Question related to calculated seismic forces for cylindrical, flat bottom vertical tank. Tank is anchored at grade.
Per asce 7-02, table 9.14.5.1.1; R = 3.0 for steel tanks.
Can I use R = 3.0 for fiberglass (FRP) tanks?
I assume you're talking about full face fiberglass pipe flanges. Steel backing rings on these have not been common for many years. Two things to look out for..
1) You can get cracking in the fillet radius on back of flange. It's often cosmetic and not a structural concern.
2) Check mating...
Is the piping already fabricated? You can spark test welds before or after frp is applied. Need a conductive backing for this. If the frp is not applied, can pressurize with helium and use sniffer to detect leaks. Good luck.
RTP-1 is a good start but probably won't cover everything. If you are not familiar with these vessels be careful with resin selection, design temperatures, laminate construction and select a good fabricator.