Design of steel and composite structures with limited ductility requirements for optimized performances in moderate earthquake areas (R-6524)

Bolted connections are the preferred solution used for diagonal steel bracings. In structures designed for seismic actions the diagonals are to be designed such that they provide not lateral stiffness and resistance only but also energy dissipation by allowing for their yielding in tension. In order to achieve the dissipative bahaviour the connections have to be capacity designed i.e. the resistance of all connection components must be higher than the plastic resistance of the gross-section of the diagonals, including overstrenght of the material. By fulfilling this requirement a behaviour factor of q=4 may be used for the seismic design. In moderate seismic regions however this value is often not needed, nevertheless the full requirements concerning the connection need to be satisfied. On the otherhand the Code permits the utilisation of dissipative connections on the structural performance have been investigated. The works to be performed within this WP aim at the practical realisation of this alternative by means of designing and investigating shear connections of diagonal memebers such, that they are able to develop local plastic mechanism (bearing resistance) and preventing brittle failure of the bolts. Such kind of connection would be of particular importance for the design of diagonally braced structures in moderate seismic regions as it would allow using existing typical solutions by providing minor modifications only, e.g. adoption of the bolt diameter. This approach is very promising due to the fact that requirements with regard tot the energy dissipation and consequently tot the deformation capability are expected to be rather small and hence it shall be possible to satisfy the by the local plastic deformations within the connection.

Keywords:steel constructions, earthquake

Disciplines:Building engineering, Ceramic and glass materials, Materials science and engineering, Semiconductor materials