Seismic Performance of Historical Masonry Structures Through Pushover and Nonlinear Dynamic Analyses

Abstract

Earthquakes are the main cause of damage for ancient masonry buildings. In order to reduce their vulnerability with compatible and light interventions, it is necessary to have accurate models for the seismic analysis, able to simulate the nonlinear behaviour of masonry, and well defined Performance-Based Assessment (PBA) procedure, aimed to guarantee acceptable levels of risk for the use of the building, the safety of occupants and the conservation of the monument itself. Displacement-based approach is the more appropriate for this type of structures, which cracks even for low intensity earthquakes and can survive to severe ones only if they have a sufficient displacement capacity. Among the wide variety of historical masonry structures, buildings characterized by a box-type behavior are here considered, which can be modeled through the equivalent frame model, considering the assembling of nonlinear piers and spandrels. Thus, the main object of the paper is to establish a strict equivalence between the use of static pushover and incremental dynamic analyses for the PBA. Pros and cons of the two methods are discussed, as well as some critical issues related to their application. A multiscale approach is proposed for the definition of the performance levels, which considers the seismic response at different scales: local damage in single elements, performance of single walls and horizontal diaphragms and global behavior. An original contribution is the use of Proper Orthogonal Decomposition (POD) technique for the correct interpretation of numerical and experimental dynamic results.

Masonry Italian Code-Conforming Buildings. Part 2: Nonlinear Modelling and Time-History Analysis

“…The selected EDP is the maximum inter-story drift (!max) assessed at the wall scale, that is defined as !max=max(!w,l) where w and l refer to the wall number and level number, respectively. It was computed by accounting for the contribution of both horizontal displacement and rotation (Lagomarsino and Cattari 2015), even though the latter has a limited role in the examined structures, due to the presence of rigid slabs and systematic r.c. tie beams.…”

Rintc-E Project: Towards the Seismic Risk of Retrofitted Existing Italian Urm Buildings

“…The risk assessment in terms of global failure was performed by multi-stripe nonlinear dynamic analyses for ten different earthquake's return periods. The equivalent frame model implemented in the Tremuri program [10] was adopted, using the available macroelement models ( [11], [12]). Pushover analyses were performed to estimate the capacity in terms of maximum wall inter-storey drift.…”

Seismic Behavior of Lisbon Mixed Masonry-RC Buildings With Historical Value: A Contribution for the Practical Assessment

“…For detailed results see Milosevic et al (2018b). Control node was selected at the top level in the wall that first collapses, as recommended in Lagomarsino and Cattari (2015). Figure 9 represents the normalized pushover curves in case of both analyzed models for each main direction and both load distributions.…”

“…Aiming to monitor the occurrence of significant damage in parts of the structure that may not be evident in the pushover curve, Lagomarsino and Cattari (2014) and Lagomarsino and Cattari (2015) proposed a multi-scale approach to define DLs on the pushover curve that defines the behavior of the buildings at three scales: (i) local, with damage on structural elements, piers and spandrels, (ii) macro-elements (like masonry walls or floors) and (iii) global (represented by the pushover curve).…”

“…Local scale: related with the assessment of the cumulative rate of damage in piers that reach DLi in accordance to the element multi-linear constitutive law (Lagomarsino and Cattari, 2015);…”