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<strong>Tilt</strong>-up <strong>Technical</strong> <strong>Manual</strong><br />
www.MeadowBurke.com<br />
Strongbacks<br />
PANELS WITH NARROW LEGS<br />
1. Panels with tall narrow concrete legs may require strong backs for<br />
added strength. As a guideline, any leg less than 2’ in width, whose<br />
width to height ratio is less than 0.12, will normally require a strong<br />
back over its entire height.<br />
2. or panel legs 7” or more thick, it may be possible to eliminate the<br />
need for added strongbacks by the addition of added reinforcing<br />
steel, and ties in a column pattern. In order for this method to work,<br />
the reinforcing steel must be detailed with minimum concrete cover.<br />
PANELS WITH NON-REINFORCEABLE SECTIONS<br />
1. A non-reinforceable section is one in which reinforcing steel cannot be added to adequately resist the bending stresses related during the lifting<br />
process. This may result from many different conditions. The following are a few typical cases.<br />
a. If the existing structural reinforcing steel is placed too deep in the panel to be used to resist the erection stresses and the structural engineer will<br />
not move the steel closer to the surface, there may not be sufficient room to add additional erection reinforcing at the required clearances.<br />
b. Deep reveals do not allow placement of the reinforcing steel close enough to the smooth surface of the panel between the reveals to prevent<br />
visible cracking. While it may be possible to place the reinforcing steel close enough to the reveals to prevent deep cracking within them, the depth<br />
of the reinforcing steel in the smooth areas between reveals will result in cracks that go deep enough into the panel surface to still be visible after<br />
the panel is erected.<br />
c. Sections of some panels can be subjected to such high bending stresses that it is impossible to fit enough reinforcing steel in the sections to pre<br />
vent visible cracks from occurring.<br />
2. If the insert spacings cannot be adjusted to reduce the concrete bending stresses and eliminate the need for the reinforcing steel the only option<br />
may be to use external strong backs to resist the erection stresses.<br />
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