Proceq PROFOSCOPE - Cover Measurement on Areas with insufficient Spacing of the Rebars

© 2015 Proceq SA 19
5.3.2 Cover Measurement on Areas with insufficient Spacing of the Rebars
An insufficient spacing is smaller than the minimum spacing defined in 3.4.4.
Special case of Rebars without spacing
In overlapping areas the rebars are normally tied together: e. g. this is the case in a cut and cover
tunnel section on the lower part of the side walls, where rebars from the bottom slab are tied to-
gether with the vertical rebars of the wall.
D
s
~ 1.4 D
r
C
D
s
D
s
= Set Diameter
Real Diameter D
r
Fig 24: Measured diameter D
s
at overlapping areas
In such areas you will measure a larger diameter and a smaller cover than it is actually the case.
However, the accuracy of the cover measurement can drastically be increased by setting the meas-
ured diameter in the Profoscope prior to the measurements. In case the diameter can not be meas-
ured the rebars should be exposed in one area. The diameter to be set is in general 1.4 times the
real diameter of a single bar.
Covers 12 18 26 34 40
Real Diameter D
r
16 25 40 40 40
Set Diameter D
s
19 1 0 0 0 1
Accuracy in mm
when measured with the
diameter D
s
set
38 2 0 0 2 3
58 3 0 1 4 4
88 4 0 0 8 10
98 4 0 0 9 12
108 0 0 10 14
128 0 -1 12 17
158 -3 12 21
163 12 22
168 13 23
178 24
Tab. 1 Accuracy of cover measurements at overlapping rebars