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ALTON HIGH SCHOOL
| PROJECT TYPE: |
Modular Retaining Walls |
| CLIENT: |
Alton School
District |
| APPROX VALUE: |
$450,000 |
| DURATION: |
Jan 2004 -
July 2004 |
PROJECT SUMMARY:
To construct an 18,000 square foot modular retaining wall for a
portion of the Alton High School project for the project
construction manager, SM Wilson.
PROJECT SOLUTION:
This project used Rockwood blocks. Over 15,000 of
backfill stone was used at the site. The major supplier
for this project was Lemay Block. The project engineer
was Ed Austin of Aspen Consultants. The geo-grid used was
Marofi 5xt.
SPECIAL CONSIDERATIONS:
The wall was designed with no setback (see drawing below) and
would be 25 feet tall at it's highest point. Additionally
the wall had to support the loads of a parking lot and new
athletic fields. On site there were access concerns to
the future wall location. The empty site was essentially
a barren field filled with a great deal of unforeseen ground
water. Consequently much remediation was necessary at the
base of the wall and behind where one-inch clean fill was used
to facilitate drainage.
As an interesting note,
with the drainage problems an independent engineering firm was
hired, eventually determining that the soil's load bearing
capacity in several areas was insufficient. To increase
the bearing capacity the areas were remediated with compacted
backfill. This slowed the progress of construction while
necessary soil compaction tests were completed. The soil
was monitored daily for two weeks.
This is one reason why
an owner should always hire an independent engineering firm to
conduct pre-construction studies of plans and proposals.
PHOTOS:
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A wide angle of the
finished wall on the final day of the project.
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The excavated trench
for the base of the wall.
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The excavated trench
is filled with rock which is compacted with a mechanical
compactor (foreground).
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A bobcat is used to
deliver backfill to the trench as well as various other
tasks around the jobsite.
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A close-up view of a
load of backfill being delivered to the site.
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The wall rises
slowly, course by course using a laser level to ensure
straight lines.
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A truck dumps one of
the thousands of truckloads of backfill behind the wall.
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This shot shows a
good cross-section of the partially constructed wall with
varying course heights and backfill in place.
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Fence post sleeves poke
up above finished courses of the wall awaiting more wall
courses and backfill.
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