Filter
Top Products
General Description
Section 1
1-76
The lateral loading must be present concurrently with the
vertical loading for proper consideration of the P-Delta effect.
The REPEAT LOAD facility (see Section 5.32.11) has been
created with this requirement in mind. This facility allows the
user to combine previously defined primary load cases to
create a new primary load case.
3) A new stiffness analysis is carried out based on the revised
load vector to generate new deflections.
4) Element/Member forces and support reactions are calculated
based on the new deflections.
This procedure yields reasonably accurate results with small
displacement problems. STAAD allows the user to go through
multiple iterations of the P-Delta procedure if necessary. The user
is allowed to specify the number of iterations based on the
requirement. To set the displacement convergence tolerance, enter
a SET DISP f command before the Joint Coordinates. If the
change in displacement norm from one iteration to the next is less
than f then it is converged.
The P-Delta analysis is recommended by several design codes such
as ACI 318, LRFD, IS456-1978, etc. in lieu of the moment
magnification method for the calculation of more realistic forces
and moments.
P-Delta effects are calculated for frame members and plate
elements only. They are not calculated for solid elements. P-Delta
and Nonlinear analysis is restricted to structures where members
and plate elements carry the vertical load from one structure level
to the next.