ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

Issue link:

Contents of this Issue


Page 15 of 59

After 29 years in the making, the first phase of the Newberg-Dundee Bypass is almost complete. Currently, Oregon Route 99 West serves as both the main street for the cities of Newberg and Dundee, Ore., as well as a major transportation route between the Portland, Ore., metropolis and the Pacific Coast. Long backups and delays are common. This bypass facility, when complete, will be an 11-mile-long, four- lane, limited-access expressway on a fully new alignment south of both Newberg and Dundee. The first phase consists of 4 miles of 2-lane roadway and includes the grade-separated Wynooski Road Bridge over Highway 99, a significant arterial into the south end of Newberg. T h e c ro s s i n g l o c a t i o n i s p i n c h e d between a major industrial facility to the south and the 60-ft-deep Hess Creek drainage to the north. The existing Wynooski Road alignment also ran along the proposed bypass alignment for almost 300 yd. The resulting design moved the Wynooski Road Bridge to the top of the drainage slope, with a 603-ft-radius horizontal curve where the road goes over the bypass roadway. The bypass is in a cut section as it drops down to cross Hess Creek; therefore, a minor vertical curve was needed on the Wynooski Road Bridge to provide adequate vertical clearance underneath. The entering and exiting grades are 3.8% and -5.0%, respectively, and the resulting finish grade at the abutment is a minimum of 8 ft above the existing ground. Post-tensioned concrete box girders and steel plate girders were considered for the Wynooski Road Bridge. The concrete structure was selected for multiple reasons: • T h e c a s t - i n - p l a c e ( C I P ) superstructure could be formed t o f o l l o w t h e v e r t i c a l l y a n d horizontally curved alignment, including the 4% superelevation. • Prestressed concrete has a long and successful history in Oregon, exhibiting exceptional durability w i t h m i n i m a l m a i n t e n a n c e required. • Concrete is also consistent with the other structures on the bypass, which all use precast, prestressed concrete girders. The bridge needed to cross over both the current phase of the bypass plus the future 4-lane build-out. Plus, the approaches to the crossing could not be supported on tall, wall-supported fills due to settlement and slope-stability concerns. Therefore, one end of the bridge was lengthened until it nearly met the existing ground at the west end. The resulting structure is 685 ft long and consists of four spans with lengths of 120, 210, 210, and 145 ft. The continuous box profile WYNOOSKI ROAD BRIDGE OVER THE HIGHWAY 99 WEST BYPASS / NEWBERG, OREGON BRIDGE DESIGN ENGINEER: OBEC Consulting Engineers, Eugene, Ore. PRIME CONTRACTOR: Wildish Construction Co., Eugene, Ore. POST-TENSIONING CONTRACTOR: Schwager Davis Inc., San Jose, Calif. by Eric E. Bonn, OBEC Consulting Engineers Wynooski Road Bridge over the Highway 99 West Bypass Aerial view of bridge formwork showing horizontal curve of structure. Photo: Oregon Department of Transportation. The completed bridge with aesthetic treatment on the exterior face of the barrier rail. Photo: OBEC Consulting Engineers. 14 | ASPIRE Winter 2018 P R O J E C T

Articles in this issue

Archives of this issue