March 3, 2021

Laser Scanning Assists with Structural Investigation

By Dan Martel, P.E.

Recently we’ve used laser-scanning technology for many applications, including the investigation of this church.

The church called us to investigate their steeple, suspecting it was leaning. We tapped Process 3-D Scanning and Surveying, who set up their laser scan in about a dozen locations around the building. (The scan is so high resolution that it sees color, what you see is millions of laser points, not a picture!) The scan told us that the steeple was leaning at the top about 4 inches relative to the rest of the building. The rest of the building was also slightly off-level, and without the laser scan we would have only been able to understand how much the steeple was leaning relative to level ground.

Armed with this information, we climbed in the attic and quickly identified structural deficiencies in the heavy timber framing. It was sagging in the roof trusses below it (probably overloaded by the steeple) causing the steeple to lean. The laser scanning data told us where and how the steeple was leaning, allowing us to identify the problem much faster.