Distributed loads in 3D

[Paolo]

Hello!
I’m trying to use command eleLoad on a 3D structure, but it doesnt’work.
The message I get is: expected integer but got “-type”.
Even if the anlysis run I don’t obtain good rusults.

I insert here two simple examples:

1) a portal with a distributed load on the beam doesn’t give the right Axial force on the columns.

model BasicBuilder -ndm 3 -ndf 6
set h 300.0
set by 500.0
set bx 500.0
node 1 [expr -$bx/2] [expr $by/2] 0
node 2 [expr $bx/2] [expr $by/2] 0
node 5 [expr -$bx/2] [expr $by/2] $h
node 6 [expr $bx/2] [expr $by/2] $h
fix 1 1 1 1 1 1 1
fix 2 1 1 1 1 1 1
geomTransf PDelta 1 1 0 0
element elasticBeamColumn 1 1 5 900 290000 126087 114210 67500 67500 1
element elasticBeamColumn 2 2 6 900 290000 126087 114210 67500 67500 1
geomTransf PDelta 2 0 1 1
element elasticBeamColumn 17 5 6 900 290000 126087 114210 67500 67500 2
set q1a 33
set g 981
# Define gravity loads
pattern Plain 1 "Linear" {
eleLoad -ele 17 -type -beamUniform 0 -$q1a
}
system BandGeneral
constraints Transformation
numberer RCM
test NormDispIncr 1.0e-12 10 3
algorithm Newton
integrator LoadControl 0.01
analysis Static
initialize
analyze 100
puts “Gravity load analysis completed”
prin ele 1 2 3

2) a Three-Dimensional frame (1 story and one bay) with a distributed load on the beam doesn’t give the same Axial force on the columns.


# OpenSees TELAIO 3D calcolo delle sollecitazioni
# Units: Kg, cm, s
# ----------------------------
# Start of model generation
model BasicBuilder -ndm 3 -ndf 6
set h 300.0
set by 500.0
set bx 500.0
node 1 [expr -$bx/2] [expr $by/2] 0
node 2 [expr $bx/2] [expr $by/2] 0
node 3 [expr $bx/2] [expr -$by/2] 0
node 4 [expr -$bx/2] [expr -$by/2] 0
node 5 [expr -$bx/2] [expr $by/2] $h
node 6 [expr $bx/2] [expr $by/2] $h
node 7 [expr $bx/2] [expr -$by/2] $h
node 8 [expr -$bx/2] [expr -$by/2] $h
node 9 0 [expr $by*$e/100] $h
fix 1 1 1 1 1 1 1
fix 2 1 1 1 1 1 1
fix 3 1 1 1 1 1 1
fix 4 1 1 1 1 1 1
rigidDiaphragm 3 9 5 6 7 8
fix 9 0 0 1 1 1 0
geomTransf PDelta 1 1 0 0
element elasticBeamColumn 1 1 5 900 290000 126087 114210 67500 67500 1
element elasticBeamColumn 2 2 6 900 290000 126087 114210 67500 67500 1
element elasticBeamColumn 3 3 7 900 290000 126087 114210 67500 67500 1
element elasticBeamColumn 4 4 8 900 290000 126087 114210 67500 67500 1
geomTransf PDelta 2 0 1 1
element elasticBeamColumn 17 5 6 900 290000 126087 114210 67500 67500 2
element elasticBeamColumn 18 6 7 900 290000 126087 114210 67500 67500 2
element elasticBeamColumn 19 7 8 900 290000 126087 114210 67500 67500 2
element elasticBeamColumn 20 8 5 900 290000 126087 114210 67500 67500 2
set q1a 33
set g 981
# Define gravity loads
pattern Plain 1 "Linear" {
eleLoad -ele 17 -type -beamUniform 0 -$q1a
eleLoad -ele 19 -type -beamUniform 0 -$q1a
}
system BandGeneral
constraints Transformation
numberer RCM
test NormDispIncr 1.0e-12 10 3
algorithm Newton
integrator LoadControl 0.01
analysis Static
initialize
analyze 100
puts “Gravity load analysis completed”
print ele 1 2 3 4


Sorry for the length....
Thank you very much for the attention.
Paolo

[silvia]

i just looked over the first case.
you are defining the beam local axes in a crooked way:
geomTransf PDelta 2 0 1 1
which means your sections is rotated a bit from what I guess you want it to be.
I would do the following:
geomTransf PDelta 2 0 0 1

and you column axial loads are different.

Make sure you have the local y and z the way you want them and that you are defining the element loads in the direction you want.

I think this resolves the problem of the first example.

.....
I just looked over the second example and I think you have the same issue.


let me know if this is it, as I didn't check the numbers and I went through it quickly.
let me know if these local-axes orientations are confusing, and if the manual's explaination (which i just saw as not too clear) helps.