AON Center, LA’s second tallest building at 61 stories and 858 feet in height, was originally constructed in 1973. The 37 year old window washing machine had been rebuilt or refurbished numerous times over the years. When the time finally came to replace the machine, Sky Rider was selected as the contractor to do the job. The Building Maintenance Unit (BMU) was manufactured by Gondolas in Design (GinD) located in Madrid, Spain. Working in concert with Sky Rider, GinD formulated a design that would work properly with the unusual facade features. While the photograph of the building exaggerates the condition, the curtain wall slopes inward at the top of the building while the corners remain vertical. This creates the need for a platform center section that moves forward (into the corner) as the platform descends at each of the four corners.
Because of the building height and the congestion of downtown Los Angeles, both a crane and a helicopter was ruled out as means to get the new BMU to the roof. Instead, the machine was designed to allow bringing it, in component parts, through the building using the freight elevator to the 61st floor.
Sky Rider installed its temporary crane on the roof to assemble the machine onto the existing track. The location for the crane was selected to enable us to lift the component parts from the 61st floor to the roof (up two floors) over the guard rail and onto the track.
As seen in the photos above, our crane played an important roll in getting the machine to the roof and in creating a safe, efficient assembly process. It is equally important in the roll of disassembling and removing the original machine as well.
With the roof car fully assembled, the wire ropes were lowered over the side of the building to the platform located at ground level. Once the wire ropes and electrical wiring was attached, the platform was raised to the roof where final commissioning could begin.