# Seismic Assessment of Historical Masonry Buildings at Different Scale Levels: A Review
## 2 Large-Scale Approaches
### Mechanical Methods
#### 2.2.1 Simplified Mechanical Methods
The method application is based on the strong simplification of no-tension material with unlimited compression strength, while more refined material properties, ignored by the current model, can influence the collapse modality, such as orthotropic behaviour, limited compressive strength and shear-normal stress interaction [93]. Further, as for all the simplified approaches, the geometry and the loading conditions are often approximated, and only a pre-defined set of collapse mechanisms is analysed, possibly leading to an inaccurate assessment of the structural capacity. The VULNUS method introduced by [PERSON], [PERSON] [68] represents one of the first relevant mechanical simplified models based on the kinematic approach developed for masonry structures. It was calibrated for small and regular buildings and provided three output indexes representing as many collapse multipliers as possible. The first two indexes accounted for in-plane and out-of-plane behaviour, concerning only two failure modes; the last was a weighted sum of parameters related to the height, connections and homogeneity between adjacent buildings. [PERSON] and [PERSON] [70] and [PERSON] and [PERSON] [94] proposed an improvement to the VULNUS method: starting from the collection of geometrical data, the spreadsheet FaMIVE, capable of identifying a wide range of the most dangerous local mechanisms for the outward facades of the masonry building aggregates, was elaborated. External inspections only were required, resulting in a quick procedure applicable even in case of dangerous and not accessible buildings in a post-emergency phase. The FaMIVE method was later improved [72; 74] by including the issues of cohesion and irregular opening layouts, the latter representing a more realistic situation for historical buildings. [PERSON] [69] introduced the limit state method, which was later applied to the city centre of Catania. The method was based on the evaluation of displacement and energy dissipation capacity, and results were presented in terms of the probability of occurrence of each damage limit state for a specified earthquake motion, depicted by means of a displacement response spectrum for each building. The method can be reliably used for a global loss prediction but lacks in evaluating single building performance. Concerning masonry structures, [PERSON] and [PERSON] [95], [PERSON] [96], and [PERSON], [PERSON] [97] proposed the MeBaSe (Mechanical Based Procedure for the Seismic Risk Estimation of Unreinforced Masonry Buildings) procedure. According to the reached damage level, the approach accounted for three limit states related to in-plane failure mechanisms; the limit state functions were determined through geometrical and material data, using correction factors to simplify a tri-dimensional building into a bidimensional model. Unlike Calvi [69], out-of-plane phenomena were included through one-way and two-way bending mechanisms. The two wide categories of simplified mechanical models above-mentioned are resumed in the approach proposed by the Italian Guidelines for cultural heritage analysis and retrofitting [98]. The Guidelines adopted the principles of the performance-based approach outlined by the Italian Code [99] to implement the Eurocode [100] prescriptions at a national level [2]. They outlined three different analysis levels of increasing complexity: the first two belonged to simplified mechanical approaches, while the last one proposed global analysis through proper numerical techniques. In particular, the first level (LV1), similar to the SAVE procedure, was meant to be applied at a territorial level, providing different prescriptions depending on the construction typology. The second level (LV2) is based on the kinematic approach applied to the structure defined in terms of macro-elements. Several have been the subject of the application of the Italian Guidelines, such as Casapulla, Argiento [101]--with reference to a masonry palace--and [PERSON], D'Ayala [2]--with reference to towers.