591STRUCTURAL PLATE PIPES,

New Hampshire Department of Transportation Standard Specifications – 2016 PIPE-ARCHES, AND ARCHES Description

1.1This work shall consist of furnishing and installing steel structural plate pipes, pipe -arches, or arches, of the size and type

specified, at the location shown on the plans or ordered. 1.1.1 Structural plate pipe as mill fabricated shall be elliptical. Materials

2.1Materials and design of plates and metal bearings shall be as specified on the plans or in the AASHTO “ LRFD Bridge Design

Specifications” unless otherwise provided hereinafter.

2.2Plates and fasteners shall conform to AASHTO M 167.

2.2.1 Dimensions, including the thickness of plates, shall be as shown on the plans.

2.3Elliptical requirements for pipe. Pipe under the item of structural plate pipe shall be fabricated elliptically so as to increase

the vertical diameter 5 percent and decrease the horizontal diameter 5 percent. These dimensions shall be subject to manufacturing tolerances.

2.4Backfill shall conform to 209.2.1.2.

Construction Requirements

3.1General.

3.1.1 The Contractor shall provide for the temporary diversion of water in order to permit the installation of the structure in a reasonably dry trench unless otherwise permitted. 3.1.2 Fabrication, assembly, and installation of structural plate structures shall be as specif ied in the AASHTO “ LRFD Bridge Construction Specifications” unless otherwise specified hereinafter. 3.1.3 Where soft or other unsuitable material is encountered, all of such unsuitable material shall be removed for the depth shown or ordered. See Figure 1-a. 3.1.4 Where bedrock or other incompressible material is encountered, it shall be removed to a minimum of 1 ft. below the flow line. See Figure 1-b. 3.1.5 Granular backfill or other approved material shall be used to backfill the spaces left by the excavation of material removed in accordance with 3.1.3 and 3.1.4. The material shall be uniformly compacted by the use of lightweight construction equipment.

3.2Bedding of Pipe and Pipe-Arches.

3.2.1 The structure shall be placed at the designated locatio n on a prepared foundation of granular backfill so that the flow line of the structure will conform to the required grade. Pipe or pipe -arch structures shall be set on a uniformly compacted bed of fine granular material 1 ft. deep, or as ordered, below th e bottom of the structure. The bed shall extend under the structure and at least 1 ft. beyond each side of the span. See Figure 1-c. 3.2.2 The granular backfill shall be carefully shaped by means of a template to fit the lower exterior of the structure, forming a trench equal in depth to at least 10 percent of the height in the case of a pipe- arch and 15 percent of the height in the case of a pipe. Care shall be taken to maintain the height of the edges of the bedding. Reasonable latitude will be permitted to allow for the field bolting of both circumferential and longitudinal seams of plates that are in the area of the shaped trench. When the top of the granular backfill is above the natural ground, fill for lateral support shall be constructed on each side of the granular backfill for a distance of approximately 2 times the span of the pipe or pipe-arch. See Figure l-c. New Hampshire Department of Transportation Standard Specifications – 2016

New Hampshire Department of Transportation Standard Specifications – 2016

3.3Arch Substructure.

3.3.1 The substructure for the arch shall be constructed as shown on the plans.

3.4Structure Assembly.

3.4.1 The plates for the structure shall be assembled according to the manufacturer’s assembly instructions and the plans. 3.4.2 Pipe or pipe -arch structures may be assembled in their final location or partially or completely assembled elsewhere and then placed on the prepared foundation. 3.4.3 Arches shall be erected in place upon the prepared substructure. 3.4.4 The structure shall be assembled by partial bolting with the plate location and sequence of plates as shown on the Fabricator’s drawings. Complete bolting and hand tightening shall follow the assembly no closer than two or three plate rings. Final tightening shall be carried out progressively and uniformly. Whenever possible, final tightening shall be completed by working from the outside and inside of the structure at the same time with the operation repeated as required, making sure that all bolts are tight. With pipe, the final tightening shall start at the bottom seams and work progressively to the top seams on each side. 3.4.5 When assembling structures intended to be used as pedestrian or animal passes, all bolts shall be placed with bolt heads on the inside of the structure. 3.4.6 Pipes shall normally be installed with the longer axis vertical. 3.4.7 Anchor bolts shall be installed when and as shown on the plans. 3.4.8 After erection of an arch and before backfilling is started, the groove of the metal bearing channel shall be filled with asphalt filler to the level of the top of the concrete. 3.4.9 When completed, the structure shall be true to the required alignment and grade and properly placed as to the center line of the road.

3.5Backfilling Structural Plate Pipe and Pipe-Arch.

3.5.1 All backfill material adjacent to a pipe or pipe -arch shall be approved compactable soil or granular fill material and shall not contain stones retained on a 3” screen. This soil shall extend to a height of at least 1 ft. above the top of the structure and the width shall fill the trench or in fills extend for a width on each side of the structure equal to t wice the diameter or 12 ft. whichever is less, with the slopes normal to the structure not steeper than 6:1. 3.5.2 This material shall be uniformly compacted at near optimum moisture content, in layers not exceeding 6” in compacted thickness, by pneumatic tampers, vibratory compactors, or other approved means. Care shall be exercised to compact the backfill thoroughly under the haunches of the pipe or pipe-arch and to ensure that the backfill soil is in intimate contact with the side of the structure. The backfill shall be brought up evenly on both sides of the structure along the full length installed. Fill at the sides may be compacted by rolling or operating heavy equipment parallel with the structure, provided care is taken to avoid displacement or injury. Material in the vicinity of pipes or pipe-arches shall be compacted to not less than 95 percent of AASHTO T 99, Method C. 3.5.3 The Contractor shall place a protecting cover of earth or other approved material over the structure before allowing equipment or traffic to pass over it. The protective cover shall be of a thickness to prevent overstress and damage to the pipe as specified by the pipe manufacturer.

3.6Arch Backfill.

3.6.1 When backfilling an arch before headwalls are placed, the first material shall be placed in the form of ramps constructed on both sides of the arch, at right angles to the axis of the arch and midway of the ends. These two ramps shall be as narro w as practicable, consistent with thorough compaction, and shall be brought up uniformly on both sides of the arch until the ramps meet and material is placed at least 1 ft. above the top of the arch. After the ramps have been joined, the remainder of the back fill shall be placed and compacted, widening the ramps uniformly along both sides and toward each end of the arch to avoid springing the arch out of shape. 3.6.2 If the headwalls are built before the arch is backfilled, the filling material shall first be placed adjacent to one headwall until the top of the arch is reached, after which the fill shall be dumped from the top of the arch toward the other headwall, with care being taken to deposit the material evenly on both sides of the arch. 3.6.3 In all cases, the filling material shall be thoroughly but not excessively tamped. 3.6.4 Puddling the backfill will not be permitted. New Hampshire Department of Transportation Standard Specifications – 2016 3.6.5 Arches shall be protected as required in 3.5.3.

3.7Workmanship.

3.7.1 It is the intent of these specifications that in addition to compliance with the details of construction, the completed structure shall show careful and finished workmanship in all particulars. 3.7.2 Structures on which the spelter coating has been bruised or broken, either in the shop or in shipping, or which show defective workmanship, shall be rejected or repaired as directed. This requirement applies not only to the individual plates but to the shipment of any Contract item as a whole. 3.7.2.1 The following defects are specified as constituting poor workmanship, and the presence of any or all of them in any individual culvert plate or in general in any shipment shall constitute sufficient cause for rejection:

3.7.2.2 Damaged spelter coating may be repaired by thoroughly wire brushing the damaged area and painting it with 2 coats of an approved zinc-rich primer. Method of Measurement

4.1Structural plate pipes, pipe-arches and arches will not be measured, but shall be the pound final pay quantity in accordance

with 109.11 for the structural plate structure required as shown on the plans. When more than one structure is sp ecified in the Contract, separate item numbers will be used for each separate and complete structure. Basis of Payment

5.1Structural plate pipes, pipe-arches and arches are final pay quantity items and will be paid for at the Contract unit price per

pound complete in place in accordance with 109.11.

5.2Excavation will be paid for under Section 504 regardless of the span.

5.3Granular backfill below the flow line or as shown on the plans will be paid for under Section 209.

5.4Paving of invert, if required, will be paid for under the hand method of Section 403.

5.5Concrete for arch substructure will be paid for under Section 520.

Pay items and units:

591.1Structural Plate Pipe (F) Pound

591.2Structural Plate Pipe-Arch (F) Pound

591.3Structural Plate Arch (F) Pound

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This work shall consist of furnishing and installing geotextile fabric as shown on the plans or as ordered, including any labor

and materials needed to anchor, splice, or repair the geotextile. Materials

General.

2.1.1 Geotextile shall be a product tested under the AASHTO National Transportation Product Evaluation Program (NTPEP) and included on the Qualified Products List for the Application, Strength Class, and Structure specified. Manufactures of geotextiles and those marketing geotextiles made by others as a “ Private Labeler” shall participate in and maintain compliance with the NTPEP audit program for geotextiles. Manufacturer’s labels providing product name, AASHTO M288 class, roll number, and production date shall be affixed to both ends of the roll. 2.1.2 All geotextile properties referenced in the specifications and certified by the Contractor , with the exception o f Apparent Opening Size (AOS), shall be considered minimum average roll values in the weaker principal direction (i.e., the average test results for any sampled roll in a lot shall meet or exceed the minimum values specified). Values for AOS shall represent maximum average roll values. 2.1.3 Fibers used in the manufacture of geotextiles, and threads used in joining geotextiles by sewing, shall meet the requirements of the most current version of the applicable sections of AASHTO M 288. 2.1.4 Geotextile shall exhibit an ultraviolet stability (retained strength) of at least 50% after 500 hours of exposure, measured in accordance with ASTM D 4355.

Application.

Following are the basic Applications of geotextile included under this specification. Applic ations are described according to their most common use(s) and may not include every function for which a geotextile is specified. 2.2.1 Application 1 – Subsurface Drainage. Geotextile for this Application consists of fabric placed against a soil to allo w for long-term passage of water into a subsurface drain system while retaining the in situ soil. 2.2.2 Application 2 – Separation. Geotextile for this Application consists of fabric placed to prevent mixing of in situ or subgrade soil with aggregate cover materials. 2.2.3 Application 3 – Stabilization. Geotextile for this Application consists of fabric placed in wet, saturated conditions to provide the coincident functions of separation and filtration. This Application may also be specified for geotextiles used to provide the function of reinforcement. 2.2.4 Application 4 – Permanent Erosion Control. Geotextile for this Application consists of fabric placed below riprap or other armor systems to prevent soil loss and/or instability of the erosion control system.

Strength Class. Following are the basic Strength Classes of geotextile included under this specification:

2.3.1 Class 1, Class 2, and Class 3. Geotextile specified as Class 1 (high strength), Class 2 (medium strength), or Class 3 (low strength) shall meet the applicable requirements of AASHTO M 288, Table 1, including sewn seam strength when sewn seams are used. A higher strength geotextile may be substituted for a lower strength geotextile provided all other specification requirements are met. 2.3.2 Class 0. Geotextile specified as Class 0 (extra high strength) shall meet the following minimum requirements: Geotextile Property Test Method Property Requirement Pounds Grab Tensile Strength ASTM D 4632 375 Sewn Seam Strength ASTM D 4632 335 Tear Strength ASTM D 4533 135 Puncture Strength ASTM D 6241 1237

Structure. The Contract Item Number for geotextile includes a designation for Structure that defines the basic composition

of the fabric. Geotextile shall conform to the specified structure as identified by the Item Number.

2.5Permittivity and Apparent Opening Size (AOS). Geotextile shall meet the requirements for permittivity and Apparent

Opening Size (AOS) as described in the Geotextile Qualification Criteria Document. Located on the Department’s Website.