Capacity Of Masonry Arch Bridges Research Articles

Effects of pre-existing damage on vertical load-bearing capacity of masonry arch bridges

In-service masonry arch road bridges, mainly realised before the first half of the last century, represent a wide portion of the entire worldwide infrastructural asset. Given their age, during their service life these structures could have experienced damage due to anthropic (i.e. traffic) and natural (i.e. earthquakes, soil settlements, degradation, etc.) actions which may have inevitably affected their load-bearing capacity. The present study addresses the problem of the residual capacity estimation of damaged bridges by investigating the impact of previous loading on the actual strength of the structure. In particular, reference to a past experimental activity retrieved from the literature on reduced-scale bridges subjected to concentrated vertical loads has been made to calibrate a reliable detailed finite element model in Abaqus software. Then, damage of different extent has been introduced by simulating the transit of vehicles of various weights on the structure and the residual capacities of the bridge have been assessed and compared against the undamaged configuration. The results confirm that pre-existing damage due to traffic loading may significantly influence the capacity of such structures, with peak load reductions up to 60% estimated through the proposed methodology.

Shakedown and dynamic behaviour of masonry arch railway bridges

Masonry arch bridges form an integral part of our rail infrastructure network and their safety is important for the functioning of our society. Although, there have been several studies to understand the in-service condition of masonry arch bridges, these are mainly focusing on static analyses. However, it is well known that moving vehicles exert a dynamic force on bridges as they cross them. This paper investigates the shakedown and dynamic behaviour of railway masonry arch bridges under traffic load conditions. A nonlinear, mixed discrete-finite element numerical model was developed to investigate static and dynamic response on a masonry arch bridge. Each voussoir of the masonry arch was represented by a distinct block, while the mortar joints were modelled as zero thickness interfaces which can open and close depending on the magnitude and direction of the stresses applied to them. Both static and real dynamic analyses were carried out investigate the effects of moving traffic loads. In addition, investigations into the train to bridge interaction were undertaken and the dynamic amplification factors (DAFs) were estimated. From the evaluation of the results, it was shown that as the external load passes through the bridge, plastic deformations and residual stresses exist in the arch barrel. Also, the dynamic amplification depends on the magnitude of the external load. As the load increases, non-linearity in the structure is evident, which decreases the natural frequency of the bridge. Hence the critical speed is decreasing. Observations provided here reveal new insight into the residual and load carrying capacity of masonry arch bridges.

Evaluation of the vertical load capacity of masonry arch bridges strengthened with FRCM or SFRM by limit analysis

The large number of existing masonry bridges still in service in the world roadway and railway networks requires that transportation system managers carry out ordinary and extraordinary maintenance. In many of these networks, the need for increasing the speed and/or weight of the traffic loads also entails the design of strengthening interventions aimed at enhancing the load-carrying capacity of masonry bridges. Among the available techniques for the strengthening of these structures, the use of fiber reinforced cementitious matrix (FRCM) composites has gained popularity due to their advantages with respect to more traditional techniques. More recently, the use of steel fiber reinforced mortars (SFRM), has also been investigated for the strengthening of masonry bridges, with promising results. In this paper, a limit analysis for assessing the vertical load-carrying capacity of single-span bridges strengthened with FRCM or SFRM, applied at the intrados, is described, and calibrated using available experimental results. The document highlights the variables that should be considered in such procedure and also discusses the similarities and differences between the two strengthening techniques. A subsequent parametrical analysis shows that both techniques produce comparable increments in the load carrying capacity of the masonry bridges when compared to unstrengthened conditions. In addition, it was seen that if the finite friction between blocks is not considered when performing the limit analysis of masonry bridges, the ultimate load capacity of the arches can be overestimated as the failure mode can be attained due to shear sliding of the masonry blocks, a hinge mechanism or a combination of both.

Estimation of the service load capacity of plain concrete arch bridges using a novel approach: Stress intensity factor

Masonry arch bridges have furnished railway networks as important infrastructures. The evaluation of the behavior of masonry arch bridges has drawn a great deal of attention over the past years due to the increase in the speed of railway fleet, need for augmentation of trains axle loads, and increase in the number of vehicles. These critical structures have been designed for service loads demanded at past times and since service loads are different in the present time, their behavior crucially needs to be assessed. Various analytical, experimental, approximate, and numerical methods have been proposed so far to estimate the residual capacity of masonry arch bridges. The present paper aims to predict the maximum service load of railway plain concrete arch bridges using a new approach with the aid of stress intensity factor in the fracture mechanics. Since stress intensity factor is solved analytically only for highly simple problems, a numerical approach and the finite element method were used in the present paper to calculate this parameter. Finally, given the stress intensity factor and proposing a relation for concrete toughness based on a statistical study, the maximum service load of these vital structures is obtained. To validate the results, two plain concrete arch bridges —located at kilometer 23 and 24 of Tehran-Qom Old Railway— were used. The results revealed that the proposed method has agreed well with the field observations.

Safety Assessment of Masonry Arch Bridges Considering the Fracturing Benefit

The evolutionary analysis of the fracturing process is an effective tool to assess of the structural bearing capacity of masonry arch bridges. Despite their plain basic assumptions, it must be remarked that elastic analysis and plastic or limit analysis can hardly be used to describe the response and predict damage for moderate or service load levels in masonry arch bridges. Therefore, a fracture mechanics-based analytical method with elastic-softening regime for masonry is suitable in order to study the global structural behaviour of arch bridges, highlighting how the arch thrust line is affected by crack formation, and the maximum admissible load evaluated by means of linear elastic fracture mechanics is larger than the load predicted by elasticity theory. Such an increment in terms of bearing capacity of the arch bridge can be defined “fracturing benefit”, and it is analogous to the “plastic benefit” of the plastic limit analysis. The fracturing process, which takes into account the fracture initiation and propagation in the masonry arch bulk, occurs before the set-in of the conditions established by means of the plastic limit analysis. In the present paper, the study of the elastic-fracture-plastic transitions is performed for three monumental masonry arch bridges with different shallowness and slenderness ratios. This application returns an accurate and effective whole service life assessment of masonry arch bridges, and more in general it can be suitable for a great number of historical masonry structures still having strategic or heritage importance in the infrastructure systems.

Probabilistic-based structural assessment of a historic stone arch bridge

A probabilistic analysis approach for reliability-based assessment of masonry arch bridges is presented in this work. The methodology is tested on a medieval in-service construction located in Galicia, northwest of Spain. To estimate its ultimate load-carrying capacity, two different numerical approaches are employed; a three-dimensional non-linear finite element model and a two-dimensional rigid blocks limit analysis model. Aiming to alleviate the computational burden associated with the probabilistic analysis procedure, a surrogate modelling strategy is adopted. A complete understanding of the influence of model input parameters on the limit load of the structure is attained through the employment of global variance-based sensitivity analysis. The reliability assessment procedure is subsequently carried out, allowing to estimate the bridge failure probability. A difference of approximately 33% is obtained between the reliability index values drawn from both structural modelling strategies, so revealing the key role played by transversal effects on the strength capacity of masonry arch bridges. The proposed probabilistic assessment framework might be deemed as a useful tool, from which more reliable and objective information about the actual safety condition of existing masonry arch bridges can be derived, taking advantage of readily available numerical tools, but still demanding an affordable computational effort.

Rapid evaluation of in-plane seismic capacity of masonry arch bridges through limit analysis

In this paper a limit analysis based procedure for the rapid evaluation of the in-plane seismic capacity of masonry arch bridges is carried out. Attention has been paid to the effect of the backfill on the collapse load. A parametric investigation has been performed by varying the rise/span ratio and the results have been compared with those obtained by finite element modelling. The comparison highlights the conservative feature of the proposed model in terms of ultimate loads and a good agreement in terms of collapse mechanisms.

Large-scale physical modelling of soil-filled masonry arch bridges

The presence of soil backfill has been shown to have a significant influence on the load-carrying capacity of masonry arch bridges, with the soil fill providing a number of important functions, including inter alia, the distribution of surface loads and passive resistance to arch deformation during loading. Large-scale physical modelling allows high-quality data to be collected under controlled conditions, while enabling essential aspects of the interaction between the soil fill, the masonry arch and the abutments to be observed. This paper considers the design and construction of a unique test facility that allows large-scale soil-filled masonry arch structures to be studied under both quasi-static and cycling loading regimes. The key challenges that were needed to be overcome to develop this facility are presented and discussed.

Influence of backfill on the capacity of masonry arch bridges

The influence of the presence of backfill on the load-carrying capacity of a masonry arch bridge can be considerable. The backfill is responsible for transmitting and distributing live loads from the road or rail surface through to the arch barrel and also for laterally stabilising the arch barrel as it sways under load. However, it can be difficult to separate these two distinct effects, and hence also difficult to ascertain whether existing assessment code recommendations are realistic. To address this, a series of experiments designed to separate these two effects have been performed. A total of 27 small-scale bridge tests were undertaken and the experimentally obtained peak loads then compared with results from limit analysis software of varying complexity. It was confirmed that passive restraint and live load distribution both contribute significantly to bridge-carrying capacity, and that, when failure involves a four-hinge failure mechanism, even comparatively simple limit analysis software can model the various effects remarkably well.

The effect of geometry on the structural capacity of masonry arch bridges

This paper presents the effect of geometry on the structural capacity of masonry arch bridges with different geometric features. This study was performed using an application (ANPAF) developed in MATLAB and based on the Linear Programming Method developed by Livesley. The geometry is read directly from an ‘a.dxf’ file, which stores the information obtained from planimetric surveying techniques. The results were compared with real and idealized geometry corresponding to each of the arches. This study aims to estimate the percentage of error that can occur in the structural assessment of masonry bridges by reading from different shapes as well as to estimate geometrical error.

Geometric issues and ultimate load capacity of masonry arch bridges from the northwest Iberian Peninsula

This paper reports the results from a geometrical survey carried out on 59 segmental masonry arch bridges from Portugal and Spain, with a focus on the adjacent geographical areas of northern Portugal and north-western Spain. Historical empirical rules are briefly presented and further compared against the bridges’ geometrical data. Departing from a detailed discussion of the geometrical results, eight reference bridges were defined as representative of the sample. Subsequently, the paper deals with a parametric assessment of the load-carrying capacity of the reference bridges and a discussion of results. It was found that arch thickness and physical properties of the fill are of paramount importance in terms of ultimate load-carrying capacity. Furthermore, the results indicate that the bridges from the sample are structurally safe with respect to applicable legislation.

Masonry arch analysis using discontinuity layout optimisation

Limit-analysis techniques have been found to provide a useful means of rapidly estimating the ultimate load-carrying capacity of masonry arch bridges. However, in most limit-analysis models only the masonry elements (e.g. arches and piers) are modelled directly, and the surrounding soil backfill material is usually modelled in an indirect and highly simplified manner. Given the likely importance of the soil backfill, this can lead to considerable imprecision when estimating load-carrying capacity, particularly when non-homogeneous backfill materials are involved. In this paper the recently developed discontinuity layout optimisation (DLO) limit-analysis procedure is extended to enable rotations at the boundaries of prescribed regions to be considered, thus allowing both soil and masonry components within a problem to be be modelled explicitly. This allows masonry arch bridges to be analysed using DLO. Results are initially validated against literature benchmarks and then compared with those obtained from carefully controlled tests recently carried out on soil-filled masonry arch bridges. It is demonstrated that reasonable estimates of bridge load-carrying capacity can be obtained provided ‘mobilised' rather than peak soil strengths are used in the analysis.

Non-linear Finite Element Analysis of Masonry Arches for Prediction of Collapse Load

The paper presents a summary of experimental and theoretical investigations on the load carrying capacity of masonry arch bridges. The experimental program includes static testing of two arches constructed in the heavy testing laboratory. Tests were also conducted on control specimens to investigate the properties of the masonry employed in the construction of the arches. The details of the two-dimensional non-linear finite element computer program developed for the analysis and load prediction of the masonry arch bridges are given. The program takes into account the non-linearity due to the non-linear stress-strain relationship and the cracking of the masonry. The load test results of the arches are compared with the results of a finite element analysis.

Load-carrying capacity of masonry arch bridges estimated from multi-span model tests

Load-carrying capacity of masonry arch bridges estimated from multi-span model tests

Discussion: Load-carrying capacity of masonry arch bridges estimated from multi-span model tests

Discussion: Load-carrying capacity of masonry arch bridges estimated from multi-span model tests

Load-Bearing Capacity of Masonry Arch Bridges Strengthened with Fibre Reinforced Polymer Composites

This paper presents a new mechanism analysis method to calculate the ultimate load-bearing capacity of masonry arch bridges strengthened by externally bonding fibre reinforced polymer (FRP) composites on the intrados. The M– N relationship of a strengthened arch ring cross section is analysed and fully considered in the mechanism analysis. The Complex Method of nonlinear programming is used to perform a constrained minimisation of the load function to obtain the minimum collapse load and its corresponding hinge positions. This has advantages because the arch ring does not need division into many discrete blocks as in traditional mechanism analysis and the solution process is fully automatic. Some initial results are presented, which show that significant strength increases can be achieved by bonding a small amount of FRP composites to the intrados of masonry arch bridges.

FINITE-ELEMENT ANALYSIS OF MASONRY ARCH BRIDGES.,

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. (A)

A METHOD OF INCREASING ARCH BRIDGE CAPACITY ECONOMICALLY.

Keywords NAPIER UNIVERSITY, EDINBURGH UNIVERSITY, MEXE BALFOUR BEATTY BRIDGES, ARCHES, CAPACITY, INCREASING, METHODS, ECONOMIC, BITUMINOUS, ROADS, PAVEMENTS, OVERLAYS, LOADS, CARRYING, MASONRY, ANALYSIS, MEXE, COMPUTERS, FINITE ELEMENTS, STRESS, DISPERSAL, GEOMETRY, COSTS, INCREASES, REHABILITATION... Show All