This paper explores the behavior of GFRP and steel reinforced concrete columns when subjected to eccentrically axial loads. Six columns of 150*150 mm cross section were tested. Four of them had GFRP reinforcement and two had steel reinforcement. The concrete strength of the GFRP reinforced columns was either 24.73 Mpa or 38.35 Mpa while for the steel reinforced columns it was 24.73 Mpa. The eccentricity was either 50 mm or 25 mm and the tie spacing was either 80 mm or 130 mm. Large longitudinal deformations were recorded for columns with GFRP reinforcement and for columns with large tie spacings. However, tie spacing had no notable effect on the maximum lateral deflection and ductility of GFRP columns of this research. The average maximum stress was about 60% of the concrete compressive strength for columns with initial eccentricity of 50 mm. GFRP bars recorded higher strains than steel bars and these strains were larger when the tie spacing was large. The increase in the strength of the concrete was associated with reduction in the GFRP bar strain. Two interaction diagrams were plotted for the columns and they present lower bound to the obtained experimental results.
The objective of the reported study was to investigate and evaluate the behaviour of one-way concrete slabs reinforced with glass-fibre-reinforced polymer (GFRP) rebars under distributed and line loads. A fibre-reinforced polymer (FRP) composite made with resin-impregnated continuous fibres is considered a promising alternative to traditional steel reinforcement. The experimental programme used eight GFRP concrete slabs to study the type of rebar (steel and GFRP), strength of concrete (25 and 45 MPa), reinforcement ratio and type of loading (distributed and line) loads. The results from a series of tests showed that strains of GFRP rebars are generally larger than those of steel rebars, increasing the ratios of the GFRP rebars led to an increase in ultimate flexural strength and increasing the concrete strength of the slabs led to an increase in slab rigidity, which improves flexural capacity. Furthermore, it was found that failure of slabs reinforced with GFRP rebars occurred by crushing and end slip of GFRP rebars must be prevented by using additional bars beyond the supports.
This paper aims to determine the efficiency of using steel Shear Bolts to strengthen RC slabs in punching shear at
interior columns. The Shear Bolts used in this study consists of a vertical rod and anchored from both ends using a
washer and nut system. Shear Bolts are installed in holes, drilled in concentric perimeters around column, after
casting and just before testing. In this Work, an experimental research program was described in which seven halfscale
models representing interior slab column connections were tested. Seven square specimens (2000 x 2000 x 150
mm) were divided into two groups. The first group deals with three specimens with square column 150 x 150 mm;
one specimen without strengthening as a control specimen and the other two specimens strengthened with shear
bolts with different strengthened length around the column. The second group deals with four specimens with
rectangular column 150 x 300 mm; one Specimen without strengthening and the other three specimens strengthened
with Shear Bolts with different strengthened length and arrangements around the column. All Specimens were loaded
until failure. The ultimate load, deformation, punching perimeter, strain in flexural reinforcing bars, strains in Shear
Bolts, and the failure mechanisms of each specimen were generated and analyzed. The load-deflection curves are
presented which show how Shear Bolts increases punching shear capacity and post failure ductility of slab-column
connections
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