Composite dowels as shear connectors for composite beams – background to the German technical approval

Abstract

Composite dowels are known as powerful shear connectors in steel‐concrete composite girders. They are being used more and more in practice, especially for prefabricated composite bridges. Compared with headed studs, they provide increased strength. They also exhibit good deformation capacity even in high‐strength concrete. Further, their use in steel sections without an upper flange is very simple. However, a lack of standards for composite dowels with the economic clothoid and puzzle shapes has led to hesitations regarding applications, which is often due to delays in the approval process. Hence, the aim of the recently finished German research project P804 funded by FOSTA, the Research Association for Steel Application, was to solve unanswered questions concerning these innovative shear connectors and to prepare a national technical approval available for any design office or construction company. This paper describes the technical rules derived for ultimate and fatigue limit states, the structural design principles and instructions for production and construction, and provides further background information.

Entwicklung eines neuen Single‐Push‐Out‐Versuchsstands zur zyklischen Untersuchung der Verbunddübelleiste

“…Neben den verfahrenstechnischen Vorteilen gegenüber der Verwendung von einzeln aufgeschweißten Kopfbolzendübeln, vor allem bei oberflanschlosen Stahlträgern, zeichnet sich die Verbunddübelleiste auch hinsichtlich der hohen Steifigkeit und Tragfähigkeit [3], des Verformungsverhaltens ( [4], [5]) und des Ermüdungsverhaltens [6] aus. Sie kann sowohl unter vorwiegend ruhenden als auch unter nicht ruhenden Belastungen [7] im positiven wie im negativen Momentenbereich ( [8] bis [10]) eingesetzt werden. Ein duktiles Verbundmittel-bzw.…”

08.16: Static shear capacity of small‐scaled pin shear connectors

“…The concrete is arranged in the compression chord and the steel is arranged in the tensile zone. To ensure the composite between both materials, effective connectors are necessary, which have a high load as well as a sufficient deformation capacity [1], [2]. The usage of high-strength materials (e.g.…”

Effects of transverse tension load on the static capacity and fatigue resistance of composite dowels

“…This approval allows the design of composite structures with composite dowels for hogging and sagging moments under static and cyclic loading. The design concepts for ultimate limit state and fatigue limit state are based on numerous experimental and theoretical investigations in recent years (e.g. , , , , , ).…”

“…The advantages of composite dowels over other shear connectors are their increased strength and sufficient slip capacity even in high‐strength concrete. The National Technical Approval for Germany , from 2013 allows the design of composite structures with composite dowels for hogging and sagging moments under static and cyclic loading. However, the design of structures with cyclic loading in combination with centric tension perpendicular to the composite dowels (transverse tension) is neglected.…”