huangyhg

massachusetts building code r=3
this question is for anybody that is familiar with the massachusetts state building code. it does not appear that the current edition allows you to take r=3 for steel design of buildings. so you would need to design and detail all buildings to meet aisc seismic requirements even if they fall into design category c. is this correct, am i missing something? thanks.
ouch!!
i would have a hard time believing that is accurate.
i'm thinking you need to look at the very bottom of the tables.
from what i understand the current "6th" edition does not allow you to design with r=3. i believe they still refer you to the 92 seismic provisions (with their own modifications shown in chapter 21). i believe the 92 seismic provisions can be found in the back of the second edition lrfd book (silver one).
this is where a debate can occur if you would like to mix and match code (use a newer version of the 92 seismic provisions of which some stuff doesn't make sense). i know people advise against doing this.
from what i have heard the new 7th of the building code is still a few months away and does not update the steel code to the 13th edition (still using the asd 89 spec).

section 1612.4.4 of the mass code states that other r-values not listed in the table are permitted, as long as they are substantiated by test data establishing the dynamic characteristics and demonstrate the lateral force resistance and energy disapating capacity listed in the tables.
i would think that with all of the newer research being done in the new seismic manual, that would substantiate an r=3 (using the same limitations), but you may want to check to see if your jurisdiction will allow it.
strguy11,
i was told at a seminar that r=3 was just an arbitrary number and was not back by test data.

fwiw here is a like to the proposed 7th edition of the massachusetts building code. i believe it is still under review and is therefore not enforces.

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