Concrete-to-concrete joints

PROFESSIONAL ADVICE, A RELIABLE CONNECTION

Correct design of embedded reinforcing bars

Embedded reinforcing bars are used for concrete-to-concrete connections. This method is suitable for reinforcing load-bearing structures or for carrying out renovation and structural alterations.

The combination of various calculation methods with specially formulated injection resins now offers a wide range of new possibilities for fixing reinforcing bars. The design of bonded reinforcing bars can be optimised in terms of scope of application and construction costs in four simple steps.

We would be happy to advise you on how to design a secure mounting system.

Step 1

The correct use of adhesive reinforcement bars

Standard applications for bonded reinforcing bars include:

So-called ‘concrete overlay solutions’ and through-reinforcement are not part of the installation of reinforcing bars, as they comply with other design standards, even where grouting systems are used in this context. Further information on shear connections using concrete cover and the reinforcement of load-bearing structures in concrete construction can be found on our website.

Step 2

Correct calculations for embedded reinforcing bars

All methods for designing reinforcing bars have their own advantages and disadvantages in terms of their scope of application and calculation results. If these are not sufficient, Hilti offers an alternative design method in accordance with EN 1992-1-1.

Design guidelines:

The PROFIS Engineering software helps you select and design bonded reinforcing bars and compare the results of different design methods.

To help you find the correct calculation basis for your application, Hilti provides the following simplified guideline:

Application:
lap joints, reinforcement for end supports of articulated structural elements, reinforcing bars subjected to compressive loads, and the design of anchorage to cover tensile forces in accordance with DIN EN 1992-1-1 (EC2).

Solution:
Select ‘Overlap connection’ or ‘Anchor bars’ and ‘EN 1992-1-1’. As a rule, these calculations result in relatively long anchorage lengths due to the limitation on permissible bond stresses.

Application:
design of rigid connections using reinforcing bars in accordance with DIN EN 1992-1-1 (EC2), but not for use as lap joints.

Solution:
In the reinforcement bars module, select ‘Initial bars’ and the bar model ‘EN 1992-1-1’. This design method is based on the truss model in accordance with EN 1992-1-1 (EC2) for frame joints.

Application:
design of rigid connections for reinforcing bars with increased bonding strength of the injection resin in accordance with the TR 069 calculation method; however, it must not be used as an overlap joint or as a tensile end anchorage.

Solution:
Select ‘End anchorage’ and EOTA Technical Report TR 069.

Our proprietary design method, the ‘Hilti Method’, within the PROFIS Engineering software enables design in accordance with EN 1992-1-1, taking into account the actual bond strength achievable with the Hilti injection system. You will find an overview of the applications and design standards for possible connections in the table below.