Thermal creep and relaxation of prestressing steel

Relaxation of Prestressing Steel at Varying Strain and Temperature: Viscoplastic Constitutive Relation

Recent studies of excessive multidecade deflections of prestressed segmentally erected box girders revealed that more accurate predictions of the prestress loss due to steel relaxation are needed for the design of large-span creep-sensitive structures. In particular, the loss needs to be calculated as part of creep structural analysis, during which the strain of concrete to which the prestressi...

Creep and Stress Relaxation Behavior of Polypropylene, Metallocene-Prepared Polyethylene and their Blends

Lecture 14 : Creep – Resistant Steel , Case Study

Introduction Typical operating parameters for steels used in the manufacture of power plant are compared against corresponding values for nickel alloys in aeroengines, in Table 1. In both cases, the service conditions are severe. But this is especially so for steels where the service life is many decades. The degree of reliability demanded of heat resistant steels is therefore extraordinary, an...

Interrelation of creep and relaxation: a modeling approach for ligaments.

Experimental data (Thornton et al., 1997) show that relaxation proceeds more rapidly (a greater slope on a log-log scale) than creep in ligament, a fact not explained by linear viscoelasticity. An interrelation between creep and relaxation is therefore developed for ligaments based on a single-integral nonlinear superposition model. This interrelation differs from the convolution relation obtai...

Creep and Stress Relaxation Anisotropy of a Single-Crystal Superalloy