Ivar Björnsson

Bio: Ivar Björnsson is an academic researcher from Lund University. The author has contributed to research in topics: Climate change & Decision support system. The author has an hindex of 7, co-authored 30 publications receiving 147 citations.

A review of the potential impacts of climate change on the safety and performance of bridges

Abstract: An overabundance of evidence, both observational and from model projections, indicate that changes to the climate system are taking place at unprecedented rates. Although the magnitudes of these ch...

Bridges in a changing climate: a study of the potential impacts of climate change on bridges and their possible adaptations

Abstract: Climate change may have multifaceted impacts on the safety and performance of infrastructure. Accounting for the different ways in which potential climate change scenarios can affect our infrastruc...

Determining Appropriate Design Impact Loads to Roadside Structures Using Stochastic Modeling

Abstract: The design and verification of built structures requires structural engineers to consider accidental loading situations. The accidental loading situation investigated in this paper is heavy-goods vehicle (HGV) collisions with roadside structures; focus is on the design of bridge-supporting structures. The impact loads were determined from Monte Carlo simulations of a probabilistic model in which highway traffic measurements and accident statistics in Sweden are input. These loads were calculated for structures adjacent to straight roads as well as roads with curvature, and include considerations of the directional load components. Comparisons were made between the simulation results and approaches given in design codes, with focus on the Eurocode. The simplified approaches provided in the code were inadequate in their treatment of these design situations. Alternative equations for calculating impact forces and energies are presented. These equations can be used for determining design values for impact forces or for conducting probability/risk-based assessments of bridge supports subjected to HGV impacts. In this way, a more consistent treatment of HGV impacts in the design of bridge structures is achieved.

Strategies to adapt to an uncertain climate change

Abstract: Many decisions concerning long-lived investments already need to take into account climate change. But doing so is not easy for at least two reasons. First, due to the rate of climate change, new infrastructure will have to be able to cope with a large range of changing climate conditions, which will make design more difficult and construction more expensive. Second, uncertainty in future climate makes it impossible to directly use the output of a single climate model as an input for infrastructure design, and there are good reasons to think that the needed climate information will not be available soon. Instead of optimizing based on the climate conditions projected by models, therefore, future infrastructure should be made more robust to possible changes in climate conditions. This aim implies that users of climate information must also change their practices and decision-making frameworks, for instance by adapting the uncertainty-management methods they currently apply to exchange rates or RD (ii) favouring reversible and flexible options; (iii) buying “safety margins” in new investments; (iv) promoting soft adaptation strategies, including long-term prospective; and (v) reducing decision time horizons. Moreover, it is essential to consider both negative and positive side-effects and externalities of adaptation measures. Adaptation–mitigation interactions also call for integrated design and assessment of adaptation and mitigation policies, which are often developed by distinct communities.

Performance Indicators for Structural Systems and Infrastructure Networks

Abstract: Establishing consistent criteria for assessing the performance of structural systems and infrastructure networks is a critical component of communities’ efforts to optimize investment decisions for the upkeep and renewal of the built environment. Although member-level performance and reliability assessment procedures are currently well-established, it is widely recognized that a member-oriented approach does not necessarily lead to an efficient utilization of limited resources when making decisions related to the management of existing deteriorating structures or lifeline systems, especially those that may be exposed to extreme events. For this reason, researchers have renewed their interests in developing system-level assessment methods as a basis to modern structural and infrastructure performance evaluation and design processes. Specifically, system-level performance metrics and characteristics such as reliability, redundancy, robustness, resilience, and risk continue to be refined. The objecti...

The Science behind Scour at Bridge Foundations: A Review

Abstract: Foundation scour is among the main causes of bridge collapse worldwide, resulting in significant direct and indirect losses. A vast amount of research has been carried out during the last decades on the physics and modelling of this phenomenon. The purpose of this paper is, therefore, to provide an up-to-date, comprehensive, and holistic literature review of the problem of scour at bridge foundations, with a focus on the following topics: (i) sediment particle motion; (ii) physical modelling and controlling dimensionless scour parameters; (iii) scour estimates encompassing empirical models, numerical frameworks, data-driven methods, and non-deterministic approaches; (iv) bridge scour monitoring including successful examples of case studies; (v) current approach for assessment and design of bridges against scour; and, (vi) research needs and future avenues.