Realistic Wind Loads on Reinforced Masonry Walls

Abstract

Wind is a primary source of out-of-plane loads for masonry wall structural members. Although wind is a dynamic loading condition, the current body of research generally considers the behaviour of masonry walls under quasi-static load conditions, whilst the dynamic aspect is not explicitly considered. Therefore, this research intends to address this gap in knowledge. The objective of this research was to investigate the behavioural characteristics of reinforced masonry walls subjected to realistic wind load conditions. Specifically, the intention was to examine the differences in strength and deflection characteristics of reinforced masonry walls under quasi-static and dynamic load conditions. In addition, differences in the behaviour of walls with different levels of reinforcement were examined under quasi-static and dynamic load conditions. The experimental program consisted of testing twenty large-scale wall specimens featuring idealized-pinned support conditions. The specimens comprised four sets of tests that addressed all possible combinations of the two primary test variables: quasi-static vs. dynamic load, and low vs. high reinforcement ratio. The partially grouted wall specimens had nominal dimensions of 3 m high and 1 m wide and were constructed using standard 200 mm hollow concrete masonry blocks arranged in a running bond pattern. The dynamic load was generated using a 4th order autoregressive function to produce a series of realistic wind load time histories for varying wind intensities. The dynamic loads and the quasi-static loads were applied using a four-point loading setup. Both the strength and deformation characteristics of the wall specimens were analyzed and compared. The results indicate that the wall specimens loaded under realistic dynamic loading conditions resisted slightly higher peak loads at higher levels of ductility compared to that of the wall specimens loaded under quasi-static loading conditions. Furthermore, the amount of reinforcement did not have significant impact on the general behaviour characteristics between the two types of loading conditions.