elastic shortening

elastic shortening

1.In a structural member, a decrease in the length (under an imposed load) which is linearly proportional to the load.
2. In prestressed concrete, the shortening of a member which occurs immediately on application of forces induced by prestressing.
Mentioned in ?
References in periodicals archive ?
The prestress loss during the releasing step was caused by the elastic shortening of the RC beam, and the strain changes in CFL during this step under the three different prestress levels (8%, 15%, and 22%) are shown in Figure 9(a).
The prestress loss in the long term was still due to the elastic shortening of the RC beam, as shown in Figure 10(a), with the three prestress levels (8%, 15%, and 22%).
As shown in Table 1, during the process of applying prestress to CFL and bonding the prestressed CFL to RC beams, the majority of prestress loss was caused by CFL slipping between the movable wave-shape grip anchors and the elastic shortening of the RC beam.
The following derivation of the prestress loss caused by elastic shortening of the RC beam was made for a beam with typical rectangular cross-section, but the method of this analysis is also applicable to any beam with arbitrary cross-sections and material properties, providing the same assumption holds.
From (5) to (10), the ratio ([[sigma].sub.l]/[[sigma].sub.pf]) of prestress loss caused by elastic shortening of the RC beam to the prestress on CFL before release can be obtained by the equation
The comparison between the two showed that the analytical model of prestress loss caused by the elastic shortening of the RC beam after release was in good agreement with the experimental data.
The measured results showed that maximum prestress loss of CFL was 14.9% and that the majority of prestress loss was caused by CFL slipping between the movable wave-shape grip anchors and the elastic shortening of the RC beam.
where [f.sub.pk]--characteristic strand stress immediately before release; [f.sub.pe]--effective stress transferred to the pretensioned member (which considers the prestress losses due to elastic shortening, conditioned by the concrete's modulus of elasticity).
where [v.sub.c]--Poisson's modulus of concrete; [v.sub.p]--Poisson's modulus of the prestressing strand or wire; [A.sub.p]--cross-sectional area of the prestressing strand; [A.sub.c]--concrete area of the prestressing strand's zone of influence; [E.sub.c]--concrete modulus of elasticity at the time of transfer; [f.sub.pk]--characteristic initial stress of the pretensioned strand; [f.sub.pe]--effective stress transferred to the pretensioned member (which considers the prestress losses due to elastic shortening, conditioned by the concrete's modulus of elasticity).
This fracture instability occurs if the elastic shortening of the system exceeds the corresponding plastic lengthening for crack extension.