IPWEA Awards 2011

Kerb drainage grate system

Project Summary

Retrofitting raised platforms to existing roads has always impacted on the kerb drainage, leading to flooding of the road and increased risk of accidents. With no standard product available, council engineers have developed various ways to overcome the issue. Typically side entry pits would be constructed in the kerb on the high side of a platform and connected into an existing drainage system. This can involve road crossings and extensive excavation if there isn’t an existing drain nearby to connect to.

Several ideas were proposed; one included the use of a trench grate style system, where storm water could continue down the kerb invert, through the `trench’ whilst pedestrians could still walk over the top. The solution also needed to match the profile of the platform with ramps at each end and a flat section in the middle. Previous attempts at placing small diameter pipes in kerb inverts and concreting over the top have made maintenance very difficult; therefore access into the `trench’ was essential to keep it clear from obstruction and maintain water flow.

Project Description

Project Objectives – the Bentons Square Shopping Centre owners submitted plans to the Mornington Peninsula Shire, stating their intention to expand their existing operation to include more shops and parking. With the expected increase in patronage the Shire placed conditions on the Planning Permit, requiring funding to improve pedestrian safety around the centre.

Formalising a pedestrian precinct around the centre included lowering the speed limit to 50km/h on both Bentons and Dunns Roads, construction of 6 raised platforms (3 with zebra crossings), additional line marking and raising the level of street lighting.

Barriers – at one of the sites for a raised platform, two new drainage pits were required to eliminate flooding on the high side. The pits were to be connected across the road and tapped in to the adjacent Melbourne Water drain (requiring an additional permit from Melbourne Water). The location of the platform made construction of the pits impractical due to the adjacent turn lane for accessing the shopping centre, another solution was therefore required.

Innovation - Several ideas were proposed; one included the use of a trench grate style system, where storm water could continue down the kerb invert, through the `trench’ whilst pedestrians could still walk over the top. The solution also needed to match the profile of the platform with ramps at each end and a flat section in the middle. Previous attempts at placing small diameter pipes in kerb inverts and concreting over the top have made maintenance very difficult; therefore access into the `trench’ was essential to keep it clear from obstruction and maintain water flow.

Initial enquiries found that there were no existing products available to meet our requirements. We contacted R&S Grating to meet on site to discuss the proposal and see if a solution could be found to meet our requirements. During the site meeting we quickly determined that R&S could develop a product to solve our problem.

Project Outcomes/Distinguished -The solution included a plastic channel with a galvanised frame bolted to the top. A slotted galvanised checker plate was then cut and bolted to the frame for maintenance access. The whole assembly could then be concreted in place, thus allowing storm water to pass through and pedestrians to pass safely over. The checker plate was incorporated to reduce the risk of slipping on the metal surface and narrow slots were cut to prevent high heels from getting caught in the grate.

Costs/Benefits –  With use of the installation of kerb drainage grate system, eliminated costly drainage works, minimum disturbance to surrounding infrastructure and community during construction. Approximate savings of $30,000 were achieved over conventional methods.