Repair of Crane Girder using CFRP
Department of Civil and Environmental Engineering

Introduction and backgroundIn recent years, crane girders using rivets
has reached their fatigue life in manyfactories. To repair these crane girders anew method was necessary.
This leaded to a new Reinforcement andrepairment method of a crane girder using
Friction-type
Sandwiching
device(Pitagrip) and a CFRP plate

Steel Structures Laboratory
Academic Advisor: Professor Takeshi Miyashita
Jacome Pecero Fernando
The tensile test parameters are:
1. Thickness of the CFRP
2. Presence of Seam in the CFRP3. Presence of Rough Surface
After carrying out 12 tests, a fourth parameter
was included

figure 2: tensile test experiments
specimens drawing
figure 1: Reinforcement andrepairment of a crane girder using
Friction-type Sandwiching device

4. Introduced axial force
This to confirm the relation between
introduced axial and the break mode of theCFRP

Objectives and research flow

The bending test parameters are:
1. Thickness of the CFRP
2. Distance Between each Pitagrip
A third parameter was added after two
experiments to confirm if the stress
distribution on the CFRP could be improved
3. Additional Reinforcement on theCFRP.

The friction-type joint device is mainly used totighten steel, so the main objective of thisresearch is to gather data about thereinforcement effect of the friction-type
sandwiching device on a riveted crane girder
By carrying out both Tensile and Bending
experiments we can collect data about this new
reinforcement method.
Trough shear test experiments the sliding
resistance of CFRP can be obtained.
Also, confirm the load that can be borne by themembers sandwiched between the pita gripsand finally decide the number of Pitagrip
needed for reinforcement
In other hand, through bending tests the stress
distribution in the cross section and theeffective cross section of the reinforced
section can be confirmed. Furthermore, verify
the validity of the required pitch for thefriction joint sandwiching device.

Experiment results and Conclusion

(a)

(b)

Figure 3 (a) 8mm thickness specimen
vs 6mm thickness specimen (b)Specimens with presence of seam

Regarding of Tensile test experiments, we
can conclude:
the thicker the CFRP plate is, the proof
stress increased. But specimens lost theirresistance with the presence of seam.
100% maximum axial force improved thestrength but destroyed CFRP as shown
below.

(c)Figure 6: (a) 6mm thickness specimen stress
distribution (b) 8 mm Specimens stress distribution(c) Additional Reinforcement specimens stress
distribution

Figure 4: damage on the CFRP with
100% introduced axial force

After carrying out 12 tensile experiments,
15 experiments were added to confirm thefourth parameter included after.
Reducing the axial force introduced on thePitagrip, the CFRP was not destroyed but
the CFRP only slipped from the pita grip
without damaging its surface.

Figure 5: damage on the CFRP with
64% introduced axial force

(a)

(b)

Figure 7: (a) 300mm pitch specimen stress
distribution (b) 900mm pitch Specimens stress
distribution

Regarding to bending tests, the strain is not
uniformly generated in the cross section.
The reinforcement effect is onlyperceptible near the Pitagrip.
the reinforcement effect is reduced as thepitch becomes bigger, the objective of
avoiding a loss in the reinforcing effectcould not be achieved after increasing thedistance between each device.

REFERENCES
M.Contreras Daniel REINFORCEMENTOF STEEL STRUCTURE JOINTSUNDER COMPRESSION FORCES BY
USING CARBON FIBER POLYMERS(CFRP), 2019

(a)

(b)

T. Taguchi, T. Kamiya, Y. HAGA,EXPERIMENTAL
STUDYONFRICTION-TYPE
JOINT
FOR
SANDWICHING STEEL PLATE, Steelconstruction Engineering, Vol.23 No. 90,(in Japanese) 2016