PSI - Issue 78

Christoph Butenweg et al. / Procedia Structural Integrity 78 (2026) 1689–1696

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Two separate calculation models were developed to represent each configuration. In the model with interacting infills, additional diagonal struts were introduced to account for the contribution of the infill panels due to the rigid frame-to-infill connection. The evaluation of the results showed that the use of the INODIS system allows for a significant reduction in the quantities of steel and concrete compared to traditional infill solutions (Fig. 6a). This also leads to improved cost efficiency, as overall costs can be reduced (Fig. 6b). In summary, higher seismic safety can be achieved with lower material usage and cost. Additionally, in the event of seismic activity, damage is prevented, which in turn avoids repair costs and downtime. The same trend can be expected for higher levels of acceleration.

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Fig. 6. a) Reduction of the quantities of concrete and reinforcement and b) savings in investment costs with INODIS.

4.2 Design example for non-interacting infills with INODIS The design concept for interacting infills, as implemented in FprEN 1998-1-2 (2025), is applied in the following to a representative RC frame with infill masonry decoupled with INODIS. In practice, the design can be performed story by story for the most unfavorable infill and the governing interstory drift. Alternatively, a story-by-story approach can be omitted if the maximum interstory drift is assumed for all stories. The masonry infill under consideration is taken from the building introduced in Section 4.2. The design of the non-interacting infill with the system INODIS is carried out for the RC frame with infill masonry shown in Fig. 7, based on a maximum design interstorey drift ratio 1,2 % , corresponding to a design interstorey drift of d   36 mm for a PGA of 0.2g.

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Fig. 7. RC frame with masonry infill and Stress-strain relationship for REGUPOL vertical with t = 25 mm and t = 50 mm. It must be verified that the shear force  , transferred from the columns to the infill panel should not exceed 30% of the in-plane design resistance in shear  , of the infill panel:  ,  0,3  , (1) The in-plane design resistance in shear  , is calculated as follows:  ,                      sin (2)