Alexandra Hills Hotel

I was contracted by CASA Engineering to produce a laser scan survey of existing steel work at the Alexandra Hills Hotel which is near my home on the Brisbane bay side. The main challenge to the steel draftys was that the new steel had to be suspended under an existing steel frame that was in the shape of a pyramid. This would be tricky to measure with a tape and line and hard with an RTS so scanning was the preferred option. Other areas were also required so a day out scanning was cost effective when compared to the amount of data we would capture.

Alexandra Hills Hotel

All full day of scanning was underway and 47 scans later I was done. The BIMTek product CASA Engineering had ordered was a geo-referenced scan survey with samples inserted into the Tekla Structures steel detailing software. This involves a lot of scan cleaning to reduce the amount of points as far as possible. Tekla Structures has no direct point cloud support so BIMTek has a work around that allows us to insert multiple scan samples of up to 2 million points each. It works very well but takes some preparation. Below are shots of the scan areas before and after clean up.

These areas are then further split up and exported to be inserted into Tekla Structures. Breaking the scan samples down helps in Tekla because you can switch off the reference objects you don't want. This speeds up a system that struggles a bit with large point cloud reference objects.

The final cleaned up frame screenshots below show how the existing steel can be exposed to give a very accurate as-built model. Its hard to argue with and you can spot a clash or design problem very early on on the project and react to it. Fitting new steel to existing steel in the laser scan is very easy and accurate and the level of detail you get reduces errors and site time making alterations.

Ian BrightmanComment