... here are some industry publications on Glulam.
APA's thing: http://www.apawood.org/pdfs/download_pdf.cfm?PDFFilename=managed/E30_Glulam.pdf (you have to register, free, if you haven't already, to see their stuff)
Span Table for 24F-V4 DF for FLOOR OCCUPANCY LIVE LOAD ... here
Span Table for 24F-V4 DF for ROOF SNOW LOAD ... here
Span Table for 24F-V4 DF for ROOF CONSTRUCTION LOAD ... here