Conor Watkins' Ozark Mountain Experience
Article 51&52
The Historic Devil’s Elbow Bridge Is In Need of Repair

The Historic Devil's Elbow Bridge Is In Need Of Repair
-Rusting Steel And Crumbling Concrete Threaten This Landmark


The scenic Devils Elbow Bridge over the Big Piney River
offers a view of one of Missouri's "Seven Scenic Wonders."

The town of Devil’s Elbow is considered to be one of the highlights of a tour on Missouri Route 66.  The area is home to the Big Piney River and its scenic bluffs, Sheldon’s Market which doubles as the Devil’s Elbow Post Office, The Elbow Inn Bar And Grill which originally opened in 1929, and last but not least, an old steel truss bridge across the river.

The town’s picturesque setting has led film producers from around the world to record parts of their movies and TV shows in the area.  Upon viewing the guest registry at Sheldon’s Market, one will discover that many of the visitors are from overseas.  Although Devil’s Elbow is a sleepy Ozark town, the fame of Route 66 and its scenery attract visitors from worldwide.  The visitor to Devil’s Elbow will also notice others slowly driving across the old steel truss bridge taking both still and moving pictures, no matter the time of day or week.  The view of the 200 foot tall bluffs of Gasconade dolomite visible from the bridge was once described as being one of the "seven scenic wonders of Missouri" in literature from the Missouri Planning Commission.


This shot of one of missouri's Seven Scenic Wonders was taken
from the Devil's Elbow Bridge.

It is obvious that the scenery of the town and the old bridge that once served Route 66 bring much tourism to Devil’s Elbow and Pulaski County.  One would think that governments would make sure the original Route 66 would be preserved for this reason.  Unfortunately, this has not been the case and the old steel bridge is now threatened by corrosion and crumbling concrete.

The bridge was constructed by use of hot rivets in 1923 to serve Missouri Route 14.  When Route 66 was laid across the country in 1926, the pre-existing bridge served as a convenient and cost saving alignment over the Big Piney River.  As war spread around the world in the late 1930’s, the United States government began to prepare for the worst while hoping for peace.  Existing military installations were improved and many new bases were constructed around the country.  Ft. Leonard Wood in Pulaski County, MO was built in a matter of months to serve as an Army training center.

It was immediately obvious that the narrow winding road and bridge through Devil’s Elbow were inadequate due to many large trucks going to and from the nearby fort.  In 1941 a straighter and flatter four-lane stretch of Route 66 was built just to the north of Devil’s Elbow.  Roadcuts were used to keep grades reasonable.  At 90 feet, the Hooker Cut, just east of Devil’s Elbow was the deepest roadcut in Missouri and one of the deepest in the country when it was excavated.  After this time, the town remained relatively isolated as travelers passed by on the new stretch of road.

When the Interstate system was commissioned in 1956, the 1940's stretch of Route 66 through the area served as Interstate 44 until a more modern highway could be constructed.  It wasn't until the early 1980's that the present day section of I-44 through the area was built.

Since this time, maintenance of the old bridge has been less of a priority to state and federal governments and Pulaski County has limited funds for highway repairs.  Two bridges, one on the 1941 stretch of Route 66 and the I-44 bridges, cross the Big Piney River and give motorists alternate routes around the Devil’s Elbow Bridge.


All three bridges over the Big Piney in the vicinity of Devil's Elbow can be seen from a bluff
overlooking the area during the winter when the leaves are down.  The 1923 Devils
Elbow Bridge may be seen along with the 1940's Route 66 Bridge (arched concrete
structure) and the 1980's I-44 bridge (green girders & crossing semi trailers visible)
in the far distance.
Additional view of Devil's Elbow Bridge

During the 1970’s, it was noticed that the concrete bridge piers were cracking and starting to spread apart.  Steel plates were attached to the top of the piers and pressed against the concrete by using tensioned steel cables in order to confine the concrete and hold the piers intact.  This was the last major maintenance performed on the old bridge.


This bridge pier has been confined with steel plates
wrapped with cables to help prevent further deterioration.

Upon driving across the bridge, it appears to need sandblasting and a paint job.  Surface rust is visible on the steel but the structure is sound.  Unfortunately it is a whole different scene underneath the bridge.  The paint has deteriorated and severe rust has set in where moisture collects, especially at the south end of the bridge.


At first glance, the bridge appears to simply need a paint job,
but one look underneath will show otherwise.

Rust has completely eaten through several gusset plates (plates used to attach different structural members) and laterals (stabilizing members) under the road deck.  The laterals serve to keep shaking and vibration due to wind and traffic on the bridge to a minimum.  These members are simple steel angles (members with an L-shaped cross section) that are placed diagonally at various points underneath the bridge.  A few of these structural parts are now completely detached from their intended connections underneath of the bridge and are hanging freely.  Parts of the laterals or their gusset plates have simply rusted through completely.  Perhaps the most serious structural issue is with a support beam underneath the bridge on the southwest side.  The beam consists of two standard channels (members with a C-shaped cross section) riveted back to back to roughly form an I-beam cross section.  One of the standard channels has rusted nearly completely though, so this beam is only able to support one half of its designed load.


This gusset plate below the bridge deck is nearly rusted through.


This lateral stabilizing member has completely rusted through
and is no longer attached.




Perhaps the most serious structural problem is the rust
that has nearly eaten away half the lower cord
under the bridge.

It appears that much of this rust has been encouraged by an expansion joint that allows water to drain directly onto the structure below.  Since this part of the structure remains wet longer than areas exposed to the sun above, it is more subject to corrosion.

The original 1923 concrete deck on the old bridge is also in need of repair, although it doesn’t appear as critical as the steel structure.  The road surface is pitted in places and other sections are noticeably crumbling.  This damage is probably due to two factors that are common in the Missouri Ozarks.  Bridges in the area are subject to frost action, especially when the temperature frequently freezes and thaws, as it does during Missouri winters.  When water freezes within concrete, it opens cracks, allowing more water to enter on the next freeze cycle.


Along with the scenic view, one may notice some surface rust
and exposed rebar in the concrete deck curbing.

Alkali-aggregate reactions are another common problem with concrete in the Ozarks.  These reactions are due to conflicting chemistry within the concrete mix itself.  Most cement is basic in chemistry and will react with acidic aggregates.  Silica based aggregates produce a mild acid as they weather.  As the dolomite bedrock in the Ozarks weathers, it leaves behind nodules of chert, because these more resistant to weathering.  These pieces of chert tend to wash down into creeks and rivers where they form the gravel bottoms and bars so common to Ozark streams.  Chert is a silica-based rock and produces mild acids as it weathers in the presence of water.  This is especially a problem when chert contains opaline quartz.  Many Ozark cherts do contain this mineral form.  Chert aggregates are commonly used in the Ozarks because they are plentiful and easy to obtain.  It isn’t hard to scoop gravel out of a river to use in concrete mixes.  Those doing this are usually unaware of the chemical reaction that lies ahead.  Although this reaction is slow and can take many years to cause noticeable damage, it is something that can be avoided by carefully selecting quality aggregates.

As acids from the weathering of the chert aggregate react with alkali compounds from the cement, a paste is formed.  This paste expands and cracks concrete, much as water does when it freezes.  The pitting on the road surface has allowed water to pool.  Since water is an important player in both freeze thaw damage and alkali-aggregate reactions, these small pools of water work to degrade the concrete.  Both freeze-thaw and alkali-aggregate reactions work together in a synergistic manner to positively reinforce the effects of each process.  This allows more water to infiltrate the concrete, causing a “Catch 22” cycle of damage.  Some concrete has spalled off, exposing rusting re-bars underneath.


Rusting rebars are exposed under the bridge deck where
some of the concrete has spalled off.  Low quality alluvial (river)
gravels are visible upon close inspection.

In June 1999, MODOT inspected the bridge and noted some of the problems described above.  The inspection report suggested removing debris underneath, to prevent the retention of moisture, and to give the bridge a paint job.  Neither task has been completed.

Pulaski County has taken steps to minimize further damage to the weakened bridge by lowering the weight limit.  A low speed limit has been instituted partly because the bridge is in a residential area.  If followed, the lower speed will also minimize shaking and vibration caused by traffic on the bridge.

Funding in the county is limited and repairs to the bridge will be costly.  The actual structural repairs are not all that expensive, but the paint job will be.  The existing paint is lead based and its removal will not be cheap.  All paint must be captured and cannot be allowed to fall into the river below.  Dr. Nanni of the UM-Rolla Department of Civil Engineering has proposed repairing the steel structure with a composite material but funding is not available as of now.  New steel members could also be welded in place to repair up the structure.

There is still hope for the Devil’s Elbow Bridge.  For the most part, most of the bridge is in decent condition and the problems are mainly concentrated at a few locations.  The state has agreed to install a car counter on the bridge during the summer of 2003. If enough traffic crosses to warrant keeping the bridge in service, the state may help influence historical organizations to help pay for its repair.  Gary Carmack and the other Pulaski County Commissioners are dedicated to saving the bridge and are always looking for funding in order to pay for its repair.  Anyone with ideas on how the bridge could be repaired or how funds could be raised is encouraged to contact the author.  This information will be passed along to parties who might be able to help.


The above two pictures of a gusset plate and the
overall view of the bridge's underside show
that most of the bridge is in decent condition
and that there is still a chance to save the structure.

The scenic town of Devils Elbow and its bridge is located in Pulaski County about 25 miles west of Rolla.  To get to the area, take I-44 west to the Hwy J Exit (exit 169).  Turn left on Hwy J and cross the interstate.  Take an immediate right on Hwy Z.  Follow Hwy Z, the “newer” four-lane stretch of Route 66, for two or so miles until Teardrop Rd. is reached.  Turn left here.  If an arched concrete bridge over the Big Piney River is crossed, one has gone too far.  Follow for a quarter mile or so to the old truss bridge.  The town of Devil’s Elbow is just on the other side of the river.  For more information on attractions in this scenic area visit http://web.umr.edu/~cwatkin/cwome/article23&24combined.htm and http://web.umr.edu/~cwatkin/cwome/article39-42combined.htm on the web.


D.) Location of Devil's Elbow.


Roadmap of Devil's Elbow area.

Thanks to Alex Primm, Bill Debo (a longtime resident of Devil’s Elbow), the MODOT 1999 Bridge 2060015 Inspection Report, Gary Carmack (a Pulaski County Commissioner), the Fall 1996 Missouri Resources Magazine, and Concrete Experts (http://www.concrete-experts.com/pages/asr.htm) for information relating to this article.

(C) 2006 by Conor Watkins