Climate Load Research Articles

THE IMPACT OF PROJECTED CANADIAN REGIONAL CLIMATE MODEL DATA ON FLEXIBLE PAVEMENT PERFORMANCE

This paper explores the impact of projected climatic loading parameters, utilizing Environment and Climate Change Canada (ECCC) data, on flexible pavement performance and design. Despite the expectation that flexible roads should endure various structural and environmental conditions throughout their design life, premature damage often occurs within the initial three to five years of service. Therefore, understanding the impact of climate change on flexible pavements in the historical, short, intermediate, and long term becomes crucial. The Pavement Mechanistic Empirical Design (PMED) was employed to assess climatic loading effects on pavement design and performance. PMED predicted rutting performances showed sensitivity when comparing historical and projected climatic loading files up to 2093. Preliminary results based on a 25-year design life for City of Windsor revealed a 72% higher rutting impact compared to historical data, shortening the pavement's design life by 28%, 56%, and 68% for short, intermediate, and long terms, respectively.

A Comprehensive Approach to Facade Design for Preventing Rainwater Penetration: Implementation in Spanish Regions

Rainwater penetration into building facades results in multiple issues, including material and structural degradation, reduced energy efficiency, and health-related concerns among occupants. Currently, the watertightness performance of building facades is assessed based on standardized tests, which simulate generic water supplies and pressure differentials that do not reflect the specific exposure conditions of each facade. Consequently, practitioners’ decisions regarding facade design often rely on qualitative and imprecise criteria that do not align with the actual climatic loads. In this article, a comprehensive approach to facade design for preventing rainwater penetration is described, incorporating specific methodological refinements for reliable and practical implementation across various Spanish regions. In this approach, the parameters surpassed during any watertightness test (defined by the magnitude and duration of the water supplies and pressure differentials) are correlated with the recurrence of equivalent climatic exposures at the facade (determined by the climatic conditions of the site, facade height, and surrounding environment), thereby quantitatively characterizing the facade watertightness performance. The findings used to refine this method for implementation in Spain are illustrated and validated using selected case studies, and a comprehensive database is provided to enable its application at 360 locations distributed across various regions of the country.

Future Climate Projections and Uncertainty Evaluations for Frost Decay Exposure Index in Norway

To implement the geographical and future climate adaptation of building moisture design for building projects, practitioners need efficient tools, such as precalculated climate indices to assess climate loads. Among them, the Frost Decay Exposure Index (FDEI) describes the risk of freezing damage for clay bricks in facades. Previously, the FDEI has been calculated for 12 locations in Norway using 1961–1990 measurements. The purpose of this study is both updating the FDEI values with new climate data and future scenarios and assessing how such indices may be suitable as a climate adaptation tool in building moisture safety design. The validity of FDEI as an expression of frost decay potential is outside the scope of this study. Historical data from the last normal period as well as future estimated climate data based on 10 different climate models forced by two emission scenarios (representative concentration pathways 4.5 and 8.5) have been analyzed. The results indicate an overall decline in FDEI values on average, due to increased winter temperatures leading to fewer freezing events. Further, the variability between climate models and scenarios necessitates explicit uncertainty evaluations, as single climate model calculations may result in misleading conclusions due to high variability between models.

Influence of pulse-like motions and extreme environmental loads on the seismic foundation response of offshore wind turbines on layered liquefiable soils

Monopile foundations are known as the most common foundation solution for offshore wind turbines (OWTs). However, the state of practice for designing monopile foundations in high seismicity areas is still limited. In particular, the impact of soil liquefaction on the seismic soil-foundation-OWT interaction is not yet well understood. In this paper, three-dimensional (3D), fully-coupled, nonlinear finite-element analyses performed in the OpenSees numerical platform were used to evaluate the seismic performance of a series of hypothetical 5 MW OWTs on monopile foundations in layered, liquefiable sites. A suite of earthquake recordings with and without strong velocity pulses (i.e., near fault, pulse-like and ordinary motions, respectively) was used to investigate the impact of ground motion characteristics on the seismic response of the OWT system. Also, the influence of soil-structure interaction and earthquake shaking coupled with extreme environmental loading (i.e., wind and wave loads) on the seismic performance of soil-OWT systems was evaluated. The numerical results showed pile movements induced by extreme climate loading led to a bias in permanent settlement accumulation across the foundation area and accumulation of soil deformations in the proximity of the pile. Ground motion velocity pulses increased the cyclic stress demand in soil and, therefore, the potential for the occurrence of soil liquefaction. A subsequent, limited numerical sensitivity study showed that the foundation rotations of the OWT system were influenced by ground motion characteristics such as polarity and velocity pulses, and the presence of the wind and wave loads. The cumulative absolute velocity (CAV) was identified as the optimum ground motion intensity measure for permanent foundation settlement and tilt as well as for peak transient foundation tilt of the OWT system under extreme environmental loadings. The net outcome of these factors determined the magnitude and orientation of the foundation rotations at the end of shaking. This study highlights the importance of considering the effects of extreme loadings and pulse-like motions in the design and performance of OWT systems.

Changes to the Regulatory Definition of Climatic Loads and Impacts on Building Structures

Purpose. The main purpose of the publication is a qualitative and quantitative analysis of changes in climate loads associated with the introduction of the DBN V.1.2–2:2006 standard in the national regulatory framework, compared to the previous standard, as well as further changes to this standard. Methodology. To achieve this goal, both the standards for determining loads and impacts on building structures and the Amendments introduced, which provided for a number of innovations, were considered. The main emphasis is placed on the methodology for determining various types of climatic loads, including loads from the self-weight of soils, snow and wind loads, ice and wind loads, as well as the system for compiling combinations of these loads. The issue of terminology for the process of determining loads is covered. Findings. Based on the comparative analysis, it has been established that the approach to load combinations proposed in the Amendments allows obtaining higher values than all previously used approaches. The methodology for determining the load from the self-weight of soils remained unchanged. The methodology for determining snow and wind loads has been fundamentally changed. The final values of the loads are 2.5–3 times higher than the values in the previous standard. This is most evident in Sumy and Chernihiv regions of Ukraine. The methodology for determining the ice and wind load was supplemented in terms of taking into account the wind pressure in the presence of ice deposits. At the same time, the correlation with wind pressure in the absence of ice deposits is not clear enough. Originality. Changes in the methodology for determining the main types of climatic loads on building structures for the conditions of Ukraine, in particular, loads from the self-weight of soils, snow and wind loads, ice and wind loads, as well as the system for compiling combinations of these loads, were qualitatively and quantitatively assessed. Practical value. The data obtained make it possible to determine the ways and directions for further improvement and refinement of the existing methods for calculating the main climatic loads for the conditions of Ukraine.

Eurocode-compliant system-level reliability analyses of trussed portal frames under climatic loads

Eurocode 3 provides Geometrically and Materially Nonlinear Analysis with Imperfections-method (GMNIA) in which the entire structure can be designed in system-level. In GMNIA, reliability of structural system is verified by using a system safety factor which is obtained in Eurocode 3 based on numerical or experimental capacity test results. Unfortunately, such test results are scarcely published in the literature thus complicating the determination of the factor for a design engineer. In the so-called Direct Design Method, however, system safety factors are provided in advance for the design engineer by system-level reliability studies. This study determines the Eurocode-compliant GMNIA system safety factor for Warren truss portal frames by using the approach of the Direct Design Method. Advanced numerical models are utilized to perform Monte Carlo-simulations for entire structural systems. These simulations provide statistical distributions of system resistances which are employed in the First-Order Reliability Method to derive the system safety factors. Studied structures are made of S700 cold-formed hollow sections. Various system geometries, system configurations and load combinations consisting of snow and wind loads are investigated and a suitable system safety factor is proposed for the ultimate limit state design of Warren truss portal frames. The proposed system safety factor is applied in a practical comparison in which Warren system is designed both by the conventional Eurocode 3 method and GMNIA. This comparison reveals that GMNIA has a remarkable potential to offer reduced material consumption in design compared to the conventional method.

Barriers to climate adaptation in Norwegian building projects – Insights from moisture safety designers’ perspective

To reduce the escalating maintenance costs for the Norwegian building stock, adapting new building designs to future climate changes becomes necessary. Currently, climate adaptation of moisture safety design by considering future climate loads is not mandatory in the Norwegian building code. This forces building designers to choose between adhering to existing standards and guidelines or investing additional efforts in adapting the building design to future climate change, at higher initial costs and with uncertain long-term benefits. This study aims to analyze the perceptions of Norwegian building physicists of future climate risks and their capacity to influence adaptation efforts in new construction projects. A thematic analysis of 15 semi-structured interviews with Norwegian building physicists from multiple companies and different regions of Norway is presented. The respondents recognize the need to adapt building designs to account for future climate loads more effectively; however, they lack the requisite influence and tools to implement the same. They look to authorities to establish requirements, and research institutes to develop tools that enable them to effectively fulfil their roles. Significant barriers for climate adaptation in building projects include lack of support from other project stakeholders, unavailability of efficient tools based on qualitative risk assessment for addressing climate adaptation, and insufficient focus on climate adaptation in building codes and guidelines. Development of methods for implementing climate adaptation in moisture safety design must reflect this, and quick-to-use robusteness assessment frameworks that treats these uncertainties in a non-quantitative manner are needed.

Shape-adaptive climate loading of tensile surface structures

Shape-adaptive climate loading of tensile surface structures

Comparing Canadian and Norwegian moisture indices for building climate adaptation

To evaluate the suitability of materials and solutions in building envelopes, it is necessary to quantify the relevant climate loads. The critical climate load is typically a combination of multiple parameters, such as temperature and precipitation. Climate indices may be used for finding critical climate loads, and their use helps guide design choices when adapting to local climates. The purpose of this study is to evaluate the suitability of the Canadian Moisture Index (MI) for use in Norway. The values of MI are linked to design recommendations in the Canadian building code, thus enabling a tangible link between index values and moisture design practice. MI has been calculated for 12 locations in Norway, and compared to two indices already in national use: the driving rain index (DRI) and wood decay potential index (WDPI). The applicability of a climate index as a design tool depends on (1) describing a relevant climate stress; (2) logical differentiation of values, and; (3) translating index values to design recommendations. These are fulfilled for MI in a Canadian context, thus making it applicable as a design tool. However, significant adaptation may be required for the index to be adopted to a Norwegian context. As MI and DRI have a similar field of application, introducing MI into a Norwegian context may therefore be redundant. A drawback with the Norwegian indices is the relative weak link between index values and design recommendations, thus further development of recommendations based on index values may improve their applicability as design tools.

Actual and design wind loads for overhead transmission lines in the Central European part of Russia

This paper reveals an impact of the climatic loads on the sustainable operation of power grid facilities. An overview is provided considering various international standards related to the design of overhead transmission lines. The aim of the research was to analyze and compare the actual and design values of wind loads for transmission lines located in the Central European part of Russia and operated by the power grid company “Rosseti Center and Volga Region”. An analysis of wind load dynamics has been carried out considering the territory of 9 subjects of Russia and 1983-2022 timeframe. The actual climate data were computed according to the direct measurements of the weather stations. Nomograms of the maximum annual wind speeds are formed utilizing the first limiting Gumbel distribution for two climatic regions of the research area. The retrospective wind loads values were compared against the design values. The results of the study show that climate standards should be updated more frequently as it is the case nowadays, in particular, it relates to revision of existing wind loads or recalculation of wind speed correction factors for the near future.

Accuracy of using Moisture Reference Years for assessing the Long-Term Moisture Performance of Wall Assemblies

Hygrothermal simulation is commonly used to understand the effects of climate loads on wall assemblies. This helps determine the risk of deterioration of wall components due to factors such as mould, wood rot, corrosion, and other modes of degradation. Owing to the lengthy computing time and high cost of undertaking simulations over extended periods of time in excess of 30 years, common practice is to select representative years, generally referred to as moisture reference years (MRYs), amongst the climate data series with the assumption that they would provide results similar to that obtained using the entire climate data series. In this study, simulations were performed for a wood-frame wall having brick veneer and fibreboard as cladding and located in 4 Canadian cities using both a 31-year climate data series and MRYs. The mould growth index on the outer layer of the sheathing panel was used as the performance indicator to permit comparing the moisture performance obtained using the long-term climate series to that obtained using MRYs. It was determined that different strategies should be implemented to analyse the MRY simulation results for different types of wall assemblies to obtain a similar conclusion as that of 31-year simulations.

ANALYSIS OF CALCULATION AND EXPERIMENTAL METHODS OF DETERMINING HEAT LOSSES THROUGH WINDOW CONSTRUCTION

Problem statement. Energy conservation in the conditions of deficit and constant growth in the cost of energy carriers is the main task of the housing and communal complex. Along with the use of energy-saving equipment in life support systems, a significant reduction in energy consumption can be achieved by introducing energy-efficient structural solutions into construction. Translucent structures are considered more unprotected, since heat losses through them can reach 54 % of the total, so they require new approaches to determining heat transfer coefficients. On the basis of the analysis of heat and mass transfer processes element by element for window blocks of non-standard shape, a correct estimate of the heat transfer coefficient was made. The purpose of the article on the basis of the analysis of the thermophysical processes formation through translucent enclosing structures, improve the dependences for calculating the heat transfer coefficient of double-glazed structures taking into acount the climatic load and establishing the relationship between their main thermotechnical characteristics. Results. Based on the analysis of thermophysical processes occurring in opaque structures, the dependence of the heat transfer coefficient of non-standard shape window block on the wind speed, taking into acount the orientation of the building height in the element-by-element determination, was obtained. The main factors affecting the value of the heat transfer coefficient of the window unit have been established, i. e., these dependencies can be used to evaluate energy-saving measures during an energy audit. Scientific novelty and practical value. Dependencies for determining the heat transfer coefficient of translucent structures, taking into acount heat loss through window frames, the location of the window in the wall opening, and structural solutions are obtained. An analysis of the results of heat transfer coefficients for windows of non-standard shape, which are aimed at choosing the optimal technical solutions of wine blocks from the standpoint of energy and resource saving, taking into acount climatic parameters, was conducted. Quantitative results of the radiant and convective components for the element-by-element determination of the heat transfer coefficient of window blocks and heat losses through them are obtained, allowing to establish the priority of energy-saving measures.

Accurate determination of the static equilibrium in insulating glass units under climatic loading

In the area of glazing façades and windows, the increasing environmental demands have boosted the development of insulating-glass units (IGUs). There is already 4–6 pane glazing on the market, with heat transmittance Ucw < 0.40 W/m2K, which offers exceptional energy efficiency and living comfort. There is still a lack of standardized engineering methods for their design, however. The lateral load resistance of glass panes in insulating glass units is addressed in the standards EN 16612 and ASTM E1300-12a, but in both, the calculation methods employed are simplified by way of the linearization of the gas law and are applicable only to double and triple glass units. In this paper, we present a recursive method that accurately satisfies the conditions of static equilibrium and the gas law. The methodology preserves the rationale of EN 16612, in which the problem is split in two components: single glass pane bending and load sharing in IGUs, with the results of the former serving as input to the latter. The proposed methodology is based on the Taylor expansion of the gas law and equilibrium equations, which, in contrast to the standard method, completely eliminates the linearization error through a recursive process. Verification cases show that the error due to linearization can reach up to 30 %, a deficiency that the proposed method eliminates. Unlike the methods in the standards, ours provides a general solution for IGUs consisting of an arbitrary number of glass panes. Despite this general applicability, it preserves computational efficiency, simplicity, and suitability for basic engineering design. Beyond improving the existing calculations for double and triple glass units, the proposed method also represents a simple, stable and robust calculation approach for multi-pane IGUs, e.g. quadruple glass units, which are already on the market, as shown by real case studies. For practical purposes, a condensed presentation of the calculation process for these IGUs is given in the Appendix.

Justification of the methods for operational research of the operational reliability of acid-resistant concrete under the influence of climate cycles “freezing – thawing” by the ultrasonic pulse method

An important task of the construction industry is to establish the operational reliability of construction objects under the influence of cyclic climatic loads from freezing and thawing on the concrete. This is especially relevant if such loads are accompanied by moistening followed by the concrete freezing. Such loads cause a violation of the structure of concrete and lead to a decrease in its strength. It is especially important to solve this problem for acid-resistant concrete, which is used in the construction of platforms for unloading or using material and liquids characterized by their aggressive action – acids, alkalis, etc. According to regulatory documents and official methods, the class of concrete in terms of its frost resistance is determined at the stage of its design using destructive methods. For this purpose, a series of concrete samples are prepared, the strength of which is determined by compressive load during a series of “moistening – freezing – thawing” cycles. Samples are frozen in a special freezer. The peculiarity of the operation with acid-resistant concrete is that its saturation in real conditions occurs not only with water, but also with a solution of an aggressive environment. This can intensify the decrease in the concrete strength, and therefore the decrease in its operational reliability. Published research results aimed at improving the determination of frost resistance of the concrete involve the use of, for example, strain gauges embedded in concrete, the acoustic emission method, etc. The main disadvantage of such methods is the significant complexity of implementation, or the impossibility to test the concrete in production conditions. The results of the experiments presented in the paper indicate a real possibility of determining the strength of acid-resistant concrete during operation using the improved ultrasonic pulse method.

ANALYSIS OF DOMESTIC AND WORLD STANDARDS REGARDING THE CRITERIA OF THE BOUNDARY STATES FOR THE STEEL SILOS FOUNDATIONS

In the process of operation the structures of steel silos undergo various failures associated with natural and climatic loads and influences, the insufficient study of engineering and geological conditions, as well as some errors during operation. Damage to the above-ground structures of steel silos is mainly caused by roof structures and silo shells failures. Whilst operating silos, various types of raw material flow are distinguished during unloading. Possible scenarios of the operating technology violations can lead to deviations from the approved flow regime during unloading and they quite often become factors of an emergency situation. The conditions of loading and operation of silos have been compared pursuant to their presentation in the domestic and the foreign regulatory documents. A significant number of industrial accidents are associated with operation failures of reinforced concrete foundations, their insufficient load-bearing capacity and their deformability. It should be noted that the construction of the foundation affects its "flexibility", which may cause uneven settlement of the foundations and their base. Sometimes this leads to extra-design loads on the upper structure of the silo. In the domestic practice of increased diameters silos construction, the foundations with an underground gallery are the most common. For the construction areas having a high level of groundwater, the foundations with an above-ground under-silo storey are used. For the silos with an above-ground discharge funnel, the type of outflow influences the load pattern of the foundation. Whilst operating normally, the loads are uniform, and when the storage material hangs on the walls, the loads are uneven, which can lead to the destruction of the above-ground structure or a foundation tilting. The type of funnel significantly determines the shape of the outflow, which affects the distribution of internal forces in the silo and the load on the foundation. In this work, a brief analysis of the failure factors of steel silos has been carried out, and a comparative analysis of modern domestic and international design standards has been suggested concerning the criteria for the occurrence of boundary states of steel silos foundations during designing. There has also been analyzed the special operational features taking into account specific technological loads on silo shells and foundations, the certain features of engineering and geological conditions of construction sites. Conclusions have been made that the main criteria for foundations designing and calculating are the deformation criteria for limiting settlement and tilting. It should be noted that the foreign regulations place the issue of limiting maximum settlements within the scope of a designer's competence. Keywords: reinforced concrete foundation, steel silo, failure, boundary state, design norms.

Reassessment of Operating Engineering Steel Structures with the First Order Reliability Method and Bayesian Inference

AbstractSince the commencement of regulations and standards, the sustainability of civil engineering structures has been a recurrent issue for the construction industry and society at large. The practical design process of engineering structures, in accordance with national guidelines, addresses uncertainties related to the stochastic nature of parameters such as climate loads, structural materials, or model limits. These uncertainties are taken into consideration through initial probabilistic assumptions and safety factors. However, safety factors derived mathematically based on code‐driven presumptions often fail to accurately represent the unique conditions of an individual structure. Although the development of structural health monitoring (SHM) techniques allows for a significant reduction in the uncertainty of the action and resistance, the ability to transform monitoring information to reevaluate the design capacity of existing structures is limited at the practical level. This paper provides an example of how design can be enhanced by incorporating sensor data and using the Bayesian inference and First Order Reliability Method (FORM), tailored to accurately reflect the current structural condition.

Passively Maintained Closed Cavity Façade—Experimental Validation of the Mathematical Thermal Model

Although glass façades have been on the market for over a century, new improvements, following sustainable standards, are still being invented. An improvement of the actively maintained CCF has occurred in passive maintenance with natural ventilation of the cavity and insulation glass unit placed on the external side, which has served as a true motivation for further research. To develop the idea, a new type of CCF was invented, followed by the creation of the software, whose purpose is to determine optimal CCF façade components. During this research, an experimental and mathematical model was made regarding the thermal behavior, later validated by the measurements on-site in Rugvica, Croatia. Using simplified but unconventional methods, numerous formulae and variables, a simulation of climatic loads onto the CCF was conducted. Validations of the thermal model were made during winter and summer periods for southern and western façade orientation, explaining how heat transfers from the environment to close cavity façade elements. It was found from the analysis that air temperatures of the façade elements follow the outer air temperature, by constant air exchange with the outer space. The results showed great potential with up to 3 °C (5–10%) of difference in experimental and calculated results, thus creating a basis for further improvement of the software with the addition of structural and hygric behavior of the façade element, regarding climate conditions.

Multilayer External Enclosing Wall Structures with Air Gaps or Channels

Precise meanings of thermophysical processes taking place in air gaps have decisive importance in composite cladding structure systems’ calculation and modeling. The climatic load conditions in Kazakhstan can significantly affect the microclimate of premises in general. In this work, a review study is carried out to obtain the relevant scientific literature on enclosing structures with air gaps under various climatic conditions. The review mainly covers research institutes from Sweden, Norway, France, Saudi Arabia, Russia, and China. On the issue of the air gap parameter’s influence on thermophysical processes, 16 papers were analyzed, and on the issue of air infiltration, 12 papers were analyzed. However, the review shows a lack of research in this area under various climatic conditions. At the same time, experience has shown that the principle of multilayer protection from climatic influences creates a favorable microclimate in buildings, but due to a possible temperature drop, wall structures made of composite building materials can be quite favorable under some conditions, and under others they may be less favorable. Therefore, working out a new energy-saving design with air gaps for climatic conditions with large temperature fluctuations during summer and winter is an urgent task.

Examining the impact of stochastic multi-year weather and air infiltration on hygrothermal moisture risks

The analysis of heat, air, and moisture (H.A.M.) transport for building envelopes are known to be highly dependent on climate loads and air infiltration rates. Moisture content within the assembly is often a key H.A.M. analysis outcome to assess risk and transport behavior. ASHRAE Standard 160-2016 states that building envelope H.A.M. analysis should be done using moisture design reference data or using a minimum of 10 consecutive years of weather. While there has been progress and methods for selecting or designing moisture reference years there has been a lack of study in the impact of multi-year (particularly 10-year) weather scenarios on simulation results in comparison to reference year simulations. This paper presents research using stochastic 1, 2, and 10-year weather data and air infiltration rates to study the range of simulated moisture content outcomes for four wall assemblies in Philadelphia and compares these to the outcomes when using reference years. Results from the study show that air infiltration, starting month, and multi-year duration have significant impacts on simulated moisture content, mold, and corrosion analysis results. Regression analysis using annual averages of climate input parameters did not yield useable models for selecting weather years, however an estimated mold index value using outdoor climate data may be useful in selecting weather years with varying starting months for mold growth assessment.

Long-term forecasting of thermal and humidity actions on buildings

Global warming leads to significant long-term changes in climate loads and effects on structures, which must be considered when designing buildings. In this study, loads on buildings and structures were examined to evaluate long-term changes in temperature and humidity of the atmospheric air and to develop a method for forecasting the estimated values of these effects. According to the data obtained via weather stations in Ukraine, it was determined that long-term changes in thermal and humidity actions at different weather stations are qualitatively similar but vary numerically by a significant extent. The increase in air temperature is generally consistent with the known trend of global warming, and relative humidity is characterized by a decrease in the variance at almost constant average annual value. The proposed method of identifying and describing trends in long-term changes in climatic influences can be used in the development of regulatory documents and in directly designing buildings and structures by considering the predicted changes in climatic influences during the future life of buildings.