External Post-tensioning System for the Strengthening of Historical Stone Masonry Bridges

Abstract

Most historical stone masonry bridges were designed and built several centuries ago based in loads comparatively lower than the ones to which those structures are subjected to nowadays. Because of this fact and the normal decay and damage presented by historical structures, the need of strengthening arises and gives place to proposals such as the one presented in this paper. The objective of this paper is to present the evaluation of the feasibility of the use of an external post-tensioning arrangement to strengthen historical stone masonry bridges. The arrangement proposed is an alternative to those already existent and developed by other authors. To verify the assumed hypothesis, the proposal was analyzed with a general-purpose finite element method software, ANSYS. A qualitative assessment of this and other strengthening techniques available and used nowadays is also presented to evaluate its application suitability to historical structures. The results obtained via simple non-linear FEM models show that the proposal effectively increases the ultimate load capacity of the arch ring. It is also shown that the external post-tensioning arrangement can contain at certain level the horizontal thrust at the abutments. The proposed technique is deemed to be sympathetic and has great potential to be used to repair, strengthen and retrofit historical stone masonry bridges.