2 and 10 for illustrations of the concrete failure cone concept.
Design of headed anchor bolts pdf full#
This is accomplished by designing the pullout strength of the "concrete failure cone" (Up) such that it equals the minimum specified tensile strength (F u A t ) or u full anchorage value" of the anchor bolt. 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 En- gineers and Constructors, Inc., Irvine, California. Shipp is Supervising Structural Engineer, Fluor Engi- neers and Constructors, Inc., Irvine, California. 7 ' 17 The headed bolt, when properly embedded and confined, will develop the full tensile capacity of even A490 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).
Design of headed anchor bolts pdf code#
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. Assumptions: Length of footing Lf 1500 mm 1.5 mWidth of footing Wf 1500 mm 1.5 m. 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. Single pattern spring washer, standard pattern spring washer, double pattern spring washer, grip pattern spring washer, and girder pattern spring washer are the structures of spring washer.Design of Headed Anchor Bolts JOHN G. There are several forms of spring washers. This puts pressure against the nut, preventing the latter (the nut) from turning and working loose. These are used where there is vibration, or jolts occur. These washers are used to prevent a nut from loosening. These washers are placed above or below the nut or bolt and tighten so much that both their ends face each other and become leveled. Its ends are slightly raised up and down due to spring tension. This washer is in the shape of a ring cut by spring steel. Read Also: What are the main fasteners used in the workshop? Types of Washersįollowing are the types of washers, as per their utility and functions: Furthermore, check out different types of screwdrivers for tightening and loosening and screws. You may like to know about types of threads in the designing of nuts and bolts. and it becomes easy to open the nut-bolts and their threads are protected.Įven if the fit is a bit larger than the diameter of the bolt, with the washers help nut bolt can be tightened easily.Īlso, check out the different types of nuts and bolts used in industries. It is used to secure the tightness of a joint, screw, etc. Before tightening the nut and bolt, it is fitted on a stud or bolt.
0 kommentar(er)
