91视频

POWER LIST: ENGINEERING

DOWL was charged with replacing six of those latter ones that connect the solid-ground portion of downtown Astoria to over-water piers. They support 鈥� quite literally 鈥� popular destinations such as Buoy Beer Co. and the Bowline Hotel.

The bridges are on Sixth through 11th streets, and support vehicle, trolley and pedestrian traffic.

鈥淚t was about 2009 that these structures kind of got on people鈥檚 radar and people started to notice that they were in really bad condition and were failing,鈥� said Jason Kelly, a DOWL senior project manager who leads the Lake Oswego office.

That year, the bridges were added to the National Bridge Inventory, making a replacement project eligible for federal funding.

DOWL surveyed the site with state-of-the-art laser technology, shooting millions of points to precisely model the existing bridges. No two bridges were alike, so different designs and fabrications were required for each.

Concrete pile caps were precast to accelerate construction. Concrete beams provide the superstructure. The steel rails and decks were cast in place.

The site is one of the oldest developed areas in the western United States, and DOWL engineers dealt with at least three generations of railroad trestles.

Construction was complicated by the need to maintain access to local businesses during the busy summer tourism months. The project also faced regulatory complications related to the presence of marine mammals such as harbor seals and stellar sea lions, as well as migrating salmon.

鈥淭his was definitely one of the most challenging (bridge projects) I鈥檝e been a part of my entire career,鈥� Kelly said. 鈥淯ltimately, it got done on time and on budget, and the quality was good.鈥�