FAQs – erosion protection
Frequently asked questions and answers about Tecomatic’s concrete mattresses.
Find our frequently asked questions and answers here
De färdigvävda textilmadrasserna har en bredd på 3-5m beroende på typ av madrass. Textilmadrassen sys samman, översida med nästa översida respektive lika undersidor och därför finns det ingen maximal bredd för hur stora betongmadrasserna kan bli.
In the case of large expanses (10 000 sqm), 5 textile mattresses of 2 000 sqm are sewn together. On site, 5 textile mattresses are sewn together, which means that when the entire mattress is assembled and cast, it becomes a single concrete structure.
To guide and pressurize the concrete in the mattress during casting, sectional seams are sewn in that open up as casting proceeds, concrete is cast against concrete. The section seams, the “dammie” clamp with the shrinkage moon that is both used to guide the concrete when casting the mattress e.g. in the slope, it is worked backwards i.e. starts at the top of the slope and then it is cast in sections down the slope.
The concrete mattress is an unreinforced structure that becomes incredibly strong when it interacts with the substrate. There is no need for a “dance floor”, however, you may need to adjust the substrate slightly to ensure a good interaction. Adjustment of the substrate can be carried out with relatively fine materials as the concrete mattress is a completely particle-tight construction, i.e. no material transport occurs through the mattress.
The filter point and block mattresses have woven filtration points through which water can pass.
The filter points will be at half the thickness/height of the concrete mattress, e.g. on an FP200, which is our thickest filter point mattress (120 mm), the filter point is 60 mm from the underlying material and is therefore not sensitive to clogging.
The extent usually depends on where and how the project is located and what materials are around where the erosion protection starts and ends.
Around bridge supports there is usually a cone that you want to protect against erosion and then the extension is relatively simple. When protecting a slope against erosion, you usually want to go down to the foot of the slope and at least about 1 m out to the bottom. When repairing stone coffins/bridge supports, the concrete mattress is used both as a permanent form and as future erosion protection on the bottom. In this case, the mattress is usually pulled out about 1.5 m on the bottom.
When it comes to the beginning and end, especially in the case of a concrete mattress, you want to remove the fine erosion-prone materials first and foremost, and preferably start and end in a ditch, so that the water naturally ends up on top of the constructed concrete mattress.
If there is a hard bottom where the concrete mattress ends, it is common to upgrade the last part of the mattress to a heavier mattress. Cast-in-place mattress also makes the mattress completely tight to the existing bottom.
The thickness, i.e. the weight per square meter, is determined on the basis of the prevailing forces to which the erosion protection can be expected to be exposed.
Most commonly in slopes that start above the water surface where you need to protect against forces from waves and swell, it is dimensioned with a heavier mattress type UCS200 down to about -2m. Along a slope, it may be customary to use a filter point mattress FP200 or FP240, depending on the forces. Finally, we usually install a heavier mattress.
There are several variants where we sew together mattresses of different thicknesses and weights and with different functions. When the mattress is cast, it becomes a single concrete structure, as the mattress is sewn together without closed seams.
Filter point mattress
A mattress with filter points that create an even pressure.
Uniformly thick mattress
A mattress with a dense and heavy construction.
Block mattress
A mattress designed with hinge joints to accommodate settlement in erosion control structures. Specialutformade madrasser kan erbjudas med andra vikter på blocken.
Customer solutions
Learn about our customers’ challenges and how we have solved 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 solution for our customers
Reliability
We are a market leader in erosion control and water treatment and have been active in this field since the 1980s. We have performed installations for customers such as Skanska, Peab, NCC and others. Read more about our customer cases.
Assured delivery
We specialize in products for environments where there are issues with the erosion of land and fine materials, as well as the spread of environmentally harmful sediment. We also design and complete fully integrated facilities for the collection and treatment of stormwater, leachate, process water, and wastewater.
Your full-service provider
Tecomatic provides services ranging from consulting to full project delivery. We always strive, together with our customers, to create the best possible solutions in water treatment and erosion control while minimizing environmental impact.
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