P

Anet where

for a row of n fasteners where holes are not staggered. W is the plate width perpendicular to the load direction. This assumes that the critical section will be through the row of holes and perpendicular to the longitudinal direction of the material. Due to the orthotropy of the pultruded material, however, the critical section may be ''staggered'' though multiple rows (Prabhakaran et al. 1996). At this time the empirical formula used for staggered rows for joints in steel members is recommended as a first approximation for orthotropic pultruded materials:

where the summation is over all diagonal distances in an assumed failure ''path.'' This equation assumes that the strength of the material is the same along all paths, which is not the case for orthotropic materials. Where elements of profile sections are connected in tension (such as flanges of angles and I-sections), it is recommended that only the area of the outstanding element be considered as being effective (and not the area of the entire section). For bolts in rows perpendicular to the load direction the load may not be distributed evenly among the bolt rows. The ''forward'' row carries a proportionally greater share that depends on fiber orientation. Recommendations are given in the ECDH for load distribution to rows of bolts. For preliminary calculations it can be assumed that load is distributed evenly among all bolts.

For a joint in tension the shear-out design stress at the bolt location at the material edge in the direction of the tensile load is given as

0 0

Post a comment