# Seismic Assessment of Historical Masonry Buildings at Different Scale Levels: A Review
## 3 Small-Scale Approaches
### Rigid Plane Approaches
\begin{table}
\begin{tabular}{c c c} \hline \multicolumn{3}{c}{**Monodimensional Models**} \\ \hline
**Rigid Plane Approaches** & **Strut Models** & **Equivalent Frame Models (EFM)** & **Bidimensional Element Models** \\ \hline \multicolumn{3}{c}{[PERSON] [232]} \\  & [PERSON], [PERSON] [233] & [PERSON] and [PERSON] [246] \\  & [PERSON] [234] & [PERSON] and [PERSON] [247] \\  & [PERSON] and [PERSON] [235] & [PERSON] and [PERSON] [248] \\  & [PERSON] [236] & [PERSON] and [PERSON] [249] \\  & [PERSON] and [PERSON] [237] & [PERSON] and [PERSON] [249] \\  & [PERSON] [224] & [PERSON], [PERSON] [250] \\  & [PERSON], [PERSON] [12] & [PERSON] and [PERSON] [238] & [PERSON], [PERSON] [251] \\  & [PERSON] [225] & [PERSON], [PERSON] [252] \\  & [PERSON] and [PERSON] [231] & [PERSON], Marietta [253] \\  & [PERSON] [227] & [PERSON], Marietta [254] \\  & [PERSON] and [PERSON] [228] & [PERSON], [PERSON] [124] & [PERSON] and [PERSON] [254] \\  & [PERSON], [PERSON] [242] & [PERSON] and [PERSON] [255], \\  & [PERSON] and [PERSON] [243] & [PERSON] and [PERSON] [256] \\  & [PERSON], [PERSON] [244] & [PERSON], [PERSON] [257] \\  & [PERSON], [PERSON] [245] & [PERSON] [258] \\  & [PERSON] and [PERSON] [189] & \\ \hline \end{tabular}
\end{table} 
Table 4: Summary of different proposals for the monodimensional models of masonry structures. elements with constant thickness, double curvature restraint conditions whose height was defined as the entire pier's height. The spandrels, on the contrary, were rigid and infinitely resistant. The method allowed the evaluation of the panel failure modes besides the maximum load of the walls transmitted to each slab. Unlike the other techniques presented, it is relatively easy to use also through a spreadsheet without resorting to a computer. [PERSON] and [PERSON] [228] proposed a method based on the rigid plane approach, requiring the additional assumptions of (a) walls carrying more than 75% of gravitational loads, (b) limitation on plan ratio, (c) limitation on the ratio between the height of the building and the shorter plan side, and (d) building height not exceeding five floors or 13 m. The method, developed with reference to regular low-rise masonry buildings, introduced a new proposal to evaluate the wall stiffness based on effective shear area factors calibrated to account for different structural performance levels, namely elastic, completely nonlinear and partially nonlinear response. The presented proposal was later partly included in the Mexican seismic code [260]. Strut models represent the panel's behaviour through a strut element that schematise the masonry wall's reactive portion. The inclination of the strut element varies according to the horizontal load, and the collapse happens when reaching excessive rotation or compression. Generally not used for historical constructions, strut models found a wide application for accounting--in a relatively easy way--the effect of masonry infills in stiffening and strengthening the surrounding concrete or steel frame in framed buildings [229, 230]. Additional information can be found in [PERSON] and [PERSON] [231]. Equivalent frame models (EFM) are widely diffused within the framework of macroelement methods, based on discretising the load-bearing wall system by means of a frameset. A two-nodes geometry connected through rigid beams or rigid offset is used to model piers and spandrels. The rigid arms schematised the joint panels, usually not showing relevant damages after earthquakes, and have the role of solving the inaccuracies arising from the