INTRODUCTION The lower ratio of dead load to live load than existing multi-girder bridges, wide girder spacing and simplified structural system of the twin-girder bridges can give rise to change of dynamic characteristics of the bridges. Wider girder spacing and changing of dynamic features will also effect on a vibration serviceability of the bridges. What is worse, according to running vehicl...

Differential settlement of the foundation of the LCLS Undulator Hall will cause quadrupoles to move and the electron beam trajectory to distort. The resulting phase errors will decrease the FEL power and require time consuming beam-based alignment sessions to correct. By supporting quadrupoles on girders, with three quadrupoles to a girder, the foundationmotion induced phase error between the b...

To the 36 meters crane girder with trapezoidal variable cross-section in a steel plant, finite element model is established reasonably according its actual size. The calculation of crane girder structure was introduced by using the finite element analysis software ANSYS. The local stress state of the cross-section is investigated and the stress concentration position of variable cross-section i...

Slab-girder structures composed of steel girder and reinforced concrete slab are widely used in buildings and bridges in the world. Their advantages are largely based on the composite action through the shear connection between slab and girder. In order to assess the integrity of this kind of structures, numerous vibration-based damage identification methods have been proposed. In this study, a...

HEPS-TF is the test facility of HEPS (High Energy Photon Source) of China. The magnet girders are used for supporting and positioning of the magnets. As the beam emittance is very low, the girder must has high adjusting precision and high stability. Besides, the girder should also be beam-based aligned. For these issues, two girder systems are designed. Both of them use cam mover mechanisms for...

Based on the theory of vehicle track coupling dynamics, the local vibration of the high-speed railway box girder is analyzed by the Finite Element Method and the model is simulated with the solid elements. Through the study of vibration characteristics of the selected 6 sensitive points, the local vibrations in different parts of the box girder are figured out. It is compared the response of th...

The LCLS x-ray FEL has recently achieved its 1.5Angstrom lasing and saturation goals upon first trial. This was achieved as a result of a thorough pre-beam checkout, both traditional and beam-based component alignment techniques, and high electron beam brightness. The x-ray FEL process demands very tight tolerances on the straightness of the electron beam trajectory (<5 μm) through the LCLS und...