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Abstract
In recent earthquake events several bridges have collapsed or were severely damaged due to the poor performance. Such performance is may be attributed to the adopted design philosophy. This indicates the need for new design strategy that makes the bridge as insensitive as possible to seismic excitations.
Current seismic design procedures are strength–based procedures which do not consider the required performance that the bridge should experience during earthquakes as well as the allowed
economics loss according to the bridge importance. Recently, there are
extensive researches to develop a new seismic design philosophy, displacement-based design.Displacement-based seismic engineering(DBSE)is one of the
promising methods, which provides design procedures allowing to achieve the required limit state of deformation under design level. DBSE may be defined as the desire to build a structure with a predictable seismic performance (which quantified by response displacements) under
different seismic hazards. So it can be said that DBSE is a promise to produce a structure that will perform in a predefined manner specified by a combination of desired performance criteria during earthquakes.
The predefined manner mainly controlled by human safety of structure users
and repair cost required for the allowed degree damage.Seismic design of bridges needs special attention this coming back to structural simplicity of bridge systems which makes it vulnerable
to seismic excitation as well as bridges are sensitive to soil structure
interaction due to traveling wave effect. In addition to the mentioned
factors for skew bridge type the seismic performance becomes more
complex and needs further investigation due to the torsional and bilateral
actions accompanied with seismic excitation, further the effect of skew
angle on the seismic behavior of skew bridge is not considered in currant
code. All the previous factors makes the seismic performance of skew
bridges needs further researches.