Experimental Study of SFRP in Retrofitting of Column

Abstract

Fiber Reinforce Polymer (FRP) composites are emerging as an important con- struction material for increasing capacity of existing structure. Presently, carbon ber reinforced polymers (CFRP) and glass ber reinforced polymer (GFRP) are being used as external reinforcement for strengthening of structure. Steel ber reinforced polymer (SFRP) composite materials have been recently introduced as an alternative to glass ber reinforced polymer (GFRP) and carbon ber reinforced polymer (CFRP) composite materials. In SFRP steel bers in form of mesh is applied on concrete surface using epoxy as grout material. The objective of present project is to evaluate axial strength of Steel Fiber Reinforced Polymer (SFRP) wrapped column specimens. Three specimens of locally available stainless steel wire mesh (SSWM) were se- lected and tested for nding the tensile strength. The average ultimate tensile strength of wire was found to be 758.91 N/mm2. To check the bond strength be- tween concrete and SSWM (Stainless steel wire mesh), 6 dumbbell shaped concrete specimens were prepared and tested. Ultimate bond strength was found to be more than 837.75 N/mm2 because the wire mesh strip got fractured but there was no bond failure between concrete and wire mesh.For experimental evaluation of axial load carrying capacity of concrete columns, total 54 cylindrical column specimens of 200 mm diameter were cast. Variation parameters considered for experimental study are: concrete grade M15,M20 and M25, height of column 400mm, 800mm and 1200mm and number of wrapping layers one and two. Axial load carrying capacity of strengthened column is compared with that without wrapping. Total 18 columns were cast in each grade of concrete. For each grade, 6 specimens were prepared for the same height but with di erent number of wrapping. Based on experimental work it has been found that for column having M15 grade concrete and 400 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 19% and respectively by 49%. In case of column with 800 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 61% and respectively by 71%. In case of column with 1200 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 61% and respectively by 86%. In M20 grade concrete and 400 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 15% and respectively by 47%. In case of column with 800 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 47% and respectively by 67%. In case of column with 1200 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 54% and respectively by 70%. In M25 grade concrete and 400 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 15% and respectively by 39%. In case of column with 800 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 30% and respectively by 52%. In case of column with 1200 mm height with one layer of SSWM and two layers of SSWM compressive strength is increased by 34% and respectively by 57%. Based on experimental work carried out in this study it is formed that SSWM can be used for structural strengthening of RCC column successfully. There are other benefits of using SFRP are inherent ductility, good bond with concrete surface, resistance to corrosion being of stainless steel, lightweight in comparison to steel plates and above all much cost effective.