Seismic Performance of Precast Hollow-core Floor Units and Residual Capacity of Web-cracked Floor Units
The susceptibility of precast hollow-core floors to sustain critical damage during an earthquake is now well-recognized throughout the structural engineering community in New Zealand. The lack of shear reinforcement in these floor units is one of the primary reasons causing issues with the seismic performance of these floors. Recent research has revealed that the unreinforced webs of these floor units can crack at drift demands as low as 0.6%. Such observation indicates that potentially many of the existing building stock incorporating hollow-core flooring systems in cities of relatively high seismic activity (e.g. Wellington and Christchurch) that probably have already experienced a level of shaking higher than 0.6% drift in previous earthquakes might already have their floor units cracked. However, there is little information available to reliably quantify the residual gravity load-carrying capacity of cracked hollow-core floor units, highlighting the need to understand the post-cracking behavior of hollow-core floor units to better quantify the extent of the risk that cracked hollow-core floor units pose.