507Reinforced Bridge Approach Fills and Reinforced Concrete Approach Slabs

Reinforced Bridge Approach Fills and Reinforced Concrete Approach Slabs

507.1DESCRIPTION

1 This section describes the requirements for constructing reinforced bridge approach fills and reinforced concrete approach slabs.

507.2MATERIALS

1 Provide materials in accordance with the following:

Material Subsection Admixtures 801.4 Aggregate for Concrete 803 Fly Ash 801.2 Geotextile 805 Pervious Backfill Material 803 Plastic Pipe for Underdrain 808.4 Portland Cement 801.1 Reinforcing Steel 811.1 Sheet Metal 815.3 Sheet Piling 815.8 Water 814.1

2 Provide cardboard void material with an initial installed compressive strength greater than 15 psi [105 kPa] and a final compressive strength, after saturation, of less than 1 psi [5 kPa].

507.3EQUIPMENT

1 Ensure that equipment meets the following requirements:

Equipment Subsection Batch Plant 513.3.1 Mixers 513.3.2 Placing and Finishing Equipment 513.3.3 Sheet Pile Driving Equipment 504.3.2

Reinforced Bridge Approach Fills and Reinforced Concrete Approach Slabs SECTION 507

507.4CONSTRUCTION

507.4.1 Steel Sheet Piling

1 When constructing bridge approach fills one-half at a time, with traffic on the other half of the roadway, use the specified size of steel sheet piling. Drive steel sheet piling where specified, in accordance with Section 504, Bearing Piles and Sheet Piling. Drive piling so that it extends from just below the proposed approach slab to the depth specified and from the abutment to the end of the approach backfill material. Do not damage the abutment corbel or footing. Leave the piling in place after construction.

507.4.2 Reinforced Bridge Approach Fills

1 Before placing backfill and perforated plastic pipe, line the bottom of the excavation with embankment and retaining wall reinforcement geotextile. Do not cover the top of the pipe or impede drainage with the geotextile.

2 Place perforated and nonperforated plastic pipe along the base of the abutment backwall, and slope to drain. Where steel sheet piling is required, provide a hole in the piling to facilitate pipe placement. If necessary for drainage, extend the pipe through the abutment wingwall. W rap perforated portions of pipe with drainage and filtration geotextile; overlap longitudinal and peripheral seams from 4 in to 5 in [100 mm to 125 mm]. Place perforated pipe with the perforations down, and cap at the high end.

3 Create a void of 2 in to 4 in [50 mm to 100 mm] between reinforced approach fill and the abutment backwall and wingwalls; use a stay- in-place honeycomb cardboard, a temporary slip form, or other approved method. Do not use polystyrene slabs and a dissolving agent. Ensure that the strength reduction of stay -in-place cardboard is controllable and that the reduction is complete before construction of the approach slab. Keep cardboard materials as dry as practical during installation and placement of backfill.

4 Place backfill and geotextile in accordance with Subsection 217.4, Construction. Place an initial lift of backfill material on the geotextile lining in the bottom of the excavation. Where steel sheet piling is required, extend the geotextile up the piling face to the bottom of the next layer of geotextile. Place and compact backfill material and wrap geotextile adjacent to the void material. Place the next layer of geotextile and compact the subsequent specified thickness of backfill on top of the fabric; re-embedment folds may be required. Repeat this procedure as necessary for the height of the abutment backfill.

5 Seams perpendicular to abutment back- or wingwalls and seams parallel to abutment back- or wingwalls and more than 13 ft [4 m] away may be constructed by overlapping the geotextile at least 24 in [600 mm]. If minimum overlap cannot be achieved, sew seams in accordance with Subsection 217.4, Construction. Leave seams exposed until the work has been inspected and repaired, if necessary.

Reinforced Bridge Approach Fills and Reinforced Concrete Approach Slabs SECTION 507

6 After completing the final lift of backfill, remove the temporary slip form or saturate the stay-in-place cardboard material to create the 2-inch to 4-inch [50 mm to 100 mm] void. If a slip form is used, remove without displacing backfill or impairing the integrity of the geotextile. If cardboard is used, saturate in-place, and continuousl y, for at least eight hours without eroding the site.

507.4.3 Reinforced Concrete Approach Slabs

1 Use class A concrete in accordance with Subsection 513.4.4, Mix Design. F inish the foundation surface at least 24 in [600 mm] outside of slab edges to provide a firm support for forms. Moisten foundation material before placing the concrete.

2 Form, place, and cure concrete in accordance with Section 513.4, Construction. Ensure that slab surfaces meet the tolerances and finish requirements of Subsection 513.4.12.2, Finishing Bridge Decks.

3 Provide and place reinforcing steel in accordance with Section 514, Reinforcing Steel.

4 Use galvanized sheet for bond breaker above corbels or sleeper slabs.

507.5MEASUREMENT and PAYMENT

507.5.1 General

1 The engineer will measure Reinforced Conc. Approach Slabs by the square yard [square meter] of the out-to-out slab dimension.

2 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Reinforced Conc Approach Slabs SY [m2] 0.1 ft [0.05 m] SY [m2]

507.5.2 Referenced Sections for Direct Payment

1 When specified, the engineer will measure and pay for the following:

dimensions specified and including geotextile required for re- embedment;

and

Underdrains.

Reinforced Bridge Approach Fills and Reinforced Concrete Approach Slabs SECTION 507

Aggregate Subbase, Base Courses, and Bed Course Material.