Tension perpendicular to the grain

Joints are often the weakest part of the structure, normally susceptible to premature risk of splitting near the mechanical fasteners. By improving the tension perpendicular to the grain of the timber in this location, failure will not occur in the wood but... 

This effect may he achieved hy using fibreglass fabric bonded separately to each of the contacting faces of the members in the joint area, in directions of 45° or 90° with respect to the wood grain direction. For members with dowels or bolts loaded perpendicular to the grain, reinforcement can ensure full load carrying capacity even for very small end-distances. Local reinforcement for tension perpendicular to the grain of the timber can also be very effective for end-notched beams. 

First, a crack will deviate toward one or the other adherend if it is softer (lower in modulus) than the adhesive [51]. This is a common condition in wood joints bonded with rigid thermosetting adhesives. The tension modulus of the wood perpendicular to the grain is typically in the range 400 to 1200 MPa [54], while the tensile modulus of adhesives used with wood will be in the range 1200 to 4700 MPa at the same moisture level [55-57]. 

In both of these processes, atom diffusion is away from boundaries under compression towards boundaries under tension, leading to relief of the stress at the grain boundaries generated by the load on the sample. This causes the grains to elongate along the direction of the stress. [Note that diagrams often show the flow of vacancies rather than the flow of atoms. Vacancy flow is opposite to atom flow, and is from boundaries more or less parallel to the compressive stress to boundaries more or less perpendicular to the compressive stress.]... 

Timber Structures, Fig. 3 Strength in tunb - in c[Pg.3744]

---