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: http://www.aspiremagazinebyengineers.com/i/297018
S TAT E S TAT E I n O c t o b e r 2 0 1 1 , a s t h e O k l a h o m a Department of Transportation (ODOT) was observing its 100th anniversar y, it received a n u n p r e c e d e n t e d b i r t h d a y p r e s e n t : G o v. Mar y Fallin announced an aggressive plan to address all currently known, structurally deficient bridges on the state-highway system. The $550-million plan would essentially fully fund the existing 2012-2019 Eight- Year Construction Work Plan, which ODOT has found to be an effective tool in working efficiently to replace and maintain bridges. T h e a n n o u n c e m e n t w a s " a p l e a s a n t s u r p r i s e ," s a y s B o b R u s c h , s t a t e b r i d g e engineer. "The Work Plan has proven to be a reliable and effective way to achieve key objectives," he says. More attention has been p a i d t o a d d r e s s i n g O k l a h o m a 's g r o w i n g inventor y of deteriorating bridges in recent years, but much more has been needed, adds David Streb, director of engineering. Now, the program will receive that additional funding. The two-phase initiative will address all of the state's current 706 structurally deficient highway bridges by the end of the decade, Streb explains. The first phase replaces or rehabilitates 539 structurally deficient bridges, including 126 added to the existing Work Plan. Phase Two, which requires legislative approval, increases funding to replace or rehabilitate the remaining 167 structurally deficient, highway-system bridges that weren't included in the Work Plan. The construction i s e x p e c t e d t o c o n s i s t o f a b o u t h a l f replacement projects and half rehabilitation, says Rusch. Eight-Year Blueprint The Work Plan is created each year by ODOT and approved by the Oklahoma Transportation Commission. Updated annually with plans for the 8th year, it outlines design and construction work based on current funding levels. "Over the years, it has allowed the department to stay on top of its goals and create credibility for the department with the public and the legislature," says Streb. The current 8-year plan includes the largest number of bridges ever targeted for work and already represents a renewed focus on highway improvements, he notes. Current law gradually increases transportation funding each year until a $435-million cap is reached in 2017. The new plan will add $15 million annually to the increase and raise the cap to $550 million, without raising state taxes. The plan also includes county bridges b y i n c r e a s i n g f u n d i n g f o r t h e C o u n t y Improvements for Roads & Bridges initiative from $80 million to $105 million annually. It also allows recycling of highway bridge beams, which will be done with beams from the 8800-ft-long I-40 Crosstown Expressway Bridge in Oklahoma City. Its beams will be shipped to counties for local bridges. This work will be complemented by ODOT's recent release of the first half of new LRFD county-bridge standards, which consist primarily of precast, prestressed concrete beams. The program's design work will be provided by outside contractors, a rarity in the state, as shorter-span and rural bridges often are designed in-house, says Rusch. Most of the replacement bridges will feature concrete, which has been the material of choice for most state bridges for decades. 2002 Turning Point Oklahoma officials have understood the need for more attention to substandard bridges since the pivotal moment during the Memorial Day weekend in 2002 when two barges collided with a pier on the Webbers Falls Bridge in Muskogee County, Streb explains. The accident caused a 580-ft section of the I-40 steel bridge to collapse, killing 14 people. T h e b r i d g e wa s i m m e d i a t e l y r e p a i r e d , replacing three steel approach spans with precast, prestressed concrete I-beams to spread out material fabrication and speed construction. The three concrete approach spans ultimately were erected faster than the remaining steel span, making an impression for concrete's capabilities. The bridge was restored to service in only 65 days. A l s o l e a v i n g a n i m p r e s s i o n w a s t h e deteriorated state of many of the highway bridges onto which vehicles had to be rerouted during construction, says Streb. "That led us to focus on inventorying and improving the number of deficient bridges in the state." They discovered that Oklahoma had the third highest number of structurally deficient bridges in the nation, with the majority built during the interstate construction boom in the 1950s and 1960s. The decline arose from flat funding from 1985 to 2005, providing no opportunity to impact the growing list, explains Rusch. "An attempt to raise the gasoline tax to fund an expanded program was resoundingly defeated, but the legislature saw that defeat as a mandate to generate funds from existing sources." The result was a commitment of an additional $100 million in 2007 to address the state's 137 load-posted bridges. The current program will eliminate those restrictions, although 32 Oklahoma's Bridge Blitz by Craig A. Shutt Governor's aggressive $550-million, 8-year plan to wipe out deﬁcient bridges in Sooner State raises the bar nationwide The Western Avenue Bridge over I-40 in Oklahoma City represents ODOT's first use of precast concrete U-beams and of self-consolidating concrete. SCC ensured smooth flowability through the complex reinforcement and delivered an aesthetically pleasing appearance. Book_Win12.indb 40 12/29/11 11:12 AM