Use of stainless steel as concrete reinforcement

Polazeći od štetnosti korozije armature na trajnost i troškove održavanja armiranobetonskih konstrukcija, u radu se kao način sprečavanja korozije armature opisuje primjena armature od određenih vrsta nehrđajućih čelika koji su otporni na koroziju. Prikazani su rezultati ispitivanja korozijske otpornosti nehrđajućih čelika i ugljičnog čelika te su dane preporuke za upotrebu nehrđajućih čelika kao armature ovisno o razredu izloženosti projektirane armiranobetonske konstrukcije.Starting from the impact the steel corrosion has on the durability and maintenance costs of reinforced- concrete structures, the authors describe how steel corrosion can be prevented by using reinforcement made of certain types of stainless steel that are resistant to corrosion. Results obtained by testing corrosion resistance of stainless steel and carbon steel are presented, and recommendations are given for the use of stainless steel as reinforcement depending on exposure category of a particular reinforced structure

Mathematical models for determining life span of reinforced concrete structures

Prikazani su postojeći matematički modeli: deterministički Life–365, Chlodif i probabilistički DuraCrete za proračun uporabnog vijeka armiranobetonskih konstrukcija izloženih djelovanju klorida, a osnovani na fizikalnom modelu prijenosa klorida u betonu.U eksperimentalnom dijelu rada prikazana je provedena analiza sadržaja klorida na Krčkom mostu. Uspoređeni su rezultati dobiveni determinističkim i probabilističkim pristupom te su predloženi koraci za daljnji razvoj modela.The use of existing mathematical models - deterministic: Life-365, Chlodif, and probabilistic: DuraCrete - in the analysis of life span of reinforced-concrete structures exposed to the action of chlorides, as based on physical model of chloride transport in concrete, are presented. The analysis of chloride content, conducted at the Krk Bridge, is presented in the experimental part of the paper. Results obtained by deterministic and probabilistic approaches are compared, and steps for further development of modelling procedures are proposed

Mathematical models for determining life span of reinforced concrete structures

Prikazani su postojeći matematički modeli: deterministički Life–365, Chlodif i probabilistički DuraCrete za proračun uporabnog vijeka armiranobetonskih konstrukcija izloženih djelovanju klorida, a osnovani na fizikalnom modelu prijenosa klorida u betonu.U eksperimentalnom dijelu rada prikazana je provedena analiza sadržaja klorida na Krčkom mostu. Uspoređeni su rezultati dobiveni determinističkim i probabilističkim pristupom te su predloženi koraci za daljnji razvoj modela.The use of existing mathematical models - deterministic: Life-365, Chlodif, and probabilistic: DuraCrete - in the analysis of life span of reinforced-concrete structures exposed to the action of chlorides, as based on physical model of chloride transport in concrete, are presented. The analysis of chloride content, conducted at the Krk Bridge, is presented in the experimental part of the paper. Results obtained by deterministic and probabilistic approaches are compared, and steps for further development of modelling procedures are proposed

Developing Decision Support Tools for Rail Infrastructure Manager

European rail infrastructure managers (IMs) are managing aging rail infrastructure with 95% of the network having been built before 1914. EU transport policy provides the challenge to IMs to increase the productivity of existing rail networks, prioritise renewal and optimise new sections to reduce bottlenecks, increase productivity and achieve a switch from freight transport by road to rail. This needs to be achieved at a time when budgets are restricted whilst improving customer satisfaction and dealing with challenges from natural hazards and extreme weather events which are affecting all of Europe. In order to deal effectively with this grand challenge, Europe will need to develop methods to manage its rail infrastructure across the single European railway area. Whilst decision support tools are widely applied across, these systems tend to concentrate on only one asset and inherently suffer from the several limitations. In this paper the European H2020 project Destination Rail that focuses on the development of decision support tool for rail infrastructure managers is presented. Within DESTination RAIL the aim is to provide solutions for a number of problems faced by EU infrastructure managers, such as assessment of existing assets, use of existing databases controlled by an information management system, risk assessment, maintenance and construction techniques for treating rail infrastructure including tracks, earthworks and structures, whole life cycle assessment and impact on the traffic flow. Each of these separate streams are incorporated into the Decision Support Tool which will be the primary exploitable deliverable from the project, and demonstrated on several railway projects across the European network

Transition zones on the railway track - overview

Transition zones between bridges, tunnels, artificial and earth structures, including transitions between ballast and non–ballast permanent way (slab track), are a part of the railway track structure where the abrupt change in the rigidity of the track structure and track settlement occurs between individual transverse profiles, as a result of the change in the structural elements and the foundation. Variation in the rigidity of the rail structure is the basic parameter influencing the generation of new impulse mechanisms during interaction between the vehicle and the structure. This causes additional dynamic loads, resulting in further degradation of the track structure and indirect decrease in the level of safety and comfort of railway traffic. Due to foregoing, the transition zones are defined as exceptionally problematic parts on the railway track. In order to limit additional and frequent costs of rehabilitation of these track parts, the degradation mechanisms are analyzed within EU funded research project (SMART RAIL), with the aim to find a high–quality, economically and environmentally acceptable solution for existing older railways. This paper presents the mechanisms influencing the degradation of tracks in the transition zones, as well as structural measures presently known and used for rehabilitation of existing railways

Developing Decision Support Tools for Rail Infrastructure Manager

European rail infrastructure managers (IMs) are managing aging rail infrastructure with 95% of the network having been built before 1914. EU transport policy provides the challenge to IMs to increase the productivity of existing rail networks, prioritise renewal and optimise new sections to reduce bottlenecks, increase productivity and achieve a switch from freight transport by road to rail. This needs to be achieved at a time when budgets are restricted whilst improving customer satisfaction and dealing with challenges from natural hazards and extreme weather events which are affecting all of Europe. In order to deal effectively with this grand challenge, Europe will need to develop methods to manage its rail infrastructure across the single European railway area. Whilst decision support tools are widely applied across, these systems tend to concentrate on only one asset and inherently suffer from the several limitations. In this paper the European H2020 project Destination Rail that focuses on the development of decision support tool for rail infrastructure managers is presented. Within DESTination RAIL the aim is to provide solutions for a number of problems faced by EU infrastructure managers, such as assessment of existing assets, use of existing databases controlled by an information management system, risk assessment, maintenance and construction techniques for treating rail infrastructure including tracks, earthworks and structures, whole life cycle assessment and impact on the traffic flow. Each of these separate streams are incorporated into the Decision Support Tool which will be the primary exploitable deliverable from the project, and demonstrated on several railway projects across the European network

Monitoring of long term deformations in Bobova tunnel

The 189.50 m long Bobova tunnel constructed in 2005 is located on the D404 state highway and passes under a part of the Vežica – Sušak town area in Rijeka. The overburden above the tunnel pipe is between 2 m to 18 m thick. The rock mass along the tunnel route is made up of karst deposits (transient carbonate breccia, dolomite and limestone interlinked with rudist limestones). Extensive geotechnical instrumentation was installed in the tunnel by researchers at the faculty of Civil Engineering at the University of Zagreb. This consisted of: measurements in the tunnel area from the ground surface using inclinometers for horizontal, and sliding micrometers for vertical soil displacements, measuring displacements around underground openings using sliding micrometers supplemented with scanning of the tunnel interior using laser scanners, and measuring the stress and deformations in elements of support complex by pressure cells and measuring anchors. Data collected during construction and in the twelve years in which the three-lane highway tunnel has been operational, presented in this paper reveal that deformations and stresses in Bobova tunnel have continued to increase with time. The possible role of the shotcrete lining, rock creep and rock-bolt corrosion in the ongoing deformations are discussed. The application of continuous monitoring data from instruments as inputs for numerical model training using a machine learning model, with the objective to improve the predictions of existing probabilistic failure models is considered. The ultimate aim of this work is to develop improved predictive maintenance plans.Geo-engineerin

Life-Cycle Management Model for Tunnels

Tunnels are a vital link in transport networks which represent a significant investment in all life cycle phases from planning, investigation works, construction and operation. Decisions through the whole life cycle of a tunnel should be based on solid facts and reliable data especially in the context of considerable impacts on both the environment and society. The calculation of total life time costs for different design alternatives, maintenance options and societal impacts can be used to compare different technical solutions and select the optimal design and maintenance alternative. Generally problems related to tunnel degradation can be divided into those caused by external pressure and those caused by the deterioration of materials. These problems are gradually increased through all life cycle stages of a concrete structure such as a tunnel, therefore decisions about the timing and the type of maintenance should be based on degradation prediction models and monitoring of the structure performance or degradation processes. Uncertainties in the decision making process can be decreased by using information from monitoring which are used to establish triggering thresholds for the structure passing certain performance levels. In this paper the use of monitored tunnel deformations in a life cycle management model for a tunnel is presented. The monitoring data gives information about tunnel long term deformations that are used in the decision making process, in order to prevent occurrence of tunnel damage and consequently large maintenance costs.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin