City National Plaza
City National Plaza is a twin tower high-rise complex located in downtown Los Angeles, California, which includes the City National Tower and Paul Hastings Tower. Originally built 1971 as the world headquarters for the Atlantic Richfield Company, they were then called ARCO Center.
The exterior of the twin 51 story towers were originally maintained using Manning & Lewis Wallglider roof car and platform systems. Considering the 35 year old technology, lack of availability of replacement components and the constant maintenance requirements, building management hired Sky Rider to replace the existing machines with modern, easy to maintain Building Maintenance Units (BMU’s).
The new BMU’s consist of winding drums with 700 feet of travel, aluminum 35 foot long platforms, and auxiliary winches for replacement of glass panels. The BMU’s were shipped to the site in component parts where they were taken from the loading dock to the 52nd floor (the main mechanical level) using the freight elevator. From the 52nd floor, they were hoisted 40’ through a small hatch to the rooftop using a gantry crane. This same gantry crane was later used assemble the BMU and again to assemble Sky Rider’s crane to remove the old Manning & Lewis machine.