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Transverse load distribution in masonry arch bridges
Abstract
Masonry arch bridges comprise a significant proportion of the bridge stock in many countries. Due to increased traffic loads and possible deterioration of the bridge structure, it is essential that the load carrying capacity of such bridges be regularly assessed. Environmental benefits can be gained if the assessment provides an accurate evaluation of the capacity of the bridge, thereby avoiding unnecessary remedial work or bridge replacement. Several methods are currently used to assess masonry arch bridges including the popular modified MEXE method and mechanism analysis. An issue of particular interest is how the loads are distributed transversely in the arch. The current load model for masonry arch bridges calls for the utilisation of an effective strip when dealing with the transverse distribution of an applied load. In this paper LUSAS finite element analysis (FEA) software is used to assess transverse load patterns on masonry arch bridges. An arch is modelled using thick shell elements to represent voussoirs and a reduced stiffness is assigned to the mortar joints between each voussoir. The overall aim is to develop a load distribution model that improves upon current mechanism methods for the design and assessment of masonry arch bridges
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ABSTRACT: Masonry arch bridges represent a large proportion of the railway bridge stock. Many of them belong to the civil engineering heritage of the railways, therefore their manage-ment require careful consideration. Maintenance strategies should promote solutions that are di-rected towards their preservation and restoration by relying on their existing structural capacity and give preference to stabilization rather than their substitution or replacement. The paper in-troduces the results of an international project entitled “Improving assessment, optimization of maintenance and development of database for masonry arch railway bridges”. The project is or-ganised by the International Union of Railways (UIC) with the participation of 14 railway ad-ministrations and many consultant institutions, spanning a period of 4 years. The principle ob-jective of the project is to collect and develop tools that help optimising the life-cycle management of masonry arch bridges, help reducing their maintenance costs and promote an ef-fective exchange of good practice between the railway administrations.
Masonry is a composite non-homogeneous structural material, whose mechanical properties depend on the properties of and the interaction between the composite components - brick and mortar, their volume ratio, the properties of their bond, and any cracking in the masonry. The mechanical properties of masonry depend on the orientation of the bed joints and the stress state of the joints, and so the values of the shear modulus, as well as the stiffness of masonry structural elements can depend on various factors. An extensive testing programme in several countries addresses the problem of measurement of the stiffness properties of masonry. These testing programs have provided sufficient data to permit a review of the influence of different testing techniques (mono and bi-axial tests), the variations caused by distinct loading conditions (monotonic and cyclic), the impact of the mortar type, as well as influence of the reinforcement. This review considers the impact of the measurement devices used for determining the shear modulus and stiffness of walls on the results. The results clearly indicate a need to re-assess the values stated in almost all national codes for the shear modulus of the masonry, especially for masonry made with lime mortar, where strong anisotropic behaviour is in the stiffness properties.
This paper describes a method of assessing the load-carrying capacity of masonry arch bridges using the general-purpose finite-element (FE) package LUSAS. Good agreement was found, in terms of collapse loads and load-deflection characteristics, between the FE analysis adopted here and the experimental data. Three bridges were assessed: Bridgemill (actual collapse load 361 kN/m, FE collapse load 362 kN/m), Strathmashie (actual collapse load 228 kN/m, FE collapse load 226 kN/m) and Barlae (actual collapse load 296 kN/m, FE collapse load 302 kN/m). These values were based on cases where the material properties were well documented, which will not always be the case for other less well-researched arches, and therefore a parametric study involving the arch's elastic modulus, its compressive strength, its tensile strength and the backfill's load dispersal angle was carried out. The progressive development of cracking in the arch ring due to the application of live loading was also analysed. The method adopted was found to be a viable assessment tool for those bridges where the cost of potential repair/maintenance justifies what can be time-consuming FE work.
Recent advances in the analysis of masonry arch bridges, substantiated by extensive testing programs in the United States and Europe, provide bridge engineers and inspectors with increasing confidence that reasonable estimates can be made of the capacity of these structures. Observations of ultimate strength testing indicate that spandrel walls and fill contribute greatly to the strength and stiffness of these structures, and that loads approaching the plastic collapse load can often be obtained. Observations from service load testing indicate that the development of cracking and non-linearity under service loads can be a significant indicator of the capacity of the structure. Modeling of these structures has shown the importance of restraint of the abutment to the overall resistance of the structure, and has recently shown the importance of transverse effects in diminishing the strength of structures with high spandrel walls or thin arch rings.
In this paper, the development of a tapered beam element model is discussed and used to simulate the behaviour of a masonry arch bridge under loading. The collapse solution recognizes the inability of the arch material to carry tension, and the effective arch ring is modified as cracks develop. At each load increment, an iterative method is adopted to predict the displacement configuration which satisfies equilibrium. The model is simple and the analysis shows good convergence characteristics. Some numerical results are compared with masonry arch load tests and show that a reasonable accuracy can be achieved.
The road network in Ireland comprises national primary and national secondary roads, and non-national regional roads and local roads. Since 1994 the responsibility for the management and maintenance of the national roads has rested with the National Roads Authority (NRA). In 2001 the Eirspan bridge management system was introduced to coordinate and integrate activities such as inspections, repairs and rehabilitation work to ensure optimal management of the national road structure stock. This paper summarises the reasons for the introduction of the system and gives a review of the distinct activities included in Eirspan. It describes how bridge components are condition rated within principal inspections and outlines how, after the completion of the inventory gathering and first principal inspections, repair works are priority ranked. Future developments within Eirspan are also discussed. Eirspan helps engineers within the NRA to prioritise maintenance needs and maximise the use of available funding. It has proved to be an invaluable tool in helping to maintain the function and safety of bridges throughout the national road network in Ireland.
Review of Assessment Methods for Masonry Arch Bridges
- C Melbourn
- J Wang
- M S C Gilbert
Melbourn, C., Wang, J. & Gilbert M. S. C. 2009. Review
of Assessment Methods for Masonry Arch Bridges',
CSS Masonry Arch Research Project, Final Draft
Report.
Obvis Masonry Arch Analysis Software. [Online] Available: www.obvis.com
- Obvis
Obvis. 2011. Obvis Masonry Arch Analysis Software.
[Online]. Available: www.obvis.com. [Accessed 22
November 2011].
Development of Pippard's elastic method for the assessment of short span masonry arch bridges
- J Wang
- C Melbourne
- A Tomor
Wang, J., Melbourne, C., & Tomor, A. 2010.
Development of Pippard's elastic method for the
assessment of short span masonry arch bridges.
ARCH'10: Proceedings of the 6th International
Conference on Arch Bridges, Fuzhou, China.
Archie-M Masonry Arch Bridge and Viaduct Assessment Software User Guide
- Obvis Ltd
Obvis Ltd. 2010. Archie-M Masonry Arch Bridge and
Viaduct Assessment Software User Guide. [Online].
Limitstate Ring Theory and Modelling Guide Version 2.0oj, Sheffield
- Limitstate
Limitstate. Limitstate Ring Theory and Modelling Guide
Version 2.0oj, Sheffield. [Online]. Available:
www.limitstate.com. [Accessed 23 November 2011].
Finite Element Analysis of Masonry Arches Using Tapered Elements
- B Choo
- N Gong
- N Coutue
Choo, B., Gong, N. & Coutue, N. 2004. Finite Element
Analysis of Masonry Arches Using Tapered Elements,
Proc. Inst. of Civ. Eng, vol. 91, no. 4, 775-770.
section 4, part 4. The Assessment of highway bridges and structures (BA16), London. The Highways Agency
The Highways Agency. 1997. Design Manual for Roads
and Bridges, vol. 3. section 4, part 4. The Assessment
of highway bridges and structures (BA16), London.
The Highways Agency. 2001. Design Manual for Roads
and Bridges, vol. 3. section 4, part 3. The Assessment
of highway bridges and structures (BD21), London.
Keooi-Hock, NG. 1999. Analysis of Masonry Arch
Bridges, PhD Thesis, Napier University, Edinburgh,
United Kingdom.
Obvis Masonry Arch Analysis Software
- Obvis
Obvis. 2011. Obvis Masonry Arch Analysis Software.
[Online]. Available: www.obvis.com. [Accessed 22
November 2011].