Strengthening of concrete structures with bonded reinforcement

The work area 'Strengthening of concrete structures with bonded reinforcement' comprises kits for retrofitting aimed at increasing the flexural and shear resistance of existing concrete structures (strengthening) with (surface-)bonded steel plates, CFRP strips or CF sheets or CFRP strips bonded into slits in the concrete.

Generally, these kits consist of a reinforcement (CFRP strips, CF sheets or steel plates), an adhesive for bonding the reinforcement to the structure and a repair mortar.

Regulatory framework

There are no conclusive technical rules neither for the kits nor for the design and execution of the strengthening measures. DIBt therefore grants national technical approvals (abZ) and general construction technique permits (aBG) under work areas Z-36.1-xx or Z-36.12-xx for structural strengthening measures for concrete structures with bonded reinforcement.

European Technical Assessments (ETAs) can also be issued for the kit itself. In this case, a general construction technique permit will generally be pertinent for the design and execution of the strengthening measure.

The general construction technique permit for the relevant kit contains design specifications and values, specifications on the detailing and execution of strengthening measures carried out with the relevant kit as well as the applicable boundary conditions for the use of the kit (temperature, humidity, outdoor/indoor areas, etc.). As far as possible, the national technical approvals/general construction technique permits will refer to the DAfStb Guideline 'Strengthening of concrete members with adhesively bonded reinforcement' (Verstärken von Betonbauteilen mit geklebter Bewehrung).

Principles, guidance, recommendations

Generally applicable approval and testing principles are not available.

In an initial meeting, applicants will receive comprehensive information on the approval and testing principles applicable to the relevant kit.

Companies that execute strengthening measures in accordance with the national technical approvals/general construction technique permits granted under Z-36.1-xx or Z-36.12-xx need a valid proof of qualification in accordance with the DAfStb Guideline 'Strengthening of concrete members with bonded reinforcement', Part 3, Annex D.

The Directory of recognised testing laboratories, inspection and certification bodies (PÜZ-Verzeichnis), Part 6, no. 8 provides a list of bodies recognised for issuing such proof of qualification for executing companies of strengthening measures with bonded reinforcement in accordance with the above-mentioned DAfStb Guideline, Part 3, Annex D.

As a service to users, DIBt publishes and regularly updates directories of companies that have the required proof of qualification. The information in these directories has been carefully compiled, based on information DIBt received from the testing laboratories in accordance with Part 6, no. 8 of the current PÜZ-Verzeichnis in accordance with the Building Codes of the federal states. However, only the original proof of qualification issued by the testing laboratories is binding. The directories below, divided into strengthening by laminating of CF sheets (Auflaminieren von CF-Gelegen), strengthening by CFRP strips bonded in slits (in Schlitze verklebte CFK-Lamellen) and strengthening by (surface-)bonding of steel plates and/or CFRP strips (Aufkleben von Stahllaschen und/oder CFK-Lamellen), are available for this purpose on the DIBt website.

Please note that in addition to the obligation for the executing company to monitor the execution in accordance with the above-named DAfStb Guideline, Part 3, Section 5, involvement of a recognised inspection body, as specified in the Directory of recognised testing laboratories, inspection and certification bodies, Part 5, no. 7, is required (also compare DafStb Guideline, Part 3, Annex C).

Verzeichnis der Firmen mit Eignungsnachweis gemäß der DAfStb-Richtlinie "Verstärken von Betonbauteilen mit geklebter Bewehrung", Teil 3, Anhang D zum Verstärken von Betonbauteilen durch Auflaminieren von CF-Gelegen (3 pages)

Stand: Mai 2022

Verzeichnis der Firmen mit Eignungsnachweis gemäß der DAfStb-Richtlinie "Verstärken von Betonbauteilen mit geklebter Bewehrung", Teil 3, Anhang D zum Verstärken von Betonbauteilen durch in Schlitze verklebte CFK-Lamellen (5 pages)

Stand: Mai 2022

Verzeichnis der Firmen mit Eignungsnachweis gemäß der DAfStb-Richtlinie "Verstärken von Betonbauteilen mit geklebter Bewehrung", Teil 3, Anhang D zum Verstärken von Betonbauteilen durch Aufkleben von Stahllaschen und/oder CFK-Lamellen (6 pages)

Stand: Mai 2022

Application forms

National procedure

A national technical approval (abZ) and/or oder general construction technique permit (aBG) is granted upon application (see Model Building Code (MBO), Sections 16a(2) and18(2) and (4)). This also applies to amendments and supplements to, or renewals of existing approvals and/or construction technique permits.

No formal requirements apply. The following information is needed: name and address of the applicant, description of the product and/or construction technique and its field of use or application, type of decision required (new decision, amendment or supplement to, or renewal of, an existing decision).

Please feel free to use the template below.

Application for a national technical approval and/or construction technique permit (3 pages)

Version: January 2018; Application form

Application for amendment / supplementation / renewal of a national technical approval and/or construction technique permit (4 pages)

Version: January 2018; Application form

Guideline: How to provide drawings for national technical approvals and general construction technique permits (5 pages)

Version: July 2017

European Technical Assessment (ETA)

To start the ETA procedure, please submit the form below. We will then check if the prerequisites for issuing an ETA are met, i.e., in particular, if the product is not fully covered by an existing harmonised standard. If the prerequisites are met, we will check whether a European Assessment Document (EAD) covering the requested assessment scope already exists or still needs to be developed. If an EAD needs to be developed or amended, a complete technical file needs to be established before the procedure can begin.

Form for requesting a European Technical Assessment (ETA) (2 pages)

Last updated: 16 June 2022

  • abZ/aBG
  • Z = new decision | E = supplement | Ä = amendment | V = renewal | G = valid until
    Subject concerned Applicant Decision no. Validity
    from / to
    Bausatz "StoGB System 1" für schubfeste Klebeverbindungen zwischen Stahlplatten und Stahl- und Spannbetonbauteilen nach der DAfStb-Verstärkungs-Richtlinie

    StoCretec GmbH

    Gutenbergstraße 6

    65830 Kriftel

    Z-36.1-87 Z: 28.01.2020
    G: 01.01.2025
    Verstärken von Betonbauteilen mit schubfest aufgeklebten CFK-Gelegen nach der DAfStb-Verstärkungsrichtlinie und Behälterumwicklungen mit "Carboplus® Sheet 240"

    Implenia Construction GmbH

    Technical Center - Baustofftechnik

    Diffenéstraße 14

    68169 Mannheim

    Z-36.12-81 Z: 17.02.2020
    G: 01.01.2025
    Verstärken von Betonbauteilen mit schubfest aufgeklebten CFK-Gelegen nach der DAfStb-Verstärkungsrichtlinie und Behälterumwicklungen mit "MC-CarbonFiber Sheet"

    MC-Bauchemie Müller GmbH & Co. KG

    Am Kruppwald 1-8

    46238 Bottrop

    Z-36.12-82 Z: 17.02.2020
    G: 01.01.2025
    Schubfest aufgeklebte Kohlefaserlamellen "CarboPlus® Kohlefaserlamellen" nach der DAfStb-Verstärkungs-Richtlinie

    Implenia Construction GmbH

    Technical Center - Baustofftechnik

    Diffenéstraße 14

    68169 Mannheim

    Z-36.12-84 Z: 28.01.2020
    G: 01.01.2025
    Verstärken von Stahlbetonbauteilen durch schubfest aufgeklebte Kohlefaserlamellen "MC-CarbonFiber Lamella" nach der DAfStb-Verstärkungs-Richtlinie

    MC-Bauchemie Müller GmbH & Co. KG

    Am Kruppwald 1-8

    46238 Bottrop

    Z-36.12-85 Z: 28.01.2020
    G: 01.01.2025
    Bausatz StoCretec zum Verstärken von Stahl- und Spannbetonbauteilen durch schubfest aufgeklebte CFK-Lamellen nach der DAfStb-Verstärkungs-Richtlinie

    StoCretec GmbH

    Gutenbergstraße 6

    65830 Kriftel

    Z-36.12-86 Z: 28.01.2020
    G: 01.01.2025
    Bausatz StoCretec zum Verstärken von Stahl- und Spannbetonbauteilen durch in Schlitze verklebte CFK-Lamellen nach der DAfStb-Verstärkungs-Richtlinie

    StoCretec GmbH

    Gutenbergstraße 6

    65830 Kriftel

    Z-36.12-88 Z: 26.05.2020
    G: 30.06.2024
    Bausatz zum Verstärken von Stahl- und Spannbetonbauteilen durch in Schlitze verklebte CarboPlus® Kohlefaserlamellen nach der DAfStb-Verstärkungs-Richtlinie

    Implenia Construction GmbH

    Project Excellence & Services - Baustofftechnik

    Diffenéstraße 14

    68169 Mannheim

    Z-36.12-89 Z: 19.03.2020
    G: 09.04.2024
    Bausatz zum Verstärken von Stahl- und Spannbetonbauteilen durch in Schlitze verklebte CFK-Lamellen "MC-CarbonFiber Lamella" nach der DAfStb-Verstärkungs-Richtlinie

    MC-Bauchemie Müller GmbH & Co. KG

    Am Kruppwald 1-8

    46238 Bottrop

    Z-36.12-90 Z: 19.03.2020
    G: 11.04.2024

Dr Lars Eckfeldt
Head of Section – Concrete and Reinforced Concrete Construction, Prestressed Concrete Construction

Phone +49 30 78730-363
Fax +49 30 78730-11363
Email lec(at)dibt(.)de

Legal reference documents

Testing, certification, inspection