When considering a retaining wall, it is important to first consider how you need the wall to perform. Is it a small domestic wall, or a large industrial wall that needs to take heavy loads? What are the ground conditions like? What is the drainage like? What is the budget? Does the wall need to be aesthetically pleasing? All of these factors will be taken into account when considering which product will be most suitable.
For small domestic walls, the most suitable products tend to be small precast concrete blocks that act as a gravity retaining wall. These can be built with products that will blend into the surrounding area. This type of wall uses inter locking blocks that often need a slight angle on the wall. They lock together and use gravity to retain earth and other materials.
For large more industrial walls, L shape concrete retaining walls blocks are one of the most widely used products. They are often bolted down to a secure foundation. The units will be reinforced or prestressed, and this gives them the required strength to retain materials. The alternative to this is using concrete panels and steels. The steels will be embedded into the foundations and this will give the wall it’s strength. Prestressed concrete panels are then clipped to the steels and act as a retaining wall by transferring the pressure onto the steels.
A precast concrete retaining wall is normally used to retain earth or similar materials. It is also used to divide agricultural buildings such as a grain sheds or waste transfer stations to create storage bays.
Concrete retaining walls have gained in favour over in-situ concrete walls or timber walls and are very popular for civil engineering projects. They tend to be more economical, easier to install and more environmentally sound than other options. There are two main methods for fixing the retaining wall in place; embedding them into a concrete floor, or alternatively, using a ground fixing kit. The advantage of the latter solution is that the concrete retaining wall can be moved at a later date.
One of the most important things to consider when building a concrete retaining wall is the force at which the retained material is attempting to move forward and slide due to the force of gravity. This creates a lateral earth pressure behind the wall. Earth pressures will push the wall forward or overturn it if not properly looked at. Also, any groundwater behind the wall that is allowed to build up will cause an additional horizontal pressure on the wall. This problem can be solved by placing suitable drainage holes in the wall. While it can be an unwanted expense, getting a design from a structural engineer is very important and can save a lot of time and expense further down the line.
There are a range of products suitable for use as a precast. The most suitable product will depend on a number of factors including; the material retained, the height of the wall, site restrictions and budget. A few products that are worth considering; concrete panels (either used horizontally or vertically), L shape retaining wall units or concrete crib wall units. While the material costs can look expensive, after taking into account the savings in terms of installation, it often works out as the desired solution.
Your first step should be to look at the precast products in the market and have a chat with the manufacturers. Often you will find they will help with the design and provide the sign off of a structural engineer. Make sure you shop around, there are lots of different products out there and the prices can vary a lot.