Asmus Skar Christiansen

• PhD
• Professor (Associate) at Technical University of Denmark

The evaluation of soil reaction in geotechnical foundation systems such as concrete pavements, mat- and raft foundations is a challenging task, as the process involves both the selection of a representative mechanical model (e.g., Winkler, Continuum, Pasternak, etc.) and identify its prevailing parameters. Moreover, the support characteristics may...

This study was motivated by the need for a road profile monitoring concept that can provide frequent measurements over large areas across all weather conditions. A profile inversion method was proposed in this context, based on measured in-vehicle accelerations alongside speed and location information. The method combined a quarter-car response mod...

The road transportation sector is a dominant and growing energy consumer. Although investigations to quantify the road infrastructure’s impact on energy consumption have been carried out, there are currently no standard methods to measure or label the energy efficiency of road networks. Consequently, road agencies and operators are limited to restr...

This work was motivated by mapping the energy consumption of road networks towards development of energy efficiency labeling-similar to what is done in consumer sectors. Specifically, the paper presents vehicle traction energy data from the LiRA project, focusing on the usability of it by looking at the effects of longitudinal slope, vehicle speed,...

This data article presents the details of the Live Road Assessment Custom Dataset (LiRA-CD), an open-source dataset for road condition modelling and research. The dataset captures GPS trajectories of a fleet of electric vehicles and their time-series data from 50 different sensors collected on 230 km of highway and urban roads in Copenhagen, Denmar...

The tire–road friction coefficient is a critical evaluation index of the service performance of roads: it governs the stopping distance, traction control, and stability of vehicles. Moreover, friction information is also needed in many function units of modern vehicles. This paper proposes a novel data-driven approach for inference of the maximum t...

This paper addressed the case of an electrically heated asphalt pavement; it explored an unconventional application of such a system – not for combating snow and ice – but for mitigating low-temperature cracking. The investigation was done in silico, considering a stratified medium to represent the asphalt pavement system, a thin heat-generating la...

This study was motivated by the need for a mechanistic-empirical (ME) design method applicable to asphalt pavements after mill-and-overlay repairs that include reinforcing grids; the focus was solely on the mechanistic component. A new model, based on layered theory, was developed – coupling in one single framework the following features: elastic l...

Asphalt pavements in cold regions are often exposed to low-temperature cracking distress. The driving mechanism for this type of damage is usually an isolated event of fast surface cooling in combination with low-temperature levels. Another common characteristic of pavements in cold regions is the need for salting or mechanical clearing operations...

The Digital Twin (DT) concept has great potential within transportation infrastructure operation and asset management. Its adaption and application could offer real-time structural monitoring, support of maintenance-related decisions and activities, and the ability to examine performance under different operational scenarios. This study commenced b...

This paper presented an analytic approach for theoretically investigate and quantify the mill-and-overlay treatment when including grid-like reinforcement in-between an existing cracked (aged) asphalt concrete (AC) and a new AC overlay. The investigation is based on an analytic layered elastic pavement model that is capable of handling a fragmented...

Modern cars are equipped with many sensors that measure information about the vehicle and its surroundings. These measurements are therefore related to the ride-surface conditions over which the vehicle is passing. The paper commences by outlining a four-component vision for performing road condition evaluation based on in-vehicle sensor readings a...

Road roughness is a very important road condition for the infrastructure, as the roughness affects both the safety and ride comfort of passengers. The roads deteriorate over time which means the road roughness must be continuously monitored in order to have an accurate understand of the condition of the road infrastructure. In this paper, we propos...

Modern cars are equipped with a great number of sensors that measure information about the vehicle and its surrounding. Thus, many of these measurements are related to the ride-surface conditions over which the vehicle is passing. In the paper, a four-component vision was outlined for advancing the idea of performing road condition evaluation based...

This paper presented an approach for mechanical pavement condition monitoring based on post-construction installation of near surface LVDTs. The concept calls for making shallow grooves or blind holes at the pavement surface, and then fixing horizontal LVDTs to measure any changes in groove length or hole diameter resulting from nearby vehicle pass...

Adaptive Layered Viscoelastic Analysis (ALVA) is a MATLAB-package for pavement modeling. The aim with the software is to equip the civil engineering community with an advanced pavement modeling tool and computer package that is highly adaptive, transparent and open-access, capable of supporting current and future pavement evaluation needs.

Layered elastic theory is a familiar and commonly accepted framework for modelling and analysis of pavement systems. In actuality however, the suitability of the theory is challenged whenever the system includes a fragmented layer – which violates the inherent layer continuity assumption. This paper addressed the modelling challenge in these situat...

An array of four synchronized single-axis accelerometers was fixed to the surface of an asphalt pavement. Vertical acceleration traces triggered by several nearby passes of a truck with known characteristics were recorded. The work focused on presenting and demonstrating an interpretation method for inferring the mechanical properties of the paveme...

Today there exists no recognized programs or codes for including asphalt reinforcement in design and analysis of flexible pavements. This complicates the engineering work when designing robust pavement solutions with embedded asphalt reinforcement, and hereby leaves the concept of asphalt reinforcement as an unredeemed potential. In order to provid...

I dag findes ingen anerkendte programmer, der kan medregne asfaltarmering til dimensionering og analyse af fleksible belægninger. Først og fremmest vanskeliggører det vejingeniørens opgave, når der skal dimensioneres stærke belægninger med asfaltarmering, og dernæst forbliver hele idéen med asfaltarmering til uforløst potentiale, der ellers ville k...

In recent years, there has been renewed interest in developing Moving Measurement Platforms (MMPs) to replace the Falling Weight Deflectometer (FWD) which currently serves as the industry standard for project-level pavement evaluation. The purpose of this study was to contribute to the transition efforts from FWD to MMPs. While focusing on a new MM...

This study offered a novel method for characterizing the soil support in slab-on-grade constructions such as rigid pavements and raft foundations. The method applies to slabs that are instrumented with fiber-optic cables for distributed strain sensing; it is based on analyzing the spatial profiles of slab bending strains generated by randomly appli...

Layered elastic theory is a familiar and commonly accepted framework for modeling and analysis of pavement systems. In actuality however, the suitability of the theory is challenged whenever the system includes a fragmented layer - which violates the inherent layer continuity assumption. This paper addressed the modeling challenge in these situatio...

In cold regions frost may penetrate to large depths below the surface of pavements, resulting in the formation and growth of subsurface ice lenses. Such frost action is accompanied by volume expansion that forcefully and unevenly displaces lower pavement boundaries. Ultimately, the subterranean deformations result in added distortion at the ride su...

Med det formål at øge både sikkerheden og effektiviteten, minimere trafikforstyrrelser, samt gøre bæreevnemålinger tilgængelige for alle typer af brugere, har Dynatest i samarbejde med DTU udviklet et nyt system til kontinuerlig måling af vejes bæreevne. Projektet, under navnet ”Advanced and Widely Available Pavement Assessment Tools for Infrastruc...

In concrete structures, fatigue is one of the major causes of material deterioration. Repeated loads result in formation of cracks. Propagation of these cracks cause internal progressive damage within the concrete material which ultimately can lead to failure. This paper presents a simplified general concept for non-linear analysis of concrete subj...

In concrete structures, fatigue is one of the major causes of material deterioration. Repeated loads result in formation of cracks. Propagation of these cracks cause internal progressive damage within the concrete material which ultimately can lead to failure. This paper presents a simplified general concept for non-linear analysis of concrete subj...

In concrete structures, fatigue is one of the major causes of material deterioration. Repeated loads result in formation of cracks. Propagation of these cracks cause internal progressive damage within the concrete material which ultimately leads to failure. This paper presents a simplified general concept for non-linear analysis of concrete subject...

September 2013 COWI A/S and the Technical University of Denmark (DTU) launched an industrial PhD project, with the aim to develop more generalised structural design methods for port-and industrial pavements. The project was completed in the autumn 2016 and have produced a number of models and concepts for numerical analysis of rigid and semi-rigid...

Cemented materials in heavy duty pavement systems are subjected to complex loading conditions which cannot be treated by existing analytical-empirical methods. For description of the fracture behaviour of the cemented material, this thesis presents a general mechanistic framework for engineering applications. The models presented includes the most...

Presentation PhD defense Assessment committee: Research Director Armelle Chabot, IFSTTAR Centre de Nantes, France Professor Lev Khazanovich, University of Pittsburgh, USA Associated Professor Eyal Levenberg, DTU Byg, Denmark

Numerical analysis of slab on grade structures subjected to mechanical loads is a complex matter often requiring computationally expensive models. In order to develop a simplified and general concept for non-linear analysis of slab on grade structures, this paper presents a cohesive cracked-hinge model aimed at the analysis of the bending fracture...

The need for mechanistic constitutive models to evaluate the complex interaction between concrete crack propagation, geometry and soil foundation in concrete- and composite pavement systems has been recognized. Several models developed are either too complex or designed to solve relatively simple problems, e.g. limited to one type of load configura...

The problem of stiffness degradation in composite pavement systems from localised fracture damage in the quasibrittle cement bound granular mixture are today taken into account only by empirical formulas. These formulas deals with a limited number of materials in a restricted range of design options and would yield unrealistic results in ultimate l...

This paper presents a numerical analysis of the fracture behaviour of the cement bound base material in composite concrete block pavement systems, using a cohesive zone model. The functionality of the proposed model is tested on experimental and numerical investigations of beam bending tests. The pavement is modelled as a simple slab on grade struc...

In the NordFoU - Pavement Performance Models (PPM) project in 2010 a set of pavement performance models for flexible pavement structures as well as a software application for prediction of pavement performance on network level were presented. In the current phase of the project (Pavement Performance Models 2 (PPM2) - Validation of Performance Model...

There are presently few recognized technical guidelines available for structural design and evaluation of port-and industrial pavements. This fact makes the job of the pavement design consultant a difficult task when considering structural design of pavements subjected to heavy duty loads. To overcome this problem COWI A/S in cooperation with The T...

I dag findes kun få anerkendte tekniske vejledninger til dimensionering og analyse af havne- og industribelægninger, hvilket vanskeliggør den rådgivende vejingeniørs opgave, når der skal dimensioneres belægninger for belastninger fra tunge køretøjer og containere. For at afhjælpe dette problem har COWI A/S i samarbejde med Danmarks Tekniske Univers...

A Nordic research project has developed a set of performance models for prediction of rutting, roughness, cracking and bearing capacity of flexible pavements at network level. Fully implemented in Pavement Management Systems it can contribute to a better platform for decision-making when the maintenance budget is allocated to specific projects. A c...