295 SECTION 624
624.01 Description
This work consists of furnishing and installing metal rail ings, rail retrofits, pedestrian canopies and fences.
624.02 Equipment
Reserved.
624.03 Materials
A.General. Item Section Structural Steel 834.01 Cast Metal 834.02 Paints, Oils, and Thinners 852 Galvanizing 854 Use galvanized steel for all elements and hardware. Galvanize the steel elements after fabrication.
B.E-Rail Retrofit. Item Reference Epoxy Resin Adhesive 806.02 Steel Plates , Bars and Angles ASTM A 36 Threaded Rods AASHTO M 270, Grade 36 Bolts and Anchor Bolts ASTM F 3125 Grade A 325 or ASTM A 449 Reduced Base Studs ASTM F 1554 , Grade 36 Nuts ASTM A 563 Washers ASTM F 436 Square Structural Steel Tubing ASTM A 500, Grade B
C.Free Standing Rail Retrofit. Item Reference Steel Posts, Plates, Bars, and Angles ASTM A 36 Bolts and Anchor Bolts ASTM F 3125 Grade A 325 or ASTM A 449 Reduced Base Studs ASTM F 1554 , Grade 36 Nuts ASTM A 563 Washers ASTM F 436 Square Structural Steel Tubing ASTM A 500, Grade B 296 D. Pedestrian Canopy or Fence. Item Reference Epoxy Resin Adhesive 806.02 Pipe and Fittings AASHTO M 181, Grade 1 Fence Fabric AASHTO M 181, Type IV, Class B Steel Anchor Base Plates ASTM A 36 Bolts and Anchor Bolts ASTM FF 3125, Grade A 325 or ASTM A 449 Provide fence fabric with the following characteristics: − 9 gauge wire; − 2 inch mesh; and − Bottom selvage that is barbed.
624.04 Construction Requirements
A.General. Grind or file welded joints to provide a smooth appearance. Field verify all dimensions for accuracy before submitting work drawings. Submit work drawings before fabrication.
B.E-Rail Retrofit. Fabricate the railing to the horizontal and vertical alignment of the structure. Attach each rail segment to a minimum of two posts. Furnish and install the guardrail connection plates. Installation may include sawing and removing portions of the curb. Embed the anchor bolts into the concrete using a chemical adhesive system as specified in Section 806.02, “Epoxy Resin Adhesives” .
C.Free Standing Retrofit. Fabricate the railing to the horizontal and vertical alignment of the structure. Posts shall be normal to grade. Attach each rail segment to a minimum of two posts. Embed the front anchor bolt a minimum of 9 inches and embed the back anchor bolt a minimum of 6 inches into the concrete using a chemical adhesive system with a minimum tensile strength of 17,500 pounds. Conduct a static tension tes t at the first four field installed anchor bolts and on 10 percent of the remaining installations on a bridge, as selected by the Engineer. Perform the installation of the anchor bolts to be tested and the static tension test in the presence of the Engineer and in accordance with the test procedures prescribed in ASTM E 488. Do not have any portion of the testing device bearing on the concrete surface within a distance equal to the anchor bolt embedment depth to the bolt being tested. Provide a minimum static tension of 15,000 pounds for all anchor bolt anchorage systems that are tested. If the anchor bolt slips during the test, the anchorage system has failed. Tap all 297 tested bolts with a hammer to determine if the bond has been broken. Failure of any ancho r bolt anchorage system tested will require modification of the installation procedures or use of a different anchor bolt anchorage system.
D.Pedestrian Canopy and Fence. Use self-locking nuts for bolts. Place bolt heads on the side of the fence adjacent to pedestrians. Use one of the following methods to install the 1/2 inch swedge bolts for anchor base plates: − Drill and place the bolt into epoxy mixed according to the epoxy manufacturer’s recommendations. Use epoxy that meets the requirements of Section 806.02, “Epoxy Resin Adhesives”; or − Place the bolt into the plastic concrete.
624.05 Method of Measurement
The Engineer will measure completed and in place as specified in Section 109.01, “Measurement of Quantities”.
624.06 Basis of Payment
Pay Item Pay Unit Pedestrian Railing Linear Foot Pedestrian Canopy Linear Foot Traffic Rail – Steel Linear Foot Railing Linear Foot W-Beam Retrofit Linear Foot Double Box Beam Rail Retrofit – Free Standing Linear Foot Double Box Beam Rail Retrofit – E-Rail Linear Foot Connection Plate Modification Each Include all costs for required sawing and removing portions of the curb in the contract unit price for “Double Box Beam Rail Retrofit - E-Rail” or “Double Box Beam Rail Retrofit – Free Standing. ” Such payment is full compensation for furnishing all materials, equipment, labor, and incidentals to complete the work as specified. Section 626 298 SECTION 626 COFFERDAMS
626.01 Description
This work consists of designing, constructing, dewatering, maintaining, removing, and backfilling cofferdams.
626.02 Equipment
Reserved.
626.03 Materials
Reserved.
626.04 Construction Requirements
A.General. Design and construct cofferdams to be watertight as necessary to perform the work. Provide sufficient clearance in the cofferdam for: − Construction; − Inspection of the exterior forms; and − Placement of pumping equipment. If foundation seal concrete is necessary, it must be placed as specified in Section 602.04
C.1.b(2), “Foundation Seal Concrete” .
B.Excavation. Perform cofferdam excavation as specified in Section 210, “Structural and Channel Excavation, Foundation Fill and Preparation” .
C.Removal of Cofferdams. Remove cofferdams when no longer needed. Do not excavate below the natural channel bottom outside the cofferdam to facilitate rem oval. After removing the cofferdam, place backfill material as specified i n Section 210.04 B.2, “Ordinary Backfill” . Fill the excavated area to the natural channel bottom.
626.05 Method of Measurement
The Engineer will measure as specified in Section 109.01, “Measurement of Quantities” and as follows: If multiple cofferdams are constructed to protect a single portion of the work, the Engineer will measure it as a single cofferdam. Excavation for cofferdam s will be measured as specified in Section 210.05, “Method of Measurement” . Excavation inside the cofferdam and outside the limits defined in the plans will not be measured.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 330–332 of 550.