bolted connection

huangyhg

bolted connection
is a bolted connection modelled as a fixed or pinned joint? example channel bolted to tubing, analyzing channel.
depends on several factors such as the number of bolts, the bolt pattern, length of the channel, stiffness of the tubing. to consider the joint fixed i would want to see multiple bolts in a relatively large pattern. my recommendation for most cases: be conservative and assume the joint is pinned.
take a step back and look at it from this perspective: does the joint allow for rotation? mechanics says that pinned joints allow rotation but not translation.
without seeing the connection or having more detail one can't say for sure. for modeling purposes, i would also assume it is a pinned connection.
re  
here is my simple response: bolted connection can be simple or fixed. it all depends on how you detail it and how you design the steel   
coming back to the original question, many connections are intermediate between pinned and fixed. in this case, the simple answer is to be conservative. that may mean for example assuming pinned for the supported member but it may mean assuming fixed for the supporting member. if you are uncertain and you are stressing the members highly, then the safest approach is to assume each in turn and design for the worst case. if the   
becareful in that it is not always conservative to assume a pinned joint.  you really need to look at both extremes to be certain your design is safe.
for example, a pinned-pinned beam, point loaded in the middle, will have a maximum bending moment in the middle, zero moment at the end, and highest shear at the ends.  a fixed-fixed beam has a moment at both the end and the middle, and a high shear at the ends.
now if the beam is uniform along it's length, then it can be easily seen that the pinned-pinned condition is conservative for all sections.  however, it the beam tappers towards the ends/attachment points, then you may have a situation where the ends are more critical under a fixed-fixed situation.
this situation of degree of restraint is very well explained by flabel in "practical stress analysis for design engineers", starting on page 39.
so a little engineering judgement is required here.
regards,
jemaker
lutfi,
i have tried locating the file, on my own, at aisc.org, as you have specified.  there are several excellent resources available for free downloads, but, i failed to locate the one which you refer to.
thank you!
let me have your e-mail address and then i will e-mail it to you. it is a bout 3 mb. you will need a cablee or dsl or faster connection.
lufti,
could you, please, e-mail that connection illustration to