FRP pultroded profiles are an anisotropic material,
its strength is very high in the fibers direction. This is very suitable for
trusses members which only bear axial loads. In addition, trusses fully constructed
by FRP profiles can reach a higher strength and lighter weight compared to the
steel which suffer from heavy weight and corrosion, and satisfying the
requirement of load capacity and stiffness. Thus, high performance and high
corrosion resistance of truss structure could be realized (Hizam, Manalo
and Karunasena, 2013).
A fully understanding of the behavior of connections
is very important, because the capacity of the structure depending on the
capacity of its connections. Several variables of material characteristics in
addition to other parameters such as the type of connection and geometrical
configurations will affect the strength and stiffness of the connections.
The efficiency of the connection, defined as the ratio
of the connection strength to the strength of the base material depends mainly
on the method of connecting its parts (bolted, bonded, and bonded-bolted
connection), and also effected by several parameters such as bolts number, bolt
patterns, and bolts type.
The bolted connections are the most common used in
structural engineering because they can be assembly and disassembly, less
effected by the environment, do not require professional workers and special
requirements like the bonded connections, which need surface treatment,
affected by the environment especially high temperature and it cannot be
disassembled. In addition, the failure of the bonded connection is catastrophic
there isn’t any warning before the failure (Mosallam, 2011). The efficiency
of the bonded connection is higher than the bolted connection, due to the
stress concentration in the bolts’ holes zones. In addition, the strength of
bolted connection might be extremely decreased because of intermittence of the
fibers during drilling the holes (Stockdale and
To get the benefit of both bolted and bonded together
bonded- bolted method could be used, and this will reduce the stress
concentration in the bolts’ holes zones (Vallée,
Tannert, Meena and Hehl, 2013).
The most challenging of FRP connections is the design
guidelines and procedures of steel connections which based on years of
researches and experience need to be modified to can be used with FRP
connections. In addition, the perfect elastic behavior of the FRP (no yielding
stage) make the failure catastrophic without warning, because there is not
stress redistributions by plasticity.