ZIM project study demonstrates the potential of the thermoset gap compensation material MM1018 in pre-stressed bolted connections

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Mönchengladbach, 13.09.2023 – Im Stahlbau werden Schraubverbindungen aus Gründen der Tragfähigkeit oder der Gebrauchstauglichkeit vorgespannt. Fertigungs- oder montagebedingte Spaltbildungen sind ein Risiko für das Aufbringen des erforderlichen Vorspannkraftniveaus und begünstigen die Entstehung von Spaltkorrosion. Eine mögliche, umweltverträgliche Alternative zum Spaltausgleich mit Futterblechen wurde im Rahmen des ZIM-Kooperationsprojekts „Bri-San-T – DuroFüllSta“ untersucht: das Flüssige Futterblech® MM1018. Die im Rahmen der zweijährigen Studie durchgeführten Gleitfaktortests zeigen ein erfreuliches Potenzial im Hinblick auf den möglichen Einsatz in rutschhemmend vorgespannten Verbindungen. Dabei wird bereits nach 24 Stunden eine ausreichend hohe Festigkeit des Materials erreicht.

Manufacturing and assembly-related imperfections cannot be ruled out in steel construction, meaning that gaps can form between the bolted components of bridges, radio masts or tower structures. These gaps can significantly impair the permanent load-bearing capacity of the prestressed bolted connection and even lead to premature failure. They must therefore be kept to a minimum in accordance with EN 1090-2.

As gaps often cannot be fully compensated for by stiffeners, the ZIM cooperation project “Bri-San-T – DuroFüllSta” focused on the development of environmentally friendly gap compensation materials that connect the gaps positively and non-positively and can be used in pre-stressed bolted connections in steel construction.

The BMWK-funded project was carried out by the Institute for Metal and Lightweight Construction at the University of Essen in cooperation with DIAMANT Polymer GmbH. For the first time, both the preload force losses and the sliding resistance were analyzed and taken into account in the development of a design concept. Various environmentally friendly materials were used in the formulation of the gap compensation materials.

The metal polymer MM1018 investigated as part of the project is a two-component reaction resin system filled with special metallic materials, which can be supplied in both liquid (MM1018 FL) and paste-like consistency (MM1018 P). The applicability of the metal polymer has been proven by the general building authority approval (abZ Z-3 82-2042) in Germany and has already been tried and tested thousands of times in practice.

The slip factor tests carried out in experimental investigations in accordance with EN 1090-2, Annex G, showed encouraging potential with regard to the possible use of Liquid Lining Sheet® MM1018 in slip-resistant prestressed joints. A further test showed that the material achieves high strength after just 24 hours.

The experimental investigations carried out have created a fundamental basis for the future design of slip-resistant prestressed joints using the gap fillers MM1018 FL and MM1018 P in terms of dimensioning and design.

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DIAMANT Polymer GmbH©.