Everything Flowing Smoothly When Fastening

Hydropower Plant Renovation in Biessenhofen with fischer Injection Mortar System FIS EM

Everything Flowing Smoothly When Fastening
References
The renovation progressed quickly – until frequent flooding damaged the temporary dam in the Wertach River, which had been filled with gravel. This dam was constructed in coordination with the responsible nature conservation authorities. All attempts to keep the water away from the weir system using “Big Bags” – one cubic meter large plastic bags filled with gravel – failed. Further flooding caused the water level to rise so much that the sluices were opened and the water management was damaged multiple times.
Thus, further work in the area of the weir system on the side facing the Bärensee had to be paused initially. In the direction of Bachtelsee, pillars and walls around the turbine inlet still needed renovation. VWEW-energie, as operator and client, mastered the challenges of flooding with the proposal of the engineering office Dr. Ing. Koch Bauplanung GmbH and in cooperation with the contracted dive master company Kerlen Taucher GmbH by having a new reinforced concrete wall constructed. This was subsequently placed next to the existing dam wall and measures about 2 m thick and 9 m long. After the “raising,” the reinforced concrete wall, together with a needle gate, will separate the Wertach River from the work areas.

Property Profile

Builder:
VWEW energy
Construction Planning:
Engineering Offices Dr. Eng. Koch Construction Planning GmbH
Project Scope:
Hydropower Renovation
Diving Company
Diving Master Company Kerlen Taucher GmbH
Suitable for the application, our fischer injection mortar FIS EM is approved for water-filled drill holes according to anchor theory
Bernd Wetzel (fischer Application Technician)
The specialists constructed the wall by securing B 500B reinforcing steel with the fischer injection mortar FIS EM 1500 S in combination with couplers with a diameter of 20 mm to an existing base plate. The installed material, which complies with ISO and Swiss SIA standards, has the property of being highly ductile, meaning it can plastically deform under load before failing.
This allowed the drill holes with a diameter of 25 cm to be successfully filled with the injection mortar and the concrete to be secured with the system. “Additional advantages include that the solution, alongside other system components, is specifically suitable for reinforcement connections from 8 to 40 mm diameter in concrete and offers high load capacities,” adds the state-certified structural technician. “The system temperature of up to 5° is also suitable for underwater installation.”
No normal concrete was present as a construction substrate. In advance, Bernd Wetzel, together with employees of the executing construction company Xaver Lutzenberger GmbH & Co. KG, conducted extensive tests. Through pull-out tests, the experts tested the load capacity of the installed system made of injection mortar FIS EM, reinforcing bar, and concrete using a rock anchor testing device at 200 kN tensile force, which was determined in coordination with the engineering office Konstruktionsgruppe Bauen AG. For this purpose, the employees of Lutzenberger GmbH traveled by boat over the fastening points where anchoring was done. Using a reinforcement coupler as a connection, they extended the bars and attached a steel pipe to it. The test device was placed on this and pulled on it.    
We generally use only fischer products for underwater assembly
Karl Kerlen (from Kerlen Taucher GmbH)

To avoid the risk of the FIS EM cooling down and becoming viscous due to the low water temperature, it was heated before installation. Subsequently, the commissioned commercial divers of Kerlen Taucher GmbH, who had previously made the boreholes, informed Bernd Wetzel by radio when they needed more mortar. The fischer specialist then injected it on call via a hose, and the commercial divers filled the boreholes with it. In this way, the weir system was successfully drained and reinforced. "When using the fischer injection mortar system to reinforce the reinforced concrete wall in the Wertach, for example, we can be absolutely sure that it withstands the extreme conditions," emphasizes Karl Kerlen from Kerlen GmbH.
The result was a stable reinforced concrete wall that enables the repair and functional preservation of the 1960s facility – and ultimately the ecological generation of electricity from water.

The fischer products used

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