Dániel Honfi

City of Stockholm · Transport Department

In many design situations the acceptable performance of structures is defined by serviceability requirements. To estimate the probability of serviceability failure three main design aspects should be considered: (1) the relevant exposures, (2) the structural response and (3) the performance criteria. This thesis presents background information and...

To achieve a relatively consistent probability of failure for structural elements, most design codes apply reliability based code calibration process. Such approaches commonly focus on the strength of the structural members, which is related to the ultimate limit state (ULS). However in the design of beams the performance of the structural elements...

Serviceability of structures has to be verified for a lower load level than the design load used for safety considerations. Representative values of actions used in serviceability load combinations are often defined in a way that the fraction of time spent above a given load level should be limited to a certain value. To determine these load levels...

In order to achieve a consistent level of failure probability, structural design codes are optimized using probabilistic methods. This optimization process traditionally focuses on the ultimate limit states (ULS). However, in the design of timber structures the performance of the structural members is often governed by the serviceability limit stat...

The condition assessment of bridges considers a combination of information from different sources rendering multiple levels of assessment possible. This paper illustrates how successive condition assessment strategies increase the expected utility compared to single choice decisions through Bayesian inference. Multiple levels of assessment allow fo...

Despite much research and applications, glass material and its use in buildings is still challenging for engineers due to its inherent brittleness and characteristic features such as sensitivity to stress concentrations, reduction in strength over time and from temperature, and breakage due to the stresses that may build up because of thermal gradi...

Risk assessment in communities or regions typically relies on the determination of hazard scenarios and an evaluation of their impact on local systems and structures. One of the challenges of risk assessment for infrastructure operators is how to identify the most critical scenarios that are likely to represent unacceptable risks to such assets in...

The impact of climate change on the deterioration of reinforced concrete elements have been frequently highlighted as worthy of investigation. This article addresses this important issue by presenting a time-variant reliability analysis to assess the effect of climate change on four limit states; the probabilities of corrosion initiation, crack ini...

Safety and security of critical infrastructure networks is one of today’s top priorities, as they are getting increasingly complex and interdependent. Thus, their potential failure due to unforeseen and extreme events may result in excessive direct and indirect losses. Recently, focus has shifted from protection to resilience, i.e. the ability of a...

Exceptional loads on buildings and structures are known to take origin and manifest from different causes, like natural hazards and possible high-strain dynamic effects, human-made attacks and impact issues for load-bearing components, possible accidents, and even unfavorable/extreme operational conditions [...]

Recent studies have identified many potential climate change impacts on bridges. Considering the sheer number of these potential impacts, how can a bridge owner prioritize which impacts to consider, and for which bridges? This paper proposes a risk-based multi-criteria decision analysis method for systematically addressing these two questions simul...

A recent research project investigating the structural safety of self-supporting glass components aims to contribute to the development of future guidelines for architectural glazing applications. A specific task within the project was concerned with extending the current knowledge about the effect of impact loading and related testing methods rega...

The potential risks of climate change on the built environment involve large uncertainties. This poses an intricate problem to designers and challenges a long-standing tradition of built infrastructure design. More specifically, designers are faced with this challenging question: how to rationally account for climate change risks when designing a n...

The presented project aims to develop prototypes for building connections inspired by the furniture and interior industry and explore them with representatives from the timber construction industry. The long-term vision is that actors from furniture and building industry together develop a smart system for assembly of building elements, which provi...

Risk assessment in communities or regions typically relies on the determination of hazard scenarios and an evaluation of their impact on local systems and structures. One of the challenges of risk assessment for infrastructure operators is how to identify the most critical scenarios that are likely to represent unacceptable risks to such assets in...

For practical decisions on common recurring maintenance actions, the information from routine inspections form a decision basis for the bridge manager. It is often difficult to assess whether this information is sufficient for deciding on a repair action, or if more information is needed. For many bridges the information for supporting decisions ma...

Exceptional loads on buildings and structures may have different causes, including high-strain dynamic effects due to natural hazards, man-made attacks, and accidents, as well as extreme operational conditions (severe temperature variations, humidity, etc [...]

Glass structures have been increasingly utilised in modern construction for decades with load-bearing walls or facades as the most common elements. However, the use of glass beams has recently been given more attention but its application as load-bearing elements has been limited by the low tensile resistance, its brittle behaviour during failure a...

This review paper analyzes factors affecting emergency response to hazardous events on highways and their bridges, with focus on man-made and natural scenarios: heavy vehicle collision with a bridge, earthquake, heavy snowfall and flooding. For each disaster scenario, selected historical events were compiled to determine influential factors and suc...

This review article analyzes factors affecting emergency response to hazardous events on highways and their bridges, with focus on man-made and natural scenarios: heavy vehicle collision with a bridge, earthquake, heavy snowfall, and flooding. For each disaster scenario, selected historical events were compiled to determine influential factors and...

A Multi-Level Assessment Strategy has previously been proposed and proved feasible for structural analysis of existing RC slabs. In this paper, the Multi-Level Assessment Strategy, which focuses on sophisticated structural analysis, was used to investigate the load-carrying capacity and structural behaviour of a composite bridge with an RC bridge d...

There is a deficit of housing in Sweden and it is built too little to compensate for this according to the National Board of Housing, Building and Planning, which, among other things, indicate resource shortages as a reason. The furniture and construction industry have much in common. However, the furniture industry has a larger share of industrial...

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 infrastructure is paramount in determining appropriate adaptation and risk management strategies. Despite gaining some attention among researchers in recent years,...

An essential aspect in the maintenance of existing bridges is the ability to adequately and accurately assess and evaluate the condition of the structure. Condition assessments, which can be carried out in any number of ways, provide valuable information concerning the actual state of a bridge, including the severity of potential damages, and form...

Dowel-type connections in timber structures should be typically designed in a way that, if the load bearing capacity is exceeded, desirable ductile failure should likely occur, i.e. yielding of the metal dowel or embedment of the timber. However, the probability of brittle failures cannot be completely avoided in many cases. If the connection is lo...

Many of modern life activities involve the risk of fire, explosions, and impacts. In addition, natural extreme events are becoming more and more common. Thus, robustness, the ability to avoid disproportionate collapse due to an initial damage, and resilience, the ability to adapt to and recover from the effects of changing external conditions, repr...

Given their intrinsic features, adaptive facades are required to satisfy rigid structural performances, in addition to typical insulation, thermal and energy requirements. These include a minimum of safety and serviceability levels under ordinary design loads, durability, robustness, fire resistance, capacity to sustain severe seismic events or oth...

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 changes involve large uncertainties, the fact that our climate is changing is unequivocal. To ensure an unimpaired functionality of our societies,it is the...

Adaptive facades are increasingly used in modern buildings, where they can take the form of complex systems and manifest their adaptivity in several ways. Adaptive envelopes must meet the requirements defined by structural considerations, which include structural safety, serviceability, durability, robustness and fire safety. For these novel skins,...

The construction and usage of transport infrastructure are major causes of greenhouse gas emissions and energy consumption. The effects of resource consumption and pollutant emissions are often quantified through Life Cycle Assessment (LCA) models. All decisions made in infrastructure projects during the whole life cycle are afflicted by uncertaint...

Many reinforced concrete bridges in Europe and around the world are damaged by reinforcement corrosion and the annual maintenance costs are enormous. It is therefore important to develop reliable methods to assess the structural capacity of corroded reinforced concrete structures and avoid unnecessary maintenance costs. Although there are advanced...

p>Climate change and its impacts on infrastructures may seriously affect the functionality of societies. Despite the alarming potential consequences climate change pose, not enough effort has been directed towards averting these impacts or managing them in some other way (e.g. mitigation, reduction, etc.). Well-functioning infrastructure networks p...

https://portal.research.lu.se/portal/en/publications/klimatfoerandringars-inverkan-paa-broars-sakerhet-och-prestanda(3f8c0a3c-7e2c-42e5-bc42-4f71f0ec43da).html

p>Practicing structural engineers may be familiar with the main principles of structural reliability but may not necessarily be experts in using such methods. This may lead to a lack in understanding the effect of uncertainties on the ensuing structural safety and to sub-optimization of more traditional structural engineering aspects. The aim of th...

p>Condition assessment of existing timber structures is typically followed by a decision about intervention options, and consequently comparing various possible scenarios. These decisions are based on the updated knowledge obtained through the assessment. Condition assessments, however, can be done in multiple ways, e.g. basic visual assessment of...

p>In this contribution a practical and rational decision-making approach is presented to be applied for common bridges typically managed by public authorities. The authors have developed a model with the intention to be applicable for practical cases for common bridges in the daily work of bride operators responsible for a large number of assets, y...

When assessing the resilience of road transport networks, users' response should be considered as they represent the main capability of the system to adapt to changes when any disruptive event occurs and to recover afterwards. Given the variability in users' response, it seems deterministic approaches might not be adequate to represent the real sys...

Nowadays, glass is increasingly being used as a load-bearing material for structural components in buildings and façades. Different structural member solutions (such as panels, beams, columns) and loading conditions were the subjects of several research studies in recent years. Most of them, however, were typically limited to experimental testing an...

Adaptive facades are getting more and more widespread in modern buildings. These facade systems, among many others, need to fulfil the requirements of several structural considerations, such as structural safety, serviceability, durability, robustness and fire safety, being typically defined for standard facades and building enclosures in general....

The use of glass as a structural material has increased in the built environment over the last decades. Despite the large number of research projects and studies, it still poses difficulties in structural design. This particularly applies to the behaviour of glass in fire and under elevated temperatures since the available data on temperature depen...

This report is a publication of the European Network COST FP1402 Basis of Structural Timber Design - from research to standards. The aim of the Action was to overcome the gap between broadly available scientific results and the specific information needed by designers, industry, authorities and code committees, providing transfer for practical appl...

Glass is largely used in architectural and engineering applications (i.e., buildings and vehicles) as a structural material, especially in the form of laminated glass (LG) sections. To achieve adequate and controlled safety levels in these applications, the well-known temperature-dependent behavior of viscoelastic interlayers for LG sections should...

Adaptive facades are getting more and more widespread in modern buildings. These facade systems, among many others, need to fulfil the requirements of several structural considerations, such as structural safety, serviceability, durability, robustness and fire safety, being typically defined for standard facades and building enclosures in general....

For most applications trying to interpret the real world uncertainties will be an important factor to consider, which is also true for Life-Cycle Assessment used for estimating total environmental impact during the life-cycle of products, services, buildings, structures, roads etc. The construction and usage of infrastructure are major causes of em...

Adaptive facade systems are getting increasingly common in modern buildings envelopes. Their adaptive behaviour poses special requirements concerning structural aspects of the façade. In the present paper, an overview of the possible classification of structurally adaptive facades and related requirements is given. Furthermore, it is discussed how...

Many bridges are approaching or have already passed their expected service life. For steel bridges, fatigue is often the decisive degradation phenomenon that theoretically puts restrictions on a continued use. At the same time, fatigue is also afflicted with large uncertainties on the resistance side as well as on the action effect side. An accurat...

Glass has been overwhelmingly used for windows and facades in modern constructions, for many practical reasons, including thermal, energy, light and aesthetics. Nevertheless, due to the relatively low tensile strength and mostly brittle behaviour of glass, compared to other traditional materials, as well as to a multitude of interacting structural...

Corrosion of steel reinforcement is a common cause of deterioration in reinforced concrete bridges and many existing bridges are damaged to varying degrees. The rate of deterioration of the bridge stock has been shown to increase due to climate change. Unsympathetically, the demand for load-carrying capacity is however often increased with time. Th...

p>Advanced inspection techniques, non-destructive (NDT) and semi-destructive (SDT) testing methods and structural health monitoring (SHM) are increasingly important for the preservation of both old and new timber structures. However, e.g. the application of SHM within the context of timber structures is not adequately represented in strategic docum...

Modern building envelopes are high-tech components that must meet requirements and constraints regarding architecture/urban planning/aesthetics, energy efficiency, indoor environmental quality, buildability and value. If a facade can respond to all the transient conditions while maintaining occupant satisfaction without imposing additional loads on...

The paper presents the first steps of the development of a theoretical framework for a rational yet practical decision making process concerning the condition assessment of existing bridges in Sweden. The main focus is on how to choose the appropriate level of enhanced conditions assessment considering aspects of model sophistication, uncertainty c...

It is vital to extend the service life of existing bridges as far as possible as a means for improved sustainability leading to reduced economic cost and resource consumption. This requirement is especially valid for bridges which are critical components of highly vulnerable infrastructure systems. Achieving this aim requires enhanced methods invol...

p>Maintenance of transportation infrastructure assets can be relatively expensive, since it does not only include the direct cost of interventions, but also the indirect consequences of traffic disruptions. To make optimal decisions about maintenance actions, including rehabilitation and upgrading, reliable information about the performance of exis...

The SESBE research project aims to develop novel smart sandwich façade elements with high insulating capabilities while providing a reduced thickness in conjunction with superior mechanical and durability properties. The present paper mainly focuses on the verification of the mechanical performance of the glass fibre reinforced polymer (GFRP) conne...

Glass is seeing a growing interest as a structural material as a result of its relatively good strength to weight ratio and the obvious aesthetic benefits of its use in buildings. However due to the sensitivity of glass to thermal shock and the considerably temperature-dependent behaviour of interlayer materials as a result of their visco-elastic n...

There is an increasing need for reliable methods to assess load-carrying capacity and remaining service life of existing infrastructure. Several previous research projects have resulted in a verified, simple 1D model for assessment of anchorage in corroded reinforced concrete structures. Previous verification has involved both experiments and detai...

This report outlines the fundamentals of hazard mapping, beginning with the 4 steps needed for hazard mapping: 1) the identification of the hazard in question and the region; 2) the specification and temporal description of the hazard; 3) the definition of the probability of occurrence of the hazard; and finally 4) the definition of the hazards’ in...

A systematic testing and modelling program has been developed for the verification of the structural performance of facade sandwich elements to take structural aspects into consideration in the SESBE research project, focusing on the development of “smart” facade elements. The present paper mainly focuses on the verification of the mechanical perfo...