Experimental and numerical analyses of strengthened rammed earth masonry arches

This paper shows experimental and numerical analyses on rammed earth arches asymmetrically loaded and successively strengthened with a natural composite. The aim is to evaluate the capability of finite element codes to faithfully describe the mechanical response, including the post peak branch and post elastic deformations. The mechanical properties of rammed earth were determined through specific experimental tests and used to calibrate uniaxial compressive parameters of the constitutive models implemented in three numerical software (ANSYS, Abaqus, ADINA). The mechanical parameters of the jute fabric are reported here together with the description of the calibration of the constitutive models. According to the experimental results, the strengthening system proposed was capable to increase the load bearing capacity and ductility of the structures, preserving their integrity for higher load levels and consequently postponing failure without adding significant mass to the system. The numerical models were able to describe the failure process in good agreement with the experimental results for both strengthened and unstrengthened arches; the effects of uncertainties on the tensile behaviour parameters of rammed earth, due to the scarce amount of data available in literature and to the difficulty in performing reliable tests for their determination, were numerically evaluated through sensitivity analysis.