Experimental Investigation on GFRP Wrapped R.C Beam Column Joint
Abstract
This paper presents the seismic behavior of beam column joint using Glass Fiber Reinforced polymer (GFRP) wraps. The dimensions of the specimens were fixed to be 0.2 m x 0.15 m cross section and the height of column was fixed as 1m and the cantilever length of the beam was fixed as 0.8m to carry out the experimental work. The column portion was reinforced with 4 No’s of 8mm diameter in tension side and 4 No’s of 8 mm diameter in compression side. The beam portion was reinforced with 2 No’s of 8 mm diameter in tension side and 2No’s of 8 mm diameter in compression side. The performances of the specimens are compared in terms of lateral load versus displacement curves. The grade of concrete proposed was M20 and the grade of steel was Fe 415. Four numbers of exterior beam column joint were cast and tested under lateral loading. The specimens was designed as per IS 13920:1993. Out of four specimens one was control specimen and the remaining three specimens were wrapped with 1 layer, 2 layers, and 3 layers of GFRP. Results by experimental work shows that GFRP specimens carries more load carrying capacity than the control specimen.
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Introduction
In RC buildings, portions of columns that are common to beams at their intersections are called beam-column joints. Beamcolumn joints being the lateral and vertical load resisting members in RC structures are particularly vulnerable to failures during earthquakes and hence their confinement is the key to successful seismic strengthening strategy.
Conclusion
Based on the experimental investigations carried out on the control and beam-column joint specimens using GFRP wrapping, the following conclusions were drawn:
1. The experimental results clearly demonstrate that GFRP wrapping can enhance the structural performance of RC beam column joint under static loading.
2. Increasing the number of GFRP layers increase the axial compressive strengths of the beam column joint.
3. Control + GFRP (1 layer) is 1.06% more load carrying capacity than the control specimen.
4. Control + GFRP (2 layers) is 1.346% more load carrying capacity than the control specimen.
5. Control + GFRP (3 layers) is 1.448% more load carrying capacity than the control specimen.