STRENGTHENING OF RC BEAM SUBJECTED TO SHEAR LOADING USING DEEP EMBEDMENT METHOD

SUBJECTED TO SHEAR LOADING USING DEEP EMBEDMENT METHOD

Ridwan et al., (2020)

Ridwan, Universitas Riau

Samir Dirar, University of Birmingham

Yaser Jemaa, Liverpool John Moores University Alfian Kamaldi, Universitas Riau

Alex Kurniawandy, Universitas Riau

Introduction

• Existing structures are not preforming well according to original purpose.

• Several efforts to provide practical and cost-effective strengthening method had been proposed.

• The proposed methods were proven to provide enhancement to the strength of RC structures.

• Unfortunately, the proposed methods were labor-intensive

and requires tedious preparation.

Research Significance

• Deep embedment (DE) method was introduced to overcome the drawbacks previous strengthening system.

• The DE method was implemented in strengthening shear- deficient BCJ (Ridwan et al., 2015; Ridwan et al., 2018).

• Strength enhancement in the DE method was positively influenced by the concrete strength and the number of embedded bars (Qapo et al., 2016; Chandra et al., 2019).

• Research on the DE strengthening of a non-engineered RC beam is limited.

• Behaviour of strengthening beam is presented in terms of

crack propagation, failure mode and shear force capacity.

Experimental Program

Description of specimens

Beam-A

Beam-B

Embedded bars

Strengthening Procedures

2

3

4 1

5

Experimental Setup

Loading frame

Load cell

LVDT

Specimen

Experimental Setup

Loading frame

Data acquisition system

Load cell

LVDT

Strain gauges

Data logger

Signal amplifier

Strain gauge amplifier

Material Properties

Concrete strength at date of beam test

Steel Reinforcement

Specimen f_c’ (MPa)

Beam-A 17

Beam-B 19

Diameter (mm)

f_y (MPa) f_u (MPa) E_s (GPa) Designation

6 373 500 200 Top longitudinal bar

Stirrup

12 362 532 200 Bottom longitudinal bar Embedded bar

Results and Discussions

Crack pattern – Beam A

• Minor flexural crack at mid-span during the early stages of loading

• With increased loading, cracks propagated to the shear span

• At end of test, shear cracks became wider and visible

Crack pattern – Beam B

• Cracks initially observed at mid-span

• With increased loading, cracks developed in the moment region in the vertical direction

• Throughout the test, cracks kept developing within flexural span

Failure mode

• Control beam experienced shear failure mechanism

• Strengthened beam failed in flexure

Beam-A Beam-B

Max. load capacity

Beam-A Beam-B 53.1 kN

69.6 kN 31%

Conclusion

• The control beam failed in shear whereas strengthened beam failed in flexure

• Embedded bars were successfully shifted failure mode from shear to flexure

• Shear force capacity of strengthened beam was enhanced by about 31% compared to that of the control beam

Acknowledgements

Authors gratefully acknowledges:

• LPPM Universitas Riau for financial supports

• Staffs at Concrete Lab. in the Civil Eng. Department Universitas Riau for technical support