A simplified approach for including the incidence angle effect in seismic risk assessment

Abstract

A simplified procedure is developed to consider the azimuthal orientation of buildings when estimating seismic risk. Two square‐plan reinforced concrete building models are considered as a testbed, one with similar and one with dissimilar properties along the two principal horizontal axes. The fragility of both structures is analysed using a set of ground motion records rotated to multiple incidence angles to develop orientation‐dependent fragility functions. It has been observed that, re‐orienting all records so that these structures have the same azimuth vis‐à‐vis the corresponding epicentre leads to significant differences compared to assuming random orientations. Additional results stemming from single‐degree‐of‐freedom oscillators further confirm such findings, showing a dependence to the proximity to the faults and the level of dissimilarity in the principal horizontal axes of the structure. The end results point to a non‐negligible bias in assessment studies when a structure's orientation with respect to governing rupture scenarios is not taken into account. It is shown that the median of fragility curves calculated for un‐rotated incidence angles can be bias‐corrected through shifted by an amount that depends on the azimuthal orientation and level of axes‐dissimilarity of structures.

New insights into the relationship between seismic intensity measures and nonlinear structural response

“…When the analysis is oriented to urban environments, it is also important to know about the geographical distribution of as many physical properties as possible. Of great importance is to know, for instance, the number of structures belonging to each structural type, distribution of the number of stories and spans, azimuthal position of buildings (Vargas-Alzate et al 2021), amongst many others. In addition, the variability level of the mechanical and geometrical properties of the elements, as well as that of acting loads, should be available.…”

A multi‐perspective framework for seismic retrofit optimization of urban infrastructure systems

“…Also, for each component 𝑗 in the ordered pair (𝑖, 𝑗), if component 𝑗 is a source node, its supply level is bounded by zero or the maximal output, as stated by Constraint (14); if component 𝑗 is a demand node, its demand level is bounded by zero or the required demand, as stated by Constraint (15); if component 𝑗 is an edge, its flow is bounded by zero or its capacity, as stated by Constraint (16). Moreover, if component 𝑗 is a damaged node, all its attached edges will fail and the flow on these edges are zero, as stated by Constraint (17). For each ordered pair (𝑖, 𝑗), if component 𝑗 is damaged, the interdependency relationship (𝑖, 𝑗) does not normally work, and the physical interdependency variable 𝛿 𝑘→𝑙 𝑖,𝑗 becomes zero, as described by Constraint (18).…”

“…Researchers have proposed many performance measures, such as reliability, risk, vulnerability, robustness, resilience and economic loss, to assess the disaster performance of urban infrastructure systems and support the seismic retrofit decision. [12][13][14][15][16][17] The first performance measure is reliability, which is defined as the probability that a network remains operative given the occurrence of a disaster or disruptive event. 18,73,74 Scherb et al 19 determined the component ranks for power systems improvement planning according to their influence on the overall system reliability.…”

Probabilistic risk assessment for reinforced concrete frame structures subject to mainshock‐aftershock sequences

“…Eads et al 11 investigated the performance of averaged spectral acceleration (Sa avg ) and induced the Sa avg in structural collapse risk assessment. Similar research has also been conducted to investigate computational framework [12][13][14] and mathematical model calibration. 15,16 Moreover, the outcomes of these studies were applied to investigate the seismic risk of various kinds of structures.…”