A host of awards
Designer Mikko Riikonen, M.Sc. (Tech.), who has been with Sito’s geotechnical department since March 2014, has won several commendations during his relatively short career. Two were awarded for his Master’s thesis, and one was granted as an incentive reward for his day job.
Mikko’s Master’s thesis “A modeling study on the effects of raising axle group masses on road structure responses” received yet more recognition from Destia as the best university graduate thesis in the infrastructure sector, at the Earthwork Day event in September. In the previous year, the Finnish earthwork advisory board Maarakennusalan neuvottelukunta MANK ry granted Mikko a scholarship awarded for the two best Master’s theses of the year.
Mikko completed his Master’s thesis at Aalto University School of Engineering under the supervision of Professor Leena Korkiala-Tanttu. The thesis was commissioned by the Finnish Transport Agency.
Leena Korkiala-Tanttu, Professor of Practice Geotechnical Engineering, Aalto University, congratulating Mikko on his award. Photo: Tanja Oksa.
Thorough and diverse
The aim of Mikko’s Master’s thesis was to use modeling based on the Plaxis 3D FEM-program to study how heavier vehicles and axle groups affect responses such as stresses, strains and displacements in a road structure. “I studied the effects of axle groups of two or three axles, as well as the general effect of articulated vehicles on various road structures.”
In addition to the effects of the heaviest allowed loads, he studied the effects of overloads, unevenly distributed loads, axle spacing, tire pressure, the stiffness of the surfacing layer, layer thickness and the height of the ground water table.
The jury commended his Master’s thesis for its thorough and varied approach. Pertti Niemi of Destia, the chairman of the jury, commended the high standard of theoretical knowledge demonstrated in the Master’s thesis.
The jury appreciated the choice of subject, which is currently topical.
The jury viewed this year’s theses as being of outstanding quality, which adds to the prestige of Mikko Riikonen’s accomplishment.
The jury members were Pertti Niemi, Liisi Vähätalo of the Finnish Road Association, Heikki Jämsä of the Infra Contractors Association in Finland, Juha Kaitera of the Confederation of Finnish Construction Industries and Esko Mälkönen of the Union of Professional Engineers in Finland.
To make a visible difference
Mikko says that he decided to study engineering because he wanted to work in an industry where he could achieve concrete results. Geotechnical engineering was a sector that seemed to offer promising employment prospects. This was a good call, since he will be kept busy in the near future with the Finavia alliance project related to the extension of Helsinki-Vantaa airport.
It is no surprise that Mikko has already won Finavia’s incentive award for active commitment, by identifying cost savings through the development of engineering solutions. When large-scale ground improvement measures are proven unnecessary and can be replaced with a more cost-effective approach, time as well as a considerable sum of money is saved.
Mikko will soon be able to admire the results of his designs at Helsinki-Vantaa airport, while the awards provide him with a lasting source of satisfaction. The best Master’s thesis of the year in the infrastructure sector is recommended reading for decision-makers, since it would help in maintaining the condition of Finland’s road network under the stress of increasingly heavy articulated vehicles.
Stress on road structures can be reduced
Heavy articulated vehicles cause particular damage to road structures founded on soft soils, roads with a small overall layer thickness and roads with light weight materials. Fatigue damage is also likely to become more common.
Replacing single wheels with dual wheels would reduce stresses and strains, particularly on the top parts of a road with a thin surfacing layer.
“Methods for reducing stress on road structures are relatively simple: larger layer thicknesses, stiffer surfacing layers and functioning drainage.” Mikko points out that – with regard to articulated vehicles – the axle group load must be optimally divided, tire pressures should be lowered and axle spacings made longer.
Above all, overloaded vehicles should not be allowed on the roads at all!
Text: Dakota Lavento