Shake-table investigation of a timber retrofit solution for unreinforced
masonry cavity-wall buildings

Associazione Nazionale Italiana di Ingegneria Sismica - ANIDIS Conference, Italy

REFERENCE

Miglietta M., Damiani N., Grottoli L., Guerrini G., Graziotti F. (2019). Shake-table investigation of a timber retrofit solution for unreinforced masonry cavity-wall buildings. In the proceedings of the Associazione Nazionale Italiana di Ingegneria Sismica - ANIDIS Conference, Ascoli Piceno, Italy

Scope and methodology

Two unreinforced masonry full-scale building prototypes representing the end-unit of a two-storey cavity-walls terraced house typical of the Groningen region of The Netherlands.

The prototypes had a reinforced concrete slab at the first floor and a flexible timber diaphragm at the second floor with a pitched timber roof supported by two gable URM walls.

The retrofit system consisted of timber frames mechanically connected to the building piers and floors, on which oriented-strand boards were nailed.

The incremental dynamic tests were performed up to the near-collapse conditions using the same input motion representative of Groningen induced seismicity.

FINDINGS

At a PGA = 0.3g the bare building developed a local mechanism: sliding of the second-floor timber diaphragm on top of the second-storey masonry piers

The as-built and retrofitted buildings sustained a maximum near-collapse PGA of 0.4g and 0.8g, respectively.

The strengthened building showed a global response up to the end of the test.

The combined improvements of connections and piers capacity allowed the retrofitted building to develop a torsional response that fully exploited the strength of all structural elements, including the in-plane resistance of the transverse squat walls. Damage was fairly distributed throughout the building.