10Road edge guide posts#

10.1General#

Clause 10 describes the work to be carried out where road edge guide posts are required to be installed under the Contract. Road edge guide posts shall fall into one of the following categories:

• Rigid: posts either incapable of returning to their original state post impact or requiring assistance by hand or mechanical means to return to, or within a margin of 5 degrees, of their original state. This category shall include all timber road edge guide posts and any other posts not meeting the requirements of Clause 10.2.3 of this document.
• Flexible: posts capable of returning to, or within a margin of 5 degrees, of their original state post impact without assistance. See Clause 10.2.3.7 of this document for more information.

10.2Material requirements#

10.2.1Rigid timber posts#

10.2.1.1Hardwood#

Hardwood posts shall be durability Class 1, 2 or 3 and have a stress grade of F5 or better, in accordance with AS 2082.

10.2.1.2Softwood#

Softwood posts shall be durability Class 1, 2, 3 or 4. Durability Class 4 softwood shall be preservative-treated to an H5 level in accordance with the Timber Utilisation and Marketing Act 1987, and any untreated heartwood shall not exceed 20% of the cross-sectional area. Softwood posts shall have a stress grade of F5 or better in accordance with AS 2858.

10.2.1.3All timber#

Timber guide posts shall be graded under the authority of a recognised timber quality assurance program and be branded with the registered trade mark of the program.

All timber which is prone to excessive shrinkage and/or distortion shall have a moisture content less than 18%. All other timber may be unseasoned.

All posts shall be cut to the dimensions shown on Standard Drawing 1356. Spring and bow in all posts shall not exceed 15 mm.

The above-ground section of posts shall be painted as follows:

1. a)the timber surface shall be cleaned
2. b)the surface shall receive one coat of pink solvent-borne wood primer in accordance with the requirements of AS 3730.13 and two coats of gloss latex paint in accordance with the requirements of AS 3730.10 with a gloss level in excess of 85 gloss units in accordance with the requirements of AS/NZS 1580.602.2.

10.2.2Rigid posts other than timber#

10.2.2.1Materials#

Road edge guide posts shall be composed of material which is heat resistant and fire retardant and which is capable of retaining 85% of its colour, appearance and physical properties for at least five years when exposed to weather conditions existing in Queensland. The materials shall be durable and resistant to mould growth and mildew and shall not be affected by hydrocarbon solvents. All materials shall be corrosion resistant or treated to resist corrosion. The post materials shall also be resistant to ultraviolet light.

10.2.2.2Colour#

The surface of road edge guide posts shall be a durable gloss or semi-gloss opaque white colour.

10.2.2.3Surface finish#

Road edge guide posts shall be free of sharp edges, burrs, discolouration or other defects which may affect appearance and/or serviceability.

10.2.2.4Dimensions#

The cross-sectional area of road edge guide posts is not critical but shall not differ from post to post by more than 3%. The following dimensional requirements shall, however, be satisfied:

1. a)rigid posts shall have a minimum width of 80 mm facing traffic over at least the top 250 mm of their length
2. b)posts shall be of such length to provide a height of 1000 mm above the ground surface and minimum anchoring depths of approximately 500 mm for buried posts and 350 mm for driven posts respectively.

10.2.2.5Bending strength#

The minimum bending strength, at yield, at the weakest point of the road edge guide post (on a partially flattened section) shall be 0.3 kNm.

10.2.2.6Weathering resistance#

If a warranty for a minimum period of five years is not available for the guidepost, then a sample of the guide post shall be subject to artificial weathering for a period of 1000 hours in either:

1. a)Atlas Twin Sunshine Carbon Arc Weatherometer, or
2. b)Xeon Arc Weatherometer at 0.55 watts/m² irradiance level with Boro / Boro filters.

During the weathering of the sample it shall be subject to:

1. a)light and dark alternating cycles 20% of the testing time
2. b)temperature during light cycles shall be a minimum of 32 degrees
3. c)humidity temperatures shall be cyclic and be 20% of the testing time.

After exposure the surface shall be free from crazing or blistering. The degree of chalking and colour change shall not fall below a rating of five and the loss of gloss shall not exceed 20 gloss units (egg shell gloss) when evaluated in accordance with AS/NZS 1580.481.1.10 Method 481.1 and AS/NZS1580.602.2 Method 602.2 (Specular Gloss).

10.2.3Flexible posts#

10.2.3.1General#

The requirements of Clause 10.2.2 above shall apply to flexible posts except as modified by Clauses 10.2.3.2 to 10.2.3.7.

10.2.3.2Dimensions#

Flexible posts shall have a minimum width facing traffic of 100 mm.

10.2.3.3Bending strength#

No minimum bending strength shall apply to flexible posts.

10.2.3.4Additional testing#

Evidence to confirm that the post has been subject to and passed the following tests shall be included in the quality records:

1. a)heat resistance in accordance with the requirements of Clause 10.2.3.5
2. b)cold resistance in accordance with the requirements of Clause 10.2.3.6
3. c)vehicle impact in accordance with the requirements of Clause 10.2.3.7.

10.2.3.5Heat resistance#

The following procedure shall be followed for heat resistance tests:

1. a)Condition two of the sampled posts at 60 ± 2°C for a minimum of two hours in an oven.
2. b)Remove one post from the oven, and clamp the base of the post at the installation mark. The post shall be clamped in a vertical position, aligned with the mark on the backboard. Inserts shaped to suit the profile of the post shall be used to ensure even clamping.
3. c)Bend the post to 90 degrees in the anticipated direction of traffic and immediately release. This process should be completed within five seconds.
4. d)The post should return to within five degrees of the vertical position within 30 seconds.
5. e)Testing as detailed in b) to d) shall be completed within two minutes of removal from the oven.
6. f)Repeat steps b) to e) a further three times, conditioning the post in the oven for two minutes between each test
7. g)Repeat steps b) to f) with the other post.

10.2.3.6Cold resistance#

The post shall be conditioned at 0ºC ± 2ºC (ice bath) for two hours prior to testing. Flexible posts shall be subjected to both the resilience and brittleness tests as detailed below. Semi flexible posts are only required to be tested to the brittleness test.

The following tests shall then be performed:

Resilience#

1. a)Remove one post from the bath and clamp the base of the post at the installation mark. The post shall be clamped in a vertical position, aligned with the mark on the backboard. Inserts shaped to suit the profile of the post shall be used to ensure even clamping.
2. b)Bend the post to 90 degrees in the anticipated direction of traffic and immediately release. This bending process shall be completed within five seconds.
3. c)The post shall return to within five degrees of the vertical position within 30 seconds.
4. d)Testing as detailed in a) to c) shall be completed within two minutes of removal from the ice bath.
5. e)Repeat steps a) to d) a further three times, conditioning the post in the bath for two minutes between each test
6. f)Repeat steps a) to e) with the other post.

Brittleness#

1. a)Place the tested post used for the resilience test in the ice bath for a further two minutes.
2. b)Remove the guidepost from bath and place horizontally between two supports, clamping each end securely. The front face of the post shall face upwards, and there shall be 1 ± 0.05 m between the two supports.
3. c)Drop a steel ball of 1 ± 0.05 kg from a height of 1.5 ± 0.05 m through a vertical guide so that it impacts on the centre of the unsupported area of the post.
4. d)Testing as detailed in b) to c) shall be completed within two minutes
5. e)Repeat steps b) to d) an additional four times (a total of five impacts) conditioning the post in the bath for two minutes between each test.

10.2.3.7Vehicle impact#

The guide post shall be capable of self-erecting and remaining serviceable after being subjected to a series of direct impacts by a typical passenger vehicle at temperatures between 15ºC and 30ºC. The guide posts to be tested shall be installed in accordance with the recommendations of the manufacturer and shall be furnished complete with delineators. The guide post shall be capable of withstanding a series of 10 bumper bar impacts at a speed of 60 km/h and five bumper bar impacts at a speed of 100 km/h directed at 90 degrees to the front face of the guide post.

The impacting vehicle shall suffer little or no damage during the impact tests. The guide post shall return to within five degrees of vertical within 30 minutes of impact. Test results which show the guide posts are capable of withstanding the above vehicle impacts are to be provided. This should include video or photographic evidence. A minimum sample of three guide posts shall be tested.

10.2.4Delineators#

Each road edge guide post shall be supplied with either two delineators (one white and one red) or with a single delineator (red, white or yellow). Road edge guide posts must be installed as specified in the MUTCD.

Delineators shall be affixed so that they are weatherproof and vandal resistant. The delineators shall be centrally located and placed so that the top of the reflector is between 50 mm and 100 mm from the top of the post. Type 1A Class material shall be rectangular with a minimum area of 100 cm² and minimum width of 50 mm. Type A Corner cube material shall be circular (80 mm diameter) in configuration.

For rigid road edge guide posts, the delineators shall consist of either:

1. a)Type A (corner cube) material which conforms with the requirements of AS/NZS 1906.2, or
2. b)Prismatic lens sheeting which meets the requirements of Class 1A material, as defined in AS/NZS 1906.2.

As stated in Clause 5 of Annexure MRTS14.1.

For flexible road edge guide posts, the delineators shall consist of prismatic lens sheeting which meets the requirements of Class 1A materials, as defined in AS/NZS 1906.2. Corner cube or rigid backed delineators that can be damaged by vehicular impact shall not be used on flexible road edge guide posts.

10.3Construction#

10.3.1Location#

Road edge guide posts shall be located as shown in the design documentation and/or as determined from Standard Drawing 1356.

10.3.2Installation#

Road edge guide posts may be installed by excavation and backfilling of a post hole or by driving, depending on the post material and the manufacturer's recommendations.

10.3.3Delineators#

On all carriageways, a red delineator shall be affixed to the face of the road edge guide post on the left-hand side of the carriageway and a white delineator shall be affixed to the face of the road edge guide post on the right hand side of the carriageway, as seen from oncoming traffic. On divided carriageways, no delineators shall be affixed to the face of the guide post facing away from oncoming traffic.

Only road edge guide posts which have been accepted for use by the Department of Transport and Main Roads shall be installed on Department of Transport and Main Roads infrastructure.

10.4Guide post warranty#

The period of warranty for guide posts shall be a minimum of five years. During the period of the warranty, the supplier shall, without delay and at no cost to the Principal, correct all defects and omissions covered by the warranty by way of repair, replacement or modification or other means. The warranty must be provided to the Department of Transport and Main Roads in writing. When a product fails this Technical Specification under the warranty period, the supplier is required to replace the product at no cost to the Principal.