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In design against fatigue, a lower bound stress range vs. endurance curve (S-N curve) is employed to characterize fatigue resistance of plain material and structural details. With respect to the inherent variability of the fatigue life, the S-N curve is related to a certain probability of exceedance, a percentile of the fatigue life. This paper is concerned with modelling and estimating uncertainties in fatigue resistance of welded joints under constant amplitude loading. A new S-N curve format is proposed and fitted to fatigue test data by using the Maximum Likelihood Method. The results have been compared with the Random Fatigue Limit Model and the Bilinear Random Fatigue Limit Model. The proposed S-N curve appears to be more accurate in describing the S-N relation in high-cycle fatigue: it presents a smooth transition from finite to infinite-life regions and, differently from previous non-linear S-N relations with fatigue limit, this transition is controlled by an independent model parameter. Thereby it provides more flexibility for statistical fitting. In addition, a Bayesian framework is defined to fit the proposed relation including informative and non-informative prior distributions. © 2017 Elsevier Ltd

This paper considers local buckling of perforated square aluminium plates. Plates of various slenderness with simply supported edges and subjected to uniaxial compression are studied using the finite element method. Different perforation patterns are investigated, from a single circular hole to 25 circular holes distributed over the plate. A number of aluminium alloys are considered and compared to steel grade A36. Results show that the resistance of the plates containing a single central cut-out is higher than that of plates with more holes and of equal total cut-out size. A further refinement beyond 5 holes does not influence the resistance.

De Afsluitdijk is op dit moment ruim tachtig jaar oud en heeft ons al die jaren goed tegen de krachten en invloeden van het zeewater beschermd (foto 1 en 2). Rijkswaterstaat gaat de Afsluitdijk nu een grote opknapbeurt geven, zodat hij tot ten minste 2050 mee kan. De dijk wordt zodanig versterkt dat hij bestand is tegen het stijgende zeewater. Bovendien worden de sluizen versterkt en verhoogd en wordt de waterafvoer verbeterd. Om dat te kunnen realiseren, was het noodzakelijk de betonnen kunstwerken, onder meer de spuisluizen, te laten inspecteren

The current theory of ASR gel formation in concrete between silicic acid anions with cations and is unable to explain the differences in concentration required for gel formation between e.g. potassium and sodium or the effect of calcium on the gel formation. In this paper, a new gelation mechanism is explained by means of a condensation between silicic acid anions. The role of salts on the ASR gel formation and gel time is described by their charge screening capacity of the silicic acid, resulting in the decreasing concentration range for gelation: Ca < Mg < Cs < Rb < K < Na < Li. A Cation Gelling Strength (CGS) is defined to assess the cation strength when different cations are present. Silica gel formation will moreover in many cases form a calcium silica precipitate rather than a gel that will be difficult to distinguish from CSH formed during hydration.

The current theory of ASR gel formation in concrete between silicic acid anions with cations and is unable to explain the differences in concentration required for gel formation between e.g. potassium and sodium or the effect of calcium on the gel formation. In this paper, a new gelation mechanism is explained by means of a condensation between silicic acid anions. The role of salts on the ASR gel formation and gel time is described by their charge screening capacity of the silicic acid, resulting in the decreasing concentration range for gelation: Ca < Mg < Cs < Rb < K < Na < Li. A Cation Gelling Strength (CGS) is defined to assess the cation strength when different cations are present. Silica gel formation will moreover in many cases form a calcium silica precipitate rather than a gel that will be difficult to distinguish from CSH formed during hydration.

Design methods for marine structures have evolved into load and resistance factor design, however existing partial safety factors related to berthing velocity and loads have not been verified and validated by measurement campaigns. In this study, field observations of modern seagoing vessels berthing in Bremerhaven, Rotterdam and Wilhelmshaven were used to evaluate partial safety factors for berthing energy and berthing impact loads. Various types of vessels and navigation conditions were statistically examined. The results show that characteristic values of berthing velocity with a return period of 50 years are in line with design recommendations in literature. Design values of berthing velocity are sensitive to the number of berthing operations during the lifetime of a marine structure. Typical partial safety factors for sheltered and exposed navigation conditions were derived by extrapolating distribution fits and applying extreme value theory. Differences in structural response due to soil stiffness and the type of berthing system installed influence partial safety factors for berthing impact loads. The probability of an uncontrolled berthing event was higher for exposed navigation conditions (strong tidal currents). In these circumstances, higher partial safety factors for berthing velocity should be considered in the design of marine structures. When berthing aid systems are used, the probability of extreme berthing velocities is lower, resulting in lower partial safety factors. The key findings of this study could be beneficial for the structural design of new and lifetime extension of existing marine structures. © 2017 Elsevier Ltd

Although the steel–concrete interface (SCI) is widely recognized to influence the durability of reinforced concrete, a systematic overview and detailed documentation of the various aspects of the SCI are lacking. In this paper, we compiled a comprehensive list of possible local characteristics at the SCI and reviewed available information regarding their properties as well as their occurrence in engineering structures and in the laboratory. Given the complexity of the SCI, we suggested a systematic approach to describe it in terms of local characteristics and their physical and chemical properties. It was found that the SCI exhibits significant spatial inhomogeneity along and around as well as perpendicular to the reinforcing steel. The SCI can differ strongly between different engineering structures and also between different members within a structure; particular differences are expected between structures built before and after the 1970/1980s. A single SCI representing all on-site conditions does not exist. Additionally, SCIs in common laboratory-made specimens exhibit significant differences compared to engineering structures. Thus, results from laboratory studies and from practical experience should be applied to engineering structures with caution. Finally, recommendations for further research are made., Materials and Structures, 50 (2), ISSN:1359-5997, ISSN:1871-6873

In a BIM data flow, an essential part of the coordination between disciplines is the agreement on recesses and openings in building elements. Different disciplines will request recesses and openings in elements that are managed and maintained by others. Using the full dataset of the elements has proven to be inoperable because of the information overload, interoperability problems and contradictions in the commonly used downstream dataflow. A group of companies has been experimenting with the exchange of data that only consists of the requested openings and recesses in IFC. Coordination is being done using BCF. This approach has been fine-tuned and adjusted during several projects. This paper describes the current status of that initiative and discusses the challenges that are still open.

Tuffstone elements with a large length/width ratio, as e.g. mullions, often suffer damage in the form of cracks parallel to the surface and spalling of the outer layer. The response of tuff to moisture might be a reason for this behaviour. This research aimed at verifying if a differential dilation between parts with different moisture content (as outer and inner part of partially encased mullion) can lead to damage. The effect of moisture on the degradation of Ettringen and Weibern tuff has been investigated. A purpose-made weathering test was carried out to simulate the wetting-drying process. Despite no cracks developed during the test, existing cracks widened up and the flexural tensile strength of both materials decreased. The moisture transport properties of the stones were determined as well as their porosity and pore size. Ettringen tuff has a considerable amount of very fine porosity, resulting in slow moisture transport and significant hygroscopic adsorption. Both tuffstones have an extreme hydric dilation. Environmental X-ray diffraction analyses showed that Ettringen tuff undergoes (reversible) mineralogical changes when subjected to RH cycles, whereas this does not occur for Weibern. All results support the hypothesis that moisture gradients in tuff elements may enhance decay in this stone.

Risk Based Asset Management (RBAM), or rather Asset Management based on both a perfor-mance requirement and a supporting Risk Analysis, is a beneficial Asset Management methodology for a number of industries, including the Asset Management of infrastructure. In the implementation of RBAM at Rijkswaterstaat a number of challenges have been faced. This paper focusses on three major challenged and the solutions adopted: 1) how to RBAM into the existing asset management processes. 2) how to communi-cate effectively about the performance and its constraints with all levels within the organization, including the communication with decision makers, maintenance engineers and operators and 3) how to scale RBAM scope into manageable implementation

Modeling the stochastic evolution of a large-scale fleet or network generally proves to be challenging. This difficulty may be compounded through complex relationships between various assets in the network. Although a great number of probabilistic graph-based models (e.g., Bayesian networks) have been developed recently to describe the behavior of single assets, one can find significantly fewer approaches addressing a fully integrated network. It is proposed an extension to the standard dynamic Bayesian network (DBN) by introducing an additional dimension for multiple elements. These elements are then linked through a set of covariates that translate the probabilistic dependencies. A Markov chain is utilized to model the elements and develop a distribution-free mathematical framework to parameterize the transition probabilities without previous data. This is achieved by borrowing from Cooke's method for structured expert judgment and also applied to the quantification of the covariate relationships. Some metrics are also presented for evaluating the sensitivity of information inserted into the covariate DBN where the focus is given on two specific types of configurations. The model is applied to a real-world example of steel bridge network in the Netherlands. Numerical examples highlight the inference mechanism and show the sensitivity of information inserted in various ways. It is shown that information is most valuable very early and decreases substantially over time. Resulting observations entail the reduction of inference combinations and by extension a computational gain to select the most sensitive pieces of information. © 2017 Computer-Aided Civil and Infrastructure Engineering

The Province of Zuid-Holland encourages the development of innovations to make the provincial road network more energy efficient. This is one way the province can contribute to reducing energy consumption and CO2 emissions in accordance with the Dutch energy agreement. To this end, the Province of Zuid-Holland, Strukton Civiel and TNO have conducted joint research on road surfacing that reduces rolling resistance and hence reduces fuel consumption and CO2 emissions. This document sets out the objective of the research, as well as the methods used and the research results (both in the laboratory and the field). It also looks ahead at the impact the results could have and how the construction of such energy-saving road surfacing could best be put out to tender by road authorities

Risk Based Asset Management (RBAM), or rather Asset Management based on both a perfor-mance requirement and a supporting Risk Analysis, is a beneficial Asset Management methodology for a number of industries, including the Asset Management of infrastructure. In the implementation of RBAM at Rijkswaterstaat a number of challenges have been faced. This paper focusses on three major challenged and the solutions adopted: 1) how to RBAM into the existing asset management processes. 2) how to communi-cate effectively about the performance and its constraints with all levels within the organization, including the communication with decision makers, maintenance engineers and operators and 3) how to scale RBAM scope into manageable implementation

Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active corrosion protective component of reinforced concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were tested both in alkaline solution and mortar for their possibilities as chloride scavengers and inhibitor release agents for application in concrete. The test in alkaline solution showed that ion exchange occurred between free chloride ions in solution and the intercalated inhibitive anions in the MHTs. The results in mortar validated that MHTs could be promising alternatives for preventing chloride-induced corrosion when an appropriate dosage is adopted and applied in a proper way, in particular, either incorporation of a certain amount (MHT-pAB to replace 5% weight of cement) in the bulk mortar or as a coating of the reinforcing steel (MHT-pAB or MHT-NO2 at 20% weight of cement).

Borax has been identified as a possible crystallization modifier for sodium sulfate. Understanding the effect of borax on factors influencing transport and crystallization kinetics of sodium sulfate helps to clarify how this modifier might limit crystallization damage. It has been observed that the addition of borax to sodium sulfate solutions has no influence on the wetting properties (contact angle on glass, surface tension, or evaporation rate) and therefore will not influence solution transport. Additionally, the influence of borax on the crystallization kinetics of sodium sulfate was studied under controlled environmental conditions. This was carried out in mixtures in glass microcapillaries, and sequentially in droplets on glass plates. Under the here studied precipitation conditions, the addition of borax has no influence on the supersaturation ratio at the onset of crystallization, but it significantly affects the crystallization pattern of anhydrous sodium sulfate crystals (thenardite). Using RAMAN spectroscopy, two different hydrates of borax were identified after precipitation, depending on the initial concentration of the solution. Each hydrate has a different effect on the subsequent crystallization of sodium sulfate. The decahydrate polymorph of borax leads to the precipitation of hydrated sodium sulfate crystals (mirabilite) and the pentahydrate form favors the precipitation of the anhydrous sodium sulfate crystals (thenardite) with an altered crystal habit. Using X-ray diffraction, overdevelopment of the (111), (131), (222) and (153) faces of thenardite was identified. Additionally, the ratios between several peaks are reversed. These results confirm the deviation of the grown crystals of the equilibrium crystal shape of thenardite as observed with optical microscopy.

In-situ load testing of reinforced concrete (RC) structures is often performed to confirm the presence of the required resistance for the intended use (Conformity Load Testing) or to support the assessments of the residual capacity by models (Supplementary Load Testing for Condition Assessment). When performing an in-situ load test, one of the main concerns is the avoidance of irreversible damage to the structure, since that may impair the structural performance after testing and eventually reduce its residual service life. Therefore performance indicator are needed to recognize the development and/or to prevent failure during an in-situ load test of real structures. For many of the existing RC structures without transverse reinforcement, shear failure is one of the governing mechanisms. Due to its brittle character, this failure mode is difficult to sense at an early stage of its development. Up to now no good performance indicator is available for shear. In the presented study, a smart key performance indicator for in-situ load tests has been developed, with particular focus on shear failure. Results of several laboratory tests on full-scale shear beams have been examined, confirming that a change in structural behaviour at an early stage during testing can be traced by the proposed indicator. With the proposed performance indicator, performing measurements only on the top or bottom of the tested specimen is necessary, which is of importance for the applications to existing structures, with limited access for measurements. An algorithm for data analysis has been developed, which can be used to control the proposed performance indicator in real time during testing. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfra

Different analytical models exist to predict the shear strength of reinforced concrete members. Generally, each of these shear strength models consists of a formulation based on certain underlying theory and fitted model coefficients. The model fitting parameters are usually established from the comparison with test data. Hence, the predictive value of a shear strength model depends, to some extent, on the quality and representativeness of the used test data. This work investigates the predictive capability of several shear strength models for reinforced concrete beams without shear reinforcement. Particular attention is given to the application domain of relatively low reinforced and high depth concrete beams where limited shear test data is available. The predictive capability of the models for this area of interest is analyzed with Bayesian Inference. This probabilistic technique calculates the posterior distributions of uncertain parameters, given a set of measured test data and some prior knowledge. The predictive capability of each shear strength model is quantified by means of a calculated model uncertainty. Furthermore, the influence of the uncertainty in model parameter values on the calculated model uncertainties is evaluated. Bayesian Inference is also used to estimate the model evidences conditionally on the used data.

In the Netherlands civil engineering structures, such as overpasses, bridges and tunnels are generally built using blast furnace slag cement (BFSC, CEM III/B) concrete, because of its high resistance against chloride penetration. Although the Dutch experience regarding durability performance of BFSC concrete has been remarkably good, its resistance to carbonation is known to be sensitive, especially when the used slag percentage is high. In a field investigation on a highway overpass damage was found in sheltered elements such as abutments and intermediate supports, which was attributed to chloride induced corrosion enhanced by carbonation that occurred prior to the chloride exposure. Many structures built using BFSC could be prone to this mechanism, i.e. carbonation enhanced chloride induced corrosion, negatively affecting their durability. Focus of the research was given on the influence of carbonation on the chloride penetration resistance of BFSC mortars with varying slag content. In light of the characteristics from the overpass case, it was assumed that first there is a period of carbonation during sheltered exposure, and subsequently joint leakage causes exposure to chlorides. In order to identify the influence of slag content on carbonation, chloride penetration resistance and their coupled effect, mortars with twelve cement blends in a range of 0-70% slag were evaluated based on chloride migration coefficient, accelerated carbonation and electrical resistivity. This study shows that carbonation of BFSC mortars increases the porosity, consequently decreasing the chloride penetration resistance. Binders with 50% or more slag were found to have a significantly lower resistance after carbonation. Consequently, the chloride penetration resistance of a given concrete cover strongly depends on the duration of carbonation and the resulting carbonation depth, hence influencing its lifespan. The service life was estimated using a simplified model for the chloride penetration time of a combined carbonated and uncarbonated layer. It was found that mortar with a slag content between 35 and 50% that was carbonated before chloride exposure show the lowest influence of carbonation on the chloride penetration resistance. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfra

Although the steel–concrete interface (SCI) is widely recognized to influence the durability of reinforced concrete, a systematic overview and detailed documentation of the various aspects of the SCI are lacking. In this paper, we compiled a comprehensive list of possible local characteristics at the SCI and reviewed available information regarding their properties as well as their occurrence in engineering structures and in the laboratory. Given the complexity of the SCI, we suggested a systematic approach to describe it in terms of local characteristics and their physical and chemical properties. It was found that the SCI exhibits significant spatial inhomogeneity along and around as well as perpendicular to the reinforcing steel. The SCI can differ strongly between different engineering structures and also between different members within a structure; particular differences are expected between structures built before and after the 1970/1980s. A single SCI representing all on-site conditions does not exist. Additionally, SCIs in common laboratory-made specimens exhibit significant differences compared to engineering structures. Thus, results from laboratory studies and from practical experience should be applied to engineering structures with caution. Finally, recommendations for further research are made.

In the Netherlands civil engineering structures, such as overpasses, bridges and tunnels are generally built using blast furnace slag cement (BFSC, CEM III/B) concrete, because of its high resistance against chloride penetration. Although the Dutch experience regarding durability performance of BFSC concrete has been remarkably good, its resistance to carbonation is known to be sensitive, especially when the used slag percentage is high. In a field investigation on a highway overpass damage was found in sheltered elements such as abutments and intermediate supports, which was attributed to chloride induced corrosion enhanced by carbonation that occurred prior to the chloride exposure. Many structures built using BFSC could be prone to this mechanism, i.e. carbonation enhanced chloride induced corrosion, negatively affecting their durability. Focus of the research was given on the influence of carbonation on the chloride penetration resistance of BFSC mortars with varying slag content. In light of the characteristics from the overpass case, it was assumed that first there is a period of carbonation during sheltered exposure, and subsequently joint leakage causes exposure to chlorides. In order to identify the influence of slag content on carbonation, chloride penetration resistance and their coupled effect, mortars with twelve cement blends in a range of 0-70% slag were evaluated based on chloride migration coefficient, accelerated carbonation and electrical resistivity. This study shows that carbonation of BFSC mortars increases the porosity, consequently decreasing the chloride penetration resistance. Binders with 50% or more slag were found to have a significantly lower resistance after carbonation. Consequently, the chloride penetration resistance of a given concrete cover strongly depends on the duration of carbonation and the resulting carbonation depth, hence influencing its lifespan. The service life was estimated using a simplified model for the chloride penetration time of a combined carbonated and uncarbonated layer. It was found that mortar with a slag content between 35 and 50% that was carbonated before chloride exposure show the lowest influence of carbonation on the chloride penetration resistance. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfra

Clause 6.2 of EN 1993-1-1 covers the cross-sectional resistance of steel sections. The bending-shear interaction design rules for I-shaped cross-sections make use of a reduced yield stress for the web area. On this basis, a reduced design plastic resistance moment allowing for the shear force is presented. The effect of shear on the bending resistance may be neglected if the shear force is less than half of the plastic shear resistance of the cross-section. Plasticity in the Eurocode is described by the well-known Von-Mises yield criterion, however, the formula used for the reduced yield stress deviates from this criterion, resulting in sometimes greater and sometimes smaller values. The background of the Eurocode formula for reduced yield stress can be found in a publication by Drucker. The purpose of the present research is to investigate the influence of shear on the bending resistance of I-shaped steel cross-sections with as result a possible reconsideration of the Eurocode design rules. At Eindhoven University of Technology an experimental investigation on bending-shear interaction in rolled steel I-shaped sections was performed. A numerical model was developed in Abaqus Finite Element software to simulate the experiments. With the validated numerical model a larger database of numerical ‘test’ results was generated, which was subsequently used in a statistical analysis following Annex D of EN 1990 as further developed in the RFCS project Safebrictile. The statistical distributions of the steel properties recommended by Safebrictile were adopted. This paper presents the results of the statistical analysis and safety assessment of the strong axis bending-shear interaction design rule currently present in Eurocode 3. The parametric test group consists of HEA, HEM and IPE sections in the steel grades S235, S355 and S460: in total 180 numerical simulations with increasing amount of shear. A stress-strain model including strain hardening was used in the numerical simulations, since the influence of strain hardening is also largely present in the experimental test program. Based on strain hardening material behavior it is show in this paper that the current partial factor is un-conservative for shear dominated beams and should be increased. Alternatively, the design rule should be modified.

De Noordersluis bij IJmuiden is één van de grote infrastructurele werken in vooroorlogs Nederland, uitgevoerd in beton (Fig. 1). De bouw van de nieuwe sluis was onderdeel van een reeks verbeteringen aan het Noordzeekanaal: In 1909 was een staatscommissie ingesteld '(om)dat opnieuw de vraag rees of de belangen van Nederland in het algemeen en van Amsterdam in het bijzonder in de toekomst wel voldoende waren gewaarborgd door een maritiem kanaal, dat toegang uit- en naar zee verleende voor bootee van 220 m lengte, 24 m breedte en ongeveer 92 dm diepgang. In het bijzonder was op het stellen van deze vraag van invloed het feit, dat sedert 1906 de werken van het Panamakanaal met kracht waren ter hand genomen, die na de voltooiing - welke inmiddels in 1914 heeft plaats gehad - doorvaart zouden bieden voor schepen van 305 x 331/2 m bij 1261/2 dm diepgang. Ook een verbetering van het Suezkanaal was inmiddels ter hand genomen. In die omstandigheden werd het noodig geacht een onderzoek in te stellen naar de wenschelijkheid van het nemen van verdere maatregelen om op den duur een geregelden toegang tot Nederland door het Noordzeekanaal te verzekeren ...' (Gelinck 1924). Op 2 Januari 1917 publiceerde Het Staatsblad een wet die verschillende verbeteringen aan het Noordzeekanaal van Rijkswege mogelijk maakte, waaronder een nieuwe schutsluis. De sluis werd ontworpen door een team ingenieurs onder leiding van Johannes Ringers (1885-1965), de latere Directeur-generaal van Rijkswaterstaat, Regeringscommissaris voor de Wederopbouw (een benoeming een week na de Duitse inval in 1940), verzetsman en als partijloos minister na de oorlog 'Vader van de Wederopbouw' (Van der Ham 1998, Pollmann 2006ab). Het team bestond verder onder andere uit de ingenieurs J.P. Josephus Jitta, C. Tellegen, F.E. Mulder en B. Peiser. De bouw trok van begin af aandacht in binnen - en buitenland (Fig. 2), -zo bracht onder in juli 1924 een gezelschap Duitse hoogleraren een bezoek aan de bouw (anoniem 1924a)-, en ging gepaard met uitgebreid toegepast-wetenschappelijk onderzoek. De ontwerpers publiceerden hun resultaten en overwegingen in De Ingenieur (Ringers 1924, Tellegen et al. 1924, Ringers & Peiser 1925, Jospehus Jitta 1928) en Ringers kreeg er in 1930 een eredoctoraat aan de TU Delft voor.

The currently available treatment techniques for concrete structures affected by alkali-silica reaction (ASR) are limited and electrochemical lithium migration has been proposed as an alternative. Lithium compounds have shown to have beneficial effects on ASR expansion when used as admixtures to fresh concrete. During the electrochemical treatment, lithium ions area transported into concrete (or mortar) by the action of an electrical field. The same principle is behind well-established techniques such as electrochemical chloride extraction (ECE). Like during ECE treatments, the reinforcement may be used as cathode during electrochemical lithium migration. In this paper, an investigation of the use of an embedded cathode during electrochemical lithium migration is presented. Mortar specimens were cast with embedded titanium meshes, which worked as cathodes. Results showed that potassium and sodium ions accumulated in the region around the embedded mesh and, under the tested conditions, few lithium ions reached that area. The accumulation of sodium and potassium is an undesirable side effect that increases the pH, which may possibly induce further ASR development, if not enough lithium ions reach the area.

Many of the Dutch movable hydraulic structures are exceeding lifetime expectancy based on the then-current standards and regulations. Also signs of ageing become apparent, regulations (e.g. about structural safety) get more and more strict and functional requirements have often increased over time due to climate change and socio-economic developments. Therefore Rijkswaterstaat wants to ensure that these hydraulic structures (and it’s system of operation) always complies to an adequate performance level. This by setting up an systematic approach replacing hydraulic structures based on their cost-effectiveness and future uncertainties. To provide useful information regarding this method a probabilistic performance framework has been set up. This framework links the performance of the object (IJmuiden Pumping Station) with the performance of the system (Noordzeekanaal & Amsterdam-Rijnkanaal) and defines, analyses and considers different measures for the object and so-called ‘adaptation’ pathways, providing insight in the most cost effective solutions considering future uncertainties

This paper discusses the development and first testing of a valid, reliable, functional and simple indicator, that represents the long term effect of short term decisions. Such an indicator can assist counteracting short term views in network level asset management decision making. Short-termism or myopia may occur in cases where service level agreements (SLA) are made upon for shorter time frames than the typical lifecycles of transport infrastructure. The developed indicator indicates the “discounted future maintenance demand” (DFMD) for a time period stretching beyond the initial agreement period (expressed in a monetary value). The main assumption here is that the effect of short term decisions are reflected in the future maintenance demand. The indicator was applied in a case using existing data and information sources. Use of the DFMD, together with other (related) indicators provides valuable insight in understanding long term effects of short term decisions.

Surface consolidation is a common practice in the conservation of the built heritage. However, the effectiveness of consolidation of calcareous materials is often doubtful, due to the lack of effective and compatible consolidation products. Dispersions of calcium hydroxide nanoparticles in alcohol, the so-called nanolimes, can recover the superficial consolidation of calcareous substrates. Nevertheless, they are often not able to guarantee an in-depth consolidation. Previous research by the authors has demonstrated that the effectiveness of nanolime can be improved by fine-tuning the properties and the application protocol of the dispersions, based on the moisture transport properties of the material to be treated. In this paper, we verify the consolidation effectiveness and physical compatibility of the developed nanolimes, when applied on coarse porous calcareous materials like Maastricht limestone and lime-based mortars. The results show that a suitable mass consolidation can be achieved with nanolimes, while maintaining a good compatibility with the substrate material. © 2017 Elsevier Ltd

In design against fatigue, a lower bound stress range vs. endurance curve (S-N curve) is employed to characterize fatigue resistance of plain material and structural details. With respect to the inherent variability of the fatigue life, the S-N curve is related to a certain probability of exceedance, a percentile of the fatigue life. This paper is concerned with modelling and estimating uncertainties in fatigue resistance of welded joints under constant amplitude loading. A new S-N curve format is proposed and fitted to fatigue test data by using the Maximum Likelihood Method. The results have been compared with the Random Fatigue Limit Model and the Bilinear Random Fatigue Limit Model. The proposed S-N curve appears to be more accurate in describing the S-N relation in high-cycle fatigue: it presents a smooth transition from finite to infinite-life regions and, differently from previous non-linear S-N relations with fatigue limit, this transition is controlled by an independent model parameter. Thereby it provides more flexibility for statistical fitting. In addition, a Bayesian framework is defined to fit the proposed relation including informative and non-informative prior distributions. © 2017 Elsevier Ltd

Testing for the chloride threshold (also called critical chloride content) for corrosion initiation of steel in concrete has been found difficult and, at best, time consuming. Nevertheless, the chloride threshold is an important parameter in service life design of new structures and for evaluation of the remaining service life of existing structures. This paper reports on an accelerated test on mortar specimens that produces results within one week to a few weeks. It is based on accelerating chloride penetration by a mild electrical field while the steel potential is monitored. Upon corrosion initiation, specimens are sampled to obtain the chloride content that initiates corrosion. Results are reported of testing in CEM I (OPC) mortar on multiple specimens. Results for reference mortar are compared to specimens with application of a hydrophobic surface treatment. The results show that in reference CEM I mortar values for the critical threshold were obtained that agree well with previous experiments using the same method. This is taken as a validation of the method. The method is thought to be suitable for comparative chloride threshold studies of different binders, without or with corrosion inhibiting additions. Results for mortar with surface applied hydrophobic treatment, however, are unexpectedly low, which is taken to suggest that the method is not suitable for (e.g. surface treated) material with inhomogeneous electrolytic conduction. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfra

Many of the Dutch movable hydraulic structures are exceeding lifetime expectancy based on the then-current standards and regulations. Also signs of ageing become apparent, regulations (e.g. about structural safety) get more and more strict and functional requirements have often increased over time due to climate change and socio-economic developments. Therefore Rijkswaterstaat wants to ensure that these hydraulic structures (and it’s system of operation) always complies to an adequate performance level. This by setting up an systematic approach replacing hydraulic structures based on their cost-effectiveness and future uncertainties. To provide useful information regarding this method a probabilistic performance framework has been set up. This framework links the performance of the object (IJmuiden Pumping Station) with the performance of the system (Noordzeekanaal & Amsterdam-Rijnkanaal) and defines, analyses and considers different measures for the object and so-called ‘adaptation’ pathways, providing insight in the most cost effective solutions considering future uncertainties

Modular expansion joints constitute a substantial part of direct and indirect costs of bridge maintenance. Joint condition assessments can be improved to predict or detect damages earlier. In this way the probability for consequential damages such as emergency repair and a shortened lifespan is reduced. Maintenance can be planned well in advance to reduce congestion. An Early Warning Monitoring System (EWMS) for a so-called lamellae joint was successfully operated on the Martinus Nijhoff bridge. Technically it is feasible to upgrade such systems to deliver predictive information. Wider application is hindered by an unclear cost/benefit ratio. A cost benefit analyses is reported for monitoring all 166 of such joints installed in 62 bridges in the Dutch highway net

Different analytical models exist to predict the shear strength of reinforced concrete members. Generally, each of these shear strength models consists of a formulation based on certain underlying theory and fitted model coefficients. The model fitting parameters are usually established from the comparison with test data. Hence, the predictive value of a shear strength model depends, to some extent, on the quality and representativeness of the used test data. This work investigates the predictive capability of several shear strength models for reinforced concrete beams without shear reinforcement. Particular attention is given to the application domain of relatively low reinforced and high depth concrete beams where limited shear test data is available. The predictive capability of the models for this area of interest is analyzed with Bayesian Inference. This probabilistic technique calculates the posterior distributions of uncertain parameters, given a set of measured test data and some prior knowledge. The predictive capability of each shear strength model is quantified by means of a calculated model uncertainty. Furthermore, the influence of the uncertainty in model parameter values on the calculated model uncertainties is evaluated. Bayesian Inference is also used to estimate the model evidences conditionally on the used data.

Tuffstone elements with a large length/width ratio, as e.g. mullions, often suffer damage in the form of cracks parallel to the surface and spalling of the outer layer. The response of tuff to moisture might be a reason for this behaviour. This research aimed at verifying if a differential dilation between parts with different moisture content (as outer and inner part of partially encased mullion) can lead to damage. The effect of moisture on the degradation of Ettringen and Weibern tuff has been investigated. A purpose-made weathering test was carried out to simulate the wetting-drying process. Despite no cracks developed during the test, existing cracks widened up and the flexural tensile strength of both materials decreased. The moisture transport properties of the stones were determined as well as their porosity and pore size. Ettringen tuff has a considerable amount of very fine porosity, resulting in slow moisture transport and significant hygroscopic adsorption. Both tuffstones have an extreme hydric dilation. Environmental X-ray diffraction analyses showed that Ettringen tuff undergoes (reversible) mineralogical changes when subjected to RH cycles, whereas this does not occur for Weibern. All results support the hypothesis that moisture gradients in tuff elements may enhance decay in this stone.

Kenmerkend voor de polders in Nederland zijn de vele waterkerin-gen die zorgen voor een fysieke scheiding tussen land en water. Aangezien men vanuit de polder tegen deze waterkeringen aan kijkt ontstaat er echter ook een visuele scheiding. Kunstenaar Paul Izeboud kwam op het idee om deze visuele scheiding op te heffen door middel van een doorzichtige waterkering

Testing for the chloride threshold (also called critical chloride content) for corrosion initiation of steel in concrete has been found difficult and, at best, time consuming. Nevertheless, the chloride threshold is an important parameter in service life design of new structures and for evaluation of the remaining service life of existing structures. This paper reports on an accelerated test on mortar specimens that produces results within one week to a few weeks. It is based on accelerating chloride penetration by a mild electrical field while the steel potential is monitored. Upon corrosion initiation, specimens are sampled to obtain the chloride content that initiates corrosion. Results are reported of testing in CEM I (OPC) mortar on multiple specimens. Results for reference mortar are compared to specimens with application of a hydrophobic surface treatment. The results show that in reference CEM I mortar values for the critical threshold were obtained that agree well with previous experiments using the same method. This is taken as a validation of the method. The method is thought to be suitable for comparative chloride threshold studies of different binders, without or with corrosion inhibiting additions. Results for mortar with surface applied hydrophobic treatment, however, are unexpectedly low, which is taken to suggest that the method is not suitable for (e.g. surface treated) material with inhomogeneous electrolytic conduction. © Springer International Publishing AG 2018. Bam; Cement and Beton Centrum; et al.; Rijkswaterstaat - Ministry of Infrastructure and the Environment; Van Hattum en Blankevoort; VolkerInfra

The KGO mixing method was developed 40 years ago. Instead of adding the bitumen at the end of the mixing cycle, the bitumen was poured down first together with the larger aggregates. After mixing the bitumen with the larger aggregates, the reamining aggregates were mixed down. As benefits of the KGO method were mentioned improving the workability and shortening the needed compaction time. In this study it was investigated if the KGO method and a longer mixing time could improve the mechanical properties of asphalt mixtures. To investigate the influence on workability and compactability the indirect tensile strength was determined of gyratory compacted specimens produced with the KGO method and different mixing times. Form the results it can be concluded that a longer mixing time didn't have an effect om both. A modified mixing sequence has a positive influence on the workability and the indirect tensile strength. © 2016 Taylor & Francis Group, London. Dutch Ministry of Infrastructure and the Environment; Fahe China; Lucobit AG

Article 13 of the EU Directive on minimum safety requirements for tunnels in the Trans-European Road Network states that a risk analysis, where necessary, shall be carried out. In the Netherlands, the risk of death for road users in a tunnel is calculated with a model for quantitative risk analysis, which is called “QRA-tunnels”. QRA-tunnels is not suitable to explicitly calculate the risk in tunnels with additional ramps, exits and weave sections. The model does not foresee input for additional ramps. In [Nelisse 2012, Nelisse 2014] the method to “Calculate Additional Ramps Explicitly (CARE)” has been presented, enabling the explicit calculation of the risk in a tunnel with additional ramps. However, in this research remained an open point: the group risk with ramps is, on some points in the fN curve, lower than the group risk without ramps. This is contradictory to our expectations. In this paper it is further explored why the group risk with ramps can be lower and recommendations are given on how the current method may be improved

Pipeline networks for gas and water are the lifelines of our society. Their presence and correct functioning translates in benefits and any disruption, malfunctioning or ruptures represent hazards for the community. Most pipelines are buried, which impedes direct monitoring of the structural reliability of the networks. The behavior of the soil surrounding the pipes in combination with the network layout may impose hazardous deformations, threatening the integrity of the network. Reducing the uncertainty with respect to present and future soil displacements and their effect on the structural response of the pipelines is one of the key instruments for improving condition and risk based asset management strategies. The paper describes steps and results from a Dutch joint research project that connects the effects of spatial variability in soil layering and properties, the effects of spatial building activities carried out in the past and the physical and geometrical properties of the pipeline networks into annual exceedance probabilities of performance loss.

Occasionally, a profound but distant connection between volcanos and culture exists. This is the case for the volcanic Eifel region in Germany and historic construction in the Netherlands, with the river Rhine as physical and enabling connection. Volcanic tuff from the Eifel comprises a significant amount of the building mass in Dutch built heritage. Tuffs from the Laacher See volcano have been imported and used during Roman occupation (hence called K5mer tuff). It was the dominant dimension stone when construction in stone revived from the 10th century onwards, becoming the visual mark of Romanesque architecture in the Netherlands. Kimer tuff gradually disappeared from the market from the 12th century onwards. Early in the 15th century, Weibern tuff from the Riedener caldera, was introduced for fine sculptures and cladding; it disappears from use after about a century. Late 19th century, this tuff is reintroduced, both for restoration and for new buildings. In this period, Ettringen tuff, also from the Riedener caldera, is introduced for the first time. Ground Rmer tuff (Rhenish trass) was used as a pozzolanic addition to lime mortars, enabling the hydraulic engineering works in masonry that facilitated life and economics in the Dutch delta for centuries

Reliability analysis is a crucial phase in assessing the safety status of new and existing structures. One of its applications is to predict the fatigue life of fatigue prone details. Two models are used to formulate the fatigue limit state: S-N curves in combination with Palmgren-Miner damage accumulation rule and linear elastic fracture mechanics using fatigue crack growth rate curves. Within each model, choices must be made on the values of the variables and these choices are sometimes different in different standards. This study investigates the consistency between the standards by determining the failure probability of the different models and values for a transverse butt weld joint under Variable Amplitude Loading. Partial factors required for the design are then derived as a function of the required reliability for each model and associated values. The influence of the uncertainties related to each involved variable is evaluated by performing a sensitivity analysis.

Clause 6.2 of EN 1993-1-1 covers the cross-sectional resistance of steel sections. The bending-shear interaction design rules for I-shaped cross-sections make use of a reduced yield stress for the web area. On this basis, a reduced design plastic resistance moment allowing for the shear force is presented. The effect of shear on the bending resistance may be neglected if the shear force is less than half of the plastic shear resistance of the cross-section. Plasticity in the Eurocode is described by the well-known Von-Mises yield criterion, however, the formula used for the reduced yield stress deviates from this criterion, resulting in sometimes greater and sometimes smaller values. The background of the Eurocode formula for reduced yield stress can be found in a publication by Drucker. The purpose of the present research is to investigate the influence of shear on the bending resistance of I-shaped steel cross-sections with as result a possible reconsideration of the Eurocode design rules. At Eindhoven University of Technology an experimental investigation on bending-shear interaction in rolled steel I-shaped sections was performed. A numerical model was developed in Abaqus Finite Element software to simulate the experiments. With the validated numerical model a larger database of numerical ‘test’ results was generated, which was subsequently used in a statistical analysis following Annex D of EN 1990 as further developed in the RFCS project Safebrictile. The statistical distributions of the steel properties recommended by Safebrictile were adopted. This paper presents the results of the statistical analysis and safety assessment of the strong axis bending-shear interaction design rule currently present in Eurocode 3. The parametric test group consists of HEA, HEM and IPE sections in the steel grades S235, S355 and S460: in total 180 numerical simulations with increasing amount of shear. A stress-strain model including strain hardening was used in the numerical simulations, since the influence of strain hardening is also largely present in the experimental test program. Based on strain hardening material behavior it is show in this paper that the current partial factor is un-conservative for shear dominated beams and should be increased. Alternatively, the design rule should be modified.

For many concrete infrastructural works a service life of 80, 100 or 200 years is required. To convince owners and authorities that these requirements can be met probability-based models for service life predictions have been developed. These models are based on theoretical and experimental laboratory studies. Many of these models focus on the probability of chloride-induced rebar corrosion. For a check of the reliability of one of these models, i.e. the DURACRETE model, predicted chloride profiles have been compared with chloride profiles measured in five marine concrete structures. Lessons learned from these existing structures in view of the reliability of numerical service life predictions are presented in this paper.

In a BIM data flow, an essential part of the coordination between disciplines is the agreement on recesses and openings in building elements. Different disciplines will request recesses and openings in elements that are managed and maintained by others. Using the full dataset of the elements has proven to be inoperable because of the information overload, interoperability problems and contradictions in the commonly used downstream dataflow. A group of companies has been experimenting with the exchange of data that only consists of the requested openings and recesses in IFC. Coordination is being done using BCF. This approach has been fine-tuned and adjusted during several projects. This paper describes the current status of that initiative and discusses the challenges that are still open.

For many concrete infrastructural works a service life of 80, 100 or 200 years is required. To convince owners and authorities that these requirements can be met probability-based models for service life predictions have been developed. These models are based on theoretical and experimental laboratory studies. Many of these models focus on the probability of chloride-induced rebar corrosion. For a check of the reliability of one of these models, i.e. the DURACRETE model, predicted chloride profiles have been compared with chloride profiles measured in five marine concrete structures. Lessons learned from these existing structures in view of the reliability of numerical service life predictions are presented in this paper.