Steel and Composite Joints for MRFs in Moderate Seismicity: Experimental and Numerical Program

Abstract

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

Steel and composite joints with dissipative connections for MRFs in moderate seismicity – Experimental and numerical programs

“…Detailed results of FEA performed on joint FE models are available in a previously published article [17]. The results of FEA performed on joints according to the German catalogue, 'Standardised Joints in Steel Structures to DIN EN 1993-1-8' [14], revealed that the demand was higher than the design hogging and sagging bending resistance.…”

“…Furthermore, the failure mechanism was brittle, with the weakest components being the bolts in tension and the fillet welds between the beam flanges and the end-plates. By comparing the joints designed according to the German catalogue with the new requirements of the seismic code [6], the following conclusions were reached in [17]:…”

“…Estimations of the performance of the joints in terms of bending resistance and rotation capacity are available in Don et al [17]. Distributions of von Mises stresses and equivalent plastic strain within the beam-to-column joints are illustrated in Fig.…”

“…3 and consists of FEA on beam-to-column joints and frames. Detailed results of FEA on joint FE models are available in Don et al [17]. The main objectives of the pre-test FEA on joints were to assess and optimise the response in terms of bending resistance, stiffness and failure mechanism of the joints designed according to the 'Standardised Joints in Steel Structures to DIN EN 1993-1-8' [14].…”

“…The innovative character of the article resides in the introduction and investigation of a set of joint solutions oped for industrial (bare steel) and office buildings (composite). A description of the structures from which the frame specimens were extracted is presented in [17]. The dimensions of the frame specimens are the following: 3.5 m overall height × 10.0 m overall length; 2.8 m column height; and two spans of 5.00 m between column axes.…”