Assessment of Sufficient Number of Samples for Full-Scale Test of Hollow- Core Slabs

Structural reliability of hollow-core slabs is critical in both new construction and reuse-oriented projects. Load testing is a central verification method, though its purpose differs between these contexts. In new construction, quality control is primarily based on material testing, with load testing serving as a voluntary method to confirm product consistency and the applicability of the resistance model used. In reuse-oriented projects, however, load testing becomes essential because material properties cannot be altered, and quality assurance relies on existing information and test results from a finite population of slabs.

This study identifies the statistical uncertainty associated with the number of samples in HCS shear testing, using 188 full-scale test results from the literature and from this research. The results show substantial variation even among slabs with identical design parameters, and no correlation between variability and production year, slab height, concrete compressive strength, or strand cover depth was found. Increasing the number of samples significantly improves the estimated characteristic resistance value, while finite-population effects remain minor except in very small populations. The findings highlight the need to account for statistical considerations when making preliminary decisions about the required number of samples.