Helix Pedestrian Bridge Oct, 2004 By David McMullen and Michael Blank In Feature This article is currently only available in PDF format, please click the link to the top right. About the author ⁄ David McMullenDavid McMullen is an Associate and Project Manager and is astructural engineer at KPFF Consulting Engineers in Seattle, WA. Prev Structural Engineering Claims Next Washed Out but not Washed Up