Full-Scale Experimental Testing of Retrofitting Techniques in Portuguese “Pombalino” Traditional Timber Frame Walls

Abstract

Traditional timber frame walls are constructive elements representative of different timber frame buildings that are well known as one of the most efficient seismic resistant structures in the world. Timber frame walls were also used in the reconstruction of buildings of the old town of Lisbon after the earthquake of 1755 aiming at improving their seismic global behaviour. As it is important to preserve these structures, a better knowledge about their behaviour under seismic actions is important and can give some indications about possible retrofitting techniques to be used to improve the seismic performance. Due to the great rehabilitation effort currently carried out in many countries, a better understanding of retrofitting techniques is also needed. Therefore, this paper aims at providing a study on possible retrofitting techniques adopting traditional solutions such as bolts and steel plates. Static cyclic tests have been performed on retrofitted traditional timber frame walls in order to study their seismic performance. The experimental results showed the overall good seismic performance of steel plates and the more ductile behaviour of retrofitted timber frame walls with bolts

Performance evaluation of traditional timber joints under cyclic loading and their influence on the seismic response of timber frame structures

“…In this case the post bended and deformations related to buckling were also observed in the steel plate ( Fig. 11), similarly to what happened in the wall tests (Poletti et al 2014).…”

“…To understand the response of these joints for vertical elements, the deformation patterns and the damage progress will be analysed in order to confirm the selection of the most appropriate retrofitting solutions which were previously adopted for the walls (Poletti et al 2014;. This study will help fill the research gap currently present on retrofitting of traditional timber frame walls and their joints.…”

“…The joints were retrofitted with some of the same strengthening solutions adopted for the tests performed on timber frame walls (Poletti et al 2014, namely using steel plates and Near Surface Mounted (NSM) steel rods. Additionally, self-tapping screws and Glass Fibre Reinforced Polymers (GFRP) sheets were also used to retrofit the connections to understand the efficiency of their adoption in walls.…”

“…The same structural timber glue used for the walls was adopted (MapeWood Paste 140 (MAPEI 2002)). Steel plates were applied in the same way as done in the walls (Poletti et al 2014), positioning two commercial steel plates, one horizontally and one vertically, on each side of the joint and connecting them with bolts and screws, forming a cross ( An alternative solution was to strengthen the connections with GFRP sheets. A uni-directional fibre glass fabric (MapeWrap G UNI-AX (MAPEI, 2012)) was used together with an appropriate epoxy resin (MapeWrap 31 (MAPEI, 2013)) for impregnation of the fibre with a dry system.…”

Timber frames as an earthquake resisting system in Portugal

“…Various strengthening techniques have been tested experimentally specifically for Pombalino timber frame walls (Gonçalves et al, 2012;Poletti et al, 2014;. From previous experimental studies (Meireles, 2012; it was seen that the cyclic behaviour of timber frame walls depends mainly on the response of the connections.…”