The static and dynamic load tests were made for structural performance of the strengthened arch seat of a flying bird type arch bridge.

The deformation of arch springs of hingeless arch has significant influence on the internal forces of arch bridge and the selection of proper arch seats to be built on the thick overburden layer ground is thus extremely important to reduce the deformation of the arch springs.

Several years after a fly-bird type self-balanced tied arch bridge was open to traffic, the vertical cracks normal to the axial of the bridge, almost running through the whole arch seats occurred in west arch seats of the main bridge of the arch bridge, and also the propagation of the cracks does not tend to be stable.

Using MatLab software for deducing safety factor of point shearing resistance on the arch abutment space;

Through the combined modeling method with Surfer and Rhinoceros,such the control factors as the topography,structural face,block,water thrust and seepage pressure are unfolded and analyzed by three-dimensional model,which could only be unfolded by two-dimensional model in stability analysis of the arch abutment with the rigid limif equilibrium method in the past.

A new joint part between steel box arch rib and concrete arch support was introduced according to an actual bridge structure.

Forces analysis and calculation on the abutment of super large bridge over Daning river;

Dynamic buckling of cracked circular arch with initial geometric imperfection subject to radius impact;

The stability equations of circular arch are obtained by the method of functional extremum.

By adopting the method of functional extremum analysis, the author derives the stability equation for section function and flexure function of circular arch.