Bruno Pedrosa

University of Porto | UP · Faculty of Engineering

Global approaches have been the main procedure for designing structural details and components under fatigue loading. This procedure is easy to apply but it disregards not only the effect of the material type but also the influence of the geometry. On the other hand, local approaches rely on the specific local parameters that can be assessed for ea...

Three different types (with glass, basalt and hybrid fibres) of composite rebars manufactured using the pultrusion process were loaded in four-point bending tests. All tests were carried out with acoustic emission sensors to better understand the mechanisms of damage. The data obtained were investigated using standard parameter analysis and also us...

Global approaches have been the main procedure to design structural details and components under fatigue loading. This procedure is easy to apply but it disregards not only the effect of the material type but also the influence of the geometry in complex components. On the other hand, local approaches rely on the specific local damage parameters th...

Fatigue crack growth modelling for S355 structural steel considering plasticity-induced crack-closure by means of UniGrow model, Abstract: The UniGrow model is an analytical procedure to assess the fatigue crack growth based on elastic-plastic crack tip stresses and strains. The assumption is that fatigue crack growth (FCG) can be considered as a p...

Injections bolts were initially conceptualized to repair riveted connections in bridges with long service lifetime and now they are widely used in steel and composite structures. Injecting steel-reinforced epoxy resin in bolted connections with oversized holes is a novel approach to enable fast and easy assembly of composite structures while limiti...

There is a significant number of old metallic bridges with high levels of structural degradation due to their long service period. Fatigue problems are especially important in these structures since the majority of them were not designed taking into account this phenomenon. Several investigations showed that riveted joints are critical details sinc...

Old metallic bridges are prone to high levels of structural degradation due to their long service life, therefore, it is essential to study strengthening techniques. Implementation of injection bolts to replace riveted joints exposed to fatigue damages has been studied. The mechanical performance of injection bolts has been studied mainly based on...

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 detec...

The paper deals with the subject of diagnostics and the quick repairs of long-term operated metallic materials. Special attention was paid to historical materials, where the structure (e.g., puddle iron) is different from modern structural steels. In such materials, the processes of microstructural degradation occur as a result of several decades o...

In North America and Europe, there is a significant number of centenary metallic bridges that require maintenance and strengthening operations. These structures need to be adapted to increasing traffic intensities, and their structural integrity should be constantly evaluated. Fatigue damages were not considered in the original design of old metall...

p>One key aspect related to structural integrity of bridges is the fatigue behavior of its materials and structural components. Generally, a fatigue crack initiates in zones where there is a concentration of stresses (geometric discontinuities, for example) and then it may propagate at an increasing growth rate leading to structural failure. Experi...

p>One important subject related to structural integrity studies of bridges is to assess the fatigue behaviour of its materials and structural components. A fatigue crack initiates in zones where there is a concentration of stresses and then it may propagate at an increasing growth rate leading to structural failure. Normally, a rehabilitation campa...

It is of high importance to develop innovative strengthening and rehabilitation operations for bridges whose design life is coming to an end. A case study concerning the centenary Portela road bridge in Coimbra is addressed. In situ experiments were performed in order to obtain a modal identification of the structure. The data was used to elaborate...

Traffic patterns increasing and the degradation of existing roadway steel bridges due to poor maintenance has led to the need of an assessment deciding whether to retrofit or to supply a structure replacement. This paper focusses on the rehabilitation of steel truss bridges in order to extend the lifetime of such bridges. Two case studies are prese...

Injection bolts have been used to replace faulty rivets on strengthening operations of old riveted steel bridges. This technology has been essentially tested for its quasi-static or creep behaviour and there are very few studies concerned the assessment of its fatigue resistance. This paper presents an experimental program developed to evaluate the...

This article presents experimental results of steel truss nodes strengthened/refurbished with concrete encasement. Four strengthened specimens are tested in total, two encased in normal class concrete and two encased in high strength concrete C80/95. The results obtained are compared with one reference bare steel node test. All specimens are loaded...

Fatigue failures are a concern for old riveted steel bridges since most of them were not originally designed taking into account fatigue. The usual fatigue assessment approach for riveted joints consists of using the fatigue class 71 S-N curve proposed in Eurocode 3, part 1-9. However, this approach may lead to excessive conservative predictions si...

The problem considered in this paper is the structural integrity of old materials from the 19th century by means of fatigue crack growth problem. The authors present an overview of the fatigue fracture properties of old puddle iron members extracted from long-term operated bridges located in France. The fracture properties and fatigue crack growth...

The maintenance and safety of ancient bridges is a major concern of governmental authorities. In particular, the safety of old riveted bridges fabricated and placed into service at the end of the 19th century deserves particular attention. These structures are susceptible to exhibit high fatigue damage levels due to their long operational period wi...

In the old steel truss bridges one particular point of interest are the nodes. While for strengthening/refurbishment of the elements of the truss engineers can rely on more conventional methods, usually, for the nodes unique solutions have to be adopted. One integral solution, which could be implemented in a variety of steel truss nodes, is strengt...

Maintenance and safety assurance of old riveted bridges designed in the period which steel has become an economically viable material for bridge construction, i.e., between the end of the 19th and the beginning of the 20th century, deserve special attention. These structures are prone to present high levels of structural degradation due to their lo...

Different strategies can be used to perform reparations and reinforcements of ancient bolted and riveted metallic bridges. As the riveting process is not currently a common practice, it requires proper equipment and skilled workers. Another solution is the use of welding. However, the weldability of old steels is poor. Bolts are very attractive alt...

The behaviour of standard bolted steel connections submitted to monotonic loads, through the use of numerical models, is presented in the current paper. The bolted connections allow speed up constructive processes in an increasingly competitive and globalized world in which the costs are a decisive factor in the development of a project. The use of...

Among the strategies that can be implemented for repairing and strengthening operations of old metallic structures, using structural adhesives to improve the fatigue strength of steel connections has been considered as a good solution. It is expected that the adhesive help to distribute and to transfer the load over a large area, thus reducing stre...

A considerable number of numerical simulations have been implemented aiming to understand the behaviour of riveted and bolted connections under static and fatigue loading conditions and stablish a comparison. Different methodologies can be used concerning the definition of the finite element, the contact algorithm and the clamping stresses. Regardi...

This paper focuses on the fatigue characterization of Sikadur®-30 and Sikadur®-52, adhesives/resins used to fill the gap between the bolt and plates of metallic connections. The fatigue tests of the resins under study were performed according to ASTM D7791-12 standard. This standard allowed to obtain the cyclic elastoplastic fatigue behaviour of th...

Inspections of ancient metallic bridges have illustrated fatigue cracking in riveted connections. This paper presents a comparison between two alternative finite element (FE) models proposed to predict the fatigue strength of a single shear and single rivet connection. The first model is based on solid finite elements as well as on contact elements...

In Portugal there is a number of old metallic riveted railway and highway bridges that were erected by the end of the 19 th century and beginning of the 20 th century, and are still in operation, requiring inspections and remediation measures to overcome fatigue damage. Residual fatigue life predictions should be based on actual fatigue data from b...

Among the different strategies that can be implemented in the repairing and strengthening operations of old riveted steel bridges, resin-injected bolts have been used to replace faulty rivets and preserve the slip resistance of the joint. This technology is preferred since it only requires a standard preparation of the holes and its structural perf...

This paper has as main theme the characterization of the monotonic and fatigue behaviour of structural adhesives/resins used in repairing and maintaining of old metallic bridges. This study aims essentially at the mechanical characterization of structural adhesives/resins, such as, Sikadur®-30 and Sikadur®-52, used to fill the gap between the bolt...

Different strategies can be implemented in the repairing and strengthening operations of old riveted steel bridges. Riveting is no longer common practice, consequently finding good equipment and skilled riveters is difficult. The use of welding may not be considered due to the poor weldability properties of the old steel. Regarding high strength fr...