REPAIR OF TIMBER BEAMS USING CFRP SHEETS Ali AWALUDIN, Afriza MARIANTI Department of Civil and Environmental Engineering, University of Gadjah Mada Email: ali.awaludin@ugm.ac.id

Exposed wooden house

Exposed timber bridge structure

OUTLINE Introduction Materials and Methods Result and Discussion Conclusion

INTRODUCTION RETROFITTING OR RENEWAL?? Historical buildings CAUSES Fungus  Decay Bacteria  Decay Borer insects (termites) Earthworms Mechanical wear RETROFITTING OR RENEWAL?? Historical buildings

INTRODUCTION What is CFRP? Composite material consisting of carbon fibers which provides strength, stiffness, load carrying capacity, and a polymer matrix Type and orientation of carbon fiber Type and percentage of resin material Curing condition Engineering properties depend on

INTRODUCTION GOALS Moment Capacity Deformation Stiffness Failure Mechanism

Materials and Methods REPAIR MATERIAL CFRP SCH-11 Tensile strength: 3790 MPa Tensile modulus: 230 GPa Ultimate elongation: 1.7%

Materials and Methods SPECIMENS 2000 mm 95 mm 55 mm 900 mm Timber used Meranti (Shorea spp.) Average density 851 kg/m3 Moisture content 17% 55 mm 95 mm 2000 mm Decay Artificial crack (depth 25 mm, a width of 2 mm) 900 mm

Materials and Methods L = Distance between two supports 1 0,33L 2000 mm CFRP-900 mm 1800 mm 2 0,5L 2000 mm 1800 mm CFRP-1800 mm 3 L L = Distance between two supports Crack depth is 25 mm

Materials and Methods Properties of beam specimens No Name Group Name MoEd (Mpa) CFRP Length (mm) CFRP Width (mm) 1 A 14039 NA 2 B-600 B 13158 600 55 3 B-900 13301 900 4 B-1800 11444 1800 5 C-600 C 17896 115 6 C-900 16330 7 C-1800 18287

Materials and Methods Four-point loading test ½ P 1800 mm 2000 mm CFRP-600 mm ½ P LVDT 1,2 LVDT 3 LVDT 4

Increase of moment capacity Increase of bending stiffness Result Specimen Maximum load  (kN) Moment capacity (kNm) Bending stiffness, EI (Nmm2) Increase of moment capacity (%) Increase of bending stiffness A 9.78 2.98 53.07 - B-600 18.46 5.59 59.19 87 12 B-900 18.92 5.72 62.16 92 17 B-1800 22.43 6.78 60.36 127 14 C-600 17.83 5.40 60.00 81 13 C-900 21.85 6.60 59.00 121 11 C-1800 30.65 9.24 63.39 210 19

Result GROUP A and B GROUP A and C Beam C-1800 Beam B-1800 Beam C-900 Beam A Beam A

Result (Failure Mode) Beam C-600 Beam B-600 Beam C-1800 Beam C-900

Conclusion CFRP reinforcement significantly increase the bending capacity of the cracked beam Increase of bending capacity in group C is much higher than group B This increase of bending capacity is a function of length of CFRP reinforcement Significant increase of bending capacity is followed by small increase of bending stiffness Increase of bending stiffness is about the same for three different lengths and two different width of CFRP: 11% to 19%

PT. Fyfe Fibrwrap Indonesia Acknowledgement PT. Fyfe Fibrwrap Indonesia to provide CFRP and share the data properties used in this study

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