Friday, November 20, 2009

Bubbling Walls

When a wall, by design, is built vertically plumb that’s great. When it’s out of plumb or warped, that could pose a problem, sometimes a costly one. Midwestern Consulting uses 3D laser scanning to help our clients determine the exact geometric shape of walls.

Engineers and architects on a project at Oakland Community College in Farmington Hills, Michigan were investigating two 40 foot by 120 foot exterior walls to a building constructed in the late 1960’s. All parties knew the walls had issues. Cracks were appearing on the exterior brick facade, as well as the interior side of the outside walls.

Varying schools of thought existed as to what was causing the cracks, one thought was that the walls were actually de-laminating and the exterior brick façade was falling away from the interior brick façade. What was known and agreed upon was the existence of a few ‘bubbles’ on the walls, but the severity of them was not known. The structural engineer and architect decided to turn to us to see if our 3D laser scanning could lead them to truly see and understand the wall’s entire geometry.

The 3D laser scanning data proved that the walls were, in fact, bubbling in several areas (see Area “B” and “C” as examples on the image below). The color images within these drawings were created directly from our scan, and color maps were applied appropriately to reveal the deviations of the wall from the plumb line. Spot elevations were set on the wall to compliment the color’s meaning.


To our client’s surprise, our scan revealed a “cavity,” or inverted bubble along the top edge of the walls that was not known previously (see Area “A” on the image). Based upon all these findings, our client was able to move forward on the project with confidence. Overall, the walls are considered to be in fairly good condition; nonetheless, some additional bracing is necessary to prevent any further movements. In the end, our client found our data to be very ‘rational and informative’ and found this to be an excellent use of 3D laser scanning.