With the push to get things ready for the commonwealth games there has been a huge amount of work done to build the New indoor sports stadium at Carrara on the Gold Coast. The final part of this project has been to refurbish the existing old indoor sports stadium next door. BIMTek was contracted by Hyforce engineering to survey the building inside and out so we could detail the new steel members and girts that needed to be installed. The survey was to be done from the floor level only as no access equipment could be used on the delicate floor. Laser Scanning seemed the obvious solution.
I went to site and instantly found that this was not just the simple survey that was described to me over the phone. Access was good but the building was bigger than I thought. However I'm up for a challenge so I started scanning. 12 hours and 75 scans later I was done and went back to the office to get the scans registered.
Once I had everything registered I matched the scans to a grid in Tekla Structures and then as a quick check I overlaid the architects plan and an extract of the scan on to the Tekla grid. That's where the fun began! Immediately I saw that the layout on the architects drawing did not match the actual column layout. In fact a few columns were nearly a meter out of position. You can see in the 2 below images the difference in just two of the column positions between the actual and the architects.
I can only guess that the as-built drawings were used and nobody thought to have a quick check. Once we had let the client know that the as-built drawings were incorrect we agreed a way forward.
My first task was to produce a column layout from the laser scan data so that the Main Contractor could re design the new ventilation louvers that were required to fit inside our new support steel work. As I started to extract the steel from the scan and import it into Tekla I realized this was going to be hard work. Some of the columns were out of plumb by up to 40mm and some were twisted and out of plumb and these were not small columns. Yes columns are never straight, especially on old buildings but these were something else. I decided to model the worst columns in sections to suit the leans and twists. We had to fit new girts between the columns so could not risk not modelling the as built conditions. This approach worked well but was very time consuming. Once the modelling of the existing structure was complete and submitted we moved onto the new steel work modelling and detailing which was produced by Paul McLeod (Ex Pacific Computing and Building Point ) quickly. One problem was that due to the existing steel being all over the place every new girt or piece of steel was a different length and this meantlots of part and assembly numbers. This was fun for Ben in the Hyforce workshop who did a great job of sorting out all of the hundreds of parts and organizing the fabrication so it all got the the site at the correct times
Above shows the steel modeled in Tekla Structures. Orange and Purple colors show the existing steels. Everything else is new and had to be fitted in and around the existing Steel, Girts and Bridging.
Below are a couple of screen shots of the existing steel with the new 3D Tekla Model merged in Trimble Realworks. Realworks is excellent for registration and getting the extracts you need for Tekla Structures. Its also excellent for a visual clash check as you can merge your Tekla model with the laser scan.
In addition to the internal steel work there was a staircase and lean-to canopy to the North elevation and another canopy to the south (Shown Below). As demolition was going on constantly I had to make a few site visits to add additional scans as the frame under the cladding was revealed. Realworks makes it easy to add more scans at a later date as a project progresses even if you dont have a control network.
This ended up being a huge project for BIMTek. The time commitment ended up being much bigger than anticipated but we got a great outcome. All of the steel work, staircase and canopies are installed with no rework. I have to also mention the fantastic job that Shayne Connolly of Hyforce does on site. You don't meet many riggers like Shayne. Anything is possible and when it gets tough he just gets stuck in and sorts it out.
This project reinforces the fact that that there is no better way of capturing the as built site conditions than a good laser scan survey. You simply cant even get close.
The truth is that we can now Capture reality and use it.