Equivalent Uniformly Distributed Loads

[krus1972]

Does anyone know if there is a reference that exists on how to approximate the equivalent uniform distributed loading on beams when there are concentrated loads on them. The uniform distributed load would provide the same or a bit more stress and deflection in the beams. I know there are many variables involved and there is no "one method fits all" ,but, I am looking for a approximate or empirical method to calculate the equivalent uniform load for any concentrated load combination a beam.

Any help would be appreciated.

 

[rb1957]

except that the bending moment for a UDL is parabolic ... three lines make a crappy parabola ... particularly if you don't want to underestimate the moment (ie pick tangents to the parabola)

 

[Lion06]

You said that he doesn't know the exact location of the mechanical equipment. I am assuming you do have a pretty good idea of the weight. Why not just plop it at midspan and call it a day. Then it doesn't matter where they put it since midspan is the worst case (unless shear controlls, which almost never happens, but if you are concerned about shear put one at midspan and one at the support and design for the worst).
There is no need to throw so much load up there and there is no way to take a load of known value and turn it into a uniform load - just put the point load at the worst place for design and let them put it where ever they want.

 

[steve1]

Quite often the design criteria for an industrial/power plant will include a uniform load allowance for for piping, conduit, and miscellaneous. I have seen these values range from 5 to 25 psf. The mechanical department at my firm does not do a flexiblity analysis on small bore and low temperature piping hence they provide no hanger loads for these systems. In the past they have informed me to use a concentrated load of 5 to 10 kips on each beam as a piping allowance. On a recent project that included four levels of steel over a plan area of 700 sf the summation of all of these 10 kip loads added up to almost one million pounds. So you can see that these things can get out of hand.

There really needs to be some guidance on setting up the design critria for industrial facilities. I have noticed that over the years building codes have greatly expanded the seismic criteria for mechanical and electrical equipment, but that the uniform design load for industrial facilities has remained light and heavy loading with no specific values based on type or use of facility.