JORDAHL® is at the forefront of connection and reinforcement technology development, enabling high load connections in concrete and steel. They have global customer base who specify their high-quality and individual products for fastening, reinforcement, mounting technology and facade connection.
JORDAHL products such as anchor channels have become milestones in the evolution of structural engineering bringing lasting changes to construction and shaping the way buildings are designed and constructed.
JORDAHL JDA Punching Shear Reinforcement is used for the transmission of high shear forces in flat floor applications, it simplifies and reduces requirements for formwork and reinforcement and optimises use of space. The system can also be used for foundations and consists of double-headed anchors connected by a strip.
Flat slab structures with large spans between supporting columns allow optimum use of factory or warehouse buildings with large floor spaces. Even in the early days of concrete structures, the problem of punching shear at the column head area was already recognized (Fig. 1). Mushroom- head construction was introduced in around 1900 as a way of countering the problem (Fig.2).
Only a short time later the Kahn steel reinforcement system (Fig.3) was used as tensile reinforcement. It possessed upturned wings which resisted transverse forces in the ceiling support area. The inventor of the Kahn steel reinforcement system, Julius Kahn, and his brother, the famous architect Albert Kahn, enjoyed great success with this product in the field of construction with steel reinforced concrete.
Using conventional methods it is often not possible to achieve thin slabs and wide spans between supporting columns or large slab breakthroughs close to the supporting column heads (Fig. 4). As an alternative, Andrä et al. developed a solution in which the area at risk of punching shear is dowelled using dowel strips.
This solution was further developed for punching shear anchoring made from reinforcing steel with two forged heads (Fig. 5). Following the introduction of the Eurocode, a fundamental reworking of the approval process became necessary.
The current European Technical Approval ETA-13/0136 corresponds to the latest state of knowledge and is successfully applied in a number of areas.
In comparison to floor slabs without studrails, the punching shear resistance and load-carrying capacity can be clearly increased:
- Reduced requirements for formwork
- Installation possible from the top and bottom
- Can be used for slabs from a thickness of 18 cm
- Quick and simple installation
- Lower construction thickness of the ceiling due to higher load-carrying capacity than conventional reinforcement technology
- Level ceiling soffit
Versatile fabrication possible depending on static requirements.
European Technical Approval ETA-13/0136
Intuitive software that takes into consideration supports, reinforcement and recesses and provides an automatic verifiable calculation. Free download on www.jp-uk.com
JORDAHL® JDA punching shear reinforcement is made of double-headed anchors which are connected by a perforated connecting strip. The double-headed anchors secure the transition between punching shear and transverse load. The double-headed anchors are made of B500B steel, and the perforated connecting strip is also made of structural steel.
For further information on JORDAHL® Punching Shear Reinforcements – download the full brochure here: http://www.jp-uk.com/files/6813/8113/1623/38.pdf
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