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Mooring systems that are used to secure position keeping of floating offshore oil and gas facilities are subject to deterioration processes, such as pitting corrosion and fatigue crack growth. Past investigations show that pitting corrosion has a significant effect on reducing the fatigue resistance of mooring chain links. In situ inspections are essential to monitor the development of the corrosion condition of the components of mooring systems and ensure sufficient structural safety. Unfortunately, offshore inspection campaigns require large financial commitments. As a consequence, inspecting all structural components is unfeasible. This article proposes to use value of information analysis to rank identified inspection alternatives. A Bayesian Network is proposed to model the statistical dependence of the corrosion deterioration among chain links at different locations of the mooring system. This is used to efficiently update the estimation of the corrosion condition of the complete mooring system given evidence from local observations and to reassess the structural reliability of the system. A case study is presented to illustrate the application of the framework.

This paper contributes to the ongoing discussion on the tentative target reliability levels for the design of structures and calibration of codes. The proposed extension of the existing approaches for code optimisation allows a consistent calibration of codes through all levels of design. The basis is taken from the normative decision theory as the rational strategy for taking decisions under risk. The method proposed supports code-making by optimizing reliability elements accounting for i) the safety format adopted in the code, ii) the design level that is regulated, and iii) the differences among the design cases regulated by the same code. Some of the decision theoretical aspects that are object of discussions in the research community are addressed. The work aims at providing a more robust and transparent background to target reliabilities in design standards.

Currently, there is a need to enhance the basis for decisions in the management of Civil Engineering infrastructure, explained by the evolution of social paradigms, such as the prioritization of gr...

With the ever-increasing popularity of engineered wood products, larger and more complex structures made of timber have been built, such as new tall timber buildings of unprecedented height. Designing for structural robustness in tall timber buildings is still not well understood due the complex properties of timber and the difficulty in testing large assemblies, making the prediction of tall timber building behaviour under damage very difficult. This paper discusses briefly the existing state-of-the-art and suggests the next step in considering robustness holistically. Qualitatively, this is done by introducing the concept of scale, that is to consider robustness at multiple levels within a structure: in the whole structure, compartments, components, connections, connectors, and material. Additionally, considering both local and global exposures is key in coming up with a sound conceptual design. Quantitatively, the method to calculate the robustness index in a building is presented. A novel framework to quantify robustness and find the optimal structural solution is presented, based on the calculation of the scenario probability-weighted average robustness indices of various design options of a building. A case study example is also presented in the end. © 2020 The Authors, Engineering Structures, 227, ISSN:0141-0296

Aging bridges in combination with an ever-growing traffic volume are a matter of concern all over the world. Consequently, the reassessment of existing bridges is gaining importance rapidly. This paper presents two bridge case studies considered within the IABSE Task Group 1.3 “Calibration of Partial Safety Factors for the Assessment of Existing Bridges”. The so-called design value method (DVM) and adjusted partial factor method (APFM), introduced in fib Bulletin 80 and both relying on a partial factor format, are considered in this paper. The objectives are (i) to illustrate how DVM and APFM can be used when specifying partial safety factors for assessment of existing bridges, and (ii) to discuss some of the assumptions that are implied by these methods. Two case studies are considered for illustration in this paper: a single span reinforced concrete slab and a 3-span continuous reinforced concrete slab.

Fatigue is one of the main failure mechanisms of catenary type mooring lines. Fatigue resistance is affected by a large number of factors. In this paper, the effect of pitting corrosion on the fatigue resistance of mooring lines is empirically estimated. Data from fatigue testing of both new and used chain links are considered. The used chain link samples were retrieved from several offshore floating units. A hierarchical statistical analysis is proposed to effectively use the available information. Mean stress effect is taken into account in the analysis of the data. Results show that the effect of pitting corrosion on the structural reliability of mooring lines is significant.

To date, our built environment is broadly developed and maintained on the basis of structural design standards. Most design standards contain simplified semi-probabilistic safety concepts that help daily structural engineering decision making using simple calculus. For few projects, the semi-probabilistic safety concept is replaced by advanced probabilistic methods that allow for reliability-based design. Neither include explicit consideration of optimality criteria. However, for the development and the calibration of the semi-probabilistic and probabilistic safety concepts it is important that societal preferences in regard to risk acceptance and the optimal use of natural resources are explicitly considered. In the present contribution, the development and calibration of semi-probabilistic and probabilistic structural design standards is represented as a formal decision problem allowing an optimal combination of reliability elements to be identified.

The performance to withstand biodeterioration of highly insulated walls is evaluated by applying a probabilistic-based methodology that accounts for the involved uncertainties and investigates their significance. Three approaches to representing the outdoor climate are investigated by varying the method and time duration. The temperature-dependent thermal conductivity of the insulation material is measured, and subsequently, a stochastic model is proposed to represent this property. Deficiencies, considering penetration of wind-driven rain, are accounted for and represented by moisture sources in a parametric way. A sensitivity analysis is performed to identify the influential parameters, and subsequently, simplify the system representation by reducing the number of input variables in order to reduce the computational efforts. The timber ventilated walls show satisfactory performance to withstand biodeterioration unless potential deficiencies are considered. The study demonstrates that the probabilistic-based methodology enables a more systematic approach to evaluate wall constructions. It accounts for the involved uncertainties, provides a clear association of the microbial growth to its likelihood, and enables the identification and significance of the dominant parameters; hence, it delivers a more comprehensive conclusion regarding the performance of constructions.

Kurzfassung Rohstoffe und Materialien stellen bei Industrieunternehmen häufig den größten Kostenblock dar. Daher lässt sich mit einer Erhöhung der Materialeffizienz direkt ein positiver Einfluss auf das Ergebnis realisieren. Trotz dieser Ergebniswirkung steht die Materialeffizienz bei vielen Unternehmen nicht im Fokus. Mit diesem Beitrag wird anhand eines Praxisbeispiels aufgezeigt, welche ergebniswirksamen Einsparungen möglich sind und ein Lösungsansatz beschrieben. Dieser beinhaltet ein zielgerichtetes Vorgehen inkl. Methoden um Unternehmen aus verschiedenen Branchen und mit unterschiedlichen Herausforderungen zum Ziel „Materialeffizienz“ zu begleiten.

A framework for calibrating the reliability elements in simplified semi-probabilistic design safety formats is presented. The objective of calibration is to minimize the increase of construction costs, compared to the non-simplified safety format, without reducing the level of structural safety. The framework is utilized for calibrating two simplified safety formats which aim at reducing the number of load combinations relevant in structural timber design. In fact, the load-duration effect makes the design of timber structures more demanding since a larger number of load combinations need to be considered compared with other construction materials. This is the authors' manuscript to the article (preprint).

This paper presents a systematic literature review about the development of criteria and models representing mould growth in wood-based materials. First, results from experimental research regarding factors governing mould growth are discussed; afterwards, they are used to analyse the comprehensiveness of current mould models. The review shows substantial discrepancies between criteria reported for mould growth. Moreover, mould models differ with respect to governing factors and their interrelations, applied methodology, experimental set-ups and nutrients, and how they express mould. Lastly, this paper proposes solutions that account for or reduce uncertainties related to the representation and design against mould occurrence.

The different phases of a structure’s life-cycle are managed by different teams with little interaction. Correspondingly, the optimization of the individual phases is isolated and does not necessarily result in optimal life-cycle decisions. This motivates the treatment of structural optimization from a broader life-cycle perspective. A framework to enhance the design of structural systems by considering the operation and maintenance phase in the decision process is proposed in this article. The framework focuses on fatigue prone details, but it can be extended to consider other deterioration mechanisms. A hierarchical influence diagram is proposed as an efficient way to represent the probabilistic decision problem while considering system effects, such as the correlation of the deterioration among hot-spots. A simple example is presented to illustrate the implementation of the framework. Challenges and potential applications are discussed. This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers.

A critical analysis of the hysteresis models of wooden connections has led to an alternative analytical formulation of the pinching phenomenon. Starting from the generalized Bouc-Wen model,...

A large part of the investment in public infrastructure is dedicated to designing and constructing the infrastructure and to mitigating deterioration processes, such as corrosion and fatigue damage. In practice, the different phases of a structure’s life-cycle are managed by different teams with little interaction. Unfortunately, the optimization of the individual phases does not necessarily result in an optimal life-cycle cost. This motivates the development of models and procedures that treat structural optimization from a broader life-cycle perspective. This paper discusses the possibility to enhance the design of structural systems by reflecting the operation and maintenance phase in the design decision framework. The inter-dependency between decisions made at different points during the life-cycle is accounted for by means of a sequential decision analysis. A hierarchical influence diagram is proposed as an efficient way to model the probabilistic decision framework while considering system effects, such as the spatial correlation of the deterioration mechanisms. Challenges in the implementation of the framework are documented and potential applications are discussed. A simple example is presented to assess the performance of the model.

Reinforced concrete structures constitute an essential part of the building infrastructure. This infrastructure is aging, and a large number of structures will exceed the prescribed service period in the near future. The aging of concrete structures is often accompanied by corresponding deterioration mechanisms. One of the major deterioration mechanisms is the corrosion of the reinforcing steel, caused by chloride ions and carbon dioxide exposure. Here, a generic framework for the stochastic modeling of reinforced concrete deterioration caused by corrosion is presented. This framework couples existing probabilistic models for chloride and carbonation initiation with models for the propagation and consequences of corrosion. For this purpose, a combination of structural reliability analysis and Bayesian networks is used to estimate the probability of failure of a reinforced concrete structure. This approach allows the calculation of probabilities of rare events for simple structures in an efficient and consistent way to update the model with new information from measurements, monitoring and inspection results. The generic framework enables a holistic view of the current service life models. Corresponding sensitivity studies, finding optimal decisions for treating deteriorated reinforced concrete structures and temporal changes of structures can also be represented and analyzed within this framework.

Assuming given corrosion states this paper studies the effect of interference of corrosion pits on adjacent rebars on the probability of bending failure of a corroded reinforced concrete beam. Spatial distribution of localised corrosion along a beam is considered in the analyses. The probability of failure is estimated using Monte Carlo simulation. Uncertainties in material properties, geometry, loads, and corrosion damage are taken into account. Statistical data for the extent and location of corrosion is taken from literature and utilized in order to calibrate parameters of corresponding probability distribution functions. Results show that considering possible interference of localised corrosion has substantial influence on the estimated probability of failure. The results are compared with results from two practical methods which appeared not always to be conservative.

The built environment, i.e. infrastructural elements, industrial buildings and facilities as well as residential buildings, constitutes the basis for our economy and the continuous development of our society. In this respect structures play an important role, since the primary purpose of structures is to provide the functionality of the built environment and the safety of its users. Consequently, a large proportion of the societal economic resources are invested into the continued development, maintenance and renewal of structures. Due to the high importance of structures and the large amount of economic resources invested for development, maintenance and renewal it is of utmost importance that decisions made in connection with structures are optimal. Optimal in the sense that the benefit of structures as well as the possible adverse consequences such as loss of lives, damage to the qualities of the environment and the direct and committed costs are considered and optimal decisions are identified.In the present contribution, risk and reliability methods in structural engineering is briefly introduced by an indicative example. It is emphasized on the general and recent challenges also for the development of semi-probabilistic design standards.

This paper provides an overview, insights, results and a classification related to development and analyses of case studies within the scientific networking project COST Action TU1402 on the value of Structural Health Monitoring (SHM) information. With an outline of the framework and approaches, a procedure on how to quantify the value of SHM information on the basis of the Bayesian decision theory is described. Various case studies with different types of structures (e.g. stadium roof, timber structures, offshore wind parks), several types of SHM systems (e.g. structural measurements, damage detection) and with diverse decision scenarios (e.g. structural system properties, SHM system properties, different SHM systems for structural service life extension) are outlined. Approaches for value of SHM information analyses visualisation and classification, both for the purposes of development of decision scenarios and for the comparison of case study results are introduced and described. Whereas the development of value of SHM information analyses is focussed on the establishment of a decision scenario, the comparison of analyses should also include the identification of optimal SHM information acquirement strategies, actions and decision rules beside an indication on which methodological and technological readiness level the analyses has been performed. The paper concludes with open fields identified when applying the visualisation and classification tools.

Monopiles are the most common offshore wind turbine support structures. They are to be designed so that resonance with the rotor-passing excitation is avoided. However, the estimation of the eigenfrequencies is strongly influenced by the soil-structure interaction, whose characterization with prior information is associated with large uncertainties. No clear guideline is given regarding the safety margin to be left between the structure first natural frequency and the excitation regions. In this paper, the expected consequences of leaving a certain margin are studied and quantified. The decisions regarding the investment in site-specific characterization are coupled into the decision scenario by means of a value of information analysis. The results provide insight on the efficient allocation of resources at the design point in time and the sensitivity of the decisions regarding the probabilistic characterization of the design scenario.

Submerged floating tunnels (SFTs), also known as Archimedes’ bridges, allow crossing waterways where common bridges, underground tunnels or immersed tunnels are not feasible. In spite of this, no SFTs have been built yet in the world except for a prototype in China. The reasons are numerous and widely discussed in literature. The lack of past experience and ad hoc design codes or guidelines represents a great challenge in design. In fact, the direct use of target reliabilities and design codes, which are specifically developed for common structures and adapted through the years based on the gained experience, is questionable. This is because STFs might be characterized by different failure consequences and marginal safety costs. Optimal target reliabilities can be estimated through a full-risk assessment following the ISO standard 2394:2015 guidelines. Successively simpler design approaches and assessment of decisions such as reliability-based and semi-probabilistic design can be calibrated.

In the presented paper, different NDT, SDT and DT inspections methods are introduced and their efficiency in respect to a quantitative estimation of the load-bearing capacity are discussed. Thereby it is particular focused on inspections methods for the estimation of the load-bearing capacity of glued laminated timber. The estimation of the load-bearing capacity of structural components, based on different types of information, is presented by using Bayes updating. For this purpose, the information is classified according to their characteristics and the corresponding procedures for estimation of the load-bearing capacity are presented. The paper concludes with a discussion about the application of Bayes updating for the decision support, of partly damaged constructions.

In this paper, a probabilistic approach for modelling the load-bearing capacity of glued laminated timber is presented. The specific characteristic of this approach is that, at first, timber boards are simulated according the natural growth characteristic of timber. Subsequent, glued laminated timber beams are virtually composed out of the simulated timber boards. Thereby, every kind of fabrication procedure, such as the length of the timber boards or the beam dimensions, can be recreated. Afterwards, a numerical model is used to estimate the load-bearing capacity, the bending stiffness and the type of failure of the simulated GLT beams. To ensure the quality of the numerical model it is validated with 24 GLT beams with a precisely-known beam setup; a wide agreement between the measured and the estimated material properties is identified. For a probabilistic investigation of different input parameters a Monte Carlo simulation is performed. The application of the presented approach is illustrated on selected examples (size effect, the quality of finger joint connections and grading criteria).

The article presents a contribution to the current debate on the probabilistic representation of the wind speed extremes for calibration of the partial safety factor covering wind action. The requirements for the probabilistic model are formulated. The Gumbel distribution is shown to represents best the 10-min mean wind velocity yearly maxima based on theoretical considerations and analyses of real data with different statistical techniques. Data from locations across a large geographical region indicate that the coefficient of variation of the distribution varies over the territory. A method is proposed for accounting this variation in order to calibrate a single partial safety factor for the whole territory. The distribution location is indirectly given in design standards through the georeferenced characteristic wind speed values. A solution for including the uncertainty affecting these values is suggested. The findings are implemented in an illustrative calibration exercise. The proposed methods and concepts might be applied to other environmental actions such as the snow loads.

A hierarchical model for the variability of material properties in ready‐mixed concrete is formulated. The model distinguishes between variation on the batch, recipe, plant, producer, durability class, strength class, and regional standard level. By considering Bayesian inference and maximum likelihood estimators, the contributions from the different hierarchical levels to the variability can be estimated. The methodology is demonstrated by considering more than 14,000 compressive strength recordings from Norwegian ready‐mixed concrete plants. The results suggest that the compressive cube strength of lab‐cured specimens can be represented by a log‐normally distributed variable with mean 1.28fck,cube and coefficient of variation Vc,cube=0.13. Prior parameters for Bayesian updating are given for a range of strength and durability classes. The application of the results is demonstrated in two examples. Since the durability class gives a required maximum water–binder ratio, and the strength of the concrete is governed by the water–binder ratio, the durability class introduces a strength potential if the concrete is subject to strict durability requirements and low‐strength requirements. It is suggested that the designer should specify a strength class that utilizes this strength potential, and it is expected that a closer collaboration between the designer, contractor, and producer will result in improved concrete specifications. This is the peer reviewed version of an article, which has been published in final form at [https://doi.org/10.1002/suco.201700950]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

The design of cross laminated timber (CLT) structures is not included in the current version of European structural timber design standards of EN 1995 (Eurocode 5, EC 5). Due to the increasing importance of CLT, in different applications such as complete wall or floor elements as well as girders, it is one of the main goals of the currently ongoing revision of EC 5 to provide design principles for CLT structures. In the present paper some general aspects, relevant for the implementation of CLT in European standards in order to be consistent with the general philosophy of the Eurocodes are summarized and discussed. The differences between standard test specimens and structural components as well as the uncertainties related to the production procedure of CLT and the non-standardized test procedure are discussed. An investigation of 12 different test series from five different producers clearly indicates a large variation between different production series. Based on the investigation from the test series a reliability analysis is performed. The results indicate that the same partial safety factor as recommended for glued laminated timber (GLT) is appropriate in order to achieve an acceptable reliability. However, the analysis also indicates the potential for a smaller partial safety factor in the future, in case that the production of CLT is standardized and appropriate standardized test methods for the individual material properties exist.

Connections with metal dowel-type fasteners are important details in timber construction, connecting single members and elements to larger structures. The load-carrying capacity can be described by different failure modes of the fasteners and in the surrounding timber. These failure modes show a dependency on different dimensions and material properties. The failure can be classified into brittle and ductile failure modes based on the deformation capacity. The limited deformation capacity of the brittle failure modes has an impact on the load-carrying capacity of the entire connection with multiple fasteners. The present study takes a critical appraisal of load-carrying capacity and deformation capacity of timber connections and the implementation of their design in the Eurocode 5. By aiming for the ductile failure modes with plastic deformation of the fasteners in the design of the connection, high load-carrying capacities and high reliability can be achieved. For brittle failure modes the reduced resistance and the reduced reliability should be accounted for, especially for connections with multiple fasteners.

Fire risk models support decision making for engineering problems under the consistent consideration of the associated uncertainties. Empirical approaches can be used for cost-benefit studies when enough data about the decision problem are available. But often the empirical approaches are not detailed enough. Engineering risk models, on the other hand, may be detailed but typically involve assumptions that may result in a biased risk assessment and make a cost-benefit study problematic. In two related papers it is shown how engineering and data-driven modeling can be combined by developing a generic risk model that is calibrated to observed fire loss data. Generic risk models assess the risk of buildings based on specific risk indicators and support risk assessment at a portfolio level. After an introduction to the principles of generic risk assessment, the focus of the present paper is on the development of a generic fire risk model for single family houses as an example. The risk model considers the building characteristics of a single family house as well as the uncertainties associated with the fire spread in a building and the intervention of the fire brigade.

The occupant load density is a crucial parameter for the design of the means of egress in buildings. In retail buildings the occupant load density is highly influenced by the individual׳s choice and the necessity of a person to visit the store. This causes a high variability of the occupant load density in time. An accurate representation of this variability will provide a basis for enhancing fire safety design. In this paper, a probabilistic approach is used to describe the variability of the occupant load density over a year, based on long-term data of customer frequencies in combination with methods from the queuing theory the distribution of the occupant load density is derived for four different types of retail chains. It is shown that the type of a retail chain has a large influence on the distribution of the occupant load density and that the exceedance probability of current design values in different standards is very small. A method is proposed to derive design values for a performance based design on the basis of probabilistic models for the occupant load density. In addition, the developed probabilistic models describing the number of occupants in a store, allow the assessment of the occupant load density for other types of retail chains, even with incomplete data.

In the present paper, a model for the prediction of the local strength and stiffness properties is developed. Compared to existing models, here the local material properties are described according to their morphological characteristics; i.e. the timber boards are subdivided into sections containing knots (knot sections) and sections without knots (clear wood sections). The strains of the corresponding sections are measured during non-destructive tensile tests using an optical camera device. Based on these measurements the tensile stiffness of each particular section is estimated. For the estimation of the tensile strength, destructive tensile tests are performed. Herewith, the tensile strength of the entire timber board is measured. The strength of the other knot clusters are estimated using censored regression analysis. Taking into account the results of the experimental investigation, material models are developed to predict the tensile strength and the tensile stiffness of knot clusters., European Journal of Wood and Wood Products, 72 (3), ISSN:0018-3768, ISSN:1436-736X

The paper presents a probabilistic model characterising tensile strength parallel to grain of Central European spruce boards without longitudinal joints. The effect of length of members on strength is considered explicitly by considering a member by a serial arrangement of weak sections triggered by major knots of knot clusters. In order to demonstrate the applicability of the proposed model the model parameters are calibrated based on the analysis of three samples of spruce of Switzerland (Mischler-Schrepfer, 2000 [25] ) and Austria (Schickhofer and Augustin, 2001 [28] ), in total 460 boards tested in full size. This model might serve as basis for studies concerning the length effect of boards relevant for solid timber structures as well as basis for judging the length effect of finger jointed construction timber and glulam, and as starting point for modelling the process of proof loading.

The present paper reports the results of an investigation regarding the study of the load-carrying capacity of connections with nails of small diameter pneumatically driven in timber-to-timber joints of fast-growing Argentinean Eucalyptus grandis. The effectiveness of the equations provided by Eurocode 5 for calculating the lateral load-carrying capacity of these joints was checked for the specimens exhibiting the geometrical parameters adopted by the European design rule and also for those with reduced spacing and end distances. A failure mode presenting features common to both j and k types of failure according to the criterion of the European design rule confirmed that the plastic hinges could be developed before brittle failure due to splitting or block shear occurred, even if the specimens present reduced spacing and end distances. The load-slip curves confirmed ductile behaviour for all cases. The empirical results showed that the structural design is situated on the conservative side if the equations adopted by Eurocode 5 are applied to the analysed connections when the spacing and end distances recommended by this design rule are used. The results also showed that the joint area may be decreased by up to 31 % in relation to that corresponding to the recommended spacing and end distances without reducing the load-bearing capacity below the characteristic value determined according to the European design rule.

Predicting mould growth on facade constructions during design is important for preventing financial loss, and ensuring a healthy and comfortable indoor environment. Uncertainties in predicting mould growth are related to the representation of the biological phenomenon, the climate exposure and the material uncertainties. This paper proposes a probabilistic-based methodology that assesses the performance of facade constructions against mould growth and accounts for the aforementioned uncertainties. A comprehensive representation of mould growth is ensured by integrating several mould models in a combined outcome. This approach enables a more comprehensible and useful illustration between continuous mould growth intensities and their corresponding likelihoods. The outdoor climate exposure is represented by stochastic models derived by real time-series analysis according to autoregressive–moving-average models. The methodology is applied to investigate the influence of several parameters and the performance of several construction assemblies. This paper proposes a method to evaluate the facade performance that can facilitate reliability-based design and optimisation of facade construction.

This paper systematically reviews mould models that are applicable to wood-based materials. Both similarities and differences are observed with respect to governing factors and their interrelations, methodology, experimental set-ups, substrate and extensiveness, and how the result is communicated. Therefore, a generic framework, representing the general computation procedure of all models, is developed considering the factors that govern mould behaviour. This framework, adapted to each model, is used to structure, evaluate and compare current models. This outline supplemented with a comparison table, revealing the models’ extensiveness and differences, establishes a basis to ensure better adequate application of the selected mould model for the case at handd © 2017 The Author(s). Published by Elsevier Ltd.. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

In order to make non-linear finite element analyses applicable during assessment of the global resistance of large concrete structures, there is need for a solution strategy with a low modelling uncertainty. A solution strategy comprises choices regarding force equilibrium, kinematic compatibility and constitutive relations. Relatively large solid finite elements and a fully triaxial material model for concrete were used in the present work. Bayesian inference was applied to results from 38 benchmark analyses. The results indicated that the modelling uncertainty could be represented as a log-normally distributed random variable with mean 1.10 and standard deviation of 0.12. A new method for characterizing the failure mode was developed. The results indicated that the physical uncertainties influenced the estimated parameters of the modelling uncertainty, and that this should be considered when other uncertainties are included in a reliability assessment. © 2016 Elsevier Ltd. This is the authors' accepted and refereed manuscript to the article, locked until 24 September 2018 due to copyright restrictions. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

This paper applies a probabilistic-based approach as a methodology to analyze and compare the mould growth computations’ results from three different mould models. This approach, instead of the conventional deterministic ones, offers the advantage of accounting for uncertainties concerning prediction of mould growth. The results are able to demonstrate more realistic and conclusive outcomes that can be applicable to real-life situations. © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC-BY-NC-ND 4.0 license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

In this paper we describe how ZF is using existing and upcoming Modelica standards for simulating a variety of systems in automotive industry. In particular, Modelica is employed for driveline modeling. The FMI standard is used to transport models over tool boundaries. The novel SSP standard will contribute towards interconnecting FMUs and defining complete system architectures.

Starting with the motivation to invent the new standard SSP (“System Structure and Parameterization”) within the Modelica Association and the need to have one more standard beyond the mature Modelica language and the already well established Functional Mockup Interface (FMI) proposed in Modelica Association (Blochwitz et al, 2011), the main use-cases are presented were SSP can help. As SSP relies on XML, the schemas and in consequence the main features for defining system structures and parameterization of models are described. The need to be able to transport complex networks of FMUs between different simulation platforms like MIL, SIL and HIL is emphasized as a motivator for SSP. A variety of prototypes are shown that support the early version of SSP. This gives a good impression how the standard can be used for quite different tasks and proofs, that system structures can be exchanged between them seamlessly. Finally the next steps for the ongoing development of SSP are outlined.

For the future development of a safe and efficient building infrastructure, it is of utmost importance to learn from past experience. In this paper, a scheme for the evaluation of experience gained from failures and malfunctions in timber structures is developed. It is highlighted that the main motivation to analyse structural failures is to learn from them. It is therefore stated that the description of the circumstances that led to structural failures is of highest importance. This is a somewhat different perspective compared to the structuring of information that can be found in existing studies on failed and malfunctioning structures in the literature. There, the focus is on the thorough description of the physical parameters related to the failures. The result of this paper is a proposed template for failure assessment that, in its complete extension, can be downloaded from the World Wide Web. The failure template is “ready to use”; however, it should mainly facilitate further discussions on the formulation on a broadly agreed format for how the structural engineering profession might standardise failure reporting.

The present paper reports on the results of an investigation regarding the determination of the embedding strength of sawn timber of Argentinean Eucalyptus grandis with dowel-type fasteners. The importance of accurately knowing this property has increased with the increasing demand for this material for structural purposes. An empirical research project with 294 specimens prepared for testing under the embedding action of rigid fasteners (nail, bolt and dowel) was carried out according to the procedures prescribed in EN 383 (2007). The results showed no significant influence of pre-drilling on the embedding strength for nailed joints, which is not in line with the European experience and the corresponding criterion adopted by the Eurocode 5 (2005). The characteristic values of the embedding strength estimated based on the timber density and by applying the corresponding equation from the Eurocode 5 (2005) for bolted joints were 45% and 176% greater than those obtained in this project for the specimens loaded parallel and perpendicular to the grain, respectively, and similar percentages were found for dowelled joints (45% and 126%). These results showed that the reliability of structural design may be strongly affected if the embedding strength of this timber species is estimated by following the procedures adopted by the Eurocode 5 (2005) for dowel-type connections.

Reliability analysis of structures for the purpose of code calibration or reliability verification of specific structures requires that the relevant failure modes are represented and analyzed. For structural timber, sustaining a life load, two failure cases for each failure mode have to be considered. These two cases are maximum load level exceeding load-carrying capacity and damage accumulation (caused by the load and its duration) leading to failure. The effect of both load intensity and load duration on the capacity of timber has been an area of large interest over the last decades; the effect of load duration is in general referred as duration of load (DOL) effect. Several research projects did address the DOL effect in the past and a number of different damage models, based on experimental evidence, have been formulated to describe the phenomenon. In the present paper, three different models for the representation of damage accumulation in timber are considered. The parameters of these models are calibrated by the use of test data whereas uncertainties associated with the model formulation and limited sample size are considered. The DOL effect is usually taken into account in code-based design of timber structures in terms of a modification factor k mod which is multiplied on the short-term resistance of the timber material. The scenario of a beam subject to office space life loads is analyzed and the modification factor k mod is calibrated by using the three different damage models.

The fire load has a strong influence on the fire development during a compartment fire and is a significant parameter in fire safety design methods. The assessment of the fire load is therefore an important task in fire safety engineering. This chapter reviews the methods to survey the fire load, discusses how variation during the life time of the building can be represented and how to derive design fire loads. An overview of past fire load surveys and a summary of fire load data for specific building types is provided as well.

In the present paper a probabilistic approach for modelling the tensile strength and tensile stiffness properties of timber boards and finger joint connections is presented. The approach includes the geometrical setup of timber boards (the position of knot clusters) and a hierarchical representation of two strength and stiffness related indicators. One indicator to describe the mean material properties of timber boards and one indicator to describe the lengthwise variability due to knots. Based on the two indicators the tensile strength and tensile stiffness of timber board sections and finger joint connections are estimated using material models. The application of the approach is illustrated. For this purpose, finger joint connections and timber boards with different length are simulated and the material properties are compared with values proposed in the literature., European Journal of Wood and Wood Products, 73 (3), ISSN:0018-3768, ISSN:1436-736X