Locate δon Base Shear vs. Roof Displacement plot.
If δis beyond effective portion of the plot, significant strengthening of the
yielding elements may be required.
If δis within the effective portion of the plot, check interstory drift and P∆
effects. If allowable limits have been exceeded, stiffening of yielding elements
may be required.
If interstory drift and P∆ effects are acceptable, check inelastic responses of
yielding elements against acceptance criteria.
If evaluations in Step 13 are negative, mathematical model must be strengthened
and/or stiffened and the analyses repeated. Available computer programs can perform
Steps 1 to 8 above, including P∆ effects. For a given building displacement,
maximum inelastic responses (∆/∆y or chord rotations) are developed which can be
checked against the acceptance criteria.
Chapter 7 provides acceptance criteria for the nonlinear response (∆/∆y or chord
Chapters 5 and 7
rotations) for the structural components of various structural systems. Acceptance
values are provided for Life Safety, Safe Egress, and Immediate Occupancy.
Table 4-7 Step-by-Step Procedure for Enhanced Performance Objective
with Nonlinear Elastic Static Analysis
Sheet 2 of 2