Anchorage strength and ductility at various loading conditions

Abstract

Article shows results of anchor pullout tests for two types of anchors: bent foundation anchor bolt and torque-controlled undercut anchor. Effective embedment depth is determined during research for bent anchors 16, 24 and 36 mm in diameter. Tests were carried out for 37 specimens with different embedment depth in a range from 150 to 650 mm. Load-displacement diagrams for static and cyclic dynamic pullout tests in uncracked and cracked concrete were acquired. Cyclic loading pattern simulated seismic loads. Test results for undercut anchors with diameter of 12, 16 and 20 mm and embedment depth of 125, 190 and 250 mm respectively allowed to estimate the influence of cracks in concrete and cyclic loads on ductility of anchor during pullout tests. It is stated that embedment depth required by regulatory documents for bent anchor bolt is higher than admissible embedment depth acquired in tests as a result of comparative analysis of design and optimal anchor bolt structure.

Anchorage strength and ductility in shear tests

“…3. In comparison to pullout tests results [1], in shear tests cracks and dynamic loading lead to decrease in anchorage strength: -in case of bent anchor bolts strength decrease by up to 7% is seen only during combination of cracks and dynamic loading;…”

“…1. Minimal anchor embedment depth established in tests [1] guarantees steel fracture for anchors in shear tests. Steel strength determines anchor strength in shear tests.…”

“…Present research results for strength and ductility in shear tests combined with pullout tests results [1] can be used in seismic design for two types of anchorage for structure and equipment in concrete base. Also, there is a possibility of test execution based on limited scheme developed in testing procedure: carrying out static tests for pullout and (or) shear using acquired data on influence of cracks and dynamic loading on anchorage deformation curve.…”

“…Anchorage strength and ductility research was carried out in three stages. On the first stage of tests [1] minimum embedment depth was determined for three diameters of bent anchor bolts in concrete blocks with strength grade B30 [2,3]. Embedment depth for torquecontrolled undercut anchors was established according to specification [4].…”