Cantilevered RC Wall Subjected to Combined Static and Impact Actions

• Published in: International journal of impact engineering 2020-09, Vol.143, p.103596, Article 103596
• Main Authors: Yong, Arnold C.Y., Lam, Nelson T.K., Menegon, Scott J., Gad, Emad F.
• Format: Article
• Language: English
• Subjects: Boulders; Computer simulation; Debris flow; Deflection; Design optimization; Impact action; Impact tests; Impactors; Large-scale experiment; Reinforced concrete; Reinforced concrete wall; Rockfall; Rockfall barrier; Tensile strain
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2020.103596

•Response of RC wall when subjected to static + impact action is investigated.•An analytical model is proposed for estimating RC wall deflection.•Structural response of RC wall is studied in a large-scale experiment.•Proposed model is validated by experimental results. A displacement-based (DB) model is introduced in this article alongside its detailed derivations to predict the flexural response behaviour of a cantilevered reinforced concrete (RC) wall that is subjected to combined actions of boulder impact and sustained load (e.g. debris flow). In order to validate the model, a large-scale experiment was carried out by striking a 1.5 m tall, 3 m long and 0.23 m thick reinforced concrete wall using of two impactors weighing 280 kg and 435 kg to simulate different boulder impact intensities. A sustained load of 36 kN was applied to the wall using two prestressed custom-fabricated spring assemblies. Wall deflection and reinforcement tensile strain values measured from the experimental tests are shown to be within about 10–20% of predictions calculated from the proposed DB model. Errors of the predictions are consistently conservative across all the considered impact scenarios. These experimental findings are original given that no impact tests of the scale presented in this paper, which incorporate the effects of co-existing sustained lateral forces (e.g. debris flow), can be found in the literature. The proposed DB model was found to accurately predict both the deflection of the wall as well as the amount of tensile strain experienced by the reinforcement at the base of the wall. This paper concludes with a step-by-step design procedure that utilises the proposed DB model for designing RC rockfall barriers, which will be useful for practitioners aiming for a more optimised barrier design.