Adaptations of the flat jack test for its application in cob walls

Abstract

The single and double flat jack tests have been successfully applied for the first time in cob walls. This technique has been used for over 40 years in the field of cultural heritage conservation to investigate the levels of stress in different masonry and earthen wall typologies and to determine their mechanical properties [1]. Two standards [2–7] have been developed for the application of the technique in masonry walls and this paper presents the adaptation of those methods for its application in cob walls. • The control points have been pinned to the material instead of glued to the surface which has facilitated its installation and speed the process. • A timber frame has been fabricated, to which the cutting device has been supported and strapped, to facilitate the cutting of the slot thus obtaining a better-quality cut and a safety increase for the ring saw operator. • The connection of the hydraulics system has been slightly modified by connecting the pressure transducer next to the flat jack's inlet, instead of just after the pump, thus avoiding the recording of pressure peaks while manually pumping the oil.

Keywords

• Minor destructive tests (mdt)
• Heritage conservation
• Earthen Buildings