STAAD.Pro Help

TR.32.3.4 Surface Loads Specification

The following loading options are available for surface entities:

Note: Surface elements have been deprecated in STAAD.Pro CONNECT Edition. The analysis and design engine will allow them but their use is not recommended.

General Format

LOAD n
SURFACE LOAD
surface-listPRESSURE | TRAPEZOIDAL } ({ GX | GY | GZ }) load-spec 

or

SSELFWT { XY | Z } f9 LIST surface-list 

Where:

GX, GY, and GZ = Global X, Y and Z directions. If the direction is omitted, the load will act along the local Z axis of the surface.

load-spec is provided for the following types of surface loads:

  • Uniform pressure across the entire surface. Use with PRE command.

    load-spec  = w

    Where:

    • w = Value of pressure. Negative value indicates load acts opposite to the direction of the axis specified.
  • Pressure load on a partial area of the surface. Use with PRE command.

    load-spec  = w x1 y1 x2 y2

    Where:

    • w = Value of pressure. Negative value indicates load acts opposite to the direction of the axis specified.
    • x1, y1 = Local X and Y coordinates of the corner nearest to the surface origin of the loaded region. Measured from the origin of the surface, in the local coordinate system of the surface.
    • x2, y2 = Local X and Y coordinates of the corner farthest from the surface origin of the loaded region. Measured from the origin of the surface, in the local coordinate system of the surface.
  • Concentrated force anywhere on the surface. Use with PRE command.

    load-spec  = p x y

    Where:

    • p = Value of the concentrated force. Negative sign indicates load acts opposite to the direction of the axis specified.
    • x, y = Local X and Y coordinates of the point of action of the force. Measured from the origin of the surface, in the local coordinate system of the surface.
  • Trapezoidal pressure load on a partial area of the surface. Use with TRAP command.

    load-spec  = f1 f2 f3 f4 CORNER f5 f6 f7 f8

    Where:

    • f1, f2, f3, f4 = the pressure at the corners of the loaded area. Negative values indicate loads act opposite to the direction of the axis specified.
    • f5, f6 = Local X and Y coordinates of the first corner of the loaded area, respectively.
    • f7, f8 = Local X and Y coordinates of the second corner of the loaded area, respectively. These values must be different than the corresponding values of the first corner so that the loaded area is rectangular.

f9 = Magnification factor for surface selfweight. Negative value indicates load acts opposite to the direction of the axis specified.

Example

LOAD 1 Uniform Pressure on Full Surface
SURFACE LOAD
1 2 PRESS GX 0.002
3 GX -0.0025
*
LOAD 2 Concentrated Force
SURFACE LOAD
10 12 PRE GZ 400 3.5 4.5
*
LOAD 3 Partial Area Load
SURFACE LOAD
23 25 PRE FY -250 4 4.3 8 9.5
*
LOAD 4 Partial Surface Trapezoidal Load
SURFACE LOAD
11 13 TRAP GY -120 -240 -240 -360 COR 2.5 6.5 3.5 4.5
*
LOAD 5 Surface Selfweight
SSELFWT Y -1 LIST ALL