Added value:
The Toronto Union Station Trainshed is one of only two remaining Canadian examples of the innovative design patented by A Lincoln Bush, its roof shelters twelve train tracks and eleven passenger platforms, more than 35,000 square feet, from the elements.
In order to carry out the rehabilitation of the historic structure, accurate structural elevations of the trusses in the current state are essential. Halcrow Yolles uses these drawings to prepare contract documents, to coordinate work by mechanical and electrical consultants, and as important documentation to be included in the required Heritage Report. A project of this magnitude and importance ($CAN 50 Million) is an ideal candidate for the application of the latest in TLS technology. By creating a series of scans, Halcrow Yolles was able to rapidly produce a set of existing condition structural drawings that is highly accurate and cost less to create.
Innovation:
A laser scanning instrument captures 3D coordinates (xyz) of millions of points that are within its line of sight. By recording the position of the instrument with high precision measurements, the ‘point cloud’ elements can be inserted into any local coordinate system if that is required.
After each scan, a high resolution camera records imagery that is mapped directly to the point cloud so that each single point is given (RGB) colour data. With the use of highly reflective targets that are carefully placed on site to act as control points, separate scans can be merged into a single point cloud that minimizes the areas left in shadow.
Team work:
Collecting point clouds in the field is very quickly done. The precise position of every feature visible to the naked eye can be recorded. An additional benefit of TLS is that it can accurately record data at great distances so that the location of inaccessible features may be easily determined. It is also a simple matter to create fly through animations of the point cloud which are ideally suited for presentations to clients and stakeholders.
The great economic value of the data becomes apparent when the skilled engineers and Geomatics experts at Halcrow Yolles take the ‘cloud’ data and process it into actual CAD files in two or three dimensions, actual working drawings.
Producing CAD files from point cloud data requires a close coordination of the architects, engineers, and Geomatics experts involved in the project.
