Assessment of the Strengthening of an RC Railway Bridge with CFRP Utilizing a Full-Scale Failure Test and Finite-Element Analysis

Abstract

A finite element (FE) model was calibrated using the data obtained from a full-scale test to failure of a 50 year old reinforced concrete (RC) railway bridge. The model was then used to assess the effectiveness of various strengthening schemes to increase the loadcarrying capacity of the bridge. The bridge was a two-span continuous single-track trough bridge with a total length of 30 m, situated in Örnsköldsvik in northern Sweden. It was tested in situ as the bridge had been closed following the construction of a new section of the railway line. The test was planned to evaluate and calibrate models to predict the load-carrying capacity of the bridge and assess the strengthening schemes originally developed by the European research project called Sustainable bridges. The objective of the test was to investigate shear failure, rather than bending failure for which good calibrated models are already available. To that end, the bridge was strengthened in flexure before the test using near-surface mounted square section carbon fiber reinforced polymer (CFRP) bars. The ultimate failure mechanism turned into an interesting combination of bending, shear, torsion, and bond failures at an applied load of 11.7 MN (2,630 kips). A computer model was developed using specialized software to represent the response of the bridge during the test. It was calibrated using data from the test and was then used to calculate the actual capacity of the bridge in terms of train loading using the current Swedish load model which specifies a 330 kN (74 kips) axle weight. These calculations show that the unstrengthened bridge could sustain a load 4.7 times greater than the current load requirements (which is over six times the original design loading), whilst the strengthened bridge could sustain a load 6.5 times greater than currently required. Comparisons are also made with calculations using codes from Canada, Europe, and the United States.

Experimental and analytical behavior of a new type of concrete‐filled steel tube tied‐arch bridge with trough girder

“…Based on the isotropic plate theory, they made theoretical analysis on concrete trough girder, proposing mathematical expression of internal force and deformation for the structure under various vertical loads. The experimental study ( [5], [16], [17], [19]) conducted a new scale model test on simple supported steel-concrete composite channel girder. Destruction load was imposed to the model in order to investigate carrying capacity, stiffness, stress distribution, and crack diagram of the structure.…”

“…( [3], [7], [10], [19]). In engineering, most trough girders are used in simple supported bridges with small span of generally less than 30 m ( [5], [17], [18], [19]) and they are not adapted to overpass and flyovers with large spans. The overpass on Nanjing-Qidong railway line in China, together with a passage of Shanghai-Nantong railway line, has a span of more than 64 m and an altitude of less than 2.4 m for girder height because of basically equal height for both railways.…”

Shear assessment of a reinforced concrete bridge deck slab according to level‐of‐approximation approach

“…Fracture energy is calculated to be G f = 140 Nm/m 2 based on MC2010 considering reduction. In addition, sensitivity analyses have been carried about these parameters (considering the variation) regarding their influence on FE analysis of structures . The values of those assumed material properties have been summarized in Table .…”

Failure tests on concrete bridges: Have we learnt the lessons?

“…Using information about the material from the bridge design, a 7 to 13 % lower capacity was given. For refined structural assessment, the bridge test was simulated using nonlinear FE analyses with various levels of approximation, ranging from a simplified 1D model (Ferreira et al 2015) to a detailed 3D model (Puurula et al 2015). The most complex 3D model, with the concrete modelled with continuum elements and the reinforcement using embedded discrete bars, was able to simulate the structural behaviour precisely, including the failure and the peak load.…”