Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS) 2011


>>CONVENTIONALLY, REINFORCED CONCRETE PIERS HAVE BEEN THE SUPPORT STRUCTURE OF CHOICE
FOR MODERN-DAY BRIDGE CONSTRUCTION. HOWEVER, AS TECHNOLOGY ADVANCES, CONVENTION SEEMS TO
BE SHIFTING. THERE’S A NEW KID ON THE BLOCK CALLED GEOSYNTHETIC REINFORCED SOIL, OR
G-R-S; AND IT’S CHANGING THE FOOTPRINT OF MANY MODERN-DAY STRUCTURES. ALTHOUGH GEOSYNTHETIC
REINFORCED SOIL HAS BEEN AROUND AWHILE, ITS USE AS PART OF AN INTEGRATED BRIDGE SYSTEM,
OR I-B-S, IS FAIRLY NEW.>”THE CONCEPT OF GEOSYNTHETIC REINFORCED SOIL CAME ABOUT IN THE EARLY 1970s
WHEN THE U.S. FOREST SERVICE USED NON-WOVEN GEOTEXTILES TO BUILD BURRITO WALLS, WRAPPED
FACED WALLS IN THE STEEP MOUNTAIN TERRAIN FOR LOGGING ROADS. THE COLORADO D-O-T, DURING
THAT TIME, TOOK NOTICE OF WHAT THE U.S. FOREST SERVICE
WAS DOING AND REFINED THE TECHNOLOGY. IN ABOUT THE MID-1990s WE ACTUALLY BUILT A
FULL-SCALE EXPERIMENT HERE AT TURNER-FAIRBANK HIGHWAY RESEARCH CENTER IN MCLEAN, VIRGINIA
TO DEMONSTRATE THE LOAD BEARING CAPACITY OF REINFORCED SOIL. WE DETERMINED THAT IT IS
EXTREMELY PREDICTABLE WHEN YOU BUILD IT IN A CLOSELY SPACED FASHION AS WE DO TODAY
IN THE I-B-S. A COUPLE OF YEARS LATER WE WERE GIVEN THE OPPORTUNITY HERE AT TURNER-FAIRBANK
TO BUILD THE PROTOTYPE I-B-S. AND AFTER THE SUCCESS OF THAT PROJECT, IN THE EARLY
2000s THE F-H-W-A INTRODUCED THE BRIDGE OF THE FUTURE INITIATIVE AND WE PIGGY-BACKED
ON THAT CONCEPT AND WE CONTINUED TO WORK WITH THE D-O-Ts AND WITH THE LOCALS TO SEEK OUT
PROJECTS TO BUILD G-R-S ABUTMENTS AND THE I-B-S.”>IN 2005, DEFIANCE COUNTY, OHIO, BUILT THE FIRST PRODUCTION I-B-S SYSTEM,
THE BOWMAN ROAD BRIDGE. TODAY, THAT BRIDGE IS PERFORMING VERY WELL, AND AS A RESULT,
THE COUNTY HAS BUILT 23 OTHER BRIDGES USING THE G-R-S I-B-S SYSTEM.
IN 2010, SAINT LAWRENCE COUNTY IN NEW YORK TOOK NOTICE OF THE SUCCESSES IN DEFIANCE
COUNTY AND ARE NOW USING THE TECHNOLOGY TO REPLACE MANY OF THEIR OWN BRIDGES.
HOW DOES THE G-R-S I-B-S SYSTEM WORK? THE G-R-S I-B-S IS SUPPORTED BY A REINFORCED
SOIL FOUNDATION, OR R-S-F. THE R-S-F IS AN ECONOMICAL, SHALLOW FOUNDATION
CONSISTING OF LAYERS OF GEOTEXTILE AND COMPACTED FILL. THE G-R-S ABUTMENT AND
INTEGRATED APPROACH IS ENGINEERED TO ACCOMMODATE SETTLEMENT, ALLOWING FOR A SMOOTH TRANSITION
FROM THE BRIDGE ONTO THE ROADWAY; THUS ALLEVIATING THE “BUMP AT THE BRIDGE”
NORMALLY CAUSED BY UNEVEN SETTLEMENT. CONSTRUCTING A G-R-S ABUTMENT IS
OFTEN DESCRIBED AS BEING AS EASY AS 1-2-3. IT REQUIRES PLACING A ROW OF FACING BLOCK,
A LAYER OF GRANULAR FILL, AND A SHEET OF GEOSYNTHETIC REINFORCEMENT AND REPEATING THE PROCESS UP
TO THE SPECIFIED HEIGHT OF THE ABUTMENT. THIS
METHOD HAS BEEN PROVEN IN THE FIELD TO FACILITATE QUICK AND EFFICIENT CONSTRUCTION WITH IMPRESSIVE
RESULTS.>”IT’S FAIRLY SIMPLE ONCE
YOU UNDERSTAND THE CONCEPT, THAT BY PUTTING THE SHEETS OF GEOTEXTILE IN THE COMPACTED
STONE THAT IT BEHAVES AS A COMPOSITE AND HAS ENGINEERING PROPERTIES. IT HAS A STRESS-STRAIN
CURVE THAT IS FAIRLY PREDICTABLE. YOU’RE REALLY DESIGNING THESE ABUTMENTS
AS A GRAVITY WALL.”>TO FULLY BENEFIT FROM THE RAPID
CONSTRUCTION AVAILABLE USING G-R-S TECHNOLOGY, IT IS IMPORTANT TO FOLLOW
GUIDELINES FOR G-R-S ABUTMENT CONSTRUCTION. FIRST, SINCE ALL OTHER COURSES OF BLOCK ARE
BUILT OFF THE FIRST ROW, MAKE SURE THAT THE BOTTOM ROW IS LEVEL AND EVEN. SECOND, FOR
OPTIMAL PRODUCTIVITY, USE ONLY THE CREW AND EQUIPMENT NECESSARY. DIVIDE THE LABOR
INTO THREE BASIC STEPS — STEP 1: LAYING THE BLOCK; STEP 2: PLACING
AND COMPACTING THE BACKFILL; AND STEP 3: LAYING A SHEET OF GEOSYNTHETIC REINFORCEMENT. FINALLY,
LIMIT THE MOVEMENT OF THE EXCAVATOR TOWARDS THE BACK
OF THE ABUTMENT WHERE IT CAN REACH AND PLACE MATERIAL WITHOUT HAVING TO BE MOVED.>”THE WHOLE PROCESS IS FAIRLY RHYTHMATIC; FAIRLY ROUTINE IN TERMS OF ONCE YOU GET THE
CONCEPT DOWN OF STACK AND COMPACT, IT IS A VERY REPETITIOUS PROCESS. THAT ONCE THAT IDEA
IS LEARNED THE REST OF IT JUST BECOMES KIND OF A RHYTHM THAT THE WALL JUST CONSTRUCTS.”>BECAUSE OF THE SIMPLE PROCESS, A LARGE CREW IS NOT NECESSARY TO SUCCESSFULLY
CONSTRUCT A G-R-S ABUTMENT. A TYPICAL CONSTRUCTION CREW CONSISTS OF LABORERS AND THE EQUIPMENT
OPERATOR.>”IN COMPARISON TO A TRADITIONAL
BRIDGE, THE G-R-S I-B-S SYSTEM, I’M GOING TO TELL YOU, IS TEN TIMES MORE SIMPLE
FOR YOUR AVERAGE LAYMAN TO BUILD. LIKE I SAID, YOU CAN TAKE MOST LOW CONSTRUCTION PEOPLE,
THEY DON’T EVEN HAVE TO BE BRIDGE PEOPLE, YOU CAN START
AT THE BOTTOM AND WITHIN A FEW WEEKS YOU CAN HAVE A BRIDGE STANDING.”>SPECIALIZED EQUIPMENT IS NOT REQUIRED TO CONSTRUCT A G-R-S ABUTMENT. READILY AVAILABLE
TOOLS LIKE HAND TOOLS AND MEASURING DEVICES ARE ALL THAT’S NECESSARY. HEAVY
EQUIPMENT, SUCH AS A TRACK HOE EXCAVATOR AND A WALK BEHIND VIBRATORY PLATE TAMPER, WILL
ALSO BE NEEDED. THE FIRST STEP IN CONSTRUCTING
THE G-R-S I-B-S IS SITE PREPARATION. SINCE G-R-S TECHNOLOGY REQUIRES BUILDING FROM THE
BOTTOM UP, STAGING, AND DELIVERY OF THE MATERIAL SHOULD NOT HAMPER CONTINUOUS
CONSTRUCTION. IT IS IMPORTANT THAT DIVERSION TRENCHES BE PLACED AROUND THE PERIMETER OF
THE SITE TO DIVERT ANY WATER. AS WITH CONSTRUCTION OF THE G-R-S ABUTMENTS, SITE PREPARATION IS
ALSO FAIRLY STRAIGHTFORWARD.>”IT’S A FAIRLY SIMPLE PROCESS
OF DIGGING DOWN TO A KNOWN ELEVATION FOR THE FOUNDATION TO BEGIN AND ONCE YOU REACH THAT
ELEVATION TO START BUILDING OR CONSTRUCTING THE WALL FROM THE BOTTOM-UP UNTIL YOU REACH
THE DESIRED ELEVATION AT THE TOP.”>ONCE THE SITE
LAYOUT AND EXCAVATION ARE COMPLETE, IT’S TIME TO BEGIN CONSTRUCTING THE REINFORCED SOIL
FOUNDATION. THE BASE SHOULD BE CUT SMOOTH, SLOPED TO DRAIN, AND EXCAVATED TO A UNIFORM
DEPTH. ALL LOOSE, UNSTABLE MATERIAL SHOULD BE REMOVED, BACKFILLED, AND COMPACTED
TO PROVIDE A GOOD FOUNDATION. LAYING THE REINFORCED SOIL BASE CAN TYPICALLY BE COMPLETED IN
1 DAY. THE NEXT STEP IN BUILDING THE G-R-S
I-B-S IS TO ENCAPSULATE THE SOIL FOUNDATION WITH GEOTEXTILE TO PREVENT EROSION. TYPICAL
SPACING IN THE REINFORCED SOIL FOUNDATION IS 12 INCHES.
ONCE THE SOIL FOUNDATION HAS BEEN FULLY ENCAPSULATED, COMPACTION BEGINS. PLACE
THE FILL FROM THE BACK TO THE EDGE OF THE R-S-F AND ROLL OUT ANY FOLDS OR WRINKLES TO
THE FREE END OF THE LAYER. THE SOIL FOUNDATION SHOULD BE BACKFILLED
IN COMPACTED LIFTS NOT TO EXCEED 6 INCHES. THE FINAL STEP IN THIS PHASE IS BUILDING THE
G-R-S BASE. THE TYPICAL BASE IS CONSTRUCTED WITH SPLIT-FACED CONCRETE MASONRY UNITS AND
COMPACTED BACKFILL. PROPERLY COMPACTED BACKFILL IS
CRUCIAL TO G-R-S I-B-S PERFORMANCE. COMPACT ALL AREAS BEHIND THE SPLIT-FACED
CONCRETE MASONRY UNITS SO THAT NO VOIDS EXIST BELOW THE GEOSYNTHETIC REINFORCEMENT. A THIN
LEVELING LAYER OF FINE AGGREGATE CAN HELP SET THE C-M-U BLOCKS TO GRADE, AND PREVENT
THEM FROM ROCKING. THE LEVELING LAYER SHOULD BE KEPT TO A MINIMUM THICKNESS
OF NO MORE THAN 0.5 INCHES. BEFORE PLACING THE GEOSYNTHETIC REINFORCEMENT,
IT IS IMPORTANT TO SWEEP OFF ANY GRANULAR FILL FROM THE TOP OF THE BLOCK. THIS WILL
PREVENT CRACKING OF THE FACING BLOCKS. THE G-R-S PROJECT WILL DETERMINE
THE NUMBER OF REINFORCEMENT ZONES NEEDED. REINFORCEMENT ZONES REPRESENT
DIFFERENT LENGTHS OF REINFORCEMENT AWAY FROM THE WALL. ROLL OUT THE GEOTEXTILES SO THAT
THE GREATEST REINFORCEMENT STRENGTH IS PERPENDICULAR TO THE WALL FACE. WHERE ONE ROLL ENDS, THE NEXT ROLL SHOULD
BEGIN. OVERLAPPING BETWEEN THE SHEETS OF REINFORCEMENT IS NOT REQUIRED. ANY EXCESS REINFORCEMENT
MATERIAL SHOULD BE REMOVED WITH A RAZOR KNIFE OR A PROPANE TORCH. PREVENTING WRINKLES IN
THE REINFORCEMENT MATERIAL IS CRUCIAL. THEREFORE, PLACE THE FILL FROM THE WALL FACE BACKWARD SO THAT ANY WRINKLES
THAT DO FORM CAN BE REMOVED. CONSTRUCTION OF THE G-R-S ABUTMENT CONTINUES WITH ALTERNATING
LAYERS OF COMPACTED GRANULAR FILL AND GEOSYNTHETIC REINFORCEMENT ACCORDING TO
THE DESIGN PLANS. AS THE ABUTMENT WALL IS BEING CONSTRUCTED,
IT IS CRUCIAL TO MAINTAIN THE PROPER WALL FACE ALIGNMENT. CHECK THE VERTICAL G-R-S WALL
FOR PLUMBNESS AT EVERY OTHER LAYER. ANY DEVIATIONS GREATER THAN 0.25 INCHES MUST BE CORRECTED.
AS THE UPPER LAYERS OF THE G-R-S WALL ARE CONSTRUCTED,
A BEARING REINFORCEMENT BED IS CONSTRUCTED TO PROVIDE ADDITIONAL STRENGTH TO SUPPORT
THE INCREASED LOADS DUE TO THE BRIDGE. THE BEARING BED REINFORCEMENT SERVES AS AN EMBEDDED
FOOTING WITHIN THE G-R-S ABUTMENT. THE SPACING OF THE REINFORCEMENT IN THIS LOCATION
IS HALF THE PRIMARY SPACING, OR TWO LAYERS PER COURSE OF BLOCK. THE DEPTH OF THE BEARING
REINFORCEMENT ZONE IS DETERMINED BASED ON THE INTERNAL STABILITY DESIGN FOR REQUIRED
REINFORCEMENT STRENGTH. AT A MINIMUM, THERE SHOULD BE FIVE BEARING
BED REINFORCEMENT LAYERS. FOR A BRIDGE WITH SUPER ELEVATION,
IT IS IMPORTANT TO ENSURE THAT THE MINIMUM NUMBER OF BEARING BED REINFORCEMENT LAYERS
BENEATH THE BEAM SEAT IS INSTALLED ACROSS THE LENGTH OF THE ABUTMENT FACE. AT THIS POINT THE REINFORCEMENT LAYERS
BECOME STAIR STEPPED WITH REINFORCEMENT TERMINATING ALONG THE ANGLED SURFACE OF THE ELEVATION.
PINNING AND GROUTING THE UPPER THREE COURSES OF BLOCK COMPLETES CONSTRUCTION OF THE FACING
WALL. IT IS IMPORTANT TO SUSPEND ANY CONSTRUCTION ACTIVITY NEAR THE FACE
ONCE THE TOP OF THE WALL HAS BEEN PINNED AND GROUTED TO AVOID WALL DISPLACEMENT.
ONCE THE ABUTMENT WALL IS COMPLETED, THE BEAM SEAT IS CONSTRUCTED DIRECTLY ABOVE
THE BEARING BED REINFORCEMENT ZONE. THE SUPERSTRUCTURE WILL BE POSITIONED ON TOP OF THE BEAM SEAT.
PROPER BEAM SEAT CONSTRUCTION BEGINS BY PLACING 4 INCHES OF PRE-CUT FOAM BOARD ON TOP OF
THE BEARING BED REINFORCEMENT. IT IS IMPORTANT TO MAKE SURE THE FOAM BOARD IS BUTTED AGAINST
THE BACK FACE OF THE BLOCK. NEXT, PLACE A SOLID CONCRETE BLOCK
ON TOP OF THE FOAM BOARD ACROSS THE ENTIRE LENGTH OF THE BEARING AREA.
THE FINAL STEP IS WRAPPING THE LAYERS OF COMPACTED FILL. THE THICKNESS OF
THE WRAPPED LAYERS IS ESSENTIAL TO MAINTAINING THE FINAL BEAM ELEVATION. THE
FILL THICKNESS OF THE FIRST 4-INCH WRAPPED LAYER SHOULD BE COMPACTED TO THE TOP OF THE
FOAM BOARD. THE FILL THICKNESS OF THE SECOND WRAPPED LAYER SHOULD BE COMPACTED TO THE TOP
OF THE SOLID BLOCK. THE TOP OF THIS SECOND LAYER CONTROLS THE BEAM ELEVATION;
THEREFORE IT SHOULD BE CAREFULLY COMPACTED AND GRADED.
AS AN OPTION, ALUMINUM FLASHING CAN BE INSTALLED AFTER CONSTRUCTION OF THE
BEAM SEAT AND PRIOR TO SETTING THE BRIDGE BEAMS. IF USED, THE FLASHING SERVES AS BOTH
A DRIP EDGE AND A CLEAR SPACE FILLER. PLACE THE FLASHING BETWEEN THE BOTTOM OF THE
BEAMS AND THE FOAM BOARD. MAKE SURE THE LENGTH OF THE FLASHING EXTENDS BEYOND THE OUTSIDE
OF THE BRIDGE BEAMS. FINALLY, TRIM THE FLASHING SO THAT IT FITS AGAINST THE PARAPETS.
PLACEMENT OF THE SUPERSTRUCTURE OCCURS FOLLOWING CONSTRUCTION OF THE BEAM
SEAT AND FLASHING INSTALLATION. MAKE SURE TO SET THE BEAMS SO THEY ARE SQUARE AND LEVEL.
NEVER DRAG THE BEAMS OVER THE BEAM SEAT SURFACE. THE WINGWALLS AND PARAPET ARE CONSTRUCTED
FOLLOWING PLACEMENT OF THE SUPERSTRUCTURE. FIRST, TRIM THE SPLIT-FACED CONCRETE
MASONRY UNIT IN THE PARAPET WALL FOR A CUSTOM FIT AGAINST THE BEAM EDGE. NEXT, FILL THE
SPACE BETWEEN THE SUPERSTRUCTURE AND THE FACING BLOCK WITH THIN LAYERS OF CUT BLOCK OR MORTAR
MIX. FOLLOWING COMPLETION OF THIS PHASE, APPROACH CONSTRUCTION CAN BEGIN.
THE G-R-S INTEGRATED APPROACH IS CONSTRUCTED OF AGGREGATE LAYERS, REINFORCED
AND WRAPPED WITH GEOTEXTILE THAT BLENDS THE APPROACH WAY TO THE BRIDGE DECK TO CREATE
A SMOOTH TRANSITION. IT IS IMPORTANT TO USE WELL GRADED MATERIAL THROUGHOUT
THIS PHASE AND TO TRIM THE GEOTEXTILE REINFORCEMENT TO THE
PRESCRIBED LENGTH AFTER IT IS WRAPPED. REPEAT THIS PROCESS UNTIL REACHING A HEIGHT APPROXIMATELY
2 INCHES FROM THE TOP OF THE BEAM GRADE. THE WRAPPED LAYERS ARE THEN PLACED
BEHIND THE BEAM END. THERE ARE A FEW GUIDELINES TO FOLLOW
FOR PAVEMENT OF A G-R-S PROJECT. FIRST, DURING PAVING, IT IS IMPORTANT TO KEEP THE TOP LAYER
OF REINFORCEMENT APPROXIMATELY 2 INCHES BELOW THE BEAM GRADE. THIS WILL ALLOW A LAYER OF
AGGREGATE COVER TO BE PLACED TO PROTECT THE GEOTEXTILE
REINFORCEMENT FROM CONTACT WITH HOT MIX ASPHALT. ALSO, THE PAVING FABRIC SHOULD EXTEND 3 FEET
OVER THE BRIDGE DECK ONTO THE APPROACH. FINALLY, IF GUARD RAIL INSTALLATION IS PART OF THE
PROJECT DESIGN, IT IS RECOMMENDED TO USE STEEL “H” POSTS FOR
ANY RAILING THAT IS DRIVEN THROUGH THE REINFORCEMENT. IT IS ALSO POSSIBLE TO DRILL THROUGH G-R-S
WITH AN AUGER TO SET OTHER TYPES OF POSTS. THESE PROCEDURES FOR CONSTRUCTING
A G-R-S I-B-S HAVE BEEN PROVEN IN THE FIELD TO FACILITATE QUICK AND EFFICIENT CONSTRUCTION. ADDITIONALLY, G-R-S I-B-S PROVIDES FASTER
PROJECT COMPLETION AT A REDUCED COST BECAUSE THE DESIGN IS FLEXIBLE AND THEREFORE EASILY
MODIFIED IN THE FIELD.>”THE BIGGEST BENEFIT TO THE G-R-S
I-B-S SYSTEM IS THE ADAPTABILITY TO THE DIFFERENT SITES AND THEN
THE OVER EXCAVATION THAT IS NOT REQUIRED AS PART OF THIS. WE CAN PUT IT ON UNSUITABLE
SOILS; WE CAN PUT IT IN WATER ENVIRONMENTS WHERE WE WOULD NORMALLY HAVE TO HAVE PILES
FOR STANDING CONCRETE. OBVIOUSLY, IT’S CHEAPER, IT’S FASTER AND
IN THESE ECONOMIC TIMES THAT WE’RE IN NOW, CHEAPER AND FASTER IS OBVIOUSLY A
BIG FACTOR.”>”IT’S NOT TRADITIONAL, SO
TO LOOK AT IT FROM THE OUTSIDE, YOU MIGHT QUESTION IT. BUT ONCE THE CONSTRUCTION PROCESS
STARTS, YOU CAN QUICKLY SEE HOW EASY THE CONCEPT IS AND HOW FLEXIBLE YOU
CAN BE IN TIMES OF CONSTRUCTION, WITH RAIN, WEATHER; IT DOESN’T REALLY SHUT ANYTHING
DOWN IN TERMS OF MOVING THE CONSTRUCTION PROCESS ALONG.”>THERE ARE THREE PRIMARY ADVANTAGES FOR USING THE G-R-S I-B-S. IT’S FASTER,
MORE ECONOMICAL, AND EASIER TO BUILD THAN TRADITIONAL BRIDGE STRUCTURES. ADDITIONALLY,
RESEARCH INDICATES THAT ITS LONG-TERM DURABILITY WILL BE BETTER BECAUSE IT HAS FEWER PARTS
AND BECAUSE THE SUBSTRUCTURE AND SUPERSTRUCTURE ARE BLENDED WITH THE APPROACH WAY
TO CREATE A JOINTLESS BRIDGE SYSTEM. THE G-R-S I-B-S SYSTEM DOESN’T HAVE MANY
OF THE COMMON ELEMENTS ASSOCIATED WITH A TRADITIONAL BRIDGE, PARTICULARLY THOSE LEADING FROM THE
ROADWAY TO THE BRIDGE. FOR EXAMPLE, IT DOESN’T HAVE AN APPROACH SLAB OR
A SLEEPER SLAB, AND IT ELIMINATES THE BRIDGE BEARINGS.
G-R-S I-B-S IS NOT FOR EVERY BRIDGE BUILDING ASSIGNMENT. IT IS, HOWEVER, A PERFECT
SOLUTION FOR SMALLER, SINGLE-SPAN BRIDGES. THE SYSTEM IS CURRENTLY TAILORED FOR SINGLE-SPAN
BRIDGES UP TO 140 FEET. THE LONGEST BRIDGE CONSTRUCTED TO DATE IS
A 140 FOOT STEEL GIRDER BRIDGE. THAT BRIDGE IS PERFORMING VERY WELL. EVEN THROUGHOUT ITS
THERMAL CYCLES, THERE HAVE BEEN NO ADVERSE EFFECTS SEEN ON THE APPROACH WAY.
G-R-S I-B-S IS GREAT FOR GRADE SEPARATIONS, ALTHOUGH THE BRIDGES COMPLETED
TO DATE ARE BUILT OVER STREAMS WITH NON-SCOUR CONDITIONS. IT
IS A SHALLOW FOUNDATION SYSTEM AND THUS NOT SUITABLE FOR SCOUR CRITICAL AREAS. HOWEVER,
THE TECHNOLOGY WORKS VERY WELL FOR BOTH STEEL AND CONCRETE SUPERSTRUCTURES. IN DEFIANCE COUNTY, THE FIRST BRIDGES BUILT USING THE G-R-S I-B-S PROVIDED THEM WITH A
21 PERCENT COST SAVINGS. TODAY, DEFIANCE COUNTY IS SAVING UP TO 40 PERCENT ON THEIR BRIDGES
BECAUSE OF THEIR ABILITY TO RAPIDLY CONSTRUCT THE SUBSTRUCTURE. THEY UNDERSTAND
HOW THE TECHNOLOGY WORKS AND THE LABOR CREW IS WELL-TRAINED.
IN SAINT LAWRENCE COUNTY, THEIR SAVINGS ARE EVEN GREATER BECAUSE IN THEIR PREVIOUS
DESIGN METHODOLOGY THEY INCLUDE MANY OF THE DETAILS ASSOCIATED WITH A TRADITIONAL BRIDGE,
SUCH AS THE APPROACH SLAB, THE SLEEPER SLAB, THE BRIDGE BEARINGS,
AND THE PARAPETS. WITH THE G-R-S I-B-S YOU DON’T NEED THESE TRADITIONAL ELEMENTS. SAINT LAWRENCE
COUNTY HAS REALIZED A SAVINGS OF BETWEEN 50 TO 60 PERCENT ON ALL THE BRIDGES THEY ARE
CURRENTLY BUILDING. RECENTLY, THE INTERIM IMPLEMENTATION GUIDE
FOR THE GRS-IBS WAS COMPLETED. THIS GUIDE IS THE RESULT OF
ABOUT 40 YEARS OF RESEARCH. IT CONSISTS OF TWO VOLUMES. ONE SPECIFICALLY FOR THE DESIGN
AND CONSTRUCTION OF THE G-R-S I-B-S; THE OTHER VOLUME CONTAINS A CENSUS REPORT
OF ALL THE AVAILABLE RESEARCH SUPPORTING THE DESIGN AND CONSTRUCTION OF THE G-R-S I-B-S.>”FOR OTHERS THINKING ABOUT G-R-S, THE THING TO DO FIRST IS KIND OF GET COMFORTABLE
WITH IT IN TERMS OF HOW IT WORKS. UNDERSTAND THE FACT THAT THERE IS A LOT OF DATA THAT
SHOWS THAT YOU CAN TRUST IT. IF YOU PUT IT TOGETHER THIS WAY, YOU’LL GET
THE KIND OF PERFORMANCE THAT WE’VE SEEN. AND THEN TO GET COMFORTABLE WITH
THE ACTUAL CONSTRUCTION. IT’S BEEN A GOOD FIT FOR US.”>”I CAN QUITE SINCERELY SAY THAT FROM THE BEGINNING OF RESEARCHING THIS TECHNOLOGY
IT HAS AMAZED ME WITH EACH EXPERIMENT. IT HAS FAR EXCEEDED OUR
EXPECTATIONS, AND WHEN WE BUILT THE I-B-S, DESIGNED THE I-B-S, WE REDESIGNED THE BRIDGE
WHERE WE GOT RID OF ALL THE COMMON ELEMENTS ASSOCIATED WITH THE BRIDGE AND
REDESIGNED IT FROM THE BOTTOM-UP. I THINK IT
CAN BE USED ON THE INTERSTATE SYSTEM, ONCE PEOPLE TAKE MORE NOTICE OF ITS LONG-TERM PERFORMANCE
ON THESE LOCAL ROAD SYSTEMS. I TRULY BELIEVE THAT THE TECHNOLOGY HAS A HOME IN ALL FACETS
OF EARTHWORK, NOT JUST IN BRIDGE SUPPORT APPLICATIONS.”>THE MANY ADVANTAGES G-R-S I-B-S TECHNOLOGY OFFERS MAKE IT A VIABLE CHOICE
FOR MANY BRIDGE PROJECTS.

16 thoughts on “Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS) 2011

  1. Hey! Av You tried – H Be Gone (Sure I saw it on Google)? Ive heard some incredible things about it and my cousin after a lifetime of fighting said good bye to pretty bad piles with it.

  2. 10 minutes into this video I realized I have no idea how I got here, or why I am watching it.

    For some reason, I found it interesting.

  3. Don't like this idea at all.

    A bridge goes from one spot over something that cannot be crossed to another spot.
    I really could not trust this so called new boy on the block.
    Maybe nothing wrong with it short term, and I am talking of very short term, but for a bridge that is not going to checked for maybe 50 or more years and say that bridge carries a railway line/s?

  4. I dread to think of the outcome of this new stuff suddenly giving way on perhaps a stretch of Rail crossing that may have just one train a day or week.

    Take care and fingers crossed you are not about to cross a bridge supported by this method!

  5. That's the dumbest thing I've ever heard. Every bridge has a risk associated with it. The bridge that just fell in Northern Washington was old and out of date. Plenty of bridges are in similar condition or worse and are needing to be replaced.

    This method is a proven, cost effective way to provide replacement bridges for small single span bridges. The MSE walls beneath them are heavily over designed to take the design loads. This system also reduces the differential settlement occur w/piles.

  6. mrbluenun: This technology is not a Cure-All design or a solution for every scenario. As Mr. Jensen points out, this is a solution in terms of cost efficiency, simplicity, and better controlled settling that creates a better finished product. This design is best tailored for use with basic, single-span bridges. Could this hold a rail bridge? I do not know. I can't speak to the strength capabilities of this technology: that should be left to a properly certified engineer to declare. I can assure you that this technology will only be used IF it is deemed structurally sound. I can appreciate healthy skepticism, but a bridge design cannot be approved for construction if it is found to be structurally deficient in any way.

    That's what engineers are here for.

  7. I would recommend and IR scan on the CMU wall.
    Wet stabbing the re-bar, not too sure about that procedure, preferably build a footing
    with vertical re-bar from the start…..just saying as a technician stand point.

  8. I don't like this at all. I'll stay with the MSE wall paneling system we use today with pile hammered steel casings for deck support. I don't believe this system would fare well for a large earthquake or major floods. Neither are common in the Midwest but they do happen. The worst that could happen under those circumstances with a MSE building system is that the approaches could sink or fall out of alignment which are easily repaired but the main deck super structure would remain unharmed since it rests on steel casings pile hammered deep into the earth.

  9. A point that I think is worth mentioning, since there was a comment about uncertain long term performance of GRS systems, is that bridges are inspected on regular intervals by trained technicians and engineers worldwide. FHWA requires every bridge in the US be inspected every two years, or more frequently if warranted. To my knowledge, there is no country in the world that allows open, public structures or structures on transportation routes to go without inspection for exceptionally long periods, certainly not fifty years.

    Additionally, special inspections are often carried out after large flood events, if needed. Related technologies also incorporate deep driven piling into the system, allowing wider applications.

    While no technology, old or new, is perfect, this is an important new development in highway technology and shouldn't be written off. I drive over one of the longest segmental concrete box bridges in the world every day, and it cost taxpayers about half of what the steel equivalent was bid at. That would not have been possible without these kinds of innovations.

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