December 30, 2020 A man-made wonder: The challenges of building the I-90 rail bridge in Washington State Written by Bill Wilson, Editor-in-Chief The I-90 rail bridge in Washington State presented some of the most complex problems in bridge construction history. Orchestrating a mosh pit cannot be easy. One needs to make sure all the participants providing stabilization are in perfect sync, and even if it is performed at a high level there is still worry that an untimed arm drop could create a disaster. Workers on the floating bridge in Washington State must have felt like they had to execute this mass coordination day after day. Even when you are dealing with obtrusive concrete pontoons, the delicacy required is equal to walking into a sea of upright hands.