Refraction of Sunlight on a Construction Crane Creates Potential for Air DisasterOn January 29, 2012, I visited the Mulholland Drive Bridge replacement project and got a close-up look at progress there. Starting in Hollywood on a clear afternoon, I drove Mulholland Drive until its intersection with Interstate I-405. There I traveled west across the remaining north side of the Mulholland Drive Bridge. After parking my car and surveying the scene, I soon found a perch that overlooked the freeway and construction project.
With the natural light on my back, the late afternoon sunshine provided good visual contrast at the ongoing project. Along with the remaining half-bridge, new support structures and construction cranes fought for dominance of the scene. The cranes had the upper hand, with their great, latticed booms dominating the vertical scene. Less than half as tall as were the twin derricks, massive new freestanding bridge-supports imparted strength and security to the scene.
Each of the massive crawler cranes had a cab painted in the signature gold color of Liebherr Cranes, a German manufacturer. That company, through its U.S. affiliate offers a wide range of mobile and fixed construction cranes. Each of the Sepulveda Pass cranes crane had a single latticed boom, which could be up to 89-meters (226 ft.) in length. With its boom painted black and sporting a white tip, the westside crane created a high visual contrast against a clear Los Angeles sky. At that time, the eastside crane stood in full sun. After lifting a load with the crane, an operator came out of the golden cab and stood upon the huge crawler treads.
On the eastside crane, I could see the bridge contractor’s logo, with the name Kiewit painted boldly on the side of the long cab. Since the Mulholland Drive Bridge project required demolishing and rebuilding the bridge one-half at a time, these cranes shall see service at this site for years to come. Rather than simply leasing them for this job, it appeared that the contractor had purchased both of these cranes.
For some reason, I kept looking back to the golden crane on the east side of the freeway. Since so much of sunlight falls into the yellow and gold portions of the visual spectrum, the entire crane appeared to glow in the lengthening light. To me, the huge crawler crane appeared as a beautiful piece of kinetic sculpture. If I starred at it long enough, the golden crane virtually disappear into the scattered light of the sky. A shake of my head brought the skyward-reaching boom back into focus.
Before I departed the west side of the bridge, I stopped to take a picture of the lane closure created by the partial demolition of the bridge. When I turned the camera from horizontal to vertical, I realized that an old friend was standing guard there both day and night. It was Coney the Traffic Cone, of course. Too shy to speak, Coney had stood there for months hoping that someone would notice him as he warned motorists that half the bridge was missing.
When it was time to leave, I drove east across the bridge and then headed for the northbound onramp of the I-405. That ramp has a straight downhill run and enters the freeway just south of the summit and the bridge replacement project. As I descended the ramp and then drove under the bridge, I fired my camera shutter repeatedly. After entering the freeway, I stopped shooting as I passed close to the eastside golden crane.
Later, I uploaded my photos and began writing this article. As usual, I selected the pictures first and then wrote the text to match. It was then that I discovered the incredible disappearing crane. As you view the accompanying animated GIF image, you will see four frames in which the golden crane fades into the northern sky. Whether the golden crane poked through the veil and into another dimension, I cannot say. Perhaps it was simple refraction and diffusion of sunlight through the golden lattice boom of the crane.
Once I got over the metaphysical possibilities inherent in the scene, I realized that no matter the cause, the beautiful golden crane was a hazard to aircraft flying near the Sepulveda Pass. Although there are minimum elevation restrictions for commercial and private aircraft in Sepulveda pass, Kiewit’s Golden Crane still represents a danger to public safety.
Police chases on the freeways of Los Angeles are a regular occurrence. The first line of defense is the police cruiser or perhaps a CHP cruiser. Following in the air, is usually an LAPD helicopter. Above that, typically there are several TV news helicopters. With the golden crane disappearing into the haze of the northern sky, a Sepulveda Pass police chase could easily become an air disaster. If the angle of the sun is right, the pilot of a fast moving helicopter might not see the crane until it is too late.
As beautiful as the golden crane may be, it should be lowered and its boom repainted in high contrast black, with a white tip, just like the crane on the west side. Until then I will not sleep easily knowing that there is a huge construction crane materializing and then dematerializing next to the busiest freeway in Los Angles.
Email James McGillis