huangyhg

pyramid beam loading
i am trying to calculate beam loading for a pyramid structure.
it consists of 4 main beams from each corner and a beams on center of each side.
a total of 8 beams coming together at the apex to an octagon ring.
do i solve as if the spans are horizontal or on a slope with actual length of member.
is there a factor that can be used for the angle of slope.
thanks for the input.
my message to the person asking you to do this project is
"never send a boy to do a man's job"
if you are an undergraduate i expect you will be taught structural analysis and on how to use a computer program to solve your three dimensional structure.
if you are not in a degree course then then show my message to your teacher.
it may be just a simple problem of statics but they are a lot of missing and confusing information. if i understand your problem correctly you are asking what is the axial forces in the 8 line members (they are not beams!) on the 4 sloping sides of the pyramid possibly truncated. it should be a high school example in statics of summing the vertical components of each
i had hoped this site would be a mentoring tool, not one of criticism.
the previous answerer left out wind as a load not in the vertical direction.
to the person 'calculate':
first apply the external loads at the panel points. make the whole thing a 3d truss with bolted connections for a simple rigid structure.
thanks for the input.
i must apologize for not making the application more clear.
this pyramid structure will actually be a building using glu-lam as the main supporting beams.
some tables tell you to base the sq. ft. load along the actual length of beam on the slope other tables are based along horizontal distance of beam. thats where the confusion is coming in. would the dead and live loads be based perdicular on the horizontal distance or along the actual length of beam on the slope.
thanks again.
look at the source of the loads and the arrangement of your axes. for example, gravity loads act toward the negative z axis, depending on your choice of axes. no matter how your member is oriented, the load (dead load in this case) acts straight down, so that if the member is not perpindicular to the gravity axis, the load will be resolved into some perpendicular and some axial as sweetnlow said. now if the source of load is something other than gravity, wind for instance, this will change. typically, wind loads given in our codes are derived so that they will be applied normal to the surface of the member. so take a look at the source of your loads and the arrangement of your members and global axes and that should help you decide which way your loads act and whether they should be applied on a horizontal projection or the full length of the member. i hope this helps a little.

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