What about our bridges?

From left: assistant bridge inspector Brad Holland, county engineer Dustin Stewart, and District 3 Commissioner Dean Calvert confer over inspection data for River Road Bridge, recently rebuilt, widened to two lanes and strengthened with abutments and steel support members. Awaiting Alabama Department of Transportation approval to remove all weight restrictions.

From left: assistant bridge inspector Brad Holland, county engineer Dustin Stewart, and District 3 Commissioner Dean Calvert confer over inspection data for River Road Bridge, recently rebuilt, widened to two lanes and strengthened with abutments and steel support members. Awaiting Alabama Department of Transportation approval to remove all weight restrictions.

First, a profile and comparisons to set the stage.

The un-named bridge. For purposes of this article, let’s call it Case History Bridge.

The un-named bridge. For purposes of this article, let’s call it Case History Bridge.

Blount County has 112 bridges outside of municipality limits. It has 97 bridges, or 86 percent, more than 25 years old: It has 64 bridges, or 57 percent, more than 50 years old.

Elmore County, across the Alabama River from Montgomery, has 123 county bridges. More than 25 years old: 91 bridges, or 74 percent. More than 50 years old: 48, or 39 percent.

Madison County in North Alabama has 248 county bridges. More than 25 years old: 220 bridges, or 89 percent. More than 50 years old: 111, or 45 percent. (The percentages don’t add to 100 and the bridge age numbers don’t add to the total number of bridges, either, because the categories overlap.) Case history

Here’s where things get interesting – an example of many of the kinds of problems Blount County’s engineering employees, commissioners, and road crews face frequently in keeping county bridges passable and safe. And it’s all wrapped up in one bridge. Perhaps the biggest problem bridge in the county, which will remain nameless, is a problem, not because it’s the bridge in the worst condition – although it’s marginal enough – but because of what’s involved in replacing it.

Here are its characteristics (based, not entirely, but substantially, on the writer’s observation). (1) It’s on a low-volume rural road, so the number of users served is low. (2) It’s functionally obsolete (see bridge terms, below) on more than one count. (3) It’s a narrow, one-lane bridge. (4) Guard cables were once in place, but are now non-existent on one side, non-functional on the other. (5) It’s situated right beside the river, and subject to fairly frequent flooding. The short bridge crosses a medium-flow deep creek about 50 yards from its junction with the main river. (6) The decking (road surface of the bridge) is submerged by two feet or more on some occasions, not rare. (5) The bridge itself and the approaches leading up to it are in the river flood plain for about a quarter-mile on one side of the bridge, and a hundred yards or so on the other. (6) The approaches are also subject to fairly frequent flooding over much, if not all, of that distance. (7) Was it mentioned all are located right beside the river? (8) Replacing the bridge would entail raising it several feet above it’s present height. (9) Since the approaches flood also, they would have to be raised an equivalent height over an extended distance (and a new road built on the raised bed) to render the bridge usable during floods. (9) The kicker: $1 million dollars wouldn’t touch the cost of construction to replace this bridge and approaches. Would $2 million do it? $3 million?

How do you deal with a problem like this? The time will come when something has to be done. What’s the answer? “Do what you can with the money you’ve got” (Civil Engineering 102), until you have to face the music, cough up the money, and launch a bridge construction project of unimaginable magnitude (to a lay person) over a middling-sized creek on a county backwater road. Or close the bridge.

Back to the everyday world

One of the main duties of county engineer Dustin Stewart and his assistant bridge inspector Brad Holland, is bridge inspections, and those inspections drive the process of bridge maintenance, replacement and in some cases closure. Many bridges – more than 60 in Blount County – are on a two-year inspection cycle. Fewer than 50 bridges are on a more frequent cycle: one year, six months, or three months, depending on each bridge’s status as reflected in bridge inspections. Bridges with lower condition ratings get more frequent inspections to determine what routine maintenance may be needed, or at what point they must be addressed with more substantial structural or other corrective action to remedy deficiencies identified – or closed.

Bridge concepts

From an engineering (and somewhat oversimplified) standpoint, bridges are inspected in terms of three major systems or assemblies: substructure (abutments and columns), superstructure (girders supporting the decking or traveling surface), and the decking itself.

For engineering inspection purposes, each system is broken down further into multiple specific members or pieces. Each is rated individually on a scale of 1 to 9, with 9 being excellent condition on down through good, satisfactory (6), fair (5), poor (4), and serious (3). A composite rating of 2 (critical) or below on any system dictates that the bridge be closed to traffic until repairs to remedy the low-rated component(s) are made.

Bridge terms

Structurally deficient: This scary-sounding term doesn’t mean the bridge is in danger of collapse, or that it is unsafe for routine travel. It indicates there are maintenance concerns that do not pose a safety risk. A deficient bridge at some point requires maintenance, repair, and/or eventual rehabilitation or replacement to remedy deficiencies. Such bridges are often posted with reduced weight limits that restrict the gross weight of vehicles using the bridge. (Source: Virginia Department of Transportation. ) Blount County has about two dozen bridges that are structurally deficient in some respect. More on this later.

Functionally obsolete: These bridges were built to standards that are no longer current. For example, one-lane bridges, even those in satisfactory condition, would normally be considered functionally obsolete. They are not automatically rated as structurally deficient, nor are they inherently unsafe (but they can be). Other conditions that characterize functionally obsolete bridges are inadequate width, absence or poor condition of guard rails, inadequate vertical clearance, and susceptibility to flooding. (Virginia Department of Transportation.) The few Blount County bridges that are functionally obsolete would generally be obvious to the public.

1-cent sales tax

For many years, Blount County had no revenue source specifically dedicated to bridge maintenance and repair. Bridge repair and upgrades (but not replacement) were paid for out of general road improvement funds. With the passage of the 1-cent sales tax increase by the voters of Blount County in 2016, the federal annual road funding allocation of $533,000, formerly devoted mainly to road paving, was designated for use, primarily but not exclusively, for permissible bridge improvement and replacement. That change of emphasis makes possible a gradual gain in overall bridge quality and condition county-wide over the coming years. It’s a slow process, however, since some bridge replacement projects will necessitate accumulating portions of annual federal funding over multiple years, while continuing to use portions of it for more routine bridge maintenance and upgrading needs.

County engineer Dustin Stewart Q&A

Bridge inspections: “All bridge inspections are done by me and my assistant Brad Holland. From those inspections, a bridge maintenance work order is generated and submitted to the commissioners. They mobilize a bridge crew to complete the work order. It is a collaborative effort and I’m very grateful they all realize the importance of the work they do to maintain our bridges.”

Worries of the job: “The part that worries me most are natural disasters such as major flood events or snow events. Water is a natural resource that can do major damage to a bridge in flood events. “

Why citizens can feel secure about bridges: “The National Bridge Inspection program is a rigorous program that is monitored by the Federal Highway Administration through the Alabama Department of Transportation. Every bridge in the county that is 20 feet or longer has to be inspected at minimum on a two-year cycle. This is a very thorough process in which every member on each individual bridge is accounted for and graded.”

Causes of bridge deterioration: “The leading cause of bridge deterioration is water. Water cause corrosion of steel beams and scouring of abutments. These are the two types of deterioration we see most during an inspection.”

Role of public awareness and public opinion: “Public awareness is extremely important. Without the bridge, road routes will not function, and the county infrastructure will deteriorate. The onecent sales tax that was voted on in 2016 was an important first step in taking care of Blount County bridges. Citizens of the county should be commended for realizing that Blount County needed additional funding for roads and bridges.”

Specific objectives for upgrading county bridges: (1) “Eliminate all county posted (weight limited) bridges within 25 years (43 bridges). (2) Eliminate all structurally deficient bridges within 20 years (20-odd bridges).”

(Ed. – Don’t be fooled by the time frame. Those are ambitious goals. )