This Clause shall apply to lighting support structures, traffic signal supports and traffic sign structures, whether post-mounted or attached to overhead gantries or other structures. 23.2 Limit states
23.2.1 Ultimate limit state
Ultimate limit state shall be defined as a loss of static equilibrium, inelastic instability and failure to further sustain the design load.
23.2.2 Serviceability limit state
Serviceability limit state shall be defined as excessive vibration from lateral or cross-wind effects induced by vortex shedding, leading to fatigue or failure of electrical components or other functional problems. The critical wind speed, where the frequency of vortex shedding equals a structure resonance frequency, shall be greater than the maximum serviceability design wind speed or low enough to produce very small vibratory amplitudes only.
23.3 Design wind speeds 23.3.1 Ultimate limit state
The ultimate limit state design wind speed shall be determined as follows:
(a) For sign structures which span over traffic, including traffic signal mast arms, the design wind speed shall be as specified in AS/NZS 1170.2 for a 1000 year return period.
(b) For light poles, signs and signals over 5 m, the design wind speed shall be as specified in AS/NZS 1170.2 for a 200 year return period.
(c) For minor sign structures less than 5 m in height, the design wind speed shall not be less than 35 m/s.
23.3.2 Serviceability limit state
The serviceability limit state design wind speed shall be determined as follows:
(a) For sign structures which span over traffic, traffic signal mast arms, light poles and signs over 5 m, the design wind speed shall be as specified in AS/NZS 1170.2 for a 20-year return period.
(b) For minor sign structures less than 5 m in height, the design wind speed shall not be less than 20 m/s.
23.4 Design wind pressure
The design wind pressure (q*) (kPa) for ultimate limit states or, serviceability limit state, shall be calculated using an equivalent dynamic pressure approach as follows:
3 2 w d *=0.6C V 10− q . . . 23.4 where
Cd = drag coefficient given in Table 23.4 or determined in accordance with AS/NZS 1170.2, as appropriate
Vw = design wind speed for the ultimate limit states or serviceability limit state determined in accordance with Clause 23.3, as appropriate
NOTE: For tall slender structures, such as high masts, the equivalent dynamic pressure approach may be unconservative. As an alternative, the dynamic response factor method of determining design wind loads may be used in accordance with AS/NZS 1170.2.
TABLE 23.4
DRAG COEFFICIENTS FOR ELEVATED SIGN PANELS, LUMINAIRES AND TRAFFIC SIGNALS
Sign panels
(more than 2 m above ground level) Width to height ratio of sign
(see Note) Drag coefficient (Cd) 1.0 1.18 2.0 1.19 5.0 1.20 10.0 1.23 15.0 1.30 Luminaires
With rounded surface 0.5 With rectangular, flat-sided shape 1.2
Traffic signals 1.2
NOTE: For immediate values, use linear interpolation.
23.5 Design loads
The design loads shall consist of a combination of the appropriate limit state design dead load and wind load. The wind load shall be assumed to come from any direction at the design wind speed specified in Clause 23.3.
23.6 Service live load on walkways
In structures fitted with walkways or service platforms, or both, the design load shall be as specified in Clause 7.2.
This design load shall be applied in conjunction with design dead and wind loads for serviceability limit states. For ultimate limit states, it shall be applied with design dead loads only.
24 NOISE BARRIERS
24.1 Wind pressure on noise barriers
Wind pressures on noise barriers shall be determined in accordance with AS/NZS 1170.2 and subject to the requirements of Clauses 24.2 to 24.8 and this Standard.
24.2 Average return interval
The average return interval to be used for the calculation of the ultimate limit state wind forces for design shall conform to the situation descriptions given as follows, subject to approval by the authority:
(a) 200 for noise barriers that are located on road or rail authority property and cannot fall onto or slide down a slope onto other property, roadway, walkway or onto traffic areas;
(b) 2000 for noise barriers that can fall onto railways and onto roadways designated as essential to post-disaster functions; and
(c) 500 for all other noise barriers.
A1
24.3 Design life
The design life for noise barriers shall be 50 years. 24.4 Change in terrain category
Any change in terrain category shall be taken into consideration in accordance with AS/NZS 1170.2.
24.5 Shielding multiplier (Ms)
The shielding multiplier (Ms) specified in AS/NZS 1170.2 shall be taken as 1.0. 24.6 Topographic multiplier
AS/NZS 1170.2 accounts for sites in relation to the topographic features of hills, ridges and escarpments.
Where the topography along a length of noise barriers varies, then each situation shall be assessed taking into account its location relative to the prevailing topographic feature. Road embankments shall be treated as a hill or an escarpment. A road embankment shall be treated as an escarpment provided it meets the requirements for an escarpment and, additionally, the top width of the embankment is greater than or equal to the greater of— (a) 5 times the upwind height of the embankment; and
(b) 5 times the height of the upwind noise barrier. 24.7 Net pressure for hoardings and freestanding walls
The pressure coefficient shall be determined in accordance with AS/NZS 1170.2.
Noise barriers on bridges shall be treated as hoardings. Other noise barriers shall be treated as freestanding walls.
Where gates and gaps occur in the noise barrier, the barrier adjacent to the gap or gate shall be treated as a free end.
24.8 Free ends
Special consideration shall be given to the design of free ends.
APPENDIX A
DESIGN LOADS FOR MEDIUM AND SPECIAL PERFORMANCE LEVEL
BARRIERS
(Informative) A1 GENERAL
This Appendix provides guidance for the authority to assist in determining the ultimate design loads and load distribution lengths for medium and special performance level barriers.
The loads given in Tables A1 and A2 are based on a lateral combined vehicle/barrier deformation of 0.5 m.
A2 DESIGN LOADS
A2.1 Medium performance level barriers
For medium performance level barriers, the loads and distribution lengths given in Table A1 may be adopted unless the authority determines that other values are appropriate.
TABLE A1
DESIGN LOADS FOR MEDIUM PERFORMANCE LEVEL BARRIERS
Ultimate transverse outward load (FT) Ultimate longitudinal or transverse inward load (FL) Vehicle contact length for transverse
loads, LT and longitudinal loads (LL) Ultimate vertical downward load (FV) Vehicle contact length for vertical loads (LV) Barrier performance level kN kN m kN m Medium 500 170 2.4 350 12.0
A2.2 Special performance level barriers
For special performance level barriers, the loads and distribution lengths given in Table A2 may be adopted unless the authority determines that other values are appropriate.
TABLE A2
DESIGN LOADS FOR SPECIAL PERFORMANCE LEVEL BARRIERS
Ultimate transverse outward load (FT) Ultimate longitudinal or transverse inward load (FL)
Vehicle contact length for transverse loads,
LT and longitudinal loads (LL) Ultimate vertical downward load (FV) Vehicle contact length for vertical loads (LV) Barrier performance level kN kN m kN m Test level 6 (36 t articulated tanker) 750 250 2.4 350 12.0
Greater than test level 6 (44 t articulated van)
1000 330 2.5 450 15.0
For other special performance level barriers, the loading criteria are to be determined by the authority.
A3 EFFECTIVE HEIGHTS
The minimum effective heights given in Table A3 may be adopted for medium and special performance level barriers unless the authority determines that other values are appropriate.
TABLE A3
MINIMUM EFFECTIVE HEIGHT OF TRAFFIC BARRIER
Barrier performance level
Minimum effective height (He) mm Medium 1100 Special (TL6–36 t Articulated tanker) 1400 Special (> TL6–44 t Articulated tanker) 1400 Special—Other To be specified by the authority
AMENDMENT CONTROL SHEET AS 5100.2—2004
Amendment No. 1 (2010)
CORRECTION
SUMMARY: This Amendment applies to the Preface, Clauses 2, 5.4, 6.7.3(ii), 7.3, 8.5.1, 8.5.2, 11.2.1, 14.7.1, 24.2, Figures 6.2.3, 6.2.4, 12.4, 15.2.1, 16.3.3 and 17.3.
NOTES
NOTES
Standards Australia
Standards Australia develops Australian Standards® and other documents of public benefit and national interest. These Standards are developed through an open process of consultation and consensus, in which all interested parties are invited to participate. Through a Memorandum of Understanding with the Commonwealth Government, Standards Australia is recognized as Australia’s peak non-government national standards body. Standards Australia also supports excellence in design and innovation through the Australian Design Awards.
For further information visit www.standards.org.au Australian Standards®
Committees of experts from industry, governments, consumers and other relevant sectors prepare Australian Standards. The requirements or recommendations contained in published Standards are a consensus of the views of representative interests and also take account of comments received from other sources. They reflect the latest scientific and industry experience. Australian Standards are kept under continuous review after publication and are updated regularly to take account of changing technology.
International Involvement
Standards Australia is responsible for ensuring the Australian viewpoint is considered in the formulation of
International Standards and that the latest international experience is incorporated in national Standards. This role is vital in assisting local industry to compete in international markets. Standards Australia represents Australia at both the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Sales and Distribution
Australian Standards®, Handbooks and other documents developed by Standards Australia are printed and distributed under license by SAI Global Limited.
For information regarding the development of Standards contact: Standards Australia Limited
GPO Box 476 Sydney NSW 2001 Phone: 02 9237 6000 Fax: 02 9237 6010 Email: [email protected] Internet: www.standards.org.au
For information regarding the sale and distribution of Standards contact: SAI Global Limited
Phone: 13 12 42 Fax: 1300 65 49 49 Email: [email protected]
ISBN 0 7337 5628 X