GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 2.2 372 corresponding sample of structural responses quantified by a proper engineering demand parameter edp (i.e., a metric that can be used to estimate the structural damage), with the following expression: Analysis method (Cornell et al. 2002) to obtain fragility curves. In detail, SDOF systems are subject to a limited set of n unscaled ground motion records an fragility curve takes origin from the sample of n ground motion intensities and the correspon sample f structural responses qu ntified by a proper engineering demand parameter edp (i.e., a m that can be used to estimate the structural damage), with the following expression: P [ f | ℑ ] = P [ EDP > edp | ℑ ] = 1 − P [ EDP≤ edp | ℑ ] = 1 − Φ [ ln ( edp ) − ln ⁡ ( edp ) σβ ] (1) (1) where alized as Single Degree of Freedom Systems (SDOFs), e idealized tri-linear capacity curve. NLTHAs are later r seismic behavior to be post-processed with the Cloud fragility curves. ited set of n unscaled ground motion records and the of n ground motion intensities and the corresponding proper engineering demand parameter edp (i.e., a metric age), with the following expression: p | ℑ ] = 1 − Φ [ ln ( edp ) − ln ⁡ ( edp ) σβ ] (1) repres nts the specific undesired threshold level of the the large computational burden, frames are idealized as Single Degree of Freedom Systems (S w th hystereti behavior calibrated based on the idealized tri-linear capacity curve. NLTHAs ar perf med to b ain samples of the non-linear seismic behavior to be post-processed with the Analysis method (Cornell et al. 2002) to obtain fragility curves. In detai , SDOF systems ar subject to a limited set of n unscaled ground motion records a fragil ty curve takes origin from the sample of n ground motion intensities and the corresp sample of structural responses quantified by a proper engineering demand parameter edp (i.e., a that can be used to estimate the structural damage), with the following expression: P [ f | ℑ ] = P [ EDP > edp | ℑ ] = 1 − P [ EDP≤ edp | ℑ ] = 1 − Φ [ ln ( edp ) − ln ⁡ ( edp ) σβ ] (1) , and σ is the demand standard deviation. Hence, under the hypothesis that the occurrence of earthquakes at the construction site is a Homogenous Poisson Process (HPP), the seismic failure rate λ f is computed as: where edp represents the specific undesired threshold level of the edp , and σ is the demand sta deviation. Hence, under the hypothesis that the oc urrence of earthquakes at the construction sit Ho og nous Poisson Process (HPP), the seismic failure rate λ f is computed as: λ f = ∫ ℑ ❑ P [ f ∨ℑ] ∙ | d λ ℑ | (2) where λ ℑ is the seismic hazard curve representative of the seismicity at the site of interest comm computed via a Probabilistic Seismic Hazard Analysis (PSHA, Cornell 1968 and McGuire 1995) im is a relevant intensity measure. Case studies. This paper investigates the seismic reliability of code-compliant residential buil with an RC frame-resisting scheme. Fig. 1 illustrates the main features of the different configura analyzed, which fulfill plan and elevation regularity criteria, and are characterized by three incre elevations, i.e. 3-, 6- and 9-stories archetypes all with a constant inter-story height equal to 3 m configurations have a rectangular plan with 5 x 3 bays of 5m span each. Fig. 1 - Main geometrical and material characteristics of the analyzed structural archetypes . Beams and columns were designed considering a C25/30 according to [NTC] with characte compressive strength f ck equal to 25 MPa, and a reinforcing steel B450C with characteristic yiel tensile strength f yk equal to 450 MPa. To account for the non-linear material behavior, suitable m are adopted: in particular, Mander et al. (1998) model Concrete04 and Menegotto and Pinto (1 model Steel02 materials for core/cover concrete and reinforcement rebars are used, whereas si strut truss elements with a non-linear behavior characterized by Di Trapani et al. (2018) mode adopted to capture the stiffening effect caused by masonry infills. Masonry compressive streng and the elastic modulus E m along the two orthogonal directions are assumed equal to 2.4 MPa 4408 MPa for the direction, and about to 7.28 MPa and 7400 MPa for the other one. Masonry i are characterized by a thickness of 25 cm and distributed over the entire external perimeter o buildings, whereas the contribution of the staircase to the stiffness of the building was negle Regarding the loading actions, 5.5 kN/m 2 and 0.5 kN/m 2 are considered as the dead and live load the roof, and a 6.5 kN/m 2 dead load and a 2 kN/m 2 live load are considered for the remaining fl Both high ductility class (DCH) and medium ductility class (DCM) are considered, thus leading total of 12 different archetypes resulting from the combination of the different number of st ductility class, and presence/absence of masonry infills. Results. The seismic hazard curves computed for each Italian municipality with reference t main soil class are coupled with the appropriate fragility curves representative of the code-comp archetype that a designer may have sized in that location to get the seismic failure rates assoc with a code-compliant design, and thus obtain the respective seismic reliability maps for bare infilled code-compliant RC frames. The following relevant damage state (DS) are defined: - Low Damage ( ds 1 ), corresponding to the achievement of the yielding point in the SD (2) where r represents t e specific undesired threshold level of th edp , and σ is the demand sta deviation. H nce, und r the hypothesis that t e occurrenc of ea thquakes t e construction sit Hom genous Poi son Process (HPP), the seismic failure rate λ f is computed as: λ f = ∫ ℑ ❑ P [ f ∨ℑ] ∙ | d λ ℑ | (2) λ ℑ is the seismic hazard curve representative of the seismicity at the site of interest com computed via a Probabilistic Seismic Hazard Analysis (PSHA, Cornell 1968 and McGuire 1995) im is a relev nt intensity measure. Case studies. This paper investigates the seismic reliability of code-compliant residential buil with an RC frame-resisting scheme. Fig. 1 illustrates the main eatur s f the diff rent config ra analyzed, which fulfill plan and elevation regularity criteria, and are characterized by hree nc e elevations, i.e. 3-, 6- and 9-stories archetypes ll with a constant inter-story height equal to 3 m configurations have a rectangular pl n with 5 x 3 bays of 5m pan each. Fig. 1 - Main geometrical and material characteristics of the analyzed structural archetypes . Beams and columns were designed considering a C25/30 according to [NTC] with characte compressive strength f ck equal to 25 MPa, and a reinforcing steel B450C with characteristic yi tensile trength f yk equal to 450 MPa. To account for the non-lin ar material behavior, su table m are adopt d: in particu ar, Mander et al. (1998) model C crete04 and Men gott and Pinto ( model St el02 m teria s for cor /cover concrete an reinforc ment rebars ar used, whereas si strut truss elements with a non-linear behavior characterized by Di Tr pani t al. (2018) mode adopted to capture the stiffeni g effect caused by masonry infills. Masonry compressive streng nd the elastic modulu E m along th two orthogonal direct ons are sumed equal to 2.4 MP 4408 MPa for the irection, nd about to 7.28 MPa n 7400 MP for the other one. Masonry i are characterized by a thickness of 25 cm and distributed over the entire external perimeter o buildings, whereas the contributi n of the stairca e to the stiffness of the building was n gle Regarding the lo ding a tions, 5.5 kN/m 2 and 0.5 kN/m 2 are considered as the dead and live loa th roof, and a 6.5 kN/m 2 dead load and a 2 kN/m 2 live load are considered for the remaining fl Both high ductility class (DCH) an medium ductility class (DCM) are considered, thus leading total of 12 different rchetypes resulting from the combination of the differ nt number of st ductility class, and presence/absence of masonry infills. Results. The seismic hazard curves computed for each Italian municipality with reference t main oil class are coupled with the appr priate fragility curves representative of the code-comp archetype that designer may av sized in that location to get the ism c failur rates assoc wit a code-compliant design, and thus obtain he respective seismic reliability maps for bare infilled - li t RC frames. The following relevant damage state (DS) are defined: - L w Damag ( ds 1 ), corresponding to the achievement of the yielding point in the SD behavior curve; r curve representative of the seismicity at he site of inter st c monly comput d via a Probabilistic Seismic Haz rd Analysis (PSHA, Cornell 1968 dMcGui e 1995), an im is a relevant intensity easure. ase studies This paper investigates the seismic reliability of code-compliant residential buildings with an RC frame-resisting scheme. Fig. 1 illustrates the main features of the different configurations analyzed, which fulfill plan and elevation regularity criteria, and are characterized by three increasing elevations, i.e. 3-, 6- and 9-stories archetypes all with a constant inter-story height equal to 3 m. All configurations have a rectangular plan with 5 x 3 bays of 5m span each. Fig. 1 - Main geometrical and material characteristics of the analyzed structural archetypes.