Assessment of the load-carrying capacity of multi-span masonry arch bridges using fibre beam elements

Estimating the saftey of an ancient masonry arch bridge is a legitimate, but very interesting, structural engineering challenge. This is due to the fact that most of these bridges are still in service and suffer from higher and more frequent cyclic loads, a problem not encountered in the past. Therefore, for these structures it is important to know the actual fatigue strength rather than the ultimate carrying capacity in order to provide useful indications on the remaining service life with also possible traffic load limitations.In this article, different models are applied according to the stress-life curve method for estimating the fatigue strength of a case study: an ancient multi-span masonry arch bridge still in service. The obtained results highlight that, unlike steel elements, current design codes do not provide any relevant indication as to the fatigue strength assessment of existing masonry membratures. Moreover, appropriate stress-life curves are needed for evaluating the actual capacit...

Stress-Life Curves Method for Fatigue Assessment of Ancient Brick Arch Bridges

The assessment of load-carrying capacity of masonry bridges is usually based on limit analysis methods, which implicitly assume that masonry has unlimited ductility capacity in compression; aiming at taking into account the effective ductility capacity of masonry, an approach that makes use of beams with fibre cross is developed. The approach is able to take into account the non-linear behaviour of masonry in compression, including the post-peak softening branch and therefore provides a reliable estimate of the ultimate load. A numerical investigation of one to three span masonry arch bridges under travelling concentrated load, shows that, by parity of constitutive assumptions, the method provides the same estimate of ultimate load given by limit analysis, as well as the same kinematics at collapse. The influence of limited ductility is then investigated and the overestimate provided by classical limit analysis is highlight for the previously examined bridge typologies.

Load-carrying capacity of multi-span masonry arch bridges having limited ductility

A low-cost retrofitting technique for masonry arch bridges: experi- mental validation

This paper describes a series of tests performed on a multi-span brick arch at the University of Edinburgh, Scotland. This research is part of an ongoing investigation into soil/structure interaction in arch bridges. The bridge is a 2m double span brick arch which is backfilled with dry silica sand. Instrumentation was installed to measure the normal and shear pressures on the arch extrados, the vertical pressure within the fill and the deflection of the brick arches. A patch and a strip load were applied to simulate the effects of a wheel and an axle load respectively. The soil pressures were compared to the Boussinesq method stress distribution and reasonable correlation has been obtained. In addition, the results are also compared to previous tests on a similar single span arch and it is shown that the behaviour is significantly different. For the covering abstract see ITRD E111699.

D Ponniah

Papers

Soil pressure measurements on a multi-span brick arch