Annual Bridge Inventory
Suggests a Better 2006
Agencies need more money to continue their slow progress
 in lowering deficient bridge numbers.

by Ruth W. Stidger, Editor-in-Chief

Better Roads’ exclusive annual bridge inventory shows a small increase in optimistic bridge engineers who expect to be able to lower their rate of deficient bridges in 2006. Of this year’s respondents, 56% say they will be able to cut their numbers. Last year, 54% offered the same hope.

In reality, lowering of deficient bridges was pretty much of a tossup. The 2004 results showed a total deficiency rate of 25.4%. This year, the figure is 25.0%

Texas Department of Transportation’s Keith Ramsey is one of the optimists. “TxDOT revised local participation to allow 100% federal/state funding of a TxDOT programmed bridge when the local government agrees to perform structural improvement work on other deficient bridges with a dollar amount equal to their normal match,” Ramsey says. “TxDOT also has a goal that 80% or more of Texas bridges will be in good or better condition by 2011 [the figure is now only 21% deficient] and [to] eliminate all structurally deficient Interstate and state bridges by 2011.” Only 14% of Interstate and state bridges are deficient this year.

In Utah, Bridge Engineer Todd Jensen says they plan to lower deficient bridge rates next year by using preventive treatment on structures in good condition and replacing and rehabbing deficient bridges. The state’s deficient rate was 18% in 2004 and is the same this year.

Pennsylvania’s Lance Savant plans to use a similar approach. PennDOT’s deficient bridge rate was 38% both last year and in 2005.

In New Mexico, Jeff C. Vigil says the state has also prioritized and increased spending for preventive bridge maintenance. Keeping bridges from becoming deficient helps control the numbers to be rehabbed or replaced. Last year, 19% of the state’s bridges were deficient; this year the rate dropped to 18%.

Frank Liss says the West Virginia Department of Transportation will lower its rate of deficient bridges next year by building more local bridges to meet Federal Highway Administration criteria, thus increasing available federal funding. West Virginia’s deficiency rate stands at 37%, for both last year and this.

In Minnesota, Bridge Management Engineer Jim Pierce says the agency plans to lower deficient bridge rates using local bridge bonds. Statewide, the agency’s deficiency rate dropped to 13% this year from 14% last year.

Paying the piper

Every survey respondent labeled funding as their number-one problem in lowering the rate of deficient bridges, both this year and last.

Building low-ADT bridges to FHWA standards (whether this means overbuilding for needs or not) to obtain federal money, local bond issues, and building toll bridges are some of the solutions agencies say can help them pay the bill.

Another aspect of the funding problem is having enough in-house staff to review projects, says Bridge Engineer Alex Bardow at the Massachusetts Department of Transportation.

Texas suffers from the same problems says Bridge Inspection Engineer Keith Ramsey. “[We need an] adequate number of employees to prepare plans, specifications, and estimates.”

Damage sources

Corrosion is the top-rated cause of bridge damage (see page 33), followed by age, and the earlier use of building specs not meant for today’s heavy volume of traffic.

“Heavy and overweight trucks followed by salt damage and freeze-thaw cycles” take the most blame in Pennsylvania, according to Lance Savant, P.E.

In Kansas, a large portion of the bridge inventory was built in the 1950s and 1960s, says Bridge Management Engineer Dan Whisler. “These bridges are approaching the end of their design life and will need significant [work] to keep up. Overweight trucks add to the problem.”

The Four Bears Bridge in northwestern North Dakota was named after leaders, both named Four Bears, from two neighboring native American tribes.  The 4,500-foot span is a cantilever precast box-beam structure that replaces a 4,483-foot-long deck and through-truss bridge.  Photo by Mike Kopp, NDDOT	The James Cowan Memorial Bridge carries State Highway 36 over Lake Belton.  It is unique because of the extensive use of precast bent-cap elements during construction.  These elements let the contractor accelerate work by eliminating any on-site forming for the bent capts.  Photo courtesy of the Texas DOT.

The FHWA should create different standards for low-ADT bridges according to many of the engineers who report their rate of deficient bridges will not drop in 2006. Gary L. Doerr at the North Dakota State Highway Department sees this as one of their greatest challenges, as does West Virginia’s Liss.

Increased construction costs stand high on the list of things to face, says Engineering Technician Ray Mumphrey.

Environmental restrictions

If you love the bridges of Madison County or other historic structures, bridge engineers may not totally agree with you. Many find the accompanying environmental restrictions costly and time consuming.

“Historic bridges and bridges that do not allow Corps of Engineers nationwide permits are very time-consuming,” says TxDOT’s Keith Ramsey, P.E.

In Utah, Bridge Engineer Todd Jensen says that bridges that need greater capacity require significant environmental work, affecting how easily deficient bridge numbers can be lowered.

Lance Savant at PennDOT says, “[environmental] permit approval turnaround times are very lengthy and delay project delivery.”

In Wyoming, State Bridge Engineer Gregg Frederick says that environmental restrictions lengthen design times and increase project costs.

“Each new year seems to bring more [environmental] issues or restrictions to deal with,” says Dan Whisler.

In Oregon, Tony Snyder at ODOT sees endangered species regulation as a new and still-developing restriction affecting deficient bridge reduction in a negative way.

Erosion control measures are increasing bridge construction costs in South Dakota says Bridge Inventory/Inspection Engineer Tracy Painter.

In Delaware, the construction season is shortened by environmental restrictions centered on birds, fish, turtles, and so on, according to Bridge Management Engineer Doug Finney.

Environmental restrictions affect maintenance and replacement, too. Terry Leatherwood at the Tennessee Department of Transportation Bridge Inspection/Repair office cites environmental restrictions as adversely affecting steel bridge painting.

“In-stream restrictions limit the time to do the work,” says Chief Bridge Inspector Joseph Miller at the Maryland Department of Transportation.

What’s needed

Further To Go

Not all states made improvements. The states that saw an increase in deficient bridges unanimously claim funding as their number-one problem in making the numbers drop. Kentucky had the largest quality drop, going from 30 to 36% total deficient bridges. Only five other states showed an increase, each of 1%. Except for Kentucky and Connecticut, all of these states have numbers below the national deficiency average of 25%, which means they are still doing well.  Since figures were collected in September before Hurricane Katrina damage was fully assessed, Louisiana, Alabama, and Mississippi undoubtedly have a greater number of deficient bridges at publication time. Next year’s inventory will show whether these states are able to bring their numbers back into line quickly.

Most bridge engineers keep a stiff upper lip to deal with lack of funding and other mounting problems, but if they could have what they wanted to improve their bridges, it would mostly be money, money, and more money.

“We need increased funding for preventive maintenance,” says North Carolina Department of Transportation Bridge Maintenance Engineer John Emerson. “It’s easier to handle preventive maintenance than to react to problems.”

In Texas, Keith Ramsey says they need to increase emphasis on bridge maintenance. “Funds are limited to replacing bridges and the bridge inventory continues to age faster than funds are increased for rehab and replacement.”

Lance Savant, P.E. at PennDOT wishes there could be a way to improve project delivery time as well as funding.

Further funding prioritization is needed says New Mexico State Highway Department’s Jeff Vigil, P.E., with increased amounts spent on preventive maintenance and rehabilitation.

Better and increased preventive maintenance would slow deterioration says Nevada Bridge Design Engineer Marc Grunert.

Bonding programs increased Kansas bridge funding through 2009. Kansas DOT’s Dan Whisler says new funding sources are needed to prevent loss of the gains they’ve made with the funds from the bonds.

Best practices can help stretch funds, says Oregon DOT’s Tony Snyder. Pontis Modeling is one tool their department uses to analyze and optimize money use.

More preventive maintenance and use of non-corrodible bridge materials could help, says West Virginia’s Liss.

The Virginia Department of Transportation uses a bridge management system to prioritize and control spending and programs and this helps, says Assistant Bridge Engineer Fred Townsend.

Top Improvements The five states making the greatest improvement in reducing their deficient bridge populations were the District of Columbia, Montana, Oklahoma, South Carolina, and Maine.  The District of Columbia and Montana showed the greatest improvements by decreasing deficient state bridges by 4% each. Numerous states improved by 1%, and in many cases their percentages were already below the average of 25%.

State Route 463 over I-55 in Madison County includes a single-point urban interchange with curved steel box girders.

Photo by Lonny Pigott, Mississippi DOT.

Rehabilitation of this historic 160-foot-long steel truss built in 1928 included truss work and reconstruction of a 30-foot approach span. The bridge crosses the West River between Newfane and Brookline, Vermont.

Photo by Roger Whitcomb, VTrans project manager.

Close-up shot of the curved steel fly over the bridge on the I-65/Briley Parkway Exchange.

Photo courtesy of the Tennessee DOT Bridge Design Office.

Exclusive 2005 Bridge Inventory

The FHWA, in consultation with the states, has assigned a sufficiency rating SR to each bridge (20 feet or more) inventoried. Formula SR rating factors are as outlined in the current Recording and Coding Guide for Structures Inven-tory and Appraisal SI&A of the Nations Bridges.

Per the FHWA:  "An SD bridge is one that (1) has been restricted to light vehicles only, (2) is closed, or (3) requires immediate rehabilitation to remain open. An FO bridge is one in which the deck geometry, load carrying capacity (comparison of the original design load to the State legal load), clearance, or approach roadway alignment no longer meets the usual criteria for the system of which it is an integral part." See also www.fhwa.dot.gov/ legsregs/directives/fapg/0650dsup.htm

Our thanks to all the state highway engineers for their continuing cooperation and special effort to provide current data through October 2005

Click here for our main Bridge Inventory Page