Surveying, Detailing and laying out.

I discovered laser scanning and surveying using high end Trimble equipment because steel fabricators rarely get the information they specifically require from the project team to successfully build to existing structures.

A Typical Small Commercial Project in Australia.

I was offered a project to produce workshop drawings for an extension to a food store but there was a catch. We had to build to the existing internal steel work but there were no as-built drawings. The architectural drawings for the existing building had no dimensions apart from the grid, in fact most of the detail drawings were missing their dimensions. The builder could not remove the cladding so we could access the steel before erection day as the rain would get in and the store would not close or remove its false ceiling due to loss of trade. There was access to the roof space so we could see the gable end truss but we would still be over 10m away from the parts we had to measure. Plus we needed to connect to every purlin. This was a challenge.

Food store Plant room - shot from a Trimble TX5 scanner

Food store Plant room - shot from a Trimble TX5 scanner

Laser scanning immediately jumped to mind because there was so much information to capture. I contacted Surepoint a company that I knew did this sort of survey work and got them to agree to train me and start me on the road to enlightenment. Paul Seifert, who is now employed by Building Point in Brisbane trained me. Paul Seifert is a scanning guru. He has supported me all the way with patience, even when my questions were repetitive and somewhat basic.

Moving on.

I soon realised the possibilities. The first project I undertook went without any problems even though I was still learning to use the data in a way that Tekla Structures could cope with. At that time there was no good application to convert a large point cloud to a usable Tekla format. On the back of the first project I got a second and again asked Surepoint (now Building Point) for help and more training. The second job went smoother that the first and this set me on the road.

Since then I have been contracted to survey and detail 5 of these stores now and each one has been a challenge as each one has its own problems to get around. A new problem raised its head. Can we set out the new steel work to the existing with limited access easily and efficiently? I again went back to Paul Seifert at Building point to get training on the Trimble RTS773 Robotic Total Station. I knew this could do the job as I had, a long time ago, seen a demo by David Grant who is now the Regional Manager for Trimble in SE Asia, Australia and New Zealand. At the time I was blown away by the simplicity of its operation and the smart way in which it took and displayed points in the field. Paul Seifert agreed to give me more training and I was amazed at how fast I learned to operate the RTS in the field. We trained on a live project and I have been hiring them ever since for every survey and for most set outs.


Today I have been on site at the trickiest set out I have done so far. This time I had to work from grid lines that another surveyor had put down. These had also been there a while so I imagine they had been knocked about or had settled over time. I shot the Grid lines and a datum and entered the coordinates into Tekla structures using the Trimble Layout Manager. Straight away I noticed that you need to find the best fit for your points as you are never going to be bang on. Once I entered this data back into Trimble Field link I checked the existing cast in base bolts. They were within 6mm so I don't think that's too bad but it does show how accurate the equipment is and how the inaccuracies in the as built situation build up. Scanning in fact makes it even easier to see walls out of plumb and sagging steel work. Knowing these things is arming yourself when problems arise and preferably before.

So with lots of help from Building Points Paul Seifert and Aiden Battenally I have set myself up to solve these problems. Now to sell this service to people that don't even know it exists or believe its even possible.


Ian BrightmanComment