arrow
PROJECTS:

ENDURING, ECONOMICAL
HOLLOWCORE BRIDGES for low traffic volume roads

WHAT: Bridges for LTV roads and sites with sensitive waterways.
Winner - 2015 IPWEAQ Awards (Projects under $1 million)
WHERE: Gympie Regional Council: Elliott Rd - Cedar Pocket, and Neilson Rd - Kandanga Creek
WHEN: 2015
BUDGET: $234,554 constructed cost per bridge (excluding roadworks & GST)
ROLE: Research, Structural and Civil engineering design, Construction Superintendency


When two timber bridges were washed away by floods in 2013, Council asked us for ideas to replace the bridges. We developed a Hollowcore bridge system: 

a) built for a similar cost to "fish-passage-ready" large box culverts 
b) environmentally superior, because of minimal construction work in the waterways, safe fish passage and intact habitat for mammals  
c) detailed for 100 year design life
d) smaller crane and equipment required for construction

The first two bridges (Elliott Rd and Neilson Rd Bridges) are designed for T44 semi-trailer loads. The next two at Fleming Rd Gympie are designed for SM1600 truck loads. Read the technical paper we presented at the 2015 Small Bridges Conference.

Individual Spans up to: 
- 13.0m (Plank Type: Hollowcore planks)
- 21.0m (Plank Type: Quickcell Precast insulated planks)

Exposure classification: B1 (1 km to 50km from coastline) at this stage. Technically, greater exposures may be possible: we are currently focused on B1 sites. 

Composite action: 
(Plank type: Hollowcore) - Planks are topped with an insitu concrete slab; these are tied together with vertical mesh cast into the plank key joints and external cores. Vertical mesh function is to: a) Tiedown against flood-induced lifting of slab, b) tiedown against traffic-vibration induced lifting of slab, and c) shear reinforcement. 

(Plank type: Quickcell) - Planks have cast-in shear ligs, which lock into the topping slab. This provides a) Tiedown against flood-induced lifting of slab, b) tiedown against traffic-vibration induced lifting of slab, and c) shear reinforcement.   

Traffic Volumes:
- (Plank type: Hollowcore) - up to 250 vehicles per day per lane (10% being commercial vehicles)
- (Plank type: Quickcell) - up to 800 vehicles per day per lane (10% being commercial vehicles)


Traffic Barrier Options:
- Kerb for low fall heights
- TL-4 Tensioned wire rope (eg. TL-4 Brifen), for low to medium fall heights, with flood overtopping every 2+ years
- TL-4 Steel or Aluminium Post and Rail, for medium to high fall heights



    SEE MORE IMAGES

 

WATCH VIDEO: