510Structural Plate Structures

Structural Plate Structures

Description

510.01This work consists of the construction of structural plate structures of the shape and

dimensions called for on the plans per these specifications and in conformity with the lines and grades shown on the plans or established.

Materials

510.02Steel structural plate materials shall conform to the requirements of AASHTO M 167

A copy of the base metal manufacturer's certificate showing the results of tests, plus the fabricator's certificate showing the results of spelter tests shall be provided to the Engineer before installation. Aluminum alloy structural plate materials shall conform to AASHTO M 219. There is no limit on overthickness. Bolt and washer shapes shall be as shown on the plans. All bolts shall be sufficiently long to provide full penetration of the nut by the threaded end. A field applied two coat coating system using materials specified in AASHTO M 243 shall be applied when called for in the Contract. The coating shall be uniformly applied by spray, brush, or trowel to the entire surface of the culvert, both inside and outside. Each coating shall be applied at the approximate rate of 60 square feet per gallon. The first coat shall be dry to touch before the second coat is applied and the second coat shall be dry to touch before any backfill operations. Thicker invert plates for round pipes shall be construed as the bottom plate. This plate shall be installed with the center of the plate as nearly on the centerline of the pipe as practicable; however, it shall extend at least 23 inches on either side of centerline, measured on the arc. Thicker invert plates for arch pipes shall be constructed as the bottom plate (or plates) between the corner plates. The Contractor shall state at the Pre-construction Conference, the type of structural plate material (steel or aluminum) intended to be furnished, unless a specific material is specified in the Contract.

Construction Requirements

510.03Fabrication. When the completed structure is to be a full circle pipe, the plates shall

be so curved that when bolted together, true circles shall be formed of the required diameter. When the completed structure is to be an arch pipe, the plates shall be so curved as to produce a structure with the span and rise dimensions shown on the plans. Each manufacturer of corrugated structural plates shall furnish data sheets showing the physical and chemical properties of all plates to be supplied under this specification. Each plate shall be curved to the proper radius, and the bolt holes shall be so punched that all except end plates shall be interchangeable in the erection process.

All structural plates made from steel shall be made from plates formed and punched per Section 6 of AASHTO M 167.

510.04 All structural plates made from aluminum shall be made from plates formed and punched per Section 6 of AASHTO M 219.

Plates for forming skewed or sloped ends shall be so cut as to give the angle of skew or slope specified. Units where the spelter coating has been burned by welding or otherwise damaged in fabrication shall be repaired as provided in subsection 707.09. Cut plates shall present a workmanlike finish with legible identification numerals placed on each plate to designate its proper position in the finished structure.

510.04Excavation. Trenches shall be excavated to the widths required by the plans

When the installation is to be placed in embankment fill, the excavation shall be made after the embankment has been completed to a height 0.3 times the diameter or 0.3 times the rise above the flow line of the structure.

The Contractor shall excavate three test pits to a depth of approximately 6 feet below proposed flow line. Pits shall be located at each end and near the center of the trench as directed. If the foundation is deemed unsuitable, a minimum of 1 foot underlying the structure shall be excavated and backfilled with suitable material per Section 206.

510.05Erection. Plates at longitudinal and circumferential seams shall be connected by

bolts. Joints shall be so staggered that no more than three plates come together at any one point. Nuts shall be so tightened that when tested with a calibrated torque wrench furnished by the Contractor, a torque of between 150- and 250-foot pounds is attained. Tightening of bolts to a torque in excess of 250-foot pounds will not be permitted. The use of wrench sockets that will damage the metal or metal coating will not be permitted.

Before backfilling operations, the full length of each round culvert shall be distorted from a true circle by pre-forming to an elliptical shape. This elongation shall approximate 5 percent of the nominal diameter of the culvert. The preformed pipe shall be placed with its greatest dimension in the vertical axis.

510.06Backfilling. Backfilling shall conform to the details shown on the plans

Pipe damaged due to Contractor's operations shall be repaired or replaced at the Contractor's expense.

Method of Measurement

510.07Structural plate structures will be measured by the linear foot in place. Length of

round or elliptical structures shall be the average of measurements along the top and bottom. Length of structural plate arch pipe will be measured along the bottom centerline only.

510.08

Basis of Payment

510.08The accepted quantities of structural plate structures will be paid for at the contract

unit price for each of the pay items listed below that appear in the bid schedule. Payment will be made under:

Pay Item Pay Unit Structural Plate Pipe (______) Linear Foot Structural Plate Arch Pipe (____x____) Linear Foot

Structure excavation and structure backfill, including test pits, will be measured and paid for per Section 206. Coating, when specified, will not be paid for separately but shall be included in the work.

510.08

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512.01