Error in ASCE Bast Design Numerical Integration Procedure? 1

[P1VPEng]

Is anyone aware of any errors in the numerical integration procedure outlined in Appendix 6 of the ASCE book titled Design of Blast Resistant Buildings in Petrochemical Facilities, Second Edition? I cannot match the results in the examples and I suspect that either the method has errors in determining Zi+1 or the results in the examples are incorrect. My first time step matches Table 11.1 perfectly but deviates from there. My Z value is “6” for the first nine time steps which makes sense (according to the NI method on page 98) because yi+1 > ye-i for those terms, but the number "6" indicates the start of plastic deformation so there cannot be successive sixes. I would certainly appreciate any input you can provide. Thank you.