![]() ![]() 3 In this paper, anchor bolt design ductility is assured by causing a failure mechanism that is controlled by yielding of the anchor bolt steel, rather than brittle tensile failure of concrete. 3 When the tension capacity of the bolt is developed, a ductile failure can be ensured by the shear friction mechanism. Haninger is Senior Structural Engineer, Fluor Engineers and Constructors, Inc., Irvine, California. ![]() ![]() Shipp is Supervising Structural Engineer, Fluor Engineers and Constructors, Inc., Irvine, California. 7 ' 17 The headed bolt, when properly embedded and confined, will develop the full tensile capacity of even A49 high John G. 7 ' 17 Shear lugs can fail in a brittle mode if not properly confined, and do not lend themselves to a shear friction analysis. For a threaded rod with a bolted washer or bearing plate embedded in concrete, tests have shown that unless the plate is properly sized it may actually decrease the anchor capacity by causing a weakened failure plane in the concrete. 13 The authors are not aware of any published data that addresses the performance of J-bolts. L-bolts have been shown to be less effective in resisting slip at service load levels than headed bolts. Other anchorages which have been used are L-bolts, J-bolts, rods with a bolted bearing plate and shear lugs. 8 THE HEADED BOLT AS AN ANCHORAGE The headed bolt, as designed herein, is recommended as the most efficient type of anchorage to use for both tension and shear loads. ![]() 6 ' 11 Therefore, there is a need for a complete design procedure for anchor bolts that will accommodate these larger loads and incorporate the proposed design philosophy, i.e., probability-based limit states design (PBLSD). 8 Larger design forces now mandated in many areas due to the revised seismic and wind loads require design capacities for anchor bolts beyond any existing code values. Also, there are no provisions to prevent a brittle failure in the concrete as opposed to a ductile failure in the anchor bolt, as provided for with a probability-based limit states design or Load and Resistance Factor Design (LRFD) for steel. The embedment requirements for anchorage steel are not clearly defined by most codes and are left largely to the discretion of the design engineer. 1) shear is transmitted to the concrete largely through anchor bolts, shear lugs or bars attached to the base plate and the tensile anchorage steel is generally proportioned only for direct stress. HANINGER In current practice the design of base plates is controlled by bearing restrictions on the concrete (see Fig. ![]()
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