1,720,967 research outputs found
Seismic capacity of masonry arches with irregular abutments and arch thickness
No full textThe simplest structural analysis for assessing the seismic capacity of a masonry arch is limit analysis. In fact, assuming an equivalent static seismic load, this method can be used to determine the lateral acceleration leading to the collapse mechanism. In this work, applying an analytical procedure, extensive parametric analysis was carried out to describe the seismic capacity of masonry arch structures with irregular geometry. In particular, arches with different abutment heights and discontinuous thicknesses have been examined. The results have been compared against those obtained by finite element analysis and by small scale experimental tests, and a good correlation has been found
Strengthening of masonry arches with SFRM
No full textResearch on the preservation and restoration of masonry arches is of interest for the scientific and civil engineering communities, and the construction industry. Among the open investigation topics in the field, the study of new materials for strengthening masonry arches has gained attention from researchers. In this context, this paper presents the experimental results from destructive tests carried out on a masonry arch strengthened with steel fiber reinforced mortar (SFRM). The tested masonry arch was made of solid clay bricks disposed in a single layer and was strengthened with a single layer of steel FRM bonded at the arch intrados. In order to replicate the possible condition of an existing arch in which acting loads exceeded the member strength, the arch was preloaded before strengthening. The performance of the strengthened arch is discussed in terms of witnessed failure mode, ductility and increase in the load carrying capacity with respect to unstrengthened condition
Experimental behaviour of damaged masonry arches strengthened with steel fiber reinforced mortar (SFRM)
No full textIn this paper, the results of an experimental campaign aimed to study the behavior of damaged solid clay brick masonry arches strengthened with steel fiber reinforced mortar (SFRM) are presented. Conditions of damage studied included preloading, horizontal displacement of one of the supports, or a combination of both. After damage was produced, the arches were strengthened with one layer of SFRM at the intrados and retested. The performance of the strengthened arches is discussed in terms of failure mode, and variation in the load carrying capacity, ductility and stiffnesses with respect to unstrengthened undamaged condition. The results show that the SFRM strengthening was able to increase significantly the strength and stiffness of the arches, although in some cases such increase was accompanied by a reduction in the specimens’ ductility. In addition, an analytical formulation for the design and assessment of the capacity of masonry arches strengthened with SFRM was developed. Comparison between predicted and experimental values show good agreement, which allowed validating the analytical method
Numerical Analysis of an FRP-Strengthened Masonry Arch Bridge
Full text linkHistorical masonry arch bridges are a fundamental part of the road and railway networks in Europe. Very often, due to factors such as lack of maintenance, increase of traffic loads, etc., these structures need interventions in order to guarantee their adequate structural performance. For this reason, an important research effort has been devoted in previous decades to study the behavior of masonry arches and to identify innovative techniques able to increase their ultimate capacity, such as fiber reinforced polymer (FRP) composites. In this paper, the results of an experimental campaign carried out on masonry arches strengthened with one FRP layer applied at the structure intrados are used to calibrate a numerical analysis model. Then, the model is used to predict the contribution that this type of strengthening would have had on the well-known Prestwood Bridge. The numerical results show that the hypothetical intervention of the Prestwood Bridge would imply an increase in the ultimate load of the structure, although it would be significantly lower than that usually obtained for the case of arches tested in laboratory
Evaluation of the vertical load capacity of masonry arch bridges strengthened with FRCM or SFRM by limit analysis
No full textThe 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
Strengthening of masonry arches with frcm composites: A review
No full textThis paper presents a review of the available literature on the use of externally bonded fiber reinforced cementitious matrix (FRCM) composites for the strengthening of masonry arches. As a first step, a detailed database of experimental tests on the topic was developed. The analysis of the database allowed evaluating the efficiency of FRCM composites in terms of gain in ductility and load carrying capacity with respect to the unstrengthened specimens and attained failure mode. In addition, influence of parameters as type of fiber, number of layers, and strengthening configuration on the overall behavior of the strengthened arches is also discussed
Retrofitting of Slender Masonry Arch Bridges
No full textThere is a large stock of masonry arch bridges built more than 100 years ago that are still in use in the world roadway and railway network. The restoration and conservation of this type of structures has become one of the main challenges of bridge engineering. As a first step, any intervention strategy requires an early stage consisting in the assessment of the structural safety (in the actual condition) of the masonry bridge. Only after that stage is performed, it is possible to design, if required, optimal repair interventions to bring the bridge to adequate safety level. In the first part of this paper, the seismic vulnerability assessment of a slender multi-span masonry arch bridge is presented. Results show that it is required to increase the flexural capacity of the structure. In the second part, an innovative intervention technique intended to increase the capacity of masonry arches is discussed. The proposed intervention technique consists on applying a layer of steel fiber reinforced mortar (SFRM) on the arch intrados. The behavior of a masonry arch strengthened with this technique is discussed by means of experimental and analytical results
Lateral response of damaged stand-alone arches: Tilting tests and rigid-block analysis
No full textArches are a structural solution widely adopted in the past, especially when masonry was the most used constructional material. Their wide-spreading can be, indeed, found in both infrastructural and monumental constructions, as well as ordinary historical buildings. From the mechanical point of view, due to their geometrical configuration, arches mainly experience compressive stresses under external loads. Thus, given also the close-to-zero tensile strength of the masonry, it is a common practice in engineering applications to consider arches as no-tension resistant element. On the other hand, due to the ancientness of masonry structures, arched structures can often experience structural defects, such as the local reduction of the thickness and the occurrence of toward-outside support movements. In this paper, the seismic response of stand-alone arches affected by these defect typologies is investigated by means of experimental tests and rigid-block analysis. In particular, 196 tilting tests on different geometrical configurations of small-scale arches affected by local reduction of the thickness and horizontal movement at one support are performed. The results of the experimental campaign generally showed that the localized defect can strongly influence the lateral capacity of the arches. Conversely, the simultaneous presence of horizontal support movement and local thickness reduction, in some cases, can return a quite different response with respect to the cases with the sole thickness reduction. Then, the obtained results are numerically interpreted by means of an automatic procedure implemented in MATLAB??, which allows for assessing the failure conditions of the performed tests by resorting to the limit analysis concepts. On the whole, a very good consistency between the experimental and numerical evidence is obtained
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