The use of post-tensioned composite (PTC) slab systems has become widespread in the construction industry, spanning from residential to commercial slab structures. The steel sheeting serves as permanent formwork, capitalising on its rigidity to significantly reduce the number of supporting props and shorten the construction progress with no removal process. However, the characteristics of steel sheeting arise from the ribbed structure, where one side, parallel to the ribs, refers to a longitudinal (strong) direction of slab. Otherwise, the other direction, perpendicular to the ribs, exhibits much lower strength, referred to as the transverse (weak) direction.

In response to this issue, certain engineering firms have adopted post-tensioning methods as a solution to effectively enhance the bending stiffness of this weaker direction and replace the use of beam systems in the current methodology. This approach, therefore, extends the floor application to flat plate slab construction, marking a significant advancement in the field. Within the current level of literature review, there is a lack of research investigating the flexural behaviour of the PTC slab systems in two-way action and the impacts of post-tensioning on the bending strength of transverse directions. In terms of practical application, there are limitations from which no standard is specified, or available design programs fail to incorporate the effect of steel sheeting under the flexural behaviour of PTC slabs. As a result, this research gap highlights the need for further exploration in this critical area of construction engineering, which is the focus of this thesis. [...]