HelCor structures are helically corrugated steel pipes. According to the European standard EN1991-2:2007 they are used in both road and railway infrastructure namely for:
- roads and railway culverts;
- underground passages;
- ecological passages;
- hydro technical structures;
- underground retention tanks;
- visiting chambers and pump stations;
- reducing the weight of the concrete decks from the bridge structure.
HelCor structures are manufactured by cold-rolling the steel strips (with thickness ranging from 1,25mm to 3,5mm) into a helically corrugated form (with two corrugation types: 68*13 mm si 125*26 mm) with a diameter ranging from 300 mm to 3600 mm.
In order to protect the integrity of the final product, a fixing joint is performed during the manufacturing process. The HelCor pipe-arches are manufactured by controlled mechanical deformation of the circular HelCor pipes with hydraulic presses.
The steel used during the manufacturing process of the HelCor pipes is according to the European Standards EN 10327:2006 and EN 10326:2006. Steel is delivered in coils, with a protection coating in accordance to the above mentioned standards:
- 600 g/m2 zinc coating on both sides, equivalent to 42μm on each side
- 1000 g/m2 zinc coating on both sides, equivalent to 70μm on each side
- 600 g/m2 zinc coating on both sides, equivalent to 42μm on each side, with an additional 250μm polymer film (TrenchcoatTM or W-Protect®) on one or both sides.
The galvanized steel strip is covered with a polymeric layer, through a controlled technological process, which protects the zinc layer. The manufacturing process is according to the standards EN 10169 [W-Protect] and ASTM 742 [TrenchcoatTM]. The polymeric foil can be applied either on one side, or on both sides of the pipe. This kind of protection is the most efficient way of preventing the corrosion, on the market, moreover it protects against mechanical deteriorations and against aggressive chemical substances, granting a service time of more than 100 years in the majority of weather conditions.
The manufacturing tolerance of the circular and pipe-arch HelCor pipe sections is of ±5,0% from the designed length. The distance between two pipes joined with connecting elements must be of maximum 30 mm.
In order to choose the optimal specifications of the pipe, the HelCor pipes need a technical design which has in view the load charges, and the hydrological and geological conditions.
The HelCor pipes can be laid on unequal surfaces. They can be used on light soil and in the areas of subsidence. This is due to the pressure distribution around the pipe, which reduces the pressure under the pipe.
The standard lengths of the HelCor pipes are 6m, 7m and 8m; they are joined together with coupling elements.
The HelCor pipes are rapidly installed by unqualified workers under the supervision of an engineer, without heavy equipment, even in unfavourable weather conditions. The rapid assembly time reduces the traffic inconveniences and the reconsolidation process allows the construction without stopping the traffic and the demolition of the old structure. The construction of culverts with the use of HelCor and HelCor Pipe Arch is much cheaper than with traditional concrete culverts.
The HelCor and HelCor Pipe Arch are manufactured in Prejmer, Brasov county and can be transported anywhere in Europe.