glulam beam load rating under csa-s6-06

huangyhg

glulam beam load rating under csa-s6-06
i'm looking for some information for any engineers that are familiar with the csa-s6-06 highway bridge design code, specifically the design of glulam beams. i'm in the process of trying load rate a 40-year-old glulam structure and our client has asked us to rate it according to the new code. i noted that the size effect factor for shear is v^-0.18, and it differs from what i was using in the past, the cwc - wood highway bridges manual still has the old ohbdc value of 2.3*v-0.15.
does anyone know when this changed (i.e. 2000), and why, was the previous factor incorrect?
this new value reduces the shear capacity significantly, factor for our site is approx 0.6 vs. 1.4 before for a v = 23.58 m3.