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Relaxation loss of prestressing steel, Δσpr

Eurocode 2 part 1-1: Design of concrete structures \$(document).ready(function () { var freeExample = \$("#freeExample").length; \$("#mainMenu li#nav-appCate, #mainMenu li#nav-appEC211").addClass("active"); var proUser = false === true || false === true || freeExample !== 0; if (!proUser) { \$('#Input input').keyup(function(){ \$('#AlertSubscribe').modal(); }); \$('#Input select').change(function(){ \$('#AlertSubscribe').modal(); }); }; var tempInput = \$("#tempInput").text(); if (tempInput != "") { \$("#Input").parent("form").deserialize(tempInput); if (proUser) { \$("#acceptBtn").trigger("click"); } }; });  3.3.2 (7)

The relaxation loss may be defined as the percentage ratio of the variation of the prestressing stress over the initial prestressing stress. Following the class of relaxation of prestressing steel, one of the Expressions below may be applied:

 Class 1: (3.28) Class 2: (3.29) Class 3: (3.30)

where:

Δσpr
is absolute value of the relaxation losses of the prestress
σpi
for post-tensioning, is the absolute value of the initial prestress,
for pre-tensioning, is the maximum tensile stress applied to the tendon minus the immediate losses occurred during the stressing process
t
is the time after tensioning
μ
= σpi/fpk, where fpk is the characteristic value of the tensile strength of the prestressing steel
ρ1000
is the value of relaxation loss (in %), at 1000 hours after tensioning and at a mean temperature of 20°C, see § 3.3.2 (6).

This application calculates the relaxation loss Δσpr from your inputs. Intermediate results will also be given.

Input
MPa
MPa
hours

Output
ρ1000
%
μ
Δσpr/σpi
%
the relaxation loss Δσpr
MPa