of 21%.
Ibrahim Mostafa, Salaheldin Mousa, Hamdy Mohamed, Brahim Benmokrane
Application of GFRP Bars in Precast Concrete Tunnel Lining Segments
The use of precast concrete tunnel linings (PCTLs) has been escalating due to its efficient and economical installation process. Such structural elements are typically designed for a service life of 100 years or greater. However, traditional steel-reinforced PCTL segments suffer from corrosion of reinforcement intensified by the corrosive environment of tunnels. Replacement of steel reinforcement with non-corroding glass fiber-reinforced polymer (GFRP) bars is a viable solution to mitigate the corrosion problem in tunnels. This study evaluates the efficiency of GFRP-reinforced PCTL segments under bending load. Two full-scale tunnel segment specimens with the arc length of 3100 mm, width of 1500 mm, and thickness of 250 mm were constructed and tested under a three-point bending load. One of the specimens was reinforced with GFRP bars and the other was reinforced with steel rebars with an identical reinforcement configuration. The structural performance of the specimens was investigated in terms of cracking, failure mechanism, serviceability, and load–deflection behavior. The results indicated that the GFRP-reinforced specimen had a favorable compression-controlled flexural failure achieving a 33% greater peak load compared to the steel-reinforced one. Besides, the service load crack width of the GFRP-reinforced specimen successfully satisfied the requirement of CAN/CSA S6-19. Furthermore, the GFRP-reinforced specimen had 33% lower deflection at service load relative to the steel-reinforced one.
Seyed Mohammad Hosseini, Salaheldin Mousa, Hamdy Mohamed, Brahim Benmokrane
8th International Conference on Advanced Composite Materials in Bridges and Structures
herausgegeben von
Brahim Benmokrane
Khaled Mohamed
Ahmed Farghaly
Hamdy Mohamed
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