A question for the structural engineers

[RooFlyer]

When visiting Seattle airport, and using the Light Rail there, I was puzzled by the Light Rail station's roof:



The station and tracks are elevated, with a flat roof, which appears to have plenty of columnar supports and of itself not greatly load bearing (except some wind).

Yet it has the large steel superstructure overhead, apparently supporting the roof load. I especially don't understand the bits at either end, that can't help support any load, nor distribute it (and would increase the wind load!)

Any engineers able to explain why the flat roof may need such elaborate support when concrete columns are not in short supply, and why the end-beams should 'cantilever' into open space?

 

[opusman]

This article suggests it's just decorative, and one that was pared-back somewhat from the original design:

Constructor Magazine - A publication of the AGC

One of the biggest money-saving efforts was the redesign of the passenger station roof. It originally was designed by Seattle-based Hewitt to be a dramatic structure enveloped in glass, but a number of its structural and design elements were altered. Team members suggested eliminating the glazing, replacing welded structural-steel tubes with less expensive bolted I-beams, replacing tiling material with a polished concrete slab at the mezzanine level and reconfiguring the windscreen. “This was going to be a signature project for light rail,” says Mike Bell, Mowat’s construction manager. “It was neutralized a little.”