General - The concrete placement for box and arch culverts is discussed in Section 706 of this manual. SSHC Subsection 717.04 further provides that foundation excavations shall be "as dry as practicable before concrete is poured". This requirement recognizes the
necessity of an adequate foundation for roadway structures. When the excavation for a footing is completed, the project manager or his/her representative should be contacted for his/her approval of the footing subgrade before any concrete is placed. In the event that unsuitable foundation subgrades are encountered, suitable ones composed of concrete aggregates or a concrete seal course must be constructed (see Subsections 702 and 702 of this manual).
Construction of curtain walls on culvert footings usually is quite a problem because of the difficulty in maintaining the excavation in proper condition while placing concrete.
If material to be excavated is of such nature that neat lines for the curtain wall cannot be maintained, the Project Manager may allow forming and placing the curtain wall to the bottom of the footing. Mud must be prevented from working up into the concrete.
Currently, the plans for box culverts show the backside of the wing battered 3/8” in 12”, which results in a varying wall thickness. Contractors may be permitted to construct walls using the wall’s base thickness, thus eliminating the batter. A plan revision or change order will not be required to effect this change.
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Placing Concrete and Form Removal Placing Concrete
Placing Concrete in Walls and Top Slab. SSHC Subsection 704.03 states that culvert, sidewalls, and top of slab may be constructed as:
• A monolith unit or,
• Concrete in sidewalls may be placed and allowed to harden before the top slab is placed.
If the contractor chooses to use the hardened concrete method, keyways will have to be installed to anchor the cover slab.
Option to Use Steel Sheet Piling in Lieu
of the Planned Turndowns at Box Culvert Ends
The Box Culvert plans show a 3’-0” concrete turndown at the end of the culvert barrel and along the wing wall footings. The culvert contractor may request the option of using steel sheet pile instead of this turndown. If steel sheet pile are to be used, the Bridge Division has requested that the steel sheet pile turndown depth remain at 3’-0”. Also, the dimension between the inside face of wing and outside edge of wing footing (including the taper), must be increased (at the same footing thickness) by an additional 1’-0” for rises of 5’-0” and 6’-0”, and, and 2’-0” for rises greater than 6’-0”. No additional concrete or reinforcing steel is required for the portion of the turndown at the end of the culvert barrel. In the wings, this option shall include the extension of the traverse reinforcing steel, placement of additional longitudinal reinforcing (same spacing at the No. 4 bars in the top of the footing), and the concrete shall be poured monolithically with the rest of the wing footing. The concrete and reinforcing steel used shall be the same as that used in the rest of the structure. All additional concrete, reinforcing steel, preparation, equipment, tools, labor and incidentals necessary to complete the work shall be supplied at no additional cost to the Department. All steel sheet piling shall conform to ASTM A-857 or A-525 grade 33 and 36 and shall meet the following minimum requirements:
Section Length 18 inches
Max. Section Depth 3 ½ inches
Min. Section Thickness 7 gage
Section Modulus 2.8 in3/foot
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Culverts
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Removal of Wall Forms
On large culvert jobs, it is a distinct advantage for the contractor to remove wall forms before the top slab has attained sufficient age to remove supporting forms. This will be permitted under the following conditions:
• Vertical forms may be removed as provided in SSHC Subsection 704.03. • Slab forms must be supported independently of the wall forms.
• Vertical supports for the slab forms must be capped with timbers. Longitudinal spacing of supports with 100 x 150 mm (4x6 inch) caps on edge should not exceed 1.4 m (4.5 ft). With 100 x 200 mm (4x8 inch) caps, spacing should not exceed 1.8 m (6 ft). Rows of supports must not be over 1.2 m (4 ft) apart. There must be at least two rows of support, with the outside rows not more than 0.6 m (2 ft) from walls. Variance from the above suggested spacing should be reviewed by the Project Manager.
• Vertical posts shall not be smaller than 100 x 100 mm (4x4 inches), but may be built up of two 50 x 100 mm (2x4 inches) pieces of lumber. Lateral bracing will be
required. A vertical clearance of 6 mm (1/4 inch) must be provided between the wall form studs and the slab form joists.
NOTE: Lumber may be sized in metrics using actual, not the conventional nominal sizes.
• The slab form must remain in place as provided in SSHC Subsection 704.03. • The interior walls of the culvert must be coated with white pigmented curing
compound as provided in SSHC Subsection 704.03. Flume Reinforcement
Regarding Type I, II, IV, and V Flumes, welded wire fabric reinforcing is now required on the Special Plan C (4341, 4342, 4344, 4345 -- both E & M) for the flume and spillway areas. This wire can be awkward to place and keep in position. Contractors may place intersecting No. 3 rebar at 12” centers as an alternative to the welded wire fabric.
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712.00 CORRUGATED METAL PIPE CULVERTS (SSHC Section 719) 712.01 DESCRIPTION
This work shall consist of furnishing and installing new corrugated galvanized metal pipes and pipe arches and the relaying of existing corrugated metal pipe and pipe arches. 712.02 MATERIAL REQUIREMENTS
SSHC Tables 1035.01 & 1036.01 contain the required minimum gage or sheet thickness for the various pipe diameters. The "Materials and Sampling Guide" provides that the necessary tests for acceptance will be handled by the Materials and Research Division. Material
samples need not be taken by project personnel unless a special request is made for samples. The diameter of the pipe and number of sections of pipe covered by each heat number and delivered to each culvert location should be recorded in the culvert notebook. The pipe shipment should be checked against the shipment report and any discrepancy should be reported to the Project Manager. The pipe shipment should also be checked for shipping damage and any damage noted should also be reported to the Project Manager. Ordering Material
The contractor is not permitted to order or deliver corrugated metal pipe or pipe arches until a "culvert list" listing the correct sizes and lengths of pipe is furnished to him/her by the Project Manager. Subsection 105.07 of this manual for detailed instructions on the field checking of culverts and the preparation and submission of the culvert list.
712.03 CONSTRUCTION METHODS