Using Linear Analysis Software
•Each analysis reflects the state
 of building at the end of
previous analysis.
•All component actions are actually
action increments
•They have to be added up to
reflect the analysis results.
•Generally, a substantial amount
of manual bookkeeping is involved.
•Results obtained by  successive linear analyses are inherently approximate, incapable of accurate modeling of the P-D effects and weak in assessment of true member forces.
•Despite these facts, if used properly, it can provide a good approximation to the global force-displacement curve for the building.