This specification covers design requirements for superstructures proposed by the Contractor as alternates to cast-in- place reinforced concrete deck girder structures. This work is limited to construction using precast reinforced or precast prestressed concrete stems, including AASHTO Type I beams. For areas not specifically covered in this specification, refer to the applicable portions of the project specifications, Standard and Supplemental Specifications of the Department, and Part I of the AASHTO Specifications for Highway Bridges with interim and Guide Specifications. General Provisions 101 through 150.
AASHTO Specifications AASHTO Specifications for Highway Bridges, including interim and Guide Specifications The Department will quickly review submittals to avoid delaying the Contractor’s scheme. The Department will judge the completeness, accuracy, and structural acceptability of submittals. Include the following in the bid price: • Costs for complying with this specification • Costs for completing and revising the Department plans The Contractor may bid based on using precast reinforced or precast prestressed concrete stems. When bidding is based on an alternate design, submit a Contractor-proposed alternate.
Follow these guidelines for submittals:
by the Design Engineer.
Structural Design section. 874 874 874 874 874 874
Even when submitting an alternate, assume responsibility for the plans and working drawings required by Subsection 105.02, Plans and Working Drawings. Submit alternate construction Plans and design notes that are prepared and stamped by the Design Engineer. The alternate plans submitted shall include, but not be limited to, the items below. Indicate the information using the same format used on the Department plans.
Show the following on this sheet for each Contractor-proposed alternate structure bid: • Span lengths • Pier locations • Minimum horizontal clearances from the pier face to the edge of the roadway • Minimum vertical clearances from the bottom of the lowest portion of the superstructure to the roadway surface (outside edge of shoulder to outside edge of shoulder) • The 28-day concrete strength for the superstructure and substructure • Yield and working strengths of the reinforcing steel proposed for the superstructure and the substructure • Design Specifications and interim specifications used during the design of the structure • Design live loading, impact factor, and the future wearing surface loading.
On projects that involve widening existing structures, eliminate the tie strips shown on the Department Plans. Include in the proposal for the project the cost savings from eliminating the tie strips. Include the following items in the structure details: • Each cross section at the midspan, end bent, and intermediate bent showing reinforcing steel size, spacing, and location • Concrete dimensions relative to computing the structural properties of the members • The dimensions of fillets • The spacing and size of the web stirrups and longitudinal reinforcing, shown in a longitudinal view of the stem • Design notes indicating how the spacings and sizes of reinforcing bars were obtained
Include on the drawings the size and type of tendons for prestressed alternate, the horizontal location, and the vertical profile. Also include the following: • Location of the hold-down point for the tendons • Initial prestress force and strength of concrete when the tendons are released • Method of retaining the depressed tendons in place • Calculations for determining the tendon elongation required to produce the specified pre-tensioning force • Calculations for determining the casting length • Detensioning schedule
Include in the camber the effects of vertical curvature. 875 875 875 875 875 875
General Provisions 101 through 150. General Provisions 101 through 150. General Provisions 101 through 150. General Provisions 101 through 150. General Provisions 101 through 150. General Provisions 101 through 150. Contractor-proposed alternates are considered a design and construct proposal. The design and construct team shall consist of a Contractor and a Design Engineer.
The Contractor is responsible for engineering design, drawing, detailing, plan preparation, printing, and other Work necessary to modify the Department Plans for the proposed scheme.
The Design Engineer must be registered as a Professional Engineer in the State of Georgia. The Design Engineer is responsible for the following: • Remain a part of the team and be available to discuss the project with the Department at any time during the project. • Keep a record of project-related communications with the Department, including copies of correspondence and transcripts of conversations. • Provide copies of the communication record to the Department and the Contractor. Contractor-proposed alternates shall be subject to the following criteria:
• Horizontal and vertical alignments • Beginning and ending bridge stations • Minimum horizontal clearance • Span lengths
and submitting mathematical computations indicating a check of revised vertical clearance. 876 876 876 876 876 876
superstructure to the roadway beneath is no less than 16.5 ft. (5.1 m) or the minimum amount shown on the plans, whichever is less.
indicated on the plans if either of these situations occur: • The proposed alternate involves a structure crossing a waterway. • The bottom of the beam intrudes into the 100-year flood plain.
that meet the following criteria:
plans if the vertical clearance requirement in of Subsection 542.3.05.B.3 Criteria for Contractor-Proposed Alternates, is satisfied. The stem depth shall be constant throughout the length of each structure unless indicated otherwise on the plans.
shall not vary.
end dimensions.
• Elevations that accommodate a deeper superstructure • Cap widths that provide adequate bearing area The Department will not allow adjustments in substructure quantities resulting from adjusting the elevations or cap widths.
• Current AASHTO Specifications for highway bridges, including interim and guide specifications • This specification If this specification and the AASHTO Specifications conflict, this specification shall apply.
• Weight of the structure • Weight of the future wearing surface • Construction loads
• Initial tension (before losses from creep and shrinkage) shall not exceed 200 psi (1.38 MPa) or 3√f’ci • Final tension (after losses) shall not exceed 3√f’c
least that indicated on the plans. For design purposes, do not consider 28-day concrete strength above 3,000 psi (20 MPa) for cast-in- place deck construction. 877 877 877 877 877 877
shown on the plans.
from the top of the top slab to the top of the reinforcing bar, is epoxy coated if the plans specify epoxy- coated bars. Barrier curb reinforcing steel is epoxy coated as shown on the Department plans.
1) When calculating design section properties, deduct 1/4 in. (6 mm) from the flange depth. However, when calculating the dead load moment, shear, and reaction, include the 1/4 in. (6 mm). 2) Where stay-in-place PSC deck panels are used, deduct 1 in. (25 mm) from the effective flange depth when calculating design section properties. However, when calculating the dead load moment, shear, and reaction, include the 1 in. (25 mm).
Place bearing pads or bearing assemblies no closer than 1-1/2 in. (40 mm) to the end of the beams and 3 in. (75 mm) to the edge of the cap.
and bottom of each neoprene pad.
Main Slab Reinforcement Normal to Beams 9.25 lbs./ft.² (45 kg/m²) Main Slab Reinforcement Skewed to Beams 16.00 lbs./ft.² (78 kg/m²) General Provisions 101 through 150. Ensure the following: • The design meets the Specification requirements for final design loads. • Calculations and construction engineering ensure that adjustments during construction account for deflections. • Proper line, grade, structural capacity, and stresses in the substructure and the superstructure are retained during construction. Material or work required to construct the Contractor-proposed concrete superstructures are not measured for payment. Payment for the superstructure will be full compensation for furnishing the labor, materials, equipment, tools, and incidentals necessary to complete the work, including the following: • Concrete • Reinforcing steel • Expansion joint material 878 878 878 878 878 878
• Waterproofing • Bearing pads • Barrier concrete • Design • Redesign • Plan preparation • Shop drawings • Concrete finish • Other superstructure elements necessary for constructing the bridge No additional compensation will be made for the following: • Additional material, equipment, or other items the Department requires after its review of the Contractor’s alternate for project specification conformance • Changes or deviations from the Contractor’s plan, as approved by the Department • Additional material, equipment, or other costs needed because of changes in the Contractor’s plan Charge the time required for preparation of construction plans and design notes to the allowable Contract time. Work performed and materials furnished in place as required by this Specification will be paid for at the Contract Price bid for Lump Superstr Conc, CL, Br. No. and Lump Superstr Reinf Steel, Br No. Work performed and materials furnished in place as required by this specification will be paid for at the Contract Price bid for Lump Construction of Bridge Complete to Bottom of Cap—Alt 4. The Department will determine a schedule for partial payments for the lump superstructure items. 879 879 879 879 879 879
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