ABSTRACT
This present paper presents some results obtained in testing campaigns in two railway bridges (Figure 1) composed of granite stone masonry arches operating in the Minho Line, carried out under the StonArcRail R&D project developed at the Faculty of Engineering, University of Porto (FEUP) and the Polytechnic Institute of Tomar (IPT) with the support of REFER, EPE. a) Durrães and b) PK124 bridges. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig166_1.jpg"/>
The experimental campaign was made on the Durrães bridge (near Barcelos) and the São Pedro da Torre bridge, next to Valença, including in situ tests for experimental material characterization drawn from flat-jack, pressuremeter, georadar or GPR (Ground-Penetration Radar) and DPSH (Dynamic Probing Super Heavy) tests, as well as laboratory tests on materials’ samples taken from the bridges.
Experiments also included global characterization by vibration testing and measurement of both brides’ responses to service traffic loading. Details of vibration tests on the PK124 bridge can be found in (Costa et al., 2015) and for the Durrães bridge in (Costa et al., 2014).
The combination of different testing techniques is quite useful to complement findings of each other. That was the case of the GPR survey and the DPSH test results to characterize the foundation soil conditions around one of the bridges.
Flat-jack and Ménard pressuremeter in situ tests were made to obtain properties of facing stone masonry and infill material, respectively.
The pressuremeter tests (Figure 2a) were made according to the French standard NF-P94-110 (2000) and provided good results for mechanical parameters of the infill material through its pressiometric stress-deformation curve (Figure 2b). From the boreholes drilled in the masonry it was possible to extract material samples for laboratory testing. Ménard pressuremeter: (a) test and (b) pressiometric stress-deformation (volumetric) curve. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig166_2.jpg"/>
The flat-jack technique was also found a possible slightly-destructive option to characterise the stone masonry behaviour, although requiring particular care on the result analysis when it is used in masonry made of large units.
By testing samples of granite stone, as well as samples representing the masonry interfaces existing between stone blocks, it was possible to estimate strength and deformability parameters of the bridge materials, including joints between stone blocks, and to achieve reliable data for use in detailed numerical models of masonry bridge analysis.
