PSI - Issue 78

Melina Bosco et al. / Procedia Structural Integrity 78 (2026) 1087–1094

1091

Specifically, continuous lines represent the response of the structure examined along the x- direction, while dashed lines represent the response along the y - direction. Interstorey drifts slightly higher than 2% have been accepted, considering that the amplification of the elastic displacements resulting from modal response spectrum analysis by q d introduces some approximations. The same figure also plots the average link overstrength Ω i at the i-storey normalized to the minimum overstrength factor Ω d . The figure shows that the ratio Ω i/ Ω d approaches the upper bound limit (i.e. 1.25) at the storeys where members have been slightly oversized to limit the interstorey drifts. Consistent with the recommendations of the upcoming Eurocode 8 for structures with seismic links, this ratio Ω i/ Ω d is intentionally maintained high at the top storey. To evaluate the economic benefit of the proposed structural configuration, the costs of links, linked columns, other columns, beams connecting columns and secondary beams for the entire building are calculated. The costs of connections and foundations are excluded from this analysis. However, this simplification is not expected to affect the results of the comparative study significantly, since connection costs can be reasonably assumed proportional to those of the adjacent steel members considered. The calculation of the above costs begins with determining the weight of the structural members, which is then multiplied by the relevant unit price of steel, based on the official price list of the Sicilia Region. Finally, the cost per square meter of plan area is obtained by dividing the total structural cost by the product of the number of storeys and the area of a single floor. The resulting cost per square meter of plan area is equal to 132€/m 2 for the building with three linked column frames and 164 €/m² for the configuration with two linked columns. Therefore, the proposed three-column configuration leads to a reduction in structural costs of approximately 20%. a b

Fig. 3. Structural layout in the case of (a) three linked columns; (b) two linked columns.

0 1 2 3 4 5 6 0.0 0.5 1.0 1.5 Ω i /Ω d limit value

0 1 2 3 4 5 6 0.0 0.5 1.0 1.5 2.0 Ω i /Ω d limit value

0 1 2 3 4 5 6 0.0% 1.0% 2.0% 3.0% drift limit value

0 1 2 3 4 5 6 0.0% 1.0% 2.0% 3.0% drift limit value

a

b

storey

storey

storey

storey

Fig. 4. Hightwise distribution of storey drifts and normalized overstrength of links layout in the case of (a) three linked columns; (b) two linked columns (continuous line = x-direction, dashed line = y-direction).