Unbonded Prestressed Panel Tendon Stresses at In-Plane Nominal Flexural Strength

Abstract

A series of in-plane tests on post-tensioned concrete wall panels with unbonded tendons are described. These tests were used to verify that tendon stresses at nominal flexural strength can be accurately predicted for concrete walls using an equation previously developed for post-tensioned concrete masonry walls. Testing showed that the equation gives more accurate prediction of tendon stress than current design methods used in New Zealand. A secondary objective was to examine the accuracy of “true” predictions of wall performance obtained by finite element analysis. Predictions of wall forcedisplacement response, tendon stress increase and concrete strain generally matched experimental data with acceptable accuracy. The experimental response of some walls was significantly influenced by the existence of a bedding layer with low stiffness, which could not be accurately modelled.