r - The Hong Kong Polytechnic University

observed between the formwork and cast concrete (Figure 6(a)), while the member made with the U-shaped
formwork (SU) failed with the formation of a flexural crack in the middle. For the beam members BF1 and
BU1, made with flat plate and U-shaped formwork respectively, BF1 failed by delamination (Figure 6(c)) at a
loading much lower than that of BU1, which failed in flexure (Figure 6(d). For BU1, the failure load was
higher than that predicted from conventional reinforced concrete theory. When the amount of GFRP in the
formwork was further increased, as in BU2, delamination failure occurs despite the use of U-shaped formwork.
However, delamination also led to a significantly higher deformation at failure.
16
SU
14
SF
Load(kN)
12
10
8
6
4
2
0
0 10 20 30 40 50 60 70 80 90
Displacement(mm)
(a) Slabs SF & SU
120
BU1
100
BF1
BU2
80
Load(kN)
60
40
20
0
0 5 10 15 20 25 30 35 40 45
Displacement(mm)
(b) Beams BF1, BU1&BU2
Figure 5 Test Results for the Various Beams
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