Providing critical data for restorations of historical landmarks and venues can often be challenging for 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.
Selected as the official consulting firm for this project, Mollenhauer Group has been involved in a wide variety of projects producing 3D models and conventional drawings for architects, property developers, building owners, urban planners, structural engineers and cultural heritage managers. Mollenhauer’s specific expertise is in the areas of civil engineering, surveying and mapping, construction surveying, subdivision mapping, and high-definition laser scanning. Since 2003 Mollenhauer has been providing their customers with laser scanning, 3D CAD modeling and BIM – ready Revit models of existing buildings, making them the premiere choice for the John Anson Ford Theatre project.
Problem
The Mollenhauers 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 phase-shift 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 theatres busy schedule. As a phase-shift laser scanner, the Focus3D can scan up to 976,000 points/sec with extreme detail and in full color. The laser scanners comprehensive data collection eliminated the need for return trips to the theatre for additional measurements. 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 software Cloudworx was then used to view and slice through the data in AutoCAD. 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.