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COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 The construction of the main masonry building of the "Quinto Orazio Flacco" school dates back to the year 1933. The three-storey masonry building is characterized by an M-shaped plan with maximum dimensions equal to 57.8 m and 82.4 m respectively in the transversal and longitudinal directions. MATERIAL PROPERTIES  The typologies of masonry employed are of three kinds: irregular quarrystones; claved stone blocks; tufa blocks.  The staircase spaces, the architraves for wide openings and the floors are realized in reinforced concrete. Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 In 1963, dictated by the necessity of finding further premises, a new reinforced concrete building, separated from the pre-existent masonry one, was realized along its free perimeter. The separation gaps between masonry and concrete buildings are about 2 cm. Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 Analysis of the seismic vulnerability of the “Quinto Orazio Flacco” school MASONRY REINFORCED CONCRETE 1. Non-linear static POUNDING POUNDING POUNDING analyses (pushover) y POUNDING x performed separately Floor Floor H=20+5 cm Floor H=20+5 cm Floor H=23.5cm H=23.5cm for the masonry and Floor H=23.5cm Floor H=23.5cm Floor reinforced concrete Floor H=23.5cm H=23.5cm Floor H=23.5cm Floor H=23.5cm 41.08 buildings (MIDAS Gen). Floor H=23.5cm Floor H=23.5cm 2. Earthquake-induced Floor H=36 cm Floor H=23.5cm 57.78 56.14 Floor H=23.5 cm pounding simulations Floor H=22cm Floor H=22cm Floor H=22cm by non-linear time- history analyses Floor Floor H=23.5cm Floor H=23.5 cm Floor H=23.5cm H=23.5 cm (MATLAB algorithm). Floor H=23.5 cm Floor H=23.5 cm Floor H=23.5 cm Floor H=36 cm Floor H=36 cm 9 15.15 4 . 5 1 Floor Floor H=22cm 5 9 3 . . 9 2 H=22cm 5 3 3 . 9 3 14.08 14.36 Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 PUSHOVER ANALYSIS Since the effective modal mass of each fundamental mode in longitudinal and transversal directions amounts to at least 58% of the total mass of the structure, the following lateral load distributions are used for both masonry and reinforced concrete buildings: a “uniform” pattern and a “modal” pattern. Masonry building 1 st Mode of vibration: T =0.27 s, M x % =1.37%, 2 nd Mode of vibration: T =0.26 s, M x % =57.7% , M y % =58.36% M y % =1.3% Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 PUSHOVER ANALYSIS Since the effective modal mass of each fundamental mode in longitudinal and transversal directions amounts to at least 58% of the total mass of the structure, the following lateral load distributions are used for both masonry and reinforced concrete buildings: a “uniform” pattern and a “modal” pattern. Reinforced concrete building 2 nd Mode of vibration: T=0.98 s, 1 st Mode of vibration: T=1.48 s, M x% =0.0%, M y% =95.7% ; M x% =98.1% , M y% =0.0%. Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 PUSHOVER ANALYSIS Finite Element model Masonry building The behaviour of the masonry building is simulated by adopting an equivalent frame element model, characterized by an assemblage of pier, spandrel and joint panels. Piers and spandrels are modeled by assuming an elastic-perfectly plastic behaviour based on the plastic hinge concept. In particular:  a suitable moment-displacement M-  M V plastic hinge (Fig. a.1) is provided at M V u u both ends of each element (CEN 2005, P.C.M. 2005, FEMA 2000);  a shear-displacement V-  plastic hinge (Fig. a.2) is located at the mid-span 0.008 H 0.004 H M V el el (CEN 2005, P.C.M. 2005, FEMA 2000). a.1) a.2) Pier panels Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 PUSHOVER ANALYSIS Finite Element model Reinforced concrete building The reinforced concrete building is treated as a frame element model, in which the spread of inelasticity is implemented through the formation of nonlinear plastic hinges at the frame element’s ends during the incremental loading process. The moment-rotation relationship of a plastic hinge is modelled as a trilinear curve constituted by the elastic segment (AB), the hardening segment (BC) and the softening segment (CD) (CEN 2001, M.I.T 2008). More precisely: M  pure moment hinges are assigned to beams; M C u  axial-moment hinges are assigned to columns. M y B M cr A D u y Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 PUSHOVER ANALYSIS Pushover curves – longitudinal direction Reinforced concrete building Masonry building Pushover curves in y direction Pushover curves in y direction uniform pattern modal pattern (1st mode) uniform pattern modal pattern (1st mode) 750 35000 SLC SLC 30000 Base Shear, F [kN] 600 Base Shear, F [kN] 25000 450 20000 15000 300 SLC 10000 SLC 150 5000 0 0 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Monitored Displacement, d [m] Monitored Displacement, d [m] The structures under examination are vulnerable to earthquake-induced structural pounding in the longitudinal direction. Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010  Building separations are insufficient to accommodate the relative motions of the three adjacent structures.  The adjacent buildings are characterized by natural vibration periods sensibly different, which produce out-of-phase vibrations. EARTHQUAKE-INDUCED STRUCTURAL POUNDING MIDAS Gen model Numerical model • non-linear viscoelastic m 3 m 6 m 9 models to simulate K y 3 K y 6 K y 9 impact c y 3 c y 6 c y 9 • elastic-perfectly plastic m 2 m 5 m 8 approximation of the K y 2 K y 5 K y 8 storey shear forces c y 2 c y 5 c y 8 d d • simulation of impact by non-linear m 1 m 4 m 7 viscoelastic models K y 1 K y 4 K y 7 c y 1 c y 4 c y 7 • elastic behaviour of the storey shear forces Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy

COST Action C26 Urban Habitat Constructions under Catastrophic Events FINAL CONFERENCE. Naples, 16th- 18th September 2010 EARTHQUAKE-INDUCED STRUCTURAL POUNDING m 3 m 6 m 9 Numerical model K y 3 K y 6 K y 9                        S M y t C y t F t F t M y t y y y g c y 3 c y 6 c y 9 shear forces mass matrix ground acceleration m 2 m 5 m 8 damping matrix pounding forces K y 2 K y 5 K y 8 c y 2 c y 5 c y 8 d d Each colliding 3-storey building is modelled as a m 1 m 4 m 7 three-degree-of-freedom system, with each storey’s mass lumped on the floor level. K y 1 K y 4 K y 7 c y 1 c y 4 c y 7 Just traslational degrees of freedom are considered, while torsional effects are neglected. Seismic vulnerability of the “Quinto Orazio Flacco” school Alessandra Fiore & Pietro Monaco Politecnico di Bari, Department of Civil and Environmental Engineering, Bari, Italy