SECTION 9072 - COMBINED CONCRETE SIDEWALK AND RETAINING WALL
Combined Concrete Sidewalk and Retaining Wall
Constructing combined concrete sidewalk and retaining wall.
Comply with Division 1 - General Provisions and Covenants, as well as the following:
Upon request, submit certification that products supplied comply with identified specifications.
Comply with Division 1 - General Provisions and Covenants.
1.05����� DELIVERY, STORAGE, AND HANDLING
Comply with Division 1 - General Provisions and Covenants.
1.06����� SCHEDULING AND CONFLICTS
Comply with Division 1 - General Provisions and Covenants.
1.07����� SPECIAL REQUIREMENTS
None.
1.08����� MEASUREMENT AND PAYMENT
A.�� Combined Concrete Sidewalk and Retaining Wall:
1.��� Measurement: �Measurement will be in cubic yards for the volume of combined sidewalk and retaining wall.
2.��� Payment: �Payment will be at the unit price per cubic yard of combined sidewalk and retaining wall.
3.��� Includes: �Unit price includes, but is not limited to, excavation; foundation preparation; furnishing and placing concrete and reinforcing steel; joint material; subdrain; porous backfill material; suitable backfill material; finishing disturbed areas; and shoring as necessary.
B.�� Fence:� If the contract documents require a fence, the fence will be measured and paid according to Section 9060.
C.�� Safety Rail:� If the contract documents require a safety rail, the railing will be measured and paid according to Section 9080.
A.�� Combined Concrete Sidewalk and Retaining Wall:
1.�� Portland Cement Concrete:� Comply with Section 6010, 2.02.
2.�� Reinforcing Steel:� Comply with Iowa DOT Section 4151.
3.�� Expansion Joint:� Comply with Iowa DOT Article 4136.02. �Use resilient filler when the type is not specified.
B.�� Subdrain: �Comply with Section 4040, 2.02. �Minimum 4 inch diameter.
C.�� Porous Backfill Material (for Subdrain):� Comply with Section 4040, 2.04.
D.�� Suitable Backfill Material: �Comply with Section 2010.
E.�� Rodent-proof Hardware Cloth:� Comply with Iowa DOT Materials I.M. 443.01.
F.�� Fence:� If the contract documents require a fence, comply with Section 9060.
G.�� Safety Rail:� If the contract documents require a safety rail, comply with Section 9080.
3.01����� EXCAVATION AND EMBANKMENT
A.�� Prior to beginning wall construction, compact proposed embankment behind the wall according to the field quality control requirements of Section 2010 with the following exception: compact to a minimum of 90% of maximum Standard Proctor Density.
B.�� Excavate to the line and grade specified in the contract documents. �Minimize over-excavation. �Install sheeting, shoring, or other retention systems as required to ensure the stability of the excavation.
1.�� Comply with Section 6010.
2.�� Forming the back of the wall is not required.� Where the back of the walls is not formed and sloughing occurs, remove the loose material, and replace with concrete at no additional cost to the Contracting Authority.
3.�� Install 3 inch diameter weep holes at 8 foot intervals.� Form weep holes with an approved rustproof device backed with rodent-proof hardware cloth.
4.�� Install 8 inch wide trench of porous backfill behind the wall. �Install subdrain within porous backfill trench. �Ensure positive drainage on subdrain.
B.�� Backfill Material Placement:
1.�� Place the backfill material in maximum 8 inch lifts, spread, and compact.
2.�� Compact granular backfill material according to the field quality control requirements of Section 2010 with the following exception: ensure the moisture content falls within a range from 3% under optimum moisture to no more than the optimum moisture content.
3.�� Use only hand-operated compaction equipment within 3 feet of the front of the wall face.
C.�� Fence:� If the contract documents require a fence, comply with Section 9060.
D.�� Safety Rail:�If the contract documents require a safety rail, comply with Section 9080.
A.�� Form ED joints in the wall at no more than 60 foot spacing. �Affix expansion material to retaining wall.
B.�� Form C joints in the wall at no more than 20 foot spacing.
C.�� Form E joints in the sidewalk to coincide with ED joints in the wall. �Form C joints in the sidewalk at spacing equal to the sidewalk width.
D.�� Form a longitudinal joint in the sidewalk when the sidewalk width is greater than 8 feet.
Decorative form liners or inserts may be used when forming the face of the wall with the approval of the Engineer.� Form rustications as specified in the contract documents.
END OF SECTION