- Trial lecture starts at 10.15
- Public defence starts at 12.15
Title of trial lecture: Mechanically consistent determination of minimum reinforcement in prestressed concrete box girders
Assessment committee:
- First Opponent: Professor Ekkehard Fehling, University of Kassel, Germany
- Second Opponent: Professor Samindi Samarakoon, University of Stavanger
- Chair of the assessment committee: Professor Henrik Kofoed Nielsen, UiA
Supervisors in the doctoral work:
- Main supervisor: Professor Terje Kanstad (NTNU, UiA)
- Co-supervisor: Associate Professor Reignard Tan (NTNU and Multiconsult)
Summary of thesis
Formulation of a consistent crack width calculation method for reinforced concrete members
A new design code formulation, an alternative to Eurocode 2 and Model Code, based on experimental, numerical and analytical considerations.
Predicting crack widths in reinforced concrete (RC) structures is essential for Serviceability Limit State (SLS) Design. Crack widths that exceed a certain limit may impair a structure's functionality, limit its use, and reduce its service life. Despite a century of research, predicting crack widths accurately and consistently is still difficult. On the other hand, the consequences of cracks related to functionality, durability, aesthetics, and economy are significant.
The research presented in the thesis focuses on different calculation methods to predict crack widths in standard and large-scale concrete structures subjected to uniaxial loading conditions. Large-scale concrete structures are, in this thesis, synonymous with RC structures, which have member dimensions that can be up to several meters in height, sections with large reinforcing bar diameters, and large covers. The investigated calculation methods range from computer-based simulations using Nonlinear Finite Element Analysis (NLFEA) to design code formulations, i.e., Eurocode 2 (EC2, FprEC2, DIN), fib Model Codes (MC2010, MC2020) in addition to the Modified Tension Chord Model (MTCM) and the simplified version of MTCM (SMTCM) developed in this thesis.
Evaluation of the semi-empirical formulas recommended by Eurocode 2, fib Model Codes, and the German National Annex (DIN) to EC2 showed that they may predict crack widths inconsistently. The assumption of a constant mean bond-stress distribution over the transfer length independent of the load level can perhaps explain the reasons for continuously calibrating the formulas, among others: i) using a lower bound for the difference in mean strains for steel and concrete to differentiate between a crack formation and a stabilized crack stage and ii) the cover addition in the crack spacing formulas.
What to do as an online audience member
The disputation is open to the public. To follow the trial lecture and the public defence online, register on Zoom.
We ask online audience members to join no earlier than 10 minutes in advance. After these times, you can leave and rejoin the meeting at any time.
Opponent ex auditorio:
Deadline for the public to pose questions is during the break between the two opponents. Questions ex auditorio can be submitted to disputation chair Emma Horneman.