No abstract

The experimental study was carried out to assess the suitability of three proprietary postinstalled anchors from Simpson Inc. for use under high strain-rate loading, such as blast loadings, in both tension and in shear. The anchors investigated included two torquecontrolled expansion anchors (Strong Bolt ® 2, Wedge-All ® ) and a screw anchor (Titen HD ® ) . While three different diameters (6.4 mm, 9.5 mm and 12.7 mm) of the Strong Bolt ® 2 and Titen HD ® anchors were investigated, only two diameters (9.5 mm and 12.7 mm) of Wedge-All ® anchors were investigated.The anchor capacities under static loading conditions with average strain rate of 3.0 × 10 -4 /s were compared with those for impact-loads with average strain rate of 1 /s to define a Dynamic Increase Factor (DIF). The failure modes under both conditions were also assessed to ascertain the change as the loading rate increased.For tensile loading, the results show that the Wedge-All ® and 6.4-mm diameter Strong Bolt ® 2 anchors may not be suitable for dynamic loading conditions. The Titen HD ® as well as the 9.5-mm and 12.7-mm diameter Strong Bolt ® 2 anchors are suitable for high strain-rate loading of up to 1 /s. The torque-controlled expansion anchors failed predominantly in pull-through failure mode under the high strain-rate loading conditions even though they failed in a variety (steel fracture failure, concrete breakout and beam splitting) of modes under static loading condition. The Titen HD ® anchors failed predominantly in a mixed pull-out and concrete breakout mode under both static and high strain-rate loading conditions. Under high strain rate shear loading, the 9.5-mm and 12.7-mm diameter anchors (Strong Bolt ® , Wedge-All ® and Titen HD) were found to be suitable for dynamic loading iii conditions. The predominant failure modes for anchors under shear loading, both under static loading and high strain-rate, was steel fracture failure.Dynamic increase factors (DIF) of 1.1 and 1.2 are recommended for Titen HD and the 9.5mm and 12.7-mm diameter Strong Bolt 2 anchors respectively for high strain rate up to 1 /s under tension loading. A DIF of 1.2 is recommended for the Titen HD anchors while DIFs of 1.0 and 1.2 are recommended for the 9.5-mm diameter and 12.7-mm diameter respectively for Strong Bolt 2 and Wedge-All anchors under shear loading up to strain rate of 1.0 /s. iv