Extensive experimental study on five types of paianta walls - StrongPa project

Timber-framed houses are widely used worldwide, with structural variations influenced by geography and tradition. In Romania, paianta houses - a vernacular timber-framed structural system - feature different infill materials based on regional availability: i.e. timber logs in mountainous areas and clay-straw mixtures in plains. Given Romania's seismic risk, particularly from the Vrancea source, concerns about the seismic resilience of paianta houses have arisen. However, studies on their structural behavior remain limited, and no standardized evaluation method exists. The StrongPa project aims to develop strengthening techniques for paianta houses through extensive experimental testing. This paper presents the first part of experimental program which investigates the in-plane static loading behavior of timber-framed walls, constructed in line with traditional Romanian methods. Key findings indicate that infills significantly increase both stiffness and strength of the walls, bi-linearization of envelope curves using EN12512 method B showed better match to experimental results, energy dissipation calculated for both experimental results and bi-linearized curves reconfirmed that the method B is appropriate for walls with infills, damping ratios, and stiffness degradation were analyzed to compare structural performance among the different types of infills. • The StrongPa project aimed to identify appropriate strengthening techniques for timber frames with infills. • First, 17 walls without retrofit were experimentally tested in static cyclic regime to obtain the seismic behavior. • Lateral shear force vs. shear angle relationships were identified for 5 types of infills. • Timber-framed walls with infill had significantly better strength and stiffness than those without. • Bi-linearization was done per EN12512, using methods A and B, with method B proving better for timber frames with infills. • Energy dissipation, damping ratio, and stiffness degradation highlighted the varying effects of the studied infill types.