Peter Collin

Integral Abutment Bridges: the European Way

Integral abutment bridges are becoming more popular in Europe, but the traditions differ from country to country. This leads to different technical solutions for the same problem in each country. A European survey was conducted in early 2007 to illustrate the design criteria used by each different country for integral abutment bridges. The survey requested information useful to a designer comparing the design requirements and restrictions of various European countries. As an added measure of comparison, these results were compared to some recently conducted surveys of state agencies within the United States. When looking at the results of the European survey responses and past surveys of U.S. transportation agencies, it is clear that there are many similarities in design assumptions and construction practices. Yet, there are also significant differences.

Monitoring of a Swedish Integral Abutment Bridge

Abstract One of the most commonly discussed problems regarding bridges with integral abutments is the influence of longitudinal elongation of the superstructure as a result of seasonal temperature variations. A bridge built with integral abutments is often supported by a row of piles made of steel or concrete. The longitudinal elongation of the superstructure induces a displacement and a rotation at the top of the pile, which in turn may cause strains that exceeds the yield strain. Such seasonal variations may lead to low-cyclic fatigue failure in the pile. Therefore, it is of great interest to investigate the amplitude of these strains, as well as the general behaviour of the bridge. In 2005, the European R&D project, INTAB (RFSR-CT-2005-00041, “Economic and Durable Design of Bridges with Integral Abutments, 2005–2008”) was started. Within the INTAB project a composite bridge was built and monitored in Northern Sweden.

Prefabricated Bridge Construction across Europe and America

AbstractDetermining the most efficient and economical way to build a new or replacement bridge is not as straightforward a process as it once was. The total cost of a bridge project is not limited to the amount spent on concrete, steel, and labor. Construction activities disrupt the typical flow of traffic around the project and results in additional costs to the public in the form of longer wait times, additional mileage traveled to get around the work zone, or business lost attributable to customers avoiding the construction. The risk of injury to workers because of traffic interactions or construction activities increase with each hour spent at the construction site. Finding a way to shorten the time spent on the jobsite is beneficial to the contractor, the owner, and the traveling public. Prefabricating certain bridge elements reduces the time spent at the construction site and reduces the effects on the road users and the surrounding community. For example, steel beams with composite concrete decks r...

Undermatching Butt Welds in High Strength Steel

The effects of different weld geometries on the mechanical properties of undermatched welds in high strength steel have been studied experimentally. Static tension- and hardness tests have been performed on 30 individual test specimens. Three parameters were chosen to be studied; width- to thickness relation, undermatching level and the ratio between the width of the weld and the thickness of the steel plate (relative thickness). The conclusion is that the weld width and volume has a strong influence on the strength of the joint, this is due to constraint. Fractures were achieved in the base metal for joints undermatched as much as 23 %. These seemingly surprising results are explained theoretically using incremental plasticity theory.

A new analytical model of inelastic local flange buckling

Abstract This paper deals with analytical modelling of inelastic local flange buckling of compressed I-beam flanges. A short discussion of the relevance of different constitutive models for the inelastic material behaviour is carried out. It is claimed that what is known as the ‘plastic buckling paradox’ is not at all a paradox but a result of improper use of plasticity theory. An analytical model for the inelastic local buckling of an I-beam flange is proposed. The model considers the buckling process as being composed of two parts. The first is associated with inelastic torsional buckling of a compressed flange and the second part corresponds to a yield line plate buckling configuration which includes the effect of stress redistribution due to large deformations. The transition between these phases is left out in the model. The model is capable of predicting approximately the force-deformation relation of a locally buckling stocky flange for different stress-strain relations. The model is evaluated against experiments and the agreement is found quite reasonable.

Monitoring of a Bridge with Integral Abutment

Preliminary results obtained from short term test-loading are used to illustrate possibilities of FEM used to calibrate complex interaction characteristics between a pile and soil in a bridge with integral abutments. The measurements are obtained during the winter season on the bridge over Ledan, Northern Sweden. The bridge is built in 2006 and used for long term monitoring within the international project supported by RFCS. The main objective of the on-going research project is to proposed recommendations for rational analysis and design of bridges with integral abutments.

Composite Bridges with Integral Abutments Minimizing Lifetime Cost

The cost of maintenance is an ever- growing problem for road administrations around the world, and bridges are no exception to the rule. One way to reduce the need for future maintenance, as well a ...

Innovative Prefabricated Composite Bridges

Summary The competitiveness of composite bridges depends on several circumstances such as site conditions, local costs of material and staff and the contractor’s experience. One major advantage compared to concrete bridges is that the steel girders can carry the weight of the formwork and the wet concrete. Another advantage is the savings in construction time, which saves some money for the contractor but even more so for the road users, a fact that usually is neglected when evaluating alternative bridge designs. A further step to improve the competitiveness of composite bridges is to prefabricate not only the steel girders, but also the concrete deck. In this paper a new concept with dry joints between the elements is described. Keywords : Composite bridges, prefabricated decks, deck elements, full scale testing. 1. Introduction Composite bridges have become a popular solution in many countries [1], [2]. The competitiveness of composite bridges depends on several circumstances such as site conditions, local costs of material and staff and the contractor’s experience. One major advantage compared to concrete bridges is that the steel girders can carry the weight of the formwork and the wet concrete, which means that the need for temporary structures is reduced, as indicated in Figure 1 and 2.

Lateral-torsional buckling of continuous bridge girders

Abstract The resistance of bridge girders with respect to lateral-torsional buckling at support is strongly influenced by the moment gradient. In most design methods this influence is taken into account by the use of a correct critical bending moment in the slenderness parameter λ. This critical moment is influenced by the shape of the moment diagram as well as the distortion of the cross-section and the restraint from the web and stiffeners, if any. In this paper, a method for the calculation of the critical moment is presented. A further effect of the moment gradient is that the stresses due to lateral bending of the flange in connection with lateral-torsional buckling does not coincide with the maximum of stresses caused by bending in the vertical plane. This is taken into account by performing the check for lateral-torsional buckling in a design section at some distance from the support. A design procedure based on this concept has been introduced in Eurocode 3 Part 2: Steel Bridges.

The behaviour of a prefabricated composite bridge with dry deck joints

Abstract This paper describes the monitoring of a one-span composite bridge in northern Sweden. The bridge was built in 2000, with prefabricated deck elements connected to steel girders, and the back walls as well as the piers were also prefabricated. The monitoring was required to clarify the doubts regarding whether a bridge with dry deck joints can be expected to perform as a conventional composite bridge, with in situ cast deck and sections with sagging moments. To get a better understanding of the long-term structural behaviour, the bridge was monitored both during 2001 and 2011, instrumented with equipment measuring the deflections and strains in the steel cross section. The bridge was loaded with a truck in midspan having a total weight of 25 t. When the truck was centred between the girders, the results showed a symmetric behaviour, with respect to deflections and stresses. For the case with the truck stationed right above one of the steel girders, anti-symmetric behaviour was observed and studied by means of finite element calculations, taking into account the stiffness of the composite section as well as the end screens and the earth pressure below them.