Experimental and finite element dynamic analysis of incrementally loaded reinforced concrete structures

This work investigates influence of damage in reinforced concrete (RC) structures on their dynamic properties through modal testing and non-linear finite element (FE) analysis. Five RC beams were designed with the fundamental flexural mode frequencies in the range of 6.5–18.0 Hz for the uncracked state. Mechanical properties of concrete, such as static and dynamic elastic moduli were determined from standard tests and ultra-sonic pulse velocity readings. The beams were incrementally loaded until the span/250 deflection limit was reached and their natural frequencies were measured from the free decay vibrations. The progressive damage reduced fundamental frequencies of tested beams by up to 25%. The non-linear FE analysis was carried out for RC beams and one two-span slab and the calculated reduced frequencies of the 1st and 2nd vibration modes were in excellent agreement with measurements. This led to the conclusion that, given that the non-linear analysis can capture degradation of dynamic stiffness due to cracking, the future dynamic performance and damage identification on the RC structure can be reliably determined from the same FE model. The results reveal potential of the combined modal testing and FE analysis to improve inspection and assessment of the in-service RC structures

Concrete beams with externally bonded flexural FRP-reinforcement: analytical investigation of debonding failure

This paper studies the problem of early concrete cover delamination and plate-end failure of reinforced concrete beams strengthened with externally bonded FRP-reinforcement. The accuracy of analytical models and finite element (FE) methods for predicting this type of failure is assessed against published experimental data. Two design approaches based on the maximum concrete tensile strength and the shear capacity of concrete beams were examined first and it was found that linear elastic analysis cannot accurately predict the brittle plate-end concrete failure. It was also found that the extent of strengthening that can be achieved is limited by the shear capacity of concrete beams. The FE analysis is used to examine the effects of internal tensile reinforcement on the magnitude of principal tensile stresses in the critical region. The non-linear behaviour of FRP-strengthened beams is also examined in the FE analysis using the smeared crack model for concrete which is shown to adequately display the inelastic deformation of the beam. Finally, the mixed mode of failure due to the combined shear and concrete cover delamination is addressed through modelling plate-end and shear crack discontinuities using the discrete crack approach

Å bygge bro for de som vandrer lengst. En kvalitativ undersøkelse av International Child Development Programme tilpasset minoritetsforeldre

I 2014 ble det innført en tilskuddsordning med formål om å gi barn tidlig hjelp, gjennom å tilby innvandrere foreldrestøttende tiltak (Meld. St. 30, 2015-2016). Utgangspunktet for tiltaket var at foreldrerollen som ny i Norge kan være utfordrende og skiller seg mye fra foreldrerollen i opprinnelseslandet. Mange innvandrere er usikre på norske verdier, og opplever stress som kan påvirke foreldrerollen og føre til nedvurdering av egen omsorgspraksis og egne verdier. Frykten for å miste barna ved offentlig inngripen i familiens sfære er stor. Foreldrene opplever også svekket status og respekt parallelt med at barna tilpasser seg gjennom å lære språket, verdier og væremåter (Barne- ungdoms og familiedepartementet, 2018). ICDP-stiftelsen har utviklet foreldreveiledningsprogram som er rettet mot foreldre med minoritetsbakgrunn. I Tromsø kommune tilbys alle nyankomne flyktninger og innvandrere som bosettes i kommunen deltakelse gjennom introduksjonsprogrammet. Målet å påvirke omsorgsgiverens forståelse av hvor viktig samhandling med barnet er for dets utvikling, og fremme en positiv oppfatning og holdning til barnet. Videre å fremme omsorgsgivers oppfatning av seg selv som kompetente. Programmet skal også bidra til å bygge bro mellom de omsorgsverdiene foreldrene har med seg fra hjemlandet, og de nye tradisjonene og omsorgsverdiene de møter i det norske samfunnet