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Providing critical data for restorations of historical landmarks and venues can often be challenging to even the most experienced surveyors. The John Ford Amphitheatre, which was built in 1931, proved to be no exception. Utilizing the FARO Focus3D Laser Scanner became a significant benefit for the Mollenhauer Group as they proceeded to carry out a detailed survey of the complete site.
With 1,200 outdoor and 87 indoor seats, the John Anson Ford amphitheatre was in desperate need of upgrades to its wooden and concrete structure. The Ford Theatre is one of the oldest performing arts venues in Los Angeles that is still in use. Completed in 1931, the theatre was designed in the Judaic style to resemble Jerusalem and constructed of poured concrete. The theatre is now undergoing a complete restoration and redevelopment program carried out by Levin and Associates Architects for the County of Los Angeles.
Problem
The Mollenhauer’s Group 3D team was contracted to provide accurate 2D plans and a 3D CAD model of the John Anson Ford Theatre site analysis and restoration to the foundation. In order to provide these deliverables, exact as-built documentation was needed not only of the structures themselves, but of the surrounding areas. Original 2D drawings or plans of the venue did not exist. Using conventional survey methods with tape measures, laser levels and laser range finders would have prolonged the data gathering. Moreover, since the theatre is still an active center for the performing arts, using the laser scanner meant little impact with ongoing production dates and performances. The laser scanner is the preferred solution wherever there are issues of complexity, speed, safety or reduced access and visibility.
Solution
Mollenhauer decided to use the phaseshift Focus3D Laser Scanner to document the entire theatre with extreme detail. All scans were tied together using overlapping spherical targets and total station control, relating the data to a common survey control framework. The entire site was measured and controlled in less than a week by a single Mollenhauer Group surveyor, who had to work around the theatre’s busy schedule.. Due to its portable weight and size, the Focus3D can be managed by a single person without the need for additonal equipment or personnel.
The data was processed in the FARO SCENE software to create a registered point cloud of the basement up to the amphitheatre and tower levels. The scan data was combined with conventional survey data to create an accurate 3D CAD model of the theatre. The model is being used by both the project architect and the structural engineers to plan the redevelopment of the site. Of critical importance is the thickness of the poured concrete across areas of the amphitheatre. The registered point cloud and 3D model will enable the engineers to view sections through the structure and analyze the relationship of the exterior to the levels below.
Return on Investment
Laser scanning enabled the structure and surrounding site to be recorded in detail with relative ease and speed. The use of laser scanning also allowed minute surface details such as undulations in the concrete floors to be recorded, which was of great importance to plan drainage improvements.
"We were early adopters of laser scanning and use this technology on most of our measured building survey of existing complicated structures. The FARO Focus3D enabled us to record and cooridnate all interior and exterior spaces rapidly and accurately reducing time on site, says Jenny Clark, the Director of 3D Surveying at Mollenhauer Group. "Another main advantage was the ability to publish the scan data on FARO Webshare (at no additional cost) to enable the client to view and share the data".
Jerry Hardy is Product Marketing Manager for the FARO Technologies Focus3D. He has a degree in Marketing from the University of Massachusetts and has more than 15 years of experience.
A 158Kb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE