Dear All ,

I had encountered some problems on underground system which need the senior members advise. Please find the question as following .

1. During i covert my model to underground model , can i put the restraint and what is the correct method to input this restraint in underground model? During input the restaint let say G/Z ( From the layout my client going to cast a concrete block on the pipe as represent a G/Z support ) , do i need to remove the bi-linear restraint or retain the bi-linear restraint ?

2. May i know the coefficient of friction between FRP pipe surface and rubber sheet & concrete between rubber sheet .

Please find enclosed is the drawing for reference .

Regards
Glenn