Civil and Structural Engineering research group

Concrete structures and technology

Cracking behaviour of reinforced concrete structures

Cracking has a significant impact on the durability of reinforced concrete structures causing high intervention and/or repair costs. There are numerous causes for initiating the cracking over concrete surfaces. During our research, cracking behaviour of reinforced concrete structures due to service load is investigated using experimental campaign and nonlinear finite element simulations.

Condition assessment and control of structures

Condition assessment of the existing structures covers the area of inspection, detail assessment and repair/rehabilitation of the structures. Reinforced/pre-stressed concrete structures are deteriorated with time due to different deterioration mechanisms. The corrosion of the rebars/pre-stressing tendons is one of the deterioration due to chloride ingress and carbonation. Our research team studies the condition of the reinforced concrete structures which are subjected to chloride ingress and carbonation. We also conduct research on the strengthening of reinforced concrete beams using CFRP composites.

Green transition; environmentally friendly building materials and applications

The practice of linear material consumption has been increasing due to the growth of the economy, population, and urbanization. As a result, substantial waste is released to the environment. A significant amount of waste is dumped in landfill without an assessment of opportunities to convert it into valuable materials/products. We research on the potential use of industrial waste to make geopolymer concrete and the use of recycled fibre instead of commercially available steel fibres. We collaborate with internally with Department of Energy and Petroleum Engineering, UiS and externally with Manchester University, UK and University of Hokkaido, Japan to develop geopolymers for construction industry.

Optimization and digitalization structural engineering applications

Generative design, machine learning methods and Building Information Modelling (BIM) help to optimize the structural design. We investigate how to integrate different digital tools to optimize the structural design effectively and efficiently.

Development of low carbon concrete and damage evolution due to cyclic loading

Offshore gravity-based structures and in particular wind turbine foundations are subjected to cyclic loading during its service life. We conduct research on the durability and mechanical properties of the low carbon concrete by considering possible damage evolution in the concrete under cyclic loading. During this research, we collaborate internally with Department of Energy and Petroleum Engineering, UiS and externally with Manchester University, UK.

Contact:

• Professor Samindi Samarakoon
• Adjunct Professor Kjell Tore Fosså
• University lector Guillermo Rojas Orts

Wind Engineering and Extreme Loads

Wind effects on structures

We work with the modelling of wind loads due to turbulence and the wind-induced response of long-span bridges. We integrate the computational and the experimental studies. Since 2013, we have been developing the full-scale wind and vibration laboratory at the Lysefjord bridge outside of Stavanger, with support from the Norwegian Publica Roads Administration. The measurements address the knowledge gaps on wind characteristics in a complex fjord environment and the full-scale bridge aerodynamics. The analyses of the recorded ambient vibration data include identification of built-in structural dynamic properties, heavy vehicle tracking etc. The monitoring system is described here.

In collaboration with our research partners (Technical University of Denmark, University of Bergen and NORCE) we have pioneered applications of lidar wind measurements at a bridge site. We use optical wind sensing to map the undisturbed wind turbulence and to monitor the wind-bridge interaction in the areas inaccessible by traditional sonic anemometry.

Our related work concerns aerodynamics of bridge stay cables in the so-called drag-crises range and a study of the rain-wind induced stay cable vibrations.
We also work with wind load and response modelling of floating bridges and offshore wind turbines.

Extreme loads on structures

Our work aims to understand the dynamic behaviour of structures under extreme loads and to design the structures against such loads. Our research covers a wide range of civil and marine structures including bridges, tunnels, wind turbines, ships, pipelines, and offshore platforms. We mainly work on blast and impact loads on structures, and structural response under multi-hazards through experimental tests and numerical simulations.

We also investigate material behaviours under dynamic loads. Concrete and steel materials are the main focus while other materials including FRP, timber, aluminium, and glass are also of interest. More information: https://www.ux.uis.no/~yanyan19/

Contact:

• Professor Jasna Bogunovic Jakobsen
• Associate professor Yanyan Sha
• Professor Jonas Snæbjørnsson
• Adjunct Professor Jungao Wang

Fatigue and structural integrity

Some of the members of structural engineering group are active researchers of the fatigue and structural integrity research group Fatigue and Structural Integrity Group (FSIG-UiS).

Assessment of structures and life extension

Responsible authorities for onshore and offshore structures are paying significant attention to the ageing issues, as most of these structures worldwide are reaching or have already exceeded their design life. Replacement of all of these is challenging, due to environmental and economic issues during both the decommissioning and the new construction. The cost for strengthening and extending the lives of bridges are less than 5% of the total cost for new constructions. Fatigue and environment-assisted (EA) degradation are identified as the main ageing mechanisms for these structures (i.e. fatigue & corrosion damages of offshore structures: 25% and 8% respectively; fatigue & EA damages of bridges in Europe: 38% and 32% respectively).To fill the research and knowledge gaps in this area, we are doing research on, (i) Structural integrity management and life extension guidelines, (ii) Improvement of stress-life approach and multiaxial fatigue damage models, (iii) Practices for the assessment of defects in pipelines and fracture control concepts, (iv) development of fatigue damage assessment and modelling techniques/tools for structural details, (v) development of frameworks for recognizing and analyzing the effect of EA damages of steels structures, (vi) Investigation of hydrogen embrittlement susceptibility of structural steel, (vii) Improvement of digital twin-based process for facilitating and optimizing the process of structural integrity assessment.

Sustainable and environmentally friendly structures

The steel and concrete industry require quite a lot of energy which significantly affect the global CO₂ emissions. Therefore, alternative building materials are currently of high importance for environmentally friendly structures. Timber, Aluminum and composites are few of the possible green building materials and is currently used in green building projects. To fill the research and knowledge gaps related to integrity aspects within this area and the competence development in the industry, our team is currently working on (i) structural integrity assessment of additively manufactured materials and components, (ii) fatigue assessment of long-span bridges with an orthotropic aluminium deck, (iii) assessment of load capacity and structural response of timber-concrete composite components. Recently started to conduct research on (i) developing the guidelines for re-using offshore steel for structural components of environmentally friendly buildings.

Structural integrity for renewable energy

Our research group recently started to conduct research and development activities related to green energy sector based on existing research competences in our group within fatigue and fracture of offshore pipelines and EA cracking of structures. The new topic areas are (i) Integrity assessment of offshore pipelines for Norwegian carbon capture and storage and hydrogen transport, (ii) studying the fatigue life assessment of a wind turbine substructure due to the effect environmental assisted cracking.

Contact:

• Emeritus Professor Ivar Langen
• Professor Kenneth Macdonald
• Adjunct Professor Gerhard Ersdal
• Professor Sudath Siriwardane
• Associate professor Nirosha Adasooriya
• Associate professor Fredrik Bjørheim