Associated with pipelines and culverts are a broad range of precast concrete products that provide for application as:
- Stormwater Pits
- Headwalls
- Endwalls
- Underground OSD and Storage Tanks
- Pump Stations
- Sewer Access Chambers
- Sewer Maintenance Chambers
CPAA Members manufacture standard and bespoke products in factory controlled conditions with design and durability in accordance with the appropriate Australian standard for the product . Where an Australian Standard does not exist, structural design is normally in accordance with the load requirements of AS5100 as many products are installed under roads or in the proximity of vehicle traffic.
For most easily accessible products where a 50 year design life is appropriate, such as headwalls and end walls, design for durability is in accordance with AS3600.
Precast civil products installed under road, difficult to maintain or replace, where a 100 year design life is appropriate, can be designed and manufactured to AS5100.
Advantages of precast civil products:
Precast civil products offer asset managers, specifiers and installers tremendous advantage:
- Durability – precast is produced in a factory controlled environment manufactured using high performance self compacting concrete or slump concrete in rigid forms with intense vibration with tighter quality and process controls than insitu poured structures
- Sustainable – precast uses less material than insitu concrete and can be manufactured using waste products such as flyash and slag. Precast can also incorporate recycled materials such as steel, recycled concrete, aggregate or fibres. Precast is 100% recycled at end of life.
- 100 year design life – following product standards such as AS1597.1, AS1597.2, AS4198 ensures 100 year design life.
- Uses less material – with factory controlled environments and rigid forms, both AS5100.5 and AS3600 require less cover to steel equating to less wall thickness for precast than insitu poured structures recognizing the increased vibration and process control. Additionally precast is specifically designed by experienced engineers to optimize material use whilst still meeting design loads and durability requirements.
- Efficient design – precast is specifically designed by experienced engineers to optimize material use whilst still meeting design loads and durability requirements. Products such as circular pits and maintenance chambers are performance load tested ensuing efficient material use.
- Speed – precast is efficiently installed with no delay due to curing of concrete and no establishment of formwork on site.
- Low impact – precast means less time on site, less time in the trench, less disruption to community.
- Non bouyant – precast civil components are designed to resist bouyancy without additional insitu concrete pours ensuring structures remain in place with variation in water table.
- Fire and high temperature resistance – Precast concrete products do not lose their structure or deform when exposed to heat. Nor do they release harmful emissions and fumes during bushfires.
Resources
Guide to AS4198:2022
Provides specifiers with an understanding of the updated standard for the design, manufacture and adoption of precast concrete access and maintenance chambers.
Assessing internal Envionment
Concrete material and performance specification, aggregate choice and cover to steel requirements combinations can be utilised to design product for a 100-year in-service life.
