Story (x ; y; z) (m) (ton) X  (ton m) X (kN) Y  (ton m) Y (kN)

1 (4。55; 5。30; 2。75)       65。86 0。669 0。362 0。533 0。297

2 (4。55; 5。30; 5。75)       65。86 1。460 0。790 1。325 0。738

3 (4。58; 5。34; 8。75)       63。28 1。847 1 1。794 1

Elastic period

T (s) = 0。62

∗Coordinate referred to the coordinate system of Figure   1。

column shear capacities (as also reported by Jeong and Elnashai [6])。 Therefore, only the inelastic flexural behavior of elements was considered by modeling the structural members with lumped plasticity at both ends; a bilinear moment–rotation relationship was used for each plastic   hinge。

The moment–rotation relationship was obtained based on moment curvature analysis carried out considering section properties and constant axial loads on the elements (axial loads on beams, due to gravity loads, were assumed equal to zero); as a design hypothesis, a parabolic–rectangular stress–strain diagram was assumed for concrete and elasto perfectly plastic for steel。 Yielding curvature, $y and moment My, corresponded to the attainment of the tensile steel yielding strain; the ultimate curvature, $u, and ultimate moment, Mu, corresponded to the attainment of ultimate strains in concrete or steel (conventionally assumed equal to 3。52 for concrete and 402 for steel, respectively)。

Yielding and ultimate rotation, 8y and 8u, as well as plastic hinge length, Lpl。, were computed according to Eurocode 8 [10] type equations

dbL fy

8y = þflex。$y LV + þshear + þslip  √

Lpl。  = aflex。 LV + ashearh + aslipdbL fy (3)

where LV is the shear span, dbL is the diameter of longitudinal bars, fy and fc are the  average steel and concrete strength, respectively, and h is the cross-section depth; factors aflex。, ashear, aslip along with þflex。, þshear, þslip and y were provided by the latest seismic guideline developed by the

Italian Department of Civil Protection, Ordinance 3431 [11]

aflex。  = 0。1 þflex。 = 1

。 h 。 1

ashear = 0。17, þshear = 0。0013

þslip = 0。13$y

where yel。  is a coefficient equal to 1。5 or 1 for primary or secondary members, respectively。

PY_AS-BUILT NY_AS-BUILT PX_AS-BUILT NX_AS-BUILT

C C LSSD