3.1.12.1.2. eleLoad Command

The eleLoad command is used to construct an ElementalLoad object and add it to the enclosing LoadPattern.

eleLoad $eleLoad $arg1 $arg2 $arg3 ....

The beam column elements all accept eleLoad commands of the following form.

Uniform (full span) – NDM=2:

eleLoad -ele $eleTag1 <$eleTag2 ....> -type -beamUniform $Wy <$Wx>

Trapezoidal (partial span, 2D) – Load varies linearly between a/L and b/L (normalized, 0 to 1). Transverse and axial intensity at start (Wy, Wx) and at end (Wyb, Wxb). Supported by 2D elasticBeamColumn and forceBeamColumn:

eleLoad -ele $eleTag1 <$eleTag2 ....> -type -beamUniform $Wya $Wxa $aOverL $bOverL $Wyb $Wxb

Point load – NDM=2:

eleLoad -range $eleTag1 $eleTag2 -type -beamPoint $Py $xL <$Px>

When NDM=3, the beam column elements accept:

eleLoad -ele $eleTag1 <$eleTag2 ....> -type -beamUniform $Wy $Wz <$Wx>

For trapezoidal loads in 3D, use Wy Wz Wx aOverL bOverL Wyb Wzb Wxb. The 3D elasticBeamColumn implementation may be triangular rather than trapezoidal; you can combine two element loads (e.g. one uniform, one triangular) to obtain a trapezoid.

eleLoad -range $eleTag1 $eleTag2 -type -beamPoint $Py $Pz $xL <$Px>

Note

The load values are reference loads values, it is the time sereries that provides the load factor. The load factor times the reference values is the load that is actually applied to the node.

Warning

At the moment, eleLoads do not work with 3D beam-column elements if Corotational geometric transformation is used.

See also

Trapezoidal beam loads

Example

Uniform distributed load; trapezoidal load on segment from 0.2*L* to 0.8*L* (2D).

1. Tcl Code

set width 20.0
set W 4000.0
set wya -0.5
set wxa 0.0
set aOverL 0.2
set bOverL 0.8
set wyb -1.0
set wxb 0.0
timeSeries Linear 1
pattern Plain 1 1 {
    eleLoad -ele 3 -type -beamUniform [expr -$W/$width]
    eleLoad -ele 4 -type -beamUniform $wya $wxa $aOverL $bOverL $wyb $wxb
}

2. Python Code

width = 20.0
W = 4000.0
wya, wxa = -0.5, 0.0
aOverL, bOverL = 0.2, 0.8
wyb, wxb = -1.0, 0.0
ops.timeSeries('Linear', 1)
ops.pattern('Plain', 1, 1)
ops.eleLoad('-ele', 3, '-type', 'beamUniform', -W/width)
ops.eleLoad('-ele', 4, '-type', 'beamUniform', wya, wxa, aOverL, bOverL, wyb, wxb)

Code Developed by: fmk