Tag Archives: anchor channels

Tag Archives: anchor channels

Precast Concrete

New guidelines for lifting inserts and systems

While precast components can benefit project delivery, there is a significant amount of planning required for the designer. Early engagement with a specialist designer is essential for the successful delivery of the project. The safe lifting of precast elements has developed over many years, but in the Eurocodes for the design of structures, such as EN 1990(1) and EN 1992-1-1(2) (Eurocode 2), there is limited information available to the designer on how to design lifting assemblies – in particular, the lifting socket placed in the concrete. Chains, slings and lifting keys for the lift operation are all covered under the Machinery Directive 2006/42/EC (https://bit.ly/2NLEJYr) but it only covers external metal parts and not the components cast into the concrete.

Working group

precast concreteA number of leading manufacturers formed a working group to clarify working practices and Standards for the production of lifting inserts to be placed into precast components. This resulted in a standard working procedure for manufacturers to produce equipment for the market and overcome this mismatch between Standards and EU law. The guideline produced was the VDI/BV-BS 6205(3). The document sets out the rules for the manufacturer of lifting components and testing regimes. A key point made by all of the manufacturers was that there should be no mix and matching of pieces from separate suppliers.

The VDI/BV-BS 6205 guideline has the objective of encouraging the sharing of information through the life cycles of precast elements. It goes on to cover fabrication work in the precast plant and recommendations for precast designers. It is not uncommon for a precast element to be rotated many times before it is ready to be lifted into place.

The planning of all these operations needs careful consideration, primarily to understand the forces imparted to the lifting inserts. A lift in the factory will see different load actions compared to those on-site. By employing a specialist in this field, all of these load actions should be considered and planned for the work’s programme. Colour coding of parts, introduced by leading manufacturers, allows compatible parts to be connected without risk. Colour coding and load ratings can be added to the model and tabulated on the parts drawing.

As more project designers consider the precast option for construction, so the complexity of the shape and form of precast elements increases. In many cases, it is still a simple process to determine the centres of gravity of precast elements, and the point of instability also needs to be considered.

Whereas beams and columns still form the bulk of components lifted, the consideration of components forming the whole structure is now the norm.

To discuss your concrete system requirements, please contact us.

Tag Archives: anchor channels

JORDAHL

JORDAHL® Toothed Straps

JORDAHL toothed straps JVB-V and JVB-N are excellent product choices when connecting precast concrete elements such as columns and walls with each other.   

In combination with JORDAHL® anchor channels and T-bolts, they form an ideal fastening system for the efficient alignment of precast elements in a 3D space. Installation is easy, and the adjustable connections compensate for the manufacturing and placement tolerances of the concrete components.

JORDAHL® toothed straps also support high loads in two directions, while a sliding connection to the JORDAHL® anchor channel allows vital differential movement between components in the third dimension. The software allows load bearing capacities to be verified analytically with accuracy. Consequently, the combined system represents a powerful, cost-effective and completely verifiable alternative to conventional connections.

Solutions
  • Toothed straps JVB-V: for shear load connections, for example: precast panel connections
  • Toothed straps JVB-N: for tension load connections. Adjustment range ± 38mm
Advantages
  • Fast, efficient and adjustable connections between precast concrete components
  • Differential movement between components combined with high load capacities
  • Very cost-effective
  • Easy positioning and alignment of precast concrete elements
  • Cast-in anchor channels add to the ability to compensate for construction tolerances
  • No welding on site required
  • Suitable for thin concrete components
  • Fast and easy installation
  • Connection recess does not need to be filled with mortar
  • Complies with fire safety requirements when used in conjunction with fire lagging rope and mortar
Easy Adjustment for Construction Tolerances while Supporting High Loads
  • Accurately adjustable connections
  • Extremely resilient interlocking of strap components
  • Easy alignment of precast concrete elements
  • Connections support loads up to 17.2 kN
  • Straps can be fully loaded immediately after installation
Design Reliability
  • Secure fastening based on Eurocode-compatible design concept
  • Fully verifiable load capacities aligned with the performance of matching anchor channels
  • Free design aid with all the important information for design and product selection

 

Speak to the J&P Building Systems for more information on H-Bau Technik GmbH.