Structural Behavior of Slender Reinforced Concrete Columns Wrapped with Fiber Reinforced Polymers Subjected to Eccentric Loads

Author(s):  
Mahmoud Anwar Gad ◽  
Amr M. Riad ◽  
Ehsan Nikbakht ◽  
Mujahid Ali ◽  
Gouda M. Ghanem
2019 ◽  
Vol 13 (3) ◽  
pp. 59-63
Author(s):  
E. TORE ◽  
A. YAVAS

Confinement with fiber reinforced polymers of reinforced concrete columns is promising retrofit solution for improving ductility of existing structure. In the study, plastic deformation capacityof fiber reinforced polymers confined square and rectangular reinforced concrete columns were parametrically evaluated. Recently released seismic strengthening recommendations of American Concrete Institute were considered for calculating plastic rotation of specified columns. Fiber reinforced polymers confined concrete model provided by the design guideline was utilized for calculating moment curvature relationship of fiber reinforced polymers confined reinforced concrete columns. Numerous sectional analysis was performed with combination of various parameters (concrete strength, axial load ratio and number of fiber reinforced polymers plies). Plastic rotations of columns were determined with plastic part of the curvature and plastic hinge length for evaluating the effects of parameters on plastic deformation capacity.


Author(s):  
Hesham A. Haggag ◽  
Nagy F. Hanna ◽  
Ghada G. Ahmed

The axial strength of reinforced concrete columns is enhanced by wrapping them with Fiber Reinforced Polymers, FRP, fabrics.  The efficiency of such enhancement is investigated for columns when they are subjected to repeated lateral loads accompanied with their axial loading.  The current research presents that investigation for Glass and Carbon Fiber Reinforced Polymers (GFRP and CFRP) strengthening as well.  The reduction of axial loading capacity due to repeated loads is evaluated. The number of applied FRP plies with different types (GFRP or CFRP) are considered as parameters in our study. The study is evaluated experimentally and numerically.  The numerical investigation is done using ANSYS software. The experimental testing are done on five half scale reinforced concrete columns.  The loads are applied into three stages. Axial load are applied on specimen in stage 1 with a value of 30% of the ultimate column capacity. In stage 2, the lateral loads are applied in repeated manner in the existence of the vertical loads.  In the last stage the axial load is continued till the failure of the columns. The final axial capacities after applying the lateral action, mode of failure, crack patterns and lateral displacements are recorded.   Analytical comparisons for the analyzed specimens with the experimental findings are done.  It is found that the repeated lateral loads decrease the axial capacity of the columns with a ratio of about (38%-50%).  The carbon fiber achieved less reduction in the column axial capacity than the glass fiber.  The column confinement increases the ductility of the columns under the lateral loads.


1999 ◽  
Vol 26 (5) ◽  
pp. 590-596 ◽  
Author(s):  
Burt K Purba ◽  
Aftab A Mufti

Recent advancements in the fields of fiber reinforced polymers (FRPs) have resulted in the development of new materials with great potential for applications in civil engineering structures, and due to extensive research over recent years, FRPs are now being considered for the design of new structures. This study describes how carbon fiber reinforced polymer jackets can be used to reinforce circular concrete columns. Fibers aligned in the circumferential direction provide axial and shear strength to the concrete, while fibers aligned in the longitudinal direction provide flexural reinforcement. Prefabricated FRP jackets or tubes would also provide the formwork for the columns, resulting in a decrease in labor and materials required for construction. Also, the enhanced behavior of FRP jacketed concrete columns could allow the use of smaller sections than would be required for conventionally reinforced concrete columns. Furthermore, FRP jacket reinforced concrete columns would be more durable than conventionally reinforced concrete columns and therefore would require less maintenance and have longer service life.Key words: bridge, carbon, column, concrete, confinement, fiber reinforced polymer, jacket, retrofitting, seismic, strengthening.


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