Abstract:
It has been found from previous research that support connections for precast concrete floor units are subjected to critical earthquake induced deformations, including a relative rotation between the unit and support beam and a pull-off effect caused by beam elongation. Traditional support connection details used for rib and timber infill (RT) floors consisted of the ends of the ribs being cast into their supporting beam. Damage to the precast ribs can occur when the end of the rib is trapped in the support beam, causing a vertical flexural crack in the rib that may compromise the vertical load carrying capacity of the floor. Such cracks were observed during the 2010/2011 Canterbury earthquakes and in response to this, SESOC have provided recommended rib seating details that enable the rib to slide and rotate without sustaining damage. An experimental programme was initiated to investigate the seismic performance of both the existing and recommended support connection details for RT floors. A test setup was developed to subject the connection to deformations simulating seismic actions in a typical structure incorporating 175 mm deep ribs in addition to gravitational loading. The first three tests have been performed and it was found that the SESOC recommended support connection details successfully enabled the rib to deform without becoming trapped in the support beam or sustaining damage.
