Sustainable Selective Mitigation Interventions towards Effective Earthquake Risk Reduction at the Community Scale

Abstract

Risk reduction policies are crucial in regions of high seismic risk, having significant exposure and building vulnerability. In Italy, the Sismabonus incentive mechanism was recently approved, which regulates the possibility of benefiting tax deductions after seismic strengthening interventions on buildings. This paper presents a simplified approach for evaluating the effects of implementation of the Sismabonus policy at the territorial scale. Considering only reinforced concrete RC building typologies, a speed method for calculating the probability of being in relevant risk classes is introduced and it is applied to a town in southern Italy. The evaluation is based on simplified modeling of lateral seismic behavior and on the estimate of the peak ground acceleration corresponding to the attainment of building capacity. The effect of possible retrofit interventions is also considered. This performance-based procedure allows for taking into account the cost for selective retrofit interventions and contemporarily to estimate the variation of mean expected annual loss that is obtained with building upgrading.

The use of Stick‐IT model for the prediction of direct economic losses

“…The following assumptions were adopted for the Stick models database generation: (a) buildings are regular both in plan and in elevation; (b) approximately rectangular shape in plan (the response is analyzed in the two separate directions); (c) constant interstory height (for the database generation, it was assumed equal to 3.0 m); (d) constant span length in each direction; and (e) uniform infills opening percentage along the height. The database was generated adopting typical features of existing RC buildings in Italy 33,67,68 and accounting for possible variabilities in structural and mechanical characteristics within each building typology. For example, for a given surface area (equal to the product L X •L Y ) and in-plane aspect ratio L X /L Y , a number of possible structural configurations (i.e., different span lengths and numbers) were considered and also the material properties for concrete, steel, and infills consistency were varied according to assigned probability distributions.…”

Seismic Vulnerability for RC Infilled Frames: Simplified Evaluation for As-Built and Retrofitted Building Typologies

“…Depending on the ratio V y /V n , three possible failure modes are expected: flexure, flexure-shear or pure shear failure. If V y /V n < 1 for any value of ductility demand, RC column is expected to fail in flexure and θ SLV corresponds to 3 4 of the ultimate chord rotation for ductile members [39]. If V y /V n ≥ 1, the column is expected to fail in shear or flexure-shear and θ SLV is evaluated correspondingly to the intersection point between column shear demand and column shear capacity (see Figure 2b).…”

“…In such a case, the damage scale is graduated with reference to selected relevant limit states and often deformation limits at a storey, or the crisis of a single element drives the "failure" of the entire building. The adoption of code-based limits for damage graduation is useful for estimating the possible overpassing of selected limit states relevant for the codes (e.g., damage limitation limit state or life safety limit state), the eventual need to retrofit or the effect of selected mitigation interventions to reduce earthquake damage [3]. This paper performs a vulnerability study on reinforced concrete (RC) infilled frame buildings, representative of existing gravity load designed typologies in Italy.…”

Effect of Masonry Infill Constitutive Law on the Global Response of Infilled RC Buildings

“…However, due to a large amount of information and the remarkable computational effort required, the adoption of simpler methods is generally preferred. In particular, the so-called macro-modeling approach that employs equivalent struts is one of the most adopted in the numerical analysis of infilled frames and widely used in loss estimation framework [9,20] or to generate mechanical-based fragility curves [21]. Different approaches are available in the literature depending on the number, the geometrical configuration of the equivalent struts, and the constitutive models describing the cyclic behavior of infill panels.…”