Bridge Contractor Mississippi
Foundation Masters, LLC. Licensed Florida engineering firm, CA# 30969. Residential and light commercial bridge design and construction across Mississippi, from the Tennessee River hills in Tishomingo County to the Gulf beaches.
Mississippi is a state of creeks, bayous, sloughs and oxbows, and a great many homes, farms and hunting camps sit on the far side of one of them. Foundation Masters designs and builds those crossings: private drives, development entrances, farm and timber access, and the replacement of spans that were never built for what crosses them today.
We are a design build firm, which means the investigation, the drawing and the structure all come out of one shop instead of three. Jeff Earl founded Foundation Masters after two decades in deep foundations, earth retention and structural repair, and a licensed professional engineer seals the plan set before anything gets driven.
Mississippi sits inside a Southeast footprint that also covers Florida, Alabama, Georgia, Tennessee, South Carolina and North Carolina. Everything is indexed on the bridge contractor hub.
Mississippi Has Almost No Rock to Drive To
In most states a bridge pile is looking for rock. In Mississippi it mostly is not going to find any. The oldest rock at the surface in the state shows up in a small patch of northern Tishomingo County, near Woodall Mountain, and the formations get younger and softer as you move west and south. Across nearly everything else, a pile is driven into clay, sand, silt or chalk and has to build its capacity there.
That single fact shapes every bridge foundation in the state. The questions are not how deep is rock, but how much does this clay move, how soft is this river bottom, and how fast is this bank going to erode. Each region answers them differently.
The Northeast Hills
Tishomingo, Iuka, Corinth and Booneville. The one corner of the state where sound rock can sit within reach, at the edge of the Appalachian foothills. Depth to it still varies across a single crossing.
The Black Prairie
Tupelo, Okolona, Aberdeen, West Point and Columbus. Heavy clay over chalk, part of the same prairie band that runs into the Alabama Black Belt. The NRCS rates these clays high for shrink and swell.
Jackson and the Yazoo Clay
Jackson, Madison, Ridgeland, Brandon, Pearl and Yazoo City. A highly expansive clay sitting right under the largest metro in the state. Covered in detail below.
The Loess Bluffs
Natchez, Vicksburg, Port Gibson and the bluff line north toward the Tennessee border. Windblown silt, thickest along the river, that stands in vertical faces and cuts into deep, steep ravines.
The Delta
Greenville, Greenwood, Clarksdale, Cleveland and Indianola. Very deep river alluvium, with clay in the backswamps, sandier ground on the old natural levees, and a water table that is rarely far down.
The Pine Belt and the Coast
Hattiesburg, Laurel, McComb, Gulfport, Biloxi, Bay St. Louis and Pascagoula. Coastal plain sand and clay inland, poorly drained flatwoods and marsh soils near the Gulf, and storm surge as a design event.
Yazoo Clay and What It Does to a Bridge Abutment
The Yazoo clay runs under central Mississippi, with most of it in Yazoo County and more under northeast Hinds, Madison, Rankin and Scott Counties. It is a highly expansive clay. It takes on water and swells, gives it back and shrinks, and it does that every wet season and every drought. The deposits run hundreds of feet deep, so there is no digging it out and starting over.
Engineers in the Jackson area have been documenting the damage since the early 1960s. A 1962 Highway Research Board paper on the Jackson area reported that road and street upheaval of up to a foot was common, that structures built on hillsides on conventional foundations had moved downhill several feet, and that excavation slopes cut into the clay had slid. Anyone who drives the dips and humps on Jackson streets is looking at the same clay.
A bridge abutment sitting in that clay heaves in the wet months and settles in the dry ones. The approach slab cracks first, then the abutment face, and eventually the bearing seats are no longer where the drawing put them. On a creek bank, where the clay is already sloping toward the water, the abutment can also creep downhill. The answer is to carry the load on piles below the zone that moves, keep water from ponding against the abutment, and take soil borings at the abutments instead of designing from a regional guess.
This page covers Mississippi. The rest of the bridge practice is below.
The FM-H20 Fire Truck Rated Bridge
A loaded pumper weighs somewhere north of fifteen tons. The pickup that has been crossing your bridge for years weighs three. Those are not the same question, and on a long private drive in rural Mississippi there is usually no second way in. The FM-H20 is the bridge we build so that the answer is yes before anybody has to ask.
FM-H20 Specification
- Steel girder superstructure with timber deck
- Fire truck H-20 loading, 20 ton deck capacity
- Maximum span up to 60 feet
- Abutments rated to 80 tons at a 2 to 1 safety factor
- Vinyl sheet piling at the abutments, driven 60 inches below the mud line
- Lifetime warranty
Why the Sheet Pile Is Not Optional
Erosion is the leading reason private bridges fail, and Mississippi ground gives water every advantage. Loess and loose coastal plain sand wash out fast, and the first thing a high creek finds is the fill packed in behind an abutment.
Vinyl sheet pile driven below the mud line puts a wall between the stream and that fill. Embedment gets set by the crossing and the soil, not by a catalog default.
Full detail on the FM-H20 fire truck rated residential bridge page. Starting price is around 3,300 dollars per linear foot.
Foundations: The FM-PP30 Driven Pipe Pile
Four FM-PP30 piles carry each abutment. Three inch schedule 40 pipe, thirty tons apiece, driven with a pneumatic hammer by our own crews. Driven rather than hydraulically pressed matters on a soft bank, because a pressed pile has to react against structure that is not there yet and a driven one does not.
In Mississippi the pile is almost never hunting for rock. Through the Yazoo clay it is driven past the zone that swells and shrinks so the abutment rides on ground that holds still. In the Delta and on the coast it is driven until it develops capacity in friction through deep, soft ground, which means a long pile. Only in the far northeast corner is refusal on rock a realistic expectation. One system, set to a very different stopping point depending on the county.
This is where the pipe pile approach earns its place over a drilled shaft on a residential job. The rig is small enough to work on a creek bank, and driving the pile tells you what the ground is doing as you go instead of after the concrete cures.
Loess Bluffs and Delta Bottoms
Loess Stands Straight Until Water Gets Behind It
The loess along the bluffs from Natchez up through Vicksburg is windblown silt that is thickest right along the river. It has the unusual habit of standing in vertical faces, which is why the roads through it run between straight walls of earth and why the creeks have carved deep, steep sided ravines.
That same silt erodes fast once water works on it. A crossing in loess country is as much a bank protection job as a bridge job, so the abutments get set back from the edge and the sheet pile does real work.
The Delta Is River Bottom All the Way Down
The Delta is level alluvial plain built by the Mississippi River, with backswamps, oxbows and old natural levees. The NRCS describes its soils as very deep and mostly poorly drained. The heavy clay of the backswamps, Sharkey clay among them, swells and cracks with the seasons.
There is nothing hard to find down there. Delta crossings over sloughs, bayous and drainage ditches are built on longer friction piles, with the deck high enough to clear the water that the flat ground holds onto after a rain.
The Gulf Coast Designs for the Water First
Hurricane Katrina put a measured storm surge of about 27.8 feet into Pass Christian in 2005, with roughly 24 to 28 feet across the stretch from Waveland through Bay St. Louis to Long Beach, and 17 to 22 feet from Gulfport east to Pascagoula. The surge reached at least six miles inland in many places and up to twelve miles along the bays and rivers.
On a crossing in Hancock, Harrison or Jackson County the governing load is often not the truck on the deck, it is the water. Scour at the supports and uplift on the superstructure get designed for, the deck gets tied down to the girders and the girders to the abutments, and the foundation goes deeper than an inland crossing of the same span would need.
What We Build in Mississippi
Private Drive Crossings
The one span standing between your house and the county road. Built so that emergency apparatus can use it, not just the vehicles already parked on your side of it.
Farm and Timber Access
Tractors, grain carts, loaded trailers and log trucks crossing a ditch or slough again and again. Repeated heavy passes call for a different deck and a different approach detail than a driveway does.
Development Entrances
The first structure anyone sees coming into a subdivision or a gated community, and the one that has to survive a full construction cycle before a single resident uses it.
Hunting Camps and Rural Land
Crossings that open up the back of a property for trucks, side by sides and equipment, often across ground that floods for part of the year.
Greenway and Trail
Foot and cart crossings over branches, ravines and wet bottoms. Light loads, but the same scour and foundation questions as anything else in a creek.
Repair and Replacement
Spans that have begun to sag, scour out at the banks, or ride up and down with the clay. We look at it and write up what we find before anyone proposes a scope.
Mississippi Service Areas
Jackson Metro
Jackson, Madison, Ridgeland, Flowood, Brandon, Pearl, Clinton and Canton. Yazoo clay country, where the foundation has to get below the clay that moves.
Northeast Mississippi
Tupelo, Corinth, Iuka, Booneville, Oxford and New Albany. Black Prairie clay around Tupelo, and the only realistic rock in the state at the Tishomingo end.
The Golden Triangle
Columbus, Starkville and West Point. Prairie clay over chalk along the Tombigbee, with shrink and swell as the main concern.
The Delta
Greenville, Greenwood, Clarksdale, Cleveland, Indianola and Yazoo City. Deep alluvium, high water and long friction piles.
River Bluffs and Southwest
Vicksburg, Natchez, Port Gibson, Brookhaven and McComb. Loess bluffs and ravines, where bank erosion sets the layout.
Pine Belt and Gulf Coast
Hattiesburg, Laurel, Gulfport, Biloxi, Ocean Springs, Bay St. Louis, Waveland and Pascagoula. Coastal plain soils, flatwoods drainage and surge exposure.
Already have a builder lined up? We will do the investigation, the design and the sealed set and hand it to them.
Mississippi Bridge FAQs
What does a residential bridge cost in Mississippi?
The FM-H20 starts around 3,300 dollars per linear foot. Span, bank condition, how far the piles have to go and how hard the crossing is to reach are what move it from there. We put a real number on it after we have stood on the bank.
My property is on Yazoo clay. Can I still build a bridge?
Yes. The clay changes the foundation, not the feasibility. Expansive clay is well understood and designed around every day. The part that is not negotiable is getting borings at the abutments so the piles carry the load below the clay that swells and shrinks.
How deep do the piles go in Mississippi?
Deeper than most people expect, because across most of the state there is no rock to stop on. The pile is driven until it develops capacity in the clay, sand or silt, and in the Delta and on the coast that means a long pile. Only in the far northeast corner of the state is refusal on rock a realistic expectation.
Do I need a permit to build over a creek or bayou?
In most cases yes, and more than one. A span over a stream generally needs the county permit plus a review of any work in the waterway, and depending on the water body a federal authorization through the Corps of Engineers. On the coast, work in tidal wetlands brings the Department of Marine Resources into it as well. Those reviews, not the construction, usually set the schedule. We prepare and file the package rather than handing you a drawing and wishing you luck.
Will a fire truck really cross it?
Yes, and that is the whole reason the rating exists. H-20 means the deck is sized for apparatus loading at 20 tons rather than for passenger vehicles. Where the bridge is part of a required fire department access road, the local fire code official sets the load it has to carry, and some codes call for 75,000 pound apparatus, so we confirm the requirement with the fire marshal before the design is set. It is worth asking your local volunteer department what they actually run, because a rural tanker carrying several thousand gallons of water can be heavier than the engine everyone pictures.
My crossing is in the Delta and floods every spring. What changes?
The deck height, the foundation and the approaches. The deck needs to clear the water the flat ground holds after a rain, the piles go long because the alluvium is deep and soft, and the approach fill needs protection so the high water does not carry it away from behind the abutments.
What about hurricanes on the Mississippi coast?
On a coastal crossing the governing event is often the water, not the truck. Scour at the supports and uplift on the superstructure both get designed for, the connections are detailed to hold the deck down, and the foundation goes deeper than an inland crossing of the same span would need.
Should I repair my existing crossing or replace it?
That depends on what is actually wrong, and the honest answer is not always the more expensive one. Scoured abutments and rotted timber on an otherwise sound steel frame are repairable. A structure that was never rated for the loads crossing it now, or one whose foundations have moved with the clay, is a replacement. We look at it and put the finding in writing before anybody talks about price.
Talk About Your Mississippi Crossing
New bridge, development entrance, farm or timber access, or a crossing that has started to move. Tell us where it is and what has to get across it.
Call 656-233-7089Or send it in writing through the contact page. Include the property address, the span and a photo of the crossing.