In New Zealand, due to a major building boom in the 1980s, many multi-story commercial buildings are of similar concrete construction with precast floors. During the 2016 Kaikōura earthquake, the damage sensitivity of this type of construction was highlighted by several buildings with precast floors damaged beyond economical repair. While the vulnerability of precast floor construction had been studied by past research, engineers lacked reliable assessment procedures that would facilitate the estimation of the floor’s residual capacity and a rapid recovery. This motivated this PhD research, whose main objective is to improve the understanding of the likely behavior of precast pre-stressed hollow-core (PPHC) floors during earthquakes.

There are many applications in which PPHC slabs are subjected to shear, torsion, or combined shear and torsion. Nonetheless, extruded PPHC units contain no transverse reinforcement, being inherently vulnerable to brittle failure modes. This research first comprises experimental investigations of the properties of extruded concrete and the shear capacity and nonlinear behavior of PPHC units. Subsequently, a detailed nonlinear finite element (FE) modelling approach is proposed and calibrated against experimental data to represent the behavior of PPHC slabs under shear and torsional actions. Results suggest that the FE model can capture the shear and torsional failure mechanisms in PPHC slabs with different shear span-to-depth ratios and with and without eccentricity. Finally, the numerical results are used to evaluate the simplified assessment methods provided by commonly used design standards.

A methodology to quantify the fragility of PPHC slabs failing in shear is then proposed by making use of the FE modelling approach, informed through experimental testing. Three damage states are identified through damage analysis, and numerical fragility curves are developed for PPHC typical of New Zealand construction practice. The outcomes from this fragility study provide a basis for improved reliability assessment of PPHC slabs.

Finally, this research proposed a mechanics-based modelling approach for the analysis of PPHC slab- to-beam seating connections. The model has been calibrated against existing test data to predict the failure of a PPHC sub-system under negative bending moments. The numerical outcomes allow comparison of the moment-drift response, principal tensile stresses, and crack progression during loading. This work illustrates the potential value of the FE modelling and analysis approach in gauging the impact of retrofit efforts for precast hollow-core flooring systems.