The monitoring of a precast, prestressed girder bridge during fabrication and service provided the opportunity to observe temperature variations and to evaluate the accuracy of calculated strains and cambers. The use of high curing temperatures during fabrication affects the level of prestress because the strand length is fixed during the heating, the coefficients of thermal expansion of steel ...

Several of the texts on prestressed concrete illustrate the magnitude of the effect of prestressing on the concrete by using a fishing pole as an example. As I recall the fishing pole described, it consists of a length of concrete one inch square in section with a single wire pretensioned through and along its central axis. Not until I was to witness the behavior of the massive precast, postten...

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...

Lattice-girder floor slabs and double-wall elements have been successfully used in building and industrial construction for decades. These precast elements of 50 – 70 mm thickness serve as permanent formwork for the subsequently added in-situ concrete creating a monolithic structure. The high prefabrication level allows the construction period to be significantly minimized. The main goal is the...

The Softened Truss Model Theory applied to a prestressed concrete multiple cell box is developed in this study. In this theory, the concrete torsional problem is solved by combining equilibrium conditions, compatibility conditions and constitutive laws of materials. Up to now the theory has been applied only to the case of pure torsion with single cell section. An algorithm is presented to deal...

This paper describes a method of performance evaluation and remaining life prediction for an aged reinforced concrete (RC) T-girder bridge by J-BMS RC version via close visual inspection data, and also verifies the assessment results obtained as outputs from the Bridge Rating Expert System (RC-BREX) which is a subsystem of the J-BMS, to evaluate the effectiveness of the system. The Bridge Manag...

Accidental damage to prestressed concrete bridge girders may occur due impact by over-height vehicles on the bottom of girder, or top flange girder be damaged during deck removal and replacement operations. Since stress checks at service loads are an important component design for beams, serviceability-based should considered when assessing structural condition girders. In this paper, step-by-s...