pin connected member

huangyhg

pin connected member
i am having a difference in interpretation with a consultant. please let me know what you think. this is my side:
aisc manual of steel construction, 9th edition.
section d3: 0.45fy applies in determining the hole diameter and plate thickness related to bearing load at the pin hole & (j8) 0.90 fy applies in determining the pin diameter.
rick

i'm not quite sure of the question, but can it be that the 0.4fy is based on the yielding of the part supporting the pin and the 0.9fy is based on the pin shearing.
dik
i think i disagree with you rickylee.  it depends on the connection requirments, but the plate must be checked for both yielding with section d3 and by bearing with section j8.  typically i will size the pin for shear and bending, then size the plate for yielding and bearing.  if the plate thickness is controlled significantly by the bearing then i may increase the diameter of the pin to compensate.  a side note is that with the same yield strength materials, if the pin or plate satisfies the bearing requirement then obviously the other part will also.
aggman:
are you interpreting d3 to apply to the design of the pin connected member with a hole, but not actually to the bearing stress of the hole......and j8 applies to the design of the pin and hole?
this is the same opinion as the consultant.
if that's true d3 really throws me off because it says:
"the allowable stress on the net area of the pin hole for a connected   
"are you interpreting d3 to apply to the design of the pin connected member with a hole, but not actually to the bearing stress of the hole......and j8 applies to the design of the pin and hole?"
yes, i interprete d3 to apply to the design of the pin connected   
the research that led to article d3 was published as asce transaction paper 2023, in 1939, by bruce g. johnston.  the research paper devotes much concern to "dishing" (or buckling) of the connected plates.  dishing can occur if the plates are too thin.  the aisc provisions of d3.2 are written to prevent dishing.  (note: the end of paragraph 2 should read "more than 0.8 times the diameter of the pin hole.")
if you follow the provisions of d3.2, the bearing stress limit of 0.9fy never governs the thickness of the plate.  in fact, algebraic manipulation of d3.2 gives an "apparent" bearing limit of 0.72fy.