How Modular systems are preferred to insitu drains
Precast drains are cheaper and easier to install
Method of construction is determined by location, size, cost and performance requirements. Trench drains can be constructed by either:
Cast-in-situ
Formwork used to create trench in surrounding concrete
- Used only in concrete pavements
- Costly, complex formwork to construct on site
- Care required to ensure frames and grates are fully supported by surrounding concrete – good vibration essential during concrete pour
- Difficulties in achieving level grate seating
- Hydraulic performance poor due to rough internal finish. Trenches susceptible to biological growth
- Difficulties creating a hydraulically efficient ‘U’ or ‘V’ shape bottom (cast in-situ usually has square base design with poor hydraulic characteristics)
- Difficulties in achieving sloped system – formwork becomes even more complex adding to installation time and labour
- Quality of finish can vary greatly, depending on contractor
Precast modular systems
Off-the-shelf factory produced channel units that connect together to create trench drain
- Some products can be used in a variety of pavement types
- Neat aesthetic appearance
- Quick to install
- Hydraulically efficient due to smooth surface and curved profile bottom
- Easier to secure grates
- Consistent quality due to factory controlled production of channels
- Cost effective when labour and material costs taken into account
- Easier to estimate costs
- Less maintenance required
