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Many old riveted steel bridges remain operational and require retrofit to accommodate ever increasing demands. Complicating retrofit efforts, riveted steel bridges are often considered historical structures where structural modifications that affect the original construction are to be avoided. The presence of rivets along with preservation requirem...
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... documents indicate that the bridge is simply supported, with pin connections on one end and simple bearing rollers on the other (allowing longitudinal translation). Figure 5 shows the boundary conditions applied to the global model, with pinned supports on one end and longitudinal rollers on the other. ...
Citations
... The progressive increase in computation power improved the modelling strategies allowing to embed in-house or commercial software with ad hoc routines for the description of different material behaviours (ductile damage [11][12][13][14], crack propagation [15,16], fatigue [17,18], spalling [19], brittle materials [20][21][22]). Moreover, the discretisation of components or structures into finite elements became more refined, allowing more accurate prediction. ...
... Composite materials are extensively used in various industries such as transportation, petrochemicals, electronics, naval, building and construction, sports, energy, biomedical, and manufacturing due to their advantageous properties. These include their lightweight nature, high strength and stiffness, corrosion resistance, reduced thermal expansion, and excellent fatigue resistance (Chung, 2010;Ghafoori et al., 2014;Martinelli et al., 2014). However, their high cost and complex characteristics, arising from heterogeneity and various laminate configurations, pose challenges in accurately characterizing their properties. ...
This study provides an overview of the recent advances in simulation techniques applied to fiber-reinforced polymer (FRP) composites, focusing on analyzing their mechanical properties and applications. FRP composites have gained significant attention in various industries due to their excellent mechanical properties, lightweight nature, and corrosion resistance. Simulating the behavior of FRP composites allows researchers and engineers to optimize their design, understand their mechanical performance, and predict their response under different loading conditions. This study explores different theoretical models for predicting the mechanical properties of composites. This study also acknowledges the challenges of characterizing these heterogeneous materials, making computational techniques such as finite element analysis indispensable for accurate predictions. In addition, simulated mechanical properties of composites with varying fibers and matrices are explored and compared with experimental results. Furthermore, the applications of simulation in different industries for characterizing FRP composites are discussed.
... Therefore, there is an urgent need to ensure a high level of quality control and that the appropriate response of products and services remains as intended over extended periods. Its application is present in several industries, including aerospace 8,9 , construction 10,11 , and electronics 12 . The development of new materials has driven the expansion of its use in other areas, reducing costs, increasing the useful life and safety of components 13-15 . ...
Polymer matrix composite (PMC) materials produced by additive manufacturing are a promising solution with several applications in industry. The presence of defects due to fabrication could undermine the performance of the component structure. PMC performance has been extensively studied using destructive tests, but reliable nondestructive testing (NDT) techniques are essential. In this study, PMC with unidirectional fibers were 3D printed with an adapted conventional fused filament fabrication printer. The matrix material was polylactic acid, and three different reinforcement fibers were used: Kevlar®, carbon, and glass fibers. The samples were 3D printed with artificial defects, to simulate delamination's 0.5 mm thick. Four NDT techniques were explored, benchmarking the inspection of PMC envisaging an automated noncontact imaging inspection for easier result interpretation. Active pulse thermography, air-coupled ultrasounds, continuous wave terahertz, and digital X-ray were the techniques chosen, and a critical comparison is presented, evaluating the performance of each technique in the detection of defects. NDT technique diversity, complementarity, and redundancy improve inspection reliability, as there is not a single inspection technique that can cover all material defects or characteristics.
... The analysis of the stress-strain state of CFRP-strengthened steel structures can be rationally performed using the finite element method [20][21][22]. In the numerical analysis of strengthened steel structures, much attention is paid to the simulation of an adhesive joint by means of which CFRP and a steel element interact. ...
Strengthening can increase or recover the bearing capacity of steel constructions of buildings and structures in operation. Besides well-known strengthening techniques, including an increase in the sectional area by means of attaching steel plates, angles, channels, pipes etc. to a strengthened element, other methods, that involve the use of carbon fiber-reinforced composite materials, have strong prospects. So far, the structural behaviour of steel constructions, strengthened with carbon fiber-reinforced composite materials, is understudied, and this fact restrains the practical application of this strengthening method. The article presents the results of complex experimental, theoretical and numerical studies of the features of the operation of steel-stretched elements reinforced with glued carbon fiber. The emphasis is on the load-bearing capacity of the reinforced element, and not on the mechanism of destruction of the glue. This is due to the use of an adhesive joint performed using the glue and gluing technology recommended by the manufacturer of carbon fiber. It has been experimentally established that, in this case, the stresses in carbon fiber cannot exceed a certain value. Theoretical dependences for the calculation of CFRP-reinforced steel stretched elements are proposed. The scientific novelty of this research project is a set of basic principles and methods, developed to identify the bearing capacity of steel rods, strengthened with carbon fiber-reinforced composite materials, taking into account the joint strength performance of a steel rod and adhesively bonded carbon-fiber-reinforced composite material, as well as the new findings thus obtained, such as the theoretical dependencies needed to identify the bearing capacity of steel rods strengthened with carbon-fiber-reinforced composite materials; experimental data on the joint strength performance of carbon-fiber-reinforced composite lamellas attached to a steel rod by an adhesive; experimental data on the performance and the bearing capacity of steel rods strengthened with carbon-fiber-reinforced composite lamellas; development of finite element models of steel rods strengthened with carbon-fiber-reinforced composite materials, and computational studies of steel rods strengthened with carbon fiber-reinforced composite materials.
... Recently, new perspectives for strengthening metallic bridges have been developed using CFRPs, following principles identical to those underlying the application of external prestressing unbounded cables in concrete structures. In order to modify the structural response of certain members, external prestressed CFRP bands may be implemented, reducing significantly effective stress ranges and respective mean stress values, which has relevant impacts in terms of fatigue life prediction [37,38]. ...
This paper proposes an integrated methodology for fatigue assessment of existing metallic railway bridges, consisting of four sequential phases to be progressively implemented. Advanced fatigue life prediction tools based on local methods are suggested, aiming to analyse fatigue critical details, fully considering the local characteristics of the existing loading transference mechanisms. A real case study is investigated using the new integrated methodology, demonstrating the relevance of efficient local fatigue analyses in this context, as well as the importance of data resulting from the multiphase fatigue assessment for the management authorities to optimise the maintenance of existing railway bridges.
... It is therefore an ideal material for structural repairs, even for temporary repairs, which allow for the preparation of an optimal final solution without disturbing or limiting the use of the facility to a small extent. Reinforcement of composites for fatigue are already in the application research phase, but there are still few of them [3,4] Since the 1970 s, the use of composite materials has resulted in a promising technology in structural engineering, especially for the reinforcement of concrete, masonry and wooden structures [5]. The number of positive effects of composites application is also increasing when increasing the load-carrying capacity of steel elements and bridges. ...
Carbon fibre reinforced polymers (CFRPs) have been widely used in the last thirty years. The main issue in rehabilitation using CFRP, is the bond between steel member and CFRP composite. The impact of shaping the FRP composite bond end the joint load capacity is one of the issues on which attention is focused. Structure rehabilitation is considered when structures have damage, cracks or need raising the load-carrying capacity. The CFRP cross section that needs to be used for strengthening or rehabilitation is based on the size of the damage, crack thickness or missing cross-section necessary to transfer loads. This paper reports the experimental and numerical effects of CFRP bond end shape properties on the bond between CFRP laminate and steel members under quasi-static loading. Normal CFRP modulus, one CFRP section (20 x 1.4 mm) and eight bond end shapes were used in this research. The results show that small CFRP sections are very sensitive to evaluate the bond properties between CFRP and steel, and the the proper bond end shape have significant effects on the bond between CFRP and steel.
... The value of rotational stiffness used in the global FE model of Redondela Bridge was obtained from the moment-rotation curve of the stringer-floor beam connection in the local FE model that is analyzed in the next section. For this global FE model, nonlinear mechanical properties of the metallic material were not considered, since only service loads were applied in the model and bridge elements are expected to remain below yielding, as also reported in [23,24] for this type of analysis. Only elastic material properties of puddle iron were used, with a modulus of elasticity of 198 GPa and a Poisson coefficient of 0.30, according to a previous characterization of this material [9]. ...
... Based on a parametric study by the authors with different pretension values, it was obtained that pretension has marginal effect on rotational stiffness of the connection and strains in the connecting angle, as also previously reported [34,37], so a fixed value of σpret = 100 MPa is adopted in this work. This pretension is within the range values (between 50-200 MPa) of rivet pretension in field observations [5] and was also adopted by other authors for similar analysis [24]. This pretension was induced with a specified equivalent displacement applied to the face of the rivet/bolt shank at the cut coincident with symmetry planes (Figure 10b), being 0.0058 mm, 0.0099 mm and 0.0075 mm for stringer flanges rivets (4), connecting angle rivets (7) and bolts (9), respectively. ...
A local and global finite element analysis of the stringer-floor beam connection of a 19th century riveted railway bridge in Spain made of puddle iron were performed to obtain the maximum principal strains in the riveted connecting angles corresponding to bending moments from train loading on the bridge. Due to the anisotropic nature of puddle iron, the connecting angles were modelled using Hill anisotropic plasticity potential and a parametric study in the local FE model of the connection was performed. A laboratory specimen fabricated with original stringers dismantled from the railway bridge was tested to calibrate the numerical models, so the yield stress ratio that best fitted experimental results was obtained. Based on the method of constant fatigue-life diagram and modified Goodman fatigue failure criterion, it was detected that the connecting angles were prone to fatigue crack initiation, as the combination of mean stress and alternating stress amplitude at the toe of the angle fillet remained outside the infinite fatigue-life region. An innovative strengthening system based on adhesively-bonded carbon-fiber reinforced polymer (CFRP) angles was designed to prevent fatigue crack initiation in the connecting angles of the stringer-floor beam connection. Different CFRP laminate layouts were numerically evaluated and a proper configuration was obtained that reduced both the mean stress and the alternating stress amplitude in the connecting angle to shift from finite fatigue-life region to infinite fatigue-life region in the constant fatigue-life diagram. To validate the effectiveness of the proposed CFRP strengthening method, its application on a second laboratory specimen fabricated with original stringers was evaluated experimentally and compared with numerical results. The research study conducted showed that the use of adhesively-bonded CFRP angles was an effective strengthening system in reducing the stress level in the fillet region of the puddle iron connecting angles (where fatigue cracks are prone to initiate) and consequently could increase fatigue life of the stringer-floor beam connection.
... FRP plates can be effective by restoring the capacity of a damaged steel section or even strengthen it for higher loads than originally designed. Recent studies have shown that fatigue strengthening of steel members with FRP composites is promising, namely by delaying initial cracking, reducing the crack growth rate, extend the fatigue life and decrease the stiffness decay with residual deflection [6][7][8][9]. Strengthening using additional steel plates can be conducted using rivets, welding, high strength friction grip bolts or injection bolts, however the use of injection bolts has been considered as a better solution concerning their mechanical performance and protection against corrosion [10,11]. Injection bolts can be used to connect new steel plates but also to replace faulty rivets. ...
All over the world, the number of civil engineering structures, particularly bridges with long service periods, has been increasing. The most common evidences of damages are the presence of corroded metallic elements and cracks in structural details due to the fatigue phenomenon. A large number of cases were found in which fatigue cracks were detected in structural details, such as riveted connections. Different strategies can be implemented for repairing and strengthening operations of old metallic riveted bridges. However, the use of injection bolts has been considered as an alternative with important advantages. In this regard, it is essential to study their performance under fatigue loading. In this investigation, an experimental campaign has been performed to assess the fatigue strength of injection bolts by means of comparison with standard bolts. These fatigue tests are defined to be representative of a structural strengthening scenario of an old metallic bridge. Experimental results show that injection bolts contribute to significantly reduce the scatter in the data related to fatigue resistance. For double shear specimens, the characteristic curve proposed for connections with injection bolts presents a detail category with 15% higher value when compared to non-injected specimens. The beneficial effect is also verified in terms of slip deformation. For single shear specimens, the overall effect of the adhesive is not clear.
... Because of these characteristics, composites are widely applied in automotive, aeronautical, petrochemical, naval, electro-electronic, civil construction, energy, biomedical, sports and manufacturing industries, among others [1,5,14,15,[18][19][20]. Their applications can be seen in several industrial sectors; however, they are expensive and difficult to characterize due to their heterogeneity and laminate configurations, which affect their final properties. ...
... Vaz [201] points out that now that the curvatures associated with the deformations and are only null if presented in Equation (19). The author cites that when it is valid, by the Kirchhoff hypothesis the rotations θ are given by the derivatives of w. ...
The use of composite materials in several sectors, such as aeronautics and automotive, has been gaining distinction in recent years. However, due to their high costs, as well as unique characteristics, consequences of their heterogeneity, they present challenging gaps to be studied. As a result, the finite element method has been used as a way to analyze composite materials subjected to the most distinctive situations. Therefore, this work aims to approach the modeling of composite materials, focusing on material properties, failure criteria, types of elements and main application sectors. From the modeling point of view, different levels of modeling—micro, meso and macro, are presented. Regarding properties, different mechanical characteristics, theories and constitutive relationships involved to model these materials are presented. The text also discusses the types of elements most commonly used to simulate composites, which are solids, peel, plate and cohesive, as well as the various failure criteria developed and used for the simulation of these materials. In addition, the present article lists the main industrial sectors in which composite material simulation is used, and their gains from it, including aeronautics, aerospace, automotive, naval, energy, civil, sports, manufacturing and even electronics.
... A trapezoidal PUR (TPUR) system for the strengthening of metallic beam systems was developed and tested under static [13] and fatigue loading [14]. The system has been used for the fatigue strengthening of a 120-year-old riveted railway bridge in Switzerland [15,16]. Each bridge girder was strengthened with three CFRP plates, which were attached to the bridge girders using a pair of friction clamps. ...
This study gives an overview on carbon fibre-reinforced polymer (CFRP) strengthening and wireless sensor network (WSN) monitoring of a 121-year-old metallic roadway bridge in Melbourne, Australia. A flat prestressed unbonded retrofit (FPUR) system was developed to apply prestressed CFRP plates to the steel cross-girders of Diamond-Creek Bridge. The bridge is subjected to daily passenger and heavy truck vehicles. Sets of laboratory tests were performed to examine the efficiency and fatigue performance of the proposed FPUR system, prior to its installation on the bridge. Furthermore, in order to demonstrate the efficiency of the proposed retrofit technique, the bridge was instrumented with different types of sensors (including strain gauges, temperature and humidity sensors), and short-and long-term measurements were performed. As for short-term measurements, the bridge was loaded by a 42.5-tonne semi-trailer before and after strengthening. For the long-term monitoring, a WSN system was used to monitor the prestress level in the CFRP reinforcements for at least one year. The CFRP plates were prestressed up to about 980 MPa (38% of the CFRP ultimate strength), which resulted in about 50% reduction in the maximum tensile stress in the bottom flanges of the strengthened I-girders. The results of the short-and long-term measurements in this study showed that the proposed FPUR system can be very effective for flexural and fatigue strengthening of such bridge girders.
