Retrofitting new openings in existing tilt-up wall

[BLayden]

We have a small project that involves retrofitting an existing tilt-up concrete wall building. The work includes cutting a few new door openings in the exterior precast walls. The kicker is that we have no drawings/design documents of the existing structure to reference for analysis purposes. Anyone have some tips on how to estimate the required reinforcing/steel channel frame installation?? I would prefer not to have to do a full-blown gravity/lateral force analysis of the entire building. Thanks for any suggestions.

 

[CAOranger]

To estimate rebars, have the owner hire a testing agency to figure out rebars and spacing. Concrete strength can be estimated or found out by another test (taking core samples form non-critical area).

Without these data to substantiate your calculations, you will be taking a huge risk. If you feel there is need for a lateral analysis, do not hesitate to tell the owner right now.