The flexural strength of externally prestressed beams depends on the tendon stress at failure. If the tendon is free to slip at the deviators its stress will depend on the global deformation of the whole structure. Thus the tendon stress at failure, and consequently, the flexural strength cannot be evaluated by a local analysis of the critical sections, but a nonlinear analysis of the whole beam-tendon structural system is required. In the past simplified formulas were proposed to calculate the tendon stress increment at failure avoiding the need for a nonlinear analysis of the entire structure. Some of these formulas have been adopted as code recommendations. Some approaches however do not seem to be consistent with the actual behaviour of externally prestressed beams and in some cases excessively high increments of stress are recommended. On the other hand, other approaches appear to be too conservative. In this work a new simplified and rational method of analysis based on shape functions approximating deformations, is proposed to study the tendon stress increment and consequently the flexural strength of externally prestressed concrete beams. The proposed simplified method reduces the analysis of externally prestressed structures from a global structure problem to an easier section problem.

Un metodo semplificato per l'analisi a collasso di travi in calcestruzzo post tese con cavi esterni

DALL'ASTA, Andrea;ZONA, Alessandro;
2006-01-01

Abstract

The flexural strength of externally prestressed beams depends on the tendon stress at failure. If the tendon is free to slip at the deviators its stress will depend on the global deformation of the whole structure. Thus the tendon stress at failure, and consequently, the flexural strength cannot be evaluated by a local analysis of the critical sections, but a nonlinear analysis of the whole beam-tendon structural system is required. In the past simplified formulas were proposed to calculate the tendon stress increment at failure avoiding the need for a nonlinear analysis of the entire structure. Some of these formulas have been adopted as code recommendations. Some approaches however do not seem to be consistent with the actual behaviour of externally prestressed beams and in some cases excessively high increments of stress are recommended. On the other hand, other approaches appear to be too conservative. In this work a new simplified and rational method of analysis based on shape functions approximating deformations, is proposed to study the tendon stress increment and consequently the flexural strength of externally prestressed concrete beams. The proposed simplified method reduces the analysis of externally prestressed structures from a global structure problem to an easier section problem.
2006
0000000000
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11581/113226
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact