Until recently, the design of steel and composite structures for the relatively low seismicity of Germany was predominantly performed in accordance with EN 1993-1-1 [9] and EN 1994-1 [10]. This was also allowed due to the low demands on joints generated by seismic loads. Alternatively, the application of capacity design in accordance with the European seismic code often led to less economical outcomes. In this context, it became common practice to design steel and composite structures considering a low ability of seismic energy dissipation (q ≤ 1.5). However, the seismic risk in moderate-to-low seismic regions is not negligible. Risk factors include increased density of the population and high industrialisation of many regions in Germany. Moreover, civil engineering design offices are generally not very familiar with seismic design. Another risk is the underestimation of the seismic hazard in Germany demonstrated by a state-of-the-art probabilistic seismic hazard assessment [11]. Consequently, new seismic hazard maps were introduced in the updated version of German National Annex DIN-EN-1998-1/NA [12]. According to these maps, the relevance of the seismic hazard in Germany had increased due to expanded seismic areas and to higher spectral accelerations. Because of this, seismic action should not be disregarded in the design of steel and composite structures. This is also of particular importance to the design of beam-to-column connections, which are regularly configured in accordance with the German catalogue of typical connections "Standardised Joints in Steel Structures to DIN EN 1993-1-8" [13] and not with EN 1998-1 [14]. The main aim of

Owing to the new rules of the German National Annex to EN 1998-1, the relevance of the seismic action has increased, materialising in extended seismic areas and higher spectral accelerations. This may lead to seismic loading being decisive on the design of steel and composite frames. However, the demand is lower in Germany than in other seismic areas. Consequently, these challenges are addressed in an ongoing German national research project, by developing joints with dissipative connections, classified as semi-rigid and partial-strength, for steel and composite frames that could allow for the use of behaviour factors in the range of 1.5 to 3. The development started with typical connections from the German catalogue, designed to withstand static loads in the elastic range, followed by performance and detailing improvements. Developments (e.g., increase in sagging/hogging bending: 125 %/18 % of steel joints and 70 %/40 % of partially composite joints) resulted from pretest finite element analyses (FEA) on joints and frame models. Improvements to joint detailing were made according to the provisions of the newest draft of Eurocode 8. The optimised joints were integrated in frame specimens, which are currently being tested under monotonic and cyclic loads at RWTH-Aachen University. This article introduces the developed joint solutions, describes the experimental and numerical programs and presents the monotonic response of frame specimens based on the results of FEA, as well as the main conclusions.

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