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Standard specification for road works 2015/2016



Standard specification for road works 2015/2016


Standard specification for road works; Reports; PublicationNT




Made available via the Publications (Legal Deposit) Act 2004 (NT).; Check within Publication or with content Publisher.


miscellaneous provisions ■ provision for traffic ■ clearing grubbing and rehabilitation ■ earthworks ■ conformance testing ■ pavements and shoulders ■ stabilisation ■ spray sealing ■ dense graded asphalt ■ slurry surfacing ■ miscellaneous concrete works ■ drainage works ■ protection works ■ road furniture and traffic control devices ■ pavement marking ■ landscape ■ ducting and conduits ■ traffic control signals ■ traffic counting stations ■ street lighting ■ directional (thrust) boring ■ measurement and payment ■ referenced documents ■ nt climate zones table ■ This document specifies the general standards of materials and workmanship required by the Department of Infrastructure for construction of civil road network assets




Roads -- Northern Territory -- Works -- Periodicals.

Publisher name

Department of Infrastructure

Place of publication



Second edition

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DRAINAGE WORKS STANDARD SPECIFICATION ROADWORKS DoI REFERENCE TEXT December 2015 Page 88 12.9 OPEN UNLINED DRAINS Excavate and dispose of all excess material as specified in EARTHWORKS. Trim drains to form neat levees. Compact levees to 95% relative compaction. Allow natural surface runoff. 12.10 REMOVAL OF EXISTING CULVERTS AND DRAINAGE STRUCTURES Demolish and remove from the site, as specified, existing culverts and drainage structures. 12.11 SUBSOIL DRAINS 12.11.1 Excavation Excavate below the top of required depth of cover to drainage devices (pipe or other) to a minimum depth equal to the outside diameter of the pipe or height of other device, plus 75 mm. Line the trench with geotextile fabric. Refer to PROTECTION WORKS. Place a bedding layer of 50 mm of filter material in the trench and compact with a vibrating plate or similar. 12.11.2 Filter Material Shall be a hard durable stone having a Los Angeles Abrasion Loss not greater than 35%. Conform to the grading specified by the manufacturer of the subsoil pipe. If manufacturer's grading not supplied, conform to Table 12.4 Filter Material Grading. 12.11.3 Geotextile Fabric Conform to the requirements of 13.3 Geotextile Fabrics in PROTECTION WORKS. 12.11.4 Subsoil Drain Pipe Use 100 mm diameter Class 400. Use compatible couplings and fittings. Connect solid wall pipe to the subsoil drain pipe for the disposal of collected water. 12.11.5 Laying and Backfilling Hold Point Fit the upper end of pipelines with inspection openings and caps supported in a concrete collar. Hold point - Obtain Superintendent's approval of the pipe installation before backfilling. Place filter material around the barrel of the pipe and to a height of 200 mm above the pipe. Compact with a vibrating plate compactor or similar. Place and compact remaining layers of the filter in layers not exceeding 300 mm. Prevent contamination of the filter. Place and compact basecourse gravel, as specified in PAVEMENTS AND SHOULDERS in the top 300 mm of trench. Place the material in two equal layers compacted to 95% relative compaction. Where trench excavated through pavement compact upper layer of base course gravel to 100% relative compaction and reinstate surface. Backfill above solid wall pipes as specified in 12.6.10 Backfill Witness Point Hold Point. 12.11.6 End Walls Witness Point Construct end walls at the outlet of subsoil drains as specified. Secure 19 mm galvanised wire mesh over the opening. Mark end walls with guide posts. Clean out new work and existing work affected by the new work. Witness Point Advise superintendent within two days when clean out is completed. Table 12.4 Filter Material Grading AS Sieve (mm) Percentage Passing 37.50 100 19.00 90 100 9.50 65 85 4.75 45 65 0.60 0 5