Experimental Investigation on the Structural Performance of Single Span Hollow Core Slab under Successive Impact Loading

Abstract

In Lebanon and many other countries where structures are vulnerable to impact loads caused by accidental rock falls due to landslides, specifically bridges with hollow core slab, it is mandatory to develop safe and efficient design procedures to design such types of structures to withstand extreme cases of loading. The structural response of concrete members subjected to low velocity high falling weight raised the interest of researchers in the previous years. The effect of impact due to landslide falling rocks on reinforced concrete (RC) slabs has been investigated by many researchers, while very few studied the effect of impact loading on pre-stressed structures, noting that a recent study was conducted at Beirut Arab University which compared the dynamic behavior of reinforced concrete and post-tensioned slabs under impact loading from a 605 kg impactor freely dropped from a height of 20 m. Hollow core slabs are widely used in bridges and precast structures. Thus, studying their behavior due to such hazards becomes inevitable. This study focuses on these types of slabs. For a better understanding of the behavior, a full scale experimental program consists of testing a single span hollow core slab. The specimen has 6000 mm × 1200 mm × 200 mm dimensions with a 100 mm cast in a place topping slab. Successive free fall drops cases from 14 m height will be investigated on the prescribed slab having a span of 6000 m. This series of impacts will be held by hitting the single span hollow core slab at three different locations: center, edge, and near the support. The data from the testing program were used to assess the structural response in terms of experimental observations, maximum impact and inertia forces, structural damage/failure: type and pattern, acceleration response, and structural design recommendations. This research showed that the hollow core slab has a different dynamic behavior compared to the post tensioned and reinforced concrete slabs mentioned in the literature review section.

Behavior of One-Way Reinforced Concrete Slabs with Polystyrene Embedded Arched Blocks

“…Voids, thin web, and thin flanges were considered the weak points of the hollow-core slab. The structural damages in these hollow-core units were not repaired or strengthened [12]. The deflections, as well as the concrete compressive strains, under service load were a little higher than those of an equivalent, solid slab [13].…”

“…During the last decays, numerous analytical and experimental studies were conducted to investigate the effect of voids embedded in concrete slabs in aspects of their materials and geometry [12][13][14][15]. Generally, the main focus of these studies was on the reductions in weight, as well as the flexural and shear strength.…”

Analytical Evaluation of Natural Frequencies in Hollow-Core Slabs: A PracticalMethodology for Civil Engineering Applications

“…Experimental programs have been conducted to assess the structural response of hollow-core slabs to impact loading. Chebo et al [9] investigate the behavior of hollowcore slabs under impact loading. The experimental program consists of testing a single span hollow-core slab with specific dimensions, and the results may not be directly applicable to slabs with different dimensions or configurations.…”