Applications

Boardwalks / Platforms

As the world becomes more aware and concerned about the human impact on our environment, boardwalks and viewing platforms of all kinds are continually being built in areas such as marshlands, riverbanks, mangroves, and sand dunes at scenic lookouts.  These sites are, by their very nature sensitive and as such, any adverse effects of construction need to be kept to a minimum.

Boardwalks may be of a simple timber design or a modern modulated aluminum structure such as PML Light Construction Pty Ltd , so the connection (interface) between the pier element of the structure and the foundation element (pile/anchor) is an important consideration when assessing suitability and costs. In some instances and wherever possible, the foundation and the structure's pier element should be combined. This is the quickest method of construction and by far the cheapest, however some boardwalk designs do not cater for this, as method and a purpose-designed head bracket or plate may be the best solution.

Ground conditions surrounding boardwalks are often poor, offering little bearing capacity at shallow depths. Corrosion protection and allowance is usually a major design issue due to tidal movement, salts or chemicals leaching from peaty soils.

Often the profile of the environment is steep, muddy, wet or loose, requiring a specialist installation approach to ensure the construction site does not end up looking like a moonscape.  The versatility of screwpiles and the varying options for installation enable screwpiles to be installed in difficult conditions such as steep gradients or wet conditions.

Images on this page show a difficult boardwalk installation where the sensitive sand embankment gradient was so steep (in excess of 40 degrees in some instances) that it was difficult for a person to stand upright without the risk of embankment collapse. The installing machine was cable-winch lowered down the embankment at the designated foundation locations.  The foundation design needed to cater for landslip, as the sands were laying over a natural limestone outcrop which extended down to the riverbank. The steel boardwalk modules were supported using compression screwpiles combined with raked tension screwpiles that were screwed back into the embankment and into the limestone to cater for the potential lateral loads that may be imposed onto the structure in the event of earthquake or landslip.   The embankment was in excess of 25m high and the boardwalk extended in excess of 100 metres.