construction procedure
DESCRIPTION
ConstructionTRANSCRIPT
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CONSTRUCTION PROCEDURESAND QUALITY CONTROL GUIDELINES FOR EARTHTRAC HA MECHANICALLY STABILIZED EARTH (MSE) STRUCTURES
TM
703.771.7305413 Browning Ct.Purcellville, VA 20132www.earthteccorp.com
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Focus Points
Materials and Components Site Preparation MSE Wall Construction Troubleshooting
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Materials and Services Suppliedby EarthTec
Precast concrete facing panels Nominal size 5 x 10
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Materials and Services Suppliedby EarthTec
Hard neoprene bearing pads for horizontal panel joints used from the second course of panels upwards.
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Materials and Services Suppliedby EarthTec
Geotextile strip, in rolls, for placing against panel joints.
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Materials and Services Suppliedby EarthTec
EarthTrac HA ribbed steel soil reinforcing strips, supplied cut to length, and galvanized. nuts and bolts complying with ASTM Grade A325.
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Materials and Services Suppliedby EarthTec
Precast Corner / Slip joint panels
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Materials and Services Suppliedby EarthTec
Site assistance and training.
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Materials and Services Suppliedby Contractor
All labor and supervision.
All safety equipment.
Project specific safety plan.
All tools, construction, earthmoving, lifting and compaction equipment as outlined in the General Notes section of the design.
Backfill in accordance with the Specification.
Materials to install all required drainage systems.
Concrete and forming materials to install levelling pad.
Material to install parapet or copings.
Timber props for first row of panels.
Large and small crow bar for adjusting panels.
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Materials and Services Suppliedby Contractor
Timber clamps for temporarily clamping each row of panels until backfilled (1 per vertical joint).
Timber wedges for maintaining panel batter during setting of panels prior to clamping (6 per vertical joint).
spacers (2 per panel). 4 Spirit level. Site level and rod. Plumb bob. Adhesive for securing geotextile at panel joints. Corner or slip joint backing blocks.
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Site Preparation
Preparation of Foundation Soils Check that foundation material is consistent with the site
investigation Local soft spots removed and replaced with compacted
granular fill Foundation area is proof rolled
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Construct Leveling Pads
Levelling pads may be precast or CIP concrete The levelling pad shall be toweled smooth Constructed to within 3mm (1/8) of the specified
level
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Site Preparation
Setting Out (Staking) String lines or pegs Define wall lines
Establishing the Wall Line Front face of the wall is established
with a chalk line drawn on the pad. Line represents the front face of the
panels including any special finish Additional points located at all bends, points of curvature or
tangency of curves
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Installing First Panels
Bottom row placed directly on top of the levelling pad Panels set out sequentially in alternating A & B pattern
Panel Installation
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Installing First Panels
spacer guide used to achieve the correct front face spacing
Panels checked for alignment and battered back a minimum of 5mm ()
Bottom course propped vertical using 2 x 4 timber props
Rubber or asphalt shims installed if necessary to level the first row
Once the panel is securely held, lifting eyes are removed
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Installing First Panels
Bottom panels propped
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Applying Geotextile
Apply geo-textile over all vertical and horizontal panel joints
Apply adhesive to panel, not to geotextile
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Backfilling to Specification
Lift thickness
First backfill stage up to level of lugs
Fill graded away from facing (temporary drainage)
Backfilling carried out in direction parallel to facing panels
Compaction not performed
directly behind panel until first
strip has been secured with fill
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Compaction Equipment
Keep equipment weighing more than 1500kg (1.5 tons) and at least 1.5m (5ft.) away from the facing panels
Fill within 1.5m of the face compacted using a vibrating pedestrian roller or a vibrating plate compactor
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Strip Installation
Strips laid out perpendicular to the wall face Connecting bolts inserted so that the nut is
installed on top
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Second Stage Backfilling
Backfill to the tops of the B panels
Compact fill outside 5 feet prior to compacting fill immediately behind the panel
Verify horizontal and vertical alignment and adjust as necessary
Provide temporary hand railing
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Intermediate Panels
Place two rubber bearing pads on top of each of the lower panels
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Intermediate Panels
Place intermediate row of panels on the bearing pads
Adjust for batter and alignment Place timber wedges in horizontal joints to maintain
batter Clamp panel corners to control movement Remove wedges from lower row as soon as the next
layer of panels is positioned
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Repeat Sequence
Remove temporary hand railing and place rubber spacers
Lift panels into position and secure with timber clamps and wedges
Check for line, level and joint consistency and record on control sheets
Fix geotextile to back of panels with adhesive Backfill and compact to next lug layer Install strip Reinstate hand railing
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Top Panels
Same as for normal panels Additional mortar bedding added to the top of the
panels to provide a smooth line Upper layer of strips deflected to avoid anchor
slabs
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Top Panels
Mortar bedding on top of panels
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Troubleshooting
Out of Tolerance Condition Negative batter (wall leaning out)
Possible Cause Insufficient batter prior to fill placement Backfill material not within specifications:
More than 2% over optimum moisture content Excessive fines (% passing 200 sieve) Plasticity Index beyond specified limits
Heavy equipment operated within 5 feet of panels Backfill material placed and compacted perpendicular to the
wall Lift thickness beyond specifications Excessive compaction of backfill Clamps and wedges not properly secured
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Troubleshooting
Out of Tolerance Condition Positive batter (wall leaning in)
Possible Cause Excessive batter on panels prior to backfill placement Insufficient compaction of backfill
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Troubleshooting
Out of Tolerance Condition Difficulty installing upper panels
Possible Cause Levelling pad out of tolerance Panels not level Incorrect horizontal spacing Differential settlement causing panel to panel contact
and spalling
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Troubleshooting
Out of Tolerance Condition Bulging or horizontal alignment out of tolerance
Possible Cause Backfill material not within specifications:
More than 2% over optimum moisture content Excessive fines (% passing 200 sieve) Plasticity Index beyond specified limits
Heavy equipment operated within 5 feet of panels Backfill material placed and compacted perpendicular to the
wall Lift thickness beyond specifications Excessive compaction of backfill Saturation of backfill due to rain
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Questions?
EARTHTEC, INC.703-771-7305703-771-7306 Fax413 Browning Ct.Purcellville, VA 20132www.earthteccorp.com
Construction ProceduresFocus PointsMaterials and Services Supplied by EarthTecMaterials and Services Supplied by EarthTecMaterials and Services Supplied by EarthTecMaterials and Services Supplied by EarthTecMaterials and Services Supplied by EarthTecMaterials and Services Supplied by EarthTecMaterials and Services Suppliedby ContractorMaterials and Services Suppliedby ContractorSite PreparationConstruct Leveling PadsSite PreparationInstalling First PanelsInstalling First PanelsInstalling First PanelsApplying GeotextileBackfilling to SpecificationCompaction EquipmentStrip InstallationSecond Stage BackfillingIntermediate PanelsIntermediate PanelsRepeat SequenceTop PanelsTop PanelsTroubleshootingTroubleshootingTroubleshootingTroubleshootingQuestions?