Vu for timber stringer
Vu for timber stringer
(OP)
Eq. 4.6.2.2.2a-1 requires that for undistributed wheel loads, one line of wheels is assumed to be carried by one bending member. If I have a condition where stringer spacing is 12" o.c., it doesn't make any sense that the load couldn't be shared by 2 bending members when calculating VsubLU. The bridge is a timber stringer with transeverse timber planks.





RE: Vu for timber stringer
See attached.
RE: Vu for timber stringer
The negative one. It seems AASHTO is saying doesn't want in place any bending member not able to carry at least an undistributed line of wheels. Hmmm. This sets a minimum for such "bending member" leading to big sizes, then the same for transverse.
Now ... I READ (sometimes do) we are talikng of Shear.
Maximum shear wheel loads near supports have almost NIL lateral distribution. How more when the bending members may be thought unable to pass shear ones to others, such in stringers. So, well, this puts the size of the overall stringer if of constant section in the need to meet such sehar when the loads are at maximum, at ends. After this thought, I would either meet the requirement or reshape the structure.