Lex,
Feel free to ignore but I have always liked considering certain builds with site specific design constraints. One such build is in a very remote location. So, no prefab'd trusses, no engineered wood products accept plywood and manageable composite lumber. Any load bearing beams and column would need to be site fabricated. One area I have seen touched on, in different civil/structural forums, is the use of plywood and mechlam beams and columns and the on site fabrication of them. A huge ding in strength needs to be accounted for because of the absence of an ASTM structural adhesive. Options of epoxies and polyurethane construction adhesives are mentioned in these conversations, and this is acknowledged in guidance from the APA, AWC and ASABE that these will add strength but there are no metrics or method I am aware of to account for it.
The reasons I have read, that guidance for the use of construction adhesives in the site fabrication of structural components, is not provided are: The lack of controlled environment, The lack of known clamping force, and that these products are too new to know their long-term reliability. The first and second reasons I feel have some teeth, but I see no reason certain constraints can't be added to the application and use of a specific adhesive and conservative assumptions be made. The later concerning long term reliably, I've been reading for 30 years, so I don't really buy it anymore except as an excuse from the engineered wood folks to only buy their products.
Is there an acceptable way that the strength added by a "non-ASTM structural" construction adhesive could be accounted for and calculated in structural components such as mechlams and plywood beams?
