response modification 9r0 for structural aluminum

huangyhg

response modification (r) for structural aluminum
i'm reviewing an aluminum bleacher design (low seismic area) and they are using r>3.  whoa!  so i look at asce 7-05 and cannot find any reference to aluminum except for mechanical piping.  i also looked at the aluminum design manual and it references asce 7.  i want to say nonbuilding structures per table 15.4-2 under all other self-supporting structures, tanks, or vessels not
covered above or by reference standards that are
similar to buildings for r=1.25.  any thoughts?
tia