1 IT3Civ4 T61 P3 In class we have learned that the full bear

1. IT3_Civ.4, T6.1, P3] In class, we have learned that the full bearing strengn upper limit of the bearing strength, expressed as n-(24 tdFu)--Alsc! 6a) on page 16.1-127. A value srull is defined as the spacing s at which the full bet strength is achieved. Similarly, Le futí is defined as the edge distance at whic bearing strength is achieved. The bearing strength is directly related to the e AISC Eq (J3- the full bearing the figure tance\" e in between holes and edges. With the relationship shown in below, on le le and s, please complete the following problems: Please derive the formulas to calculate sfutl and Le full, in terms o d; Hint: Find out when lc is equal to what value, can the full achieved? And then write out the formula for sfulu and Le full a. f bolt diameter bearing strength be Piease compare the Sput and Le ful values calculated using the formulas obtained in a) with the tabulated values (for only) in Table 7-4 and Table 7-5 in AISCM pages 7-26 and 7-28. Are they the same or close to each other? What are your findings? cases d-5/8 in., 3/4 in., 7/8 in, and 1 in. standard hole O: O

Solution

a) There is a discontinuity in the bearing strength limit state when end distance equals 1.5 times bolt diameter. LRFD states that for connections with two or more bolts in the line of force , once the distance from the end of the connected part to the center of a standard hole reaches 1.5 times the bolt diameter and the spacing is 3 times bolt diameter, the designer may use the full bearing strength (2.4 db.t.Fu) of the plate for all holes.

b) d= 5/8 = 0.625 , spacing = 3*0.625= 1.875, Le = 1.5*0.625= 0.937

From table values , Minimum Le =0.875 which is not the same

For d = 3/4, spacing = 2.25, Le = 1.125

Table value Le = 1 (not same)

For d = 7/8, spacing = 2.625, Le = 1.31

Table value = Le = 1.125 (not same)

For d= 1, spacing = 3,Le = 1.5

Table value Le = 1.25 (not same)