The Roof Bracing as Minimum Intervention for the Reduction of the Seismic Vulnerability of Historical Industrial Buildings: Analytical and Numerical Simplified Strategies for the Assessment of the Performances

The paper deals with the reduction of the seismic vulnerability of historical masonry buildings characterized by a wide room, of significant height, provided by a multi-sloping timber roof lying on perimeter walls and, internally, on columns or pillars (e.g. industrial buildings). Typically, these structures are extremely vulnerable to earthquakes but a minimum intervention, consisting in the bracing of the timber roof through wooden-based sheathing panels, can improve the seismic performances providing an adequate restraint against the walls overturning and fostering the box-behaviour of the entire structure. The case study of an ancient industrial building is analyzed. A smart analytical design strategy for the dimensioning of the bracings and the evaluation of the resisting ground acceleration is developed. A simplified numerical modelling strategy for pushover analysis, based on the equivalent frame method for the masonry walls and on equivalent diagonal springs for the roof bracings, is also presented.