Numerical Analysis of Hollow Core Slabs in Relation to Pedestrian Traffic

Abstract

Prefabricated concrete floor slabs are well-established types of flooring and are widely used in the construction industry. Concrete floor slabs have almost never had problems with vibrations caused by pedestrians. It is only in recent times, with modern constructions demanding longer spans and thus slimmer floor slabs, that vibration issues have begun to arise.This thesis has investigated how vibrations caused by pedestrian traffic in hollow-core floor slabs affect individuals according to the requirements and standards in place. The investigation was conducted using simulations in the finite element program RFEM. Various configurations of hollow-core floor slabs were modeled and subjected to different load cases by applying a load function representing the dynamic movement of pedestrians. The slabs were placed adjacent to each other and in succession to attempt a nuanced analysis. An extreme case was also examined to determine when the number of pedestrians became critical. The load function is derived from a Swedish standard, and the load has been reduced according to that standard. Checks with manual calculations were performed to confirm the program's accuracy.The results obtained from this study were presented in terms of maximum accelerations and Root Mean Square (r.m.s.) values, as these evaluation methods were the most recommended. The accelerations were then compared with the requirements from the standard ISO 10137. During the analysis, it was found that the load cases with the highest pedestrian frequencies also exhibited the highest acceleration values. The study also revealed that the lightest floor slab was most affected from a structural dynamic perspective. The simulations also showed that vibrations from a realistic pedestrian scenario posed no risk of disturbance. This is explained by the fact that the required number of pedestrians to generate a risk on the floor slab exceeds the number that can fit on a single floor slab. The number of elements in the width was found to have a negligible impact on the accelerations, provided that the number of pedestrians per slab remained constant