MINNUM ROAD CULVERT CROSSING
Product:Â Bridge Traffic Barriers, W-Beam Guardrail and ET2000 Terminal
Application:Â Department of Transport and Main Roads
Sectors:Â Infrastructure; Government
Location:Â Queensland
Forged In Steel worked with the Department of Transport and Main Roads (TMR) to fabricate bridge traffic barriers, W-beam guardrail, and ET2000 Terminal of Minnum Road Culvert Crossing located in Balonne Shire, Queensland.
Following TMR Standard Drawing No. 2200, which provides the details of regular performance level post and rail bridge traffic barriers. The intermediate posts are typically made with 150 x 90 square hollow sections that are 700 mm long from the cap plate to the base plate. The 6mm cap plate is made with 140×140 Grade 250 plate. The ends of the cap plate are welded and ground to profile to the intermediate post. The rails are a 150x100x9 rectangular hollow section attached to the intermediate posts with M20 x 60 long bolt Class 8.8/S and a 50x50x50 washer made from Grade 300 flat bar. The base plate is a 32-mm-thick Grade 350 plate with five 30-diameter drilled holes for the post anchorages. The typical post anchorage is made with M24 threaded bar Class 8.8/S with three nuts Class 8 and one structural washer. The post is welded into the base plate, and the base is bolted into the kerb, with at least 25mm thick cement mortar seating in between.
Rail connectors are installed at the end of the rails with four M30 x 170mm long bolts Class 8.8/S, nut Class 8, two structural washers, and thin nut Class 5. Type C1 rail connectors are used at fixed joints and continuous decks, while Type C2 rail connectors are used at expansion joints. Rail support plates are 90×20 flat bars with two holes for the bolts.
For rails that are placed at the end of the bridge traffic barrier, they’re tilted at a 10-degree angle and attached to the end post with M24 x 60mm long bolt Class 8.8/S and 75x75x6 washer made from Grade 300 flat bar. Similar to the base plate of the intermediate post, the base plate of the end post is bolted into the wingwall with post anchorages.
The end block connects to the terminal block, which holds the third beam and W-beam guardrail. The terminal block has a 6 mm-thick cap plate and bottom plate made from Grade 250 steel. At the end of the W-beam guardrail is the ET2000 Terminal, which is meant to absorb the kinetic energy of an impacting vehicle. Delineators are installed at intervals on the bridge traffic barrier, consistent with the requirements specified in MRTS 14.
All the steelwork in this project is fabricated to MRTS78, which outlines the requirements for the fabrication of structural steelwork. The hollow sections used are Grade C450L0 per AS/NZS 1163, or the requirements for the production and supply of cold-formed, electric resistance-welded steel hollow sections for structural purposes. Moreover, all hollow sections underwent abrasive blasting to develop a surface profile prior to hot dip galvanising. The steel plates used are compliant with AS/NZS 3678, which specifies the requirements in the production and supply of hot-rolled structural steel plates and floor plates.
The steel components are hot dip galvanised as required by AS/NZS 4680. Before they are hot dip galvanised, the weld splatters and welding slag are removed. All welds are compliant with AS/NZS 1554.1, or the requirements for the welding of steel structures made up of combinations of steel plate, sheet, or sections. The welds are in the structural purpose (SP) category to ensure tolerance for dynamically loaded or highly stressed members.