PSI - Issue 44

Alessandro Fulco et al. / Procedia Structural Integrity 44 (2023) 195–202 Alessandro Fulco et al. / Structural Integrity Procedia 00 (2022) 000–000

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and restoring of elements constituting the cladding/partition panel, for state D2 (NS) ; demolition and restoring of the whole panel, for state D3 (NS) . The unit parametric costs are multiplied by the areas of claddings and partitions present at the story along two reference orthogonal directions obtaining the total cost related to non structural elements C DN at the story. 5. Damage states and consequences for contents Three classes of contents are defined: closets/cabinets, electronic equipment, ceilings. For each class a control parameter among the EDP's characterizing the seismic response of the construction and the value of this parameter for which contents damage is activated, are defined. Cabinets and electronic equipment, are controlled by the floor acceleration: a damage activation value equal to 0.25 g is assumed. Ceilings are controlled by the interstory drift ratio: a damage activation value equal to 0.005 is assumed. Since it is difficult, or even impossible, defining damage levels for these elements, only one damage state, D1 (CO) , is considered for the contents. Contents can be undamaged or damaged: if damaged it should be substituted. The maximum potential cost of contents is defined as a rate b 1 of the total construction cost of the building, Taghavi S. et al.(2003). Different values of b 1 for different type of building occupancy are assumed as following: for dwelling building b 1 is between 0,067 and 0,075, for office building b 1 is between 0,075 and 0,125, for hospitals b 1 is between 0,075 and 0,100. The cost associated to the loss of contents can be evaluated as being N the number of classes of contents; β 1,j the rate of the total construction cost (structural and non structural elements) for the j -th class of contents; β 2,j = k 1,j · k 2,j with k 1,j varying from 0 to 1, according to the actual presence of the j -th class of contents with respect to the potential maximum presence; k 1,j = 1 or 0, according to the circumstance that the activation level of the control parameter of the j -th class of contents was reached or not, respectively, in the scenario under consideration. 6. Building vulnerability: assessment of global performance scenarios Different global damage conditions (damage scenarios) should be defined for the construction, they identify the performance levels for which to evaluate the structure capacity and the consequences. Each scenario is characterized by the damage level of structural and non structural element (each element attains a damage state) as well as by the damage of equipment and contents and is defined on the basis of: (i) the number of structural elements attaining critical conditions (local damage state D4 (ST) ); (ii) the interstory drift ratio; (iii) the floor accelerations (estimated from the story shears). The state of the structure correspondent to each scenario is automatically identified within the pushover analyses of the numerical model. The scenarios to be used within the procedure are defined by the user: the predefined damage scenarios are listed in the following and can be used as reference. Scenario L0 - "Light Damage". Non structural elements attain damage states D1 (NS) or D2 (NS) . Structural elements attain damage lower or equal D1 (ST) . In terms of building response, the scenario correspond to the achievement of a story drift ratio Δ ≥ 0.003 at least at one story and/or of a damage state D2 (ST) for at least one structural element (with any number of structural elements at a damage state D1 (ST) ). Scenario L1 - "Limited Damage". One structural element attains the collapse damage state D4 (ST) . The situation corresponds to a very limited damage with a reduced impact in terms of repairing cost and consequences on the occupants, but it identifies the "life safety" limit state according to the current Italian standard NTC2018 and therefore corresponds to the conventional vulnerability level of the r/c structure. Scenario L2 - "Extended Damage". 10% of the vertical structural elements of the whole building or 20% of the elements at a single story attain the collapse damage state D4 (ST) . The assumed criterion is adopted by analogy to the 1, b b × 2, 1 [ ( C C + )] N å DC j j DS DN j C = = × (2)