3Anti-gawking screens#
3.1Background#
Anti-gawking screens should be used at work sites to minimise visibility of construction activities to the travelling public where specified in the Department of Transport and Main Roads Technical Specification MRTS02 Provision for Traffic.
Department of Transport and Main Roads SD1473 Single Slope Concrete Barrier – Precast Concrete Barrier Installation Details provides typical details for a fabricated timber screen installed on a Single Slope Precast Concrete Barrier (PCB).
Use of anti-gawking screens constructed from other materials shall be as per the relevant manufacturer’s specifications and only used with the relevant Transport and Main Roads approved proprietary temporary barrier system.
Proprietary screens may be adopted, or other screens may be developed on a project by project basis. Such screens should be compliant with the principles set out in this section.
3.2Considerations#
3.2.1General#
When using anti gawking screens at roadworks sites, the following characteristics should be considered:
- a) the screens are or of adequate height and opacity to function as a screen
- b) installation does not adversely affect or alter the performance of the barrier system
- c) installation will not present an undue risk to workers and other traffic during an impact (for example, by spearing / penetrating the passenger compartment)
- d) performance will be in a suitable predictable manner should impact occur (for example, will not shatter or create debris which would become a hazard or projectile)
- e) resistance to vandalism and vehicle damage
- f) ease of repair, and
- g) potential to protrude or lean into vehicle path, especially when subject to wind loading.
3.2.2Specific requirements#
Crash testing / analysis barrier performance is tested against the requirements of AS 3845. It should be demonstrated by crash testing or modelling / analysis that any anti gawking screen does not modify the performance of the safety barrier system to which it is to be attached. These requirements notwithstanding, it is expected that anti gawking screens will be independently mounted; that is, will not be connected together across couplings between barriers.
The Austroads Guide to Road Design and relevant supplements expressly prohibits the erection of fencing with horizontal rails within the clear zone or in any location where there is the possibility of impaling an impacting vehicle. In this regard, the principles applying to fencing also apply to anti gawking screens; that is, anti-gawking screens erected within the clear zone shall not comprise horizontal rails.
Screens should be constructed from materials that are robust and should demonstrate the following:
- resistant to impact: that is, materials are not brittle or prone to become brittle and do not create a hazard when hit, for example, by shattering or disintegration into sharp edged fragments which would be a hazard to adjacent parties
- durable: that is, resistant to ignition by cigarettes or similar, or defacement by sharp implements, and
- resistant to fatigue failure, for example, due to cyclic wind loading including buffeting from truck movements.
Subject to these, materials used should be appropriate for the design life of the screen.
3.2.3Stability#
Any anti-gawking screening should be designed to withstand design wind loads without toppling, displacing or becoming detached from the barrier system to which it is attached. The method of attachment to the barrier system should not compromise performance of the barrier system.
3.2.4Delineation#
It is recommended that anti-gawking screens do not compromise the capacity of a barrier system to display delineation. Consideration should be given to reflectivity of screen faces, with particular attention to headlight glare under wet conditions.
3.2.5Installation and maintenance#
Screens should be maintained, removed or replaced when damaged or deteriorated through prolonged use. Contractors should be encouraged to attend to damaged or deteriorated screens as soon as practicable. In this regard, manufacturers should give consideration to ease of handling and installation, and method of removal in an emergency.
Anti-gawking screens shall be in accordance with SD1473 Single Slope Concrete Barrier – Precast Concrete Barrier Installation Details (if timber) and as per the manufacturer’s specifications for other materials and be:
- a minimum of 2.2 m total height
- of sufficient extent to fully screen the work area from the public, and
- designed, installed and maintained to enable the safe and continuous passage of traffic through the construction site.
