Ching Chiaw Choo

Bio: Ching Chiaw Choo is an academic researcher from University of Kentucky. The author has contributed to research in topics: Carbon fiber reinforced polymer & Fibre-reinforced plastic. The author has an hindex of 7, co-authored 21 publications receiving 352 citations. Previous affiliations of Ching Chiaw Choo include Indian Institute of Technology Madras.

Flexural Behavior of R/C Beams Strengthened with Carbon Fiber Reinforced Polymer Sheets or Fabric

Abstract: Their resistance to electro-chemical corrosion, high strength-to-weight ratio, larger creep strain, fatigue resistance, and nonmagnetic and nonmetallic properties make carbon fiber reinforced polym...

Structural Behavior of FRP Composite Bridge Deck Panels

Abstract: Fiber-reinforced polymer (FRP) composite bridge deck panels are high-strength, corrosion resistant, weather resistant, etc., making them attractive for use in new construction or retrofit of existing bridges. This study evaluated the force-deformation responses of FRP composite bridge deck panels under AASHTO MS 22.5 (HS25) truck wheel load and up to failure. Tests were conducted on 16 FRP composite deck panels and four reinforced concrete conventional deck panels. The test results of FRP composite deck panels were compared with the flexural, shear, and deflection performance criteria per Ohio Department of Transportation specifications, and with the test results of reinforced concrete deck panels. The flexural and shear rigidities of FRP composite deck panels were calculated. The response of all panels under service load, factored load, cyclic loading, and the mode of failure were reported. The tested bridge deck panels satisfied the performance criteria. The safety factor against failure varies from 3 to 8.

Strength of Rectangular Concrete Columns Reinforced with Fiber-Reinforced Polymer Bars

Abstract: The strength interaction behavior of fiber-reinforced polymer (FRP) reinforced concrete (RC) columns is presented using an ultimate strength approach A numerical integration technique is used to examine the slenderness effects of columns The authors demonstrate that FRP RC columns have a propensity to undergo brittle-tension failure This failure is generally sudden, and is associated with tension rupture of FRP bars when the strain in outer bar layer reaches or exceeds its ultimate load at the same time, or before, the concrete reaches its ultimate strain in compression For RC columns reinforced with FRP bars, the current American Concrete Institute’s ratio limits may not be adequate

Minimum Reinforcement Ratio for Fiber-Reinforced Polymer Reinforced Concrete Rectangular Columns

Abstract: Two failure mechanisms were identified through a strength interaction analysis of rectangular concrete columns reinforced with fiber-reinforced polymer (FRP) bars. While the failure mechanisms identified were premature-compression failure and brittle-tension failure, the study demonstrated that, due to the low ultimate tensile strain for FRP bars, the brittle-tension failure was more likely to occur. Interaction design diagrams provide the process for identifying a reinforcement ratio that is greater than a minimum required ratio, which will identify the failures, and prevent brittle-tension failure. The authors recommend that only FRP reinforcing bars with ultimate compression strains larger than the concrete compression strain should be used in column applications.

Shear strength of r/c beams wrapped with cfrp fabric

Abstract: The emergence of high strength epoxies has enhanced the feasibility of increasing the shear strength of concrete beams by wrapping with carbon fiber reinforced polymer (CFRP) fabric. The objective of this investigation is to evaluate the increase in shear strength of concrete beams wrapped with different configurations of CFRP fabric. Shear tests are conducted up to failure on two reinforced concrete control beams and twelve reinforced concrete beams wrapped with four different configurations of CFRP fabric. An analytical procedure is presented to predict the shear strength of beams wrapped with CFRP fabric. Comparisons are made between the test results and the analytical calculations. The shear strength is increased up to 33% on concrete beams wrapped with CFRP fabric at an angle of +/- 45 deg to the longitudinal axis of the beam.

Fiber-Reinforced Polymer Composites: Manufacturing, Properties, and Applications.

Abstract: Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.

Axial Capacity of Circular Concrete Columns Reinforced with GFRP Bars and Spirals

Abstract: Several codes and design guidelines are now available for the design of concrete structures reinforced with fiber-reinforced polymer (FRP) bars under flexural and shear loads. Yet, because of a lack of research, North American codes and design guidelines do not recommend using FRP bars as longitudinal reinforcement in columns to resist compressive stresses. This paper reports on 12 full-scale circular reinforced concrete (RC) columns that were tested under concentric axial loads. The columns were reinforced with longitudinal glass FRP (GFRP) bars and newly developed GFRP spirals. The 300-mm diameter columns were designed according to code requirements. The test parameters included reinforcement type (GFRP versus steel); longitudinal FRP reinforcement ratio; and the volumetric ratios, diameters, and spacing of spiral reinforcement. The test results indicated that the GFRP and steel RC columns behaved in a similar manner. The average load carried by the longitudinal GFRP bars ranged between 5% and 1...

Behavior of full-scale glass fiber-reinforced polymer reinforced concrete columns under axial load

Abstract: Most current design guidelines and codes do not allow glass fiber-reinforced polymer (GFRP) bars to be used as compression reinforcement. This study investigates the compressive behavior of longitudinal GFRP bars in reinforced concrete (RC) columns. An experimental campaign on full-scale GFRP RC columns under pure axial load was undertaken using specimens with a 24 x 24 in. (0.61 x 0.61 m) square cross section. The results showed that the GFRP RC specimens behaved similarly to the steel RC counterpart when the longitudinal reinforcement ration is equal to 1.0%. The use of longitudinal GFRP bars was not found to be detrimental to the performance of RC columns, but the contribution of GFRP bars to column capacity was significantly lower than that of the steel bars in the steel RC counterpart. The 3 inch spacing of the GFRP ties strongly influenced the failure mode by delaying the buckling of the longitudinal bars, initiation and propagation of unstable cracks and crushing of the concrete core. Considerations for including GFRP reinforced columns in current ACI practice are discussed.

Performance Evaluation of Concrete Columns Reinforced Longitudinally with FRP Bars and Confined with FRP Hoops and Spirals under Axial Load

Abstract: Nowadays, AASHTO LRFD Bridge Design Specifications and the Canadian Highway Bridge Design Code contain flexural and shear provisions for the design of concrete bridge members reinforced with fiber-reinforced polymer (FRP) bars. Because of a lack of research, these standards do not recommend using FRP bars to resist compressive stresses in compression members. This paper reports on 14 full-scale circular RC columns tested under concentric axial load. The columns were reinforced with longitudinal FRP bars and confined with circular FRP spirals or hoops. Sand-coated glass-FRP (GFRP) and carbon-FRP (CFRP) reinforcement was used. The test parameters included configuration of the confinement reinforcement (spirals versus hoops), hoop lap length, volumetric ratio, and FRP reinforcement type (glass versus carbon). The test results indicate that the GFRP and CFRP RC columns behaved similarly to columns reinforced with steel. Using GFRP and CFRP spirals or hoops according to the provisions of the Canadian S...

Experimental Investigations on Circular Concrete Columns Reinforced with GFRP Bars and Helices under Different Loading Conditions

Abstract: Glass-fiber-reinforced polymer (GFRP) bar has emerged as a preferable alternative to steel bar in reinforced concrete (RC) members in harsh, corrosive, coastal environments in order to eliminate corrosion problems. However, only limited experimental studies are available on the performance and behavior of concrete columns reinforced with GFRP bars under different loading conditions. This study investigates the use of GFRP bars and GFRP helices (spirals) as longitudinal and transversal reinforcement, respectively, in RC columns. A total of 12 circular concrete specimens with 205-mm diameter and 800-mm height were cast and tested under different loading conditions. The effect of replacing steel with GFRP reinforcement and changing the spacing of the GFRP helices on the behavior of the specimens was investigated. The experimental results show that the axial load and bending moment capacity of the GFRP-RC columns are smaller than those of the conventional steel-RC columns. However, the ductility of th...