Search

The measured strains in the continuously reinforced concrete pavement (CRCP) cannot simply be used to calculate the concrete stresses by multiplying the elastic modulus of concrete, because the measured strains include both the stress dependent and independent strains. The setting temperature of concrete and the measured strain at this temperature should be used to calculate the temperature difference and the strain increment. The early-age strains in the concrete and steel of CRCP were measured in this paper. The measured concrete strains include the total strain, the stress independent strain and the initial strain at setting temperature. These measured values can be used not only to accurately calculate the stresses in concrete and steel but also to determine the accurate boundary conditions in the numerical modeling of CRCP subject to environmental loading. On the boundary conditions used in analysis of the early-age CRCP under environmental loading, epoxy coated steel is not completely bonded with concrete. Additionally, the perfectly free or restrained boundary condition across cracking is not true, and the longitudinal steel strains across cracking will help develop the proper boundary condition across cracking. The calculated stress was verified from the comparison between the calculated stress at the instant of cracking and the measured tensile strength. [ABSTRACT FROM AUTHOR]

A bump develops when there is differential settlement between a bridge abutment and an approach embankment. The determination of the allowable differential settlement is important for the design and maintenance of the bridge approach, so it is studied theoretically in this paper. Because the longitudinal roughness in the bridge approach is much more serious than that in general highway sections, the pitch movement of vehicles cannot be ignored. One adds rider and seat to a half-truck model to build a five- degree-of-freedom vehicle model. The dynamic response analysis to Man-Vehicle-Road system passing over the bridge approaches with and without approach-relative slopes are carried out by means of the Laplace transform. Comparative calculations show that much difference will be produced in the maximum transient vibration value of the acceleration and the vibration frequency when different vehicle models are used. So it is more reasonable to use the five-degree-of-freedom vehicle model than to use the three-degree-of-freedom vehicle model for the determination of the allowable differential settlement. After all the required parameters are determined, the allowable differential settlement can be obtained by trial calculations. [ABSTRACT FROM AUTHOR]