THE USE OF TIMBER INTO THE TRADITIONAL NEPALESE ARCHITECTURE

Following the occurrence of a major seismic event in Nepal on April 2015, several technical reports based on field surveys have documented recurring forms of damage in traditional buildings, discussing the possibility of recognizing seismic protection solutions. In the opinion of several authors, originally anti-seismic awareness was present in the builders, but was lost mainly in recent times due to the uncontrolled modernization of the main cities. This viewpoint is here discussed with reference to the frequent presence of wooden elements among the ruins of masonry buildings and the peculiarity of some timber details. Based on the damage surveys which followed the earthquake and some drawings from Nepalese historical manuals, the use of timber appears to be systematic within the local building tradition, both for structural and aesthetic purposes. In addition to the use in roof structures and floors, timber is present also in portico systems and articulated massive frames around openings, probably intended as seismic protection solutions. However, despite the level of seismic hazard in the area, it is surprising to note the total lack of simple measures such as chains, curbs and tie rods. One reason could be found in the poor quality of masonry which, as it is known, can make solutions of this kind totally ineffective. The opinion of limited anti seismic awareness in builders is also supported by the lack of truss systems in roofs. The analysis of both recent pictures and historical drawings, indeed, reveals the systematic presence of thrust actions on the walls; this can be noticed not only in vernacular buildings, but also in the monumental religious ones. Throughout the present work, an overview of the use of wood and relative criteria is given, highlighting the details of the traditional system with special reference to local characteristic roofing systems