AISC LRFD 1.pdf

Sect. D3.] PIN-CONNECTED MEMBERS AND EYEBARS 25Either perforated cover plates or tie plates without lacing are permitted to be usedon the open sides of built-up tension members. Tie plates shall have a length not lessthan two-thirds the distance between the lines of welds or fasteners connectingthem to the components of the member. The thickness of such tie plates shall not beless than one-fiftieth of the distance between these lines. The longitudinal spacingof intermittent welds or fasteners at tie plates shall not exceed six in. (150 mm). Thespacing of tie plates shall be such that the slenderness ratio of any component in thelength between tie plates should preferably not exceed 300.D3. PIN-CONNECTED MEMBERS AND EYEBARS1. Pin-Connected Members1a. Design StrengthThe design strength of a pin-connected member, P n ,shall be the lowest value of thefollowing limit states:(a) Tension on the net effective area: = t = 0.75(D3-1)P n = 2tb eff F u(b) Shear on the effective area: = sf = 0.75(D3-2)P n = 0.6A sf F u(c) For bearing on the projected area of the pin, see Section J8.(d) For yielding in the gross section, use Equation D1-1.whereA sf = 2t(a + d / 2), in. 2 (mm 2 )a = shortest distance from edge of the pin hole to the edge of the member measuredparallel to the direction of the force, in. (mm)b eff =2t + 0.63, in. (= 2t + 16, mm) but not more than the actual distance from theedge of the hole to the edge of the part measured in the direction normal tothe applied forced = pin diameter, in. (mm)t = thickness of plate, in. (mm)1b. Detailing RequirementsThe pin hole shall be located midway between the edges of the member in the directionnormal to the applied force. When the pin is expected to provide for relativemovement between connected parts while under full load, the diameter of the pinhole shall not be more than 1 32-in. (1 mm) greater than the diameter of the pin.The width of the plate beyond the pin hole shall not be less than 2b eff + d and the minimumextension, a, beyond the bearing end of the pin hole, parallel to the axis of themember, shall not be less than 1.33 x b eff .The corners beyond the pin hole are permitted to be cut at 45° to the axis of themember, provided the net area beyond the pin hole, on a plane perpendicular to theLRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION