The Sands Expo Convention Center Lobby Renovation project consists of a +/- 25,000 square foot indoor area that would be retrofitted with a new custom “Ribbon” ceiling system. The steel ribbons were to be varying in size and height, but would be approximately 20’ above the ground and would hang from the ceiling girders by using all thread and unistrut. An asbuilt of the walls and ceiling girders was needed in order to design support system that would be incorporated into the ribbon design. A “conventional” survey presented many problems. First, was the time frame. There was a very limited amount of time allowed to collect the data. The convention center would still remain active and all trades would be in the same area during the allotted work schedule. Second was Access. A scissor lift would be needed to access the 20’ height area of the walls and the 35’ height of the beams. A conventional survey simply would have taken too long to complete and would be too expensive. It was decided that a 3D scan would be the most accurate, cost efficient and complete method to acquire the necessary data.
Utilizing 3D laser scanning technology, we were able to create a highly accurate 3d model of the Lobby floor, walls, columns and the steel girder ceiling all from ground level set ups. Strategically placed scans and targeting were used to generate the kind of accuracies that our client was looking to achieve. The scan was completed in one working shift by one person and no scissor lifts were needed. The data was then brought into the office, downloaded and processed. This information was then coupled with high accuracy survey control to relate it to coordinate system being used for the design. The raw 3d scan files and AutoCAD drawings were provided to the client for their design. Once the design was complete, the same control was then used to layout the “pick” points on the floor and brought up vertically to the ceiling to allow for the installation of 48 ceiling ribbons (750 points total). This ensured that ribbon panel locations were placed precisely where they were designed.
Survey Control: The Sands Expo Convention Center is one of the largest convention centers in the world. The lobby would have to remain active and work schedules would have to be flexible to accommodate any conventions that were taking place. This also meant that the 25,000sf area would have to remain presentable and no evidence of survey control or scan control could remain up. Once the survey/scan control was established, discreet survey targeting would be placed in many locations around the lobby. This would allow the same control to be perpetuated for survey layout and for any future 3D scanning that may need to be acquired.
Existing conditions: The existing asbuilt conditions were found to be considerably different than what was thought to be constructed. The 3D scan asbuilt would have to be used solely for the purposes of design. During the analysis, it was determined that many of the steel ceiling girders were lower than anticipated. Since this was caught early on, the design was able to be adjusted to fit rather than having the conflict discovered in the field. This approach saved money as well as time for the schedule of the project.