A series of experimental data show that there is a certain relationship between the prestress
of the steel strand and the frequency of oscillation.
For PSC members, however, since the elastic deflection due to member weight at the release of the prestress
, not at the standard age of 28 days, is multiplied by the long-time factor, the factor should be calculated considering the elastic modulus [E.sub.ci] at the time of release, not the elastic modulus [E.sub.c] at 28 days, as follows:
where [DELTA][[sigma].sub.l1] is the prestress
loss associated with anchorage set (MPa), [[DELTA].sub.a] is the slip of the anchorage integrated from measured strains (mm), Ecf is the elastic modulus of the CFRP plate (MPa), and l is the CFRP length (mm).
effect was assigned for 2D plane stress elements.
NSMR introduces prestress
to improve actively the performance based upon the behaviour of NSMR, its behaviour is closely related to that of NSMR.
In this section, in order to investigate the effect of prestress
on the yield strength, ultimate strength and ductility of RC (reinforced concrete) beam, SRC (steel reinforced concrete) beam, and the changes of mechanical properties of beam after built-in H-steel, four same size numerical models were made, which are prestressed
steel reinforced concrete (PSRC) beams, steel reinforced concrete (SRC) beams, prestressed
reinforced concrete (PRC) beams, and reinforced concrete (RC) beams, and their mechanical properties were analyzed.
Segmentally erected prestressed
bridges are becoming very popular for moderate spans all over the world (Ketchum, 1986).
As for the research of prestress
anchor frame beam, it is mainly focused on prestress
anchor mechanism, calculation method of frame beam internal force, and some field test research, but all these mainly aim at the internal force calculation of frame beam [1-5].
At an approximate contract value of $570,000, Oldcastle Precast - Central Pre-Mix Prestress
manufactured and delivered the prestressed
concrete Super Girders: (5) five Super Girders at 157'-8” long; (5) five Super Girders at 154'-8” long and (5) five Super Girders at 170'-2” long.
The experimental program was developed with two main objectives: to study the time evolution of the prestress
applied to the structure and to verify the bridge structural behavior under the action of loads simulating the action of a vehicle.
Wave-prestress and wave-material interactions are described for nonlinear propagation of longitudinal waves in materials (i) with inhomogeneous prestress
and (ii) with weakly variable physical properties.