FAQs - erosion protection
Frequently asked questions about Tecomatic concrete mattresses.
Explore our frequently asked questions and answers here
The pre-woven textile mattresses have a width of 3–5 meters, depending on the type of mattress. The textile mattress is sewn together by joining the top sides with the next top sides and the bottom sides with the next bottom sides, which eliminates any maximum width limitation for the concrete mattresses.
For large areas (e.g., 10,000 square meters), five textile mattresses of 2,000 square meters each are sewn together. On-site, these textile mattresses are joined, and once the entire assembly is cast, it becomes a single, continuous concrete structure.
To guide and pressurize the concrete during casting, sectional seams are sewn into the mattress. These seams open progressively as the casting proceeds, ensuring that concrete is cast against concrete. The sectional seams, along with the “dammie” clamp and shrinkage moon, guide the concrete during casting, particularly in sloped areas. The process works backward, starting at the top of the slope and progressing downward in sections.
The concrete mattress is an unreinforced structure that becomes incredibly strong through its interaction with the substrate. While there is no need for a ‘dance floor,’ it may be necessary to make slight adjustments to the substrate to ensure optimal interaction. These adjustments can be carried out using relatively fine materials, as the concrete mattress is completely particle-tight, meaning no material transport occurs through the mattress.
Filter point and block mattresses are designed with woven filtration points that allow water to pass through.
The filtration points are located at half the thickness of the concrete mattress. For example, on the FP200, our thickest filter point mattress (120 mm), the filtration point is positioned 60 mm from the underlying material. This placement ensures that the filter points are not prone to clogging.
The extent of a concrete mattress typically depends on the project’s location, surrounding conditions, and the type of materials present where the erosion protection starts and ends.
For bridge supports, there is often a cone-shaped area that requires protection from erosion, making the extension relatively straightforward. When protecting a slope, the mattress usually extends down to the foot of the slope and at least 1 meter beyond the bottom. In cases of stone coffin or bridge support repairs, the concrete mattress serves both as a permanent formwork and as long-term erosion protection at the bottom. Here, the mattress typically extends about 1.5 meters along the bottom.
At the starting and ending points, particularly with a concrete mattress, it is essential to remove fine, erosion-prone materials. Ideally, the mattress should begin and end in a ditch to ensure water naturally flows over the constructed concrete mattress.
If the mattress ends on a hard bottom, it is common to upgrade the final section to a heavier mattress for additional durability. A cast-in-place mattress ensures a completely tight fit to the existing bottom.”
The thickness, or the weight per square meter, is determined based on the prevailing forces the erosion protection is expected to withstand.
In slopes starting above the water surface, where protection against waves and swell is needed, a heavier mattress type, such as UCS200, is typically used down to a depth of around -2 meters. Along the slope, a filter point mattress, such as FP200 or FP240, may be used depending on the forces acting on the area. Heavier mattresses are often installed at the base for added stability.
There are several configurations where mattresses of different thicknesses, weights, and functions are sewn together. Once the mattress is cast, it forms a single, cohesive concrete structure, as the seams are sewn without being fully closed.
Filter point mattress
A mattress with filter points designed to distribute pressure evenly.
Uniformly thick mattress
A mattress with a dense, heavy construction.
Block mattress
A mattress with buckling joints to accommodate settling. Customized mattresses can be customized with varying block weights.
Customer solutions
Discover our customers’ challenges and see how we’ve provided solutions to meet their needs.
Skanska - New Slussen
The redevelopment of the Slussen area in Stockholm has been ongoing for some time. Tecomatic is working on erosion protection in several parts of the area and in Mälardalen. One of the reasons for rebuilding Slussen is that the water level, and therefore the risk of flooding, is too high.
Merab
Merab (Mellanskånes Renhållnings AB) operates a waste facility and recycling center at Rönneholms mosse. The site also has three landfills, two closed and one active.
Baltic Offshore
Baltic Offshore was commissioned by Ellevio to install 420 kV (kilovolt) HVAC (heating, ventilation, air conditioning) cable and in connection with this protect Beckomberga-Bredäng.
Recycling industry
A customer in the recycling industry who, among other things, is engaged in the recycling of metals in southern Sweden needs sediment discharge in one of its treatment ponds.
Nacka municipality
Järlasjön is Nacka's largest lake and very important for outdoor recreation in the municipality, but despite reduced emissions from industries and households in the surrounding area, the water quality of the lake is threatened by poorly treated stormwater.
A complete end-to-end solution for our customers
Your security
As a market leader in erosion control and water treatment, we have been delivering expertise in these fields since the 1980s. Our extensive experience includes installations for prominent clients such as Skanska, Peab, NCC, and more. Discover our wide range of tailored customer solutions.
Safe delivery
We specialize in solutions for environments affected by land erosion, fine material degradation, and the spread of environmentally hazardous sediment. Additionally, we design and construct comprehensive facilities for the collection and treatment of stormwater, leachate, process water, and wastewater.
Your full-service provider
At Tecomatic, we offer support at every stage—from expert advice to full-scale contracts. Together with our customers, we are committed to developing the best solutions in water treatment and erosion control, always with a focus on minimizing environmental impact.
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