Investigation of the Dynamic Performance of Large Reinforcement Bar Mechanical Couplers

Abstract

Criteria for designing hardened, heavily-reinforced concrete structures to resist blast effects from accidental explosions are defined by Unified Facilities Criteria 3-340-02 formerly Army Technical Manual TM 5-1300 (Departments of the Army, Navy, and Air Force. 1990). Lap splicing of the required steel reinforcing bars is the current practice in the construction of these reinforced concrete structures. Lap splicing of reinforcing bars often creates congested areas within the formwork that limit working space and hinder proper placement of concrete. In 1971, a limited number of splice types were tested at the ERDC (formerly Waterways Experiment Station) to investigate their performance under dynamic load conditions (Flathau 1971). Subsequently, several types of mechanical couplers have been tested and validated for developing the strength of reinforcing steel for cyclic loading and strain rates expected during earthquakes. The ERDC recently conducted a series of high strain-rate tests on five different types of American Concrete Institute 318 type II mechanical couplers, used for splicing of flexural reinforcing steel, to obtain their measured performance when loaded at high strain-rates. This paper compares the performance of the different types of mechanical couplers to control bars tested at the same high strain rates, and evaluates their performance to meet the service requirements of UFC 3-340-02.