Climate Load Research Articles

Analysis of roof membranes damaged by mechanical and climatic loads – pilot research

Realization of roof construction has many hidden risks, especially in buildings with diverse architecture. There is a problem about cooperation of individual works (vertical and horizontal constructions) on roof in this type of architecture, during the process of realization. Purpose of this research is to reveal risks in form of the group of major source of defects by mechanical damages. The most often types of mechanical damages were chosen in this research, which then were applied on individual types of roof membranes. Response of this damage was found out during the test procedure of water pressure by special laboratory machines. Furthermore, samples of roof membranes were subjected to the Impact test, which was actually focused on damage by hailstone impact from the atmosphere. The final outcomes of the measurements show that the material composition of each roof membrane can influence their whole waterproofing after application of certain type of mechanical damage. In the Impact test, samples were suffered from impact of the hails. This test signified that the choice of base material of thermal insulation below the roof membrane plays an important role.

Analysis of roof membranes damaged by mechanical and climatic loads – pilot research

Analysis of roof membranes damaged by mechanical and climatic loads – pilot research

Corrosion test improvement by data driven climatic modeling

Many corrosion test experiments, using a range of testing methods and car body materials, are done by the automotive industry worldwide to meet the corrosion requirements in the field. In this paper, we use test data and climate field data for data driven modeling of the test results. One contribution reported here is to find the most influencing factors for corrosion test progress and field correlation. Therefore, iron and zinc panels with automotive paintings conducted in several corrosion tests are measured and transformed into suitable data. The corrosion parameters are defined as factors and the result of corrosion testing (i.e., scribe creepage values) as output variable. With this data, a statistical model is generated and validated. The best fit model is analyzed to find sensible testing parameters effecting the corrosion results. The same procedure is also applied for climatic field data, which is first transformed into characteristics such as humidity, duration of wetness, and salt load. The data from corrosion testing experiments are then mapped to the climatic load in the field. A match to the field correlation can be found, as demonstrated by our results.

Геоинформационное моделирование климатических нагрузок на ЛЭП (на примере юга о. Сахалин)

Геоинформационное моделирование климатических нагрузок на ЛЭП (на примере юга о. Сахалин)

Microstructural Optimization Approach of Solar Cell Interconnectors Fatigue Behavior for Enhanced Module Lifetime in Extreme Climates

Fatigue of the cell interconnectors is one of the main reasons for module failure. Especially with respect to module application in extreme climates new demands on solar cell interconnectors will arise. Optimizations in the manufacturing process to generate a product demand related microstructure are a key to improve the material behavior of interconnectors with respect to extreme climate loading conditions without increasing costs. For achieving this goal several aspects were considered in this paper: Influence of the annealing process on the fatigue behavior: Due to an optimization of the annealing process an increase in ribbon fatigue strength by a factor of four could be achieved. The effect consists of two parts: Firstly, annealing influences the geometrical shape generated during the fatigue experiment. Secondly, it affects crack formation and crack growth during fatigue. Influence of temperature on fatigue behavior: an increase in temperature leads to a significant reduction in fatigue strength (from 25 to 100 °C by factor 3). This results from increased dislocation creep at higher temperatures. Microstructural comparison of fracture patterns: The loading amplitude determines the roughness of the fracture surface: Smaller amplitudes lead to a coarser surface structure. This is important to compare accelerated lifetime testing in the lab and modules failures from the field. Simulation of temperature and microstructure dependent fatigue for lifetime prediction: Exemplarily it will be depicted how optimized fatigue behavior in the lab translates into real module lifetime under extreme climate conditions. Despite the actual numbers which show the potential of the approach, but could vary from sample to sample, the focus of the paper is the method itself and its physical background.

AN OVERVIEW OF MOISTURE DAMAGE PERFORMANCE TESTS ON ASPHALT MIXTURES

This paper presents a review of moisture damage performance tests on asphalt mixtures. The moisture damage remains to be a detriment to the durability of the Hot Mix Asphalt (HMA) pavement. Moisture damage can be defined in forms of adhesive failure between bitumen and aggregates and cohesive failure within bitumen. Aggregate mineralogy, bitumen characteristics and anti-stripping additive dominantly influence the performance of asphalt mixtures towards moisture damage alongside construction methods, climate and traffic loading. Various laboratory test methods have been developed to quantify the moisture damage performance of asphalt mixtures by resembles the action in the field, including qualitative test such as Boiling Water Test (ASTM D3625) and quantitative tests such as Modified Lottman Test (AASHTO T283). Both of these tests consist of two phases, which are conditioning and evaluation phase. This paper will review the effectiveness of the selected available tests based on various asphalt mixtures materials. Generally, this study indicates that asphalt mixtures consisted of limestone aggregates, modified bitumen and addition of anti-stripping additives will provide more resistant towards moisture damage.

Impact of Climatic Ageing on the Basic Mechanical Properties of Viscoelastic Sealants

The aim of the research presented here was to assess the influence of climatic loading on the basic mechanical properties of polymer sealants, from the viewpoint of their application in creating and repairing outdoor mosaics. Six promising sealants were selected for the measurements. They were tested in their native state and also after four different model types of physical-chemical ageing were applied. We used a combination of ultra-violet radiation with the influence of enhanced temperature, moisture and also soaking in water and freezing. The Hysitron TI 750D TriboIndeterTM system, equipped with a Berkovich indenter, was used for tests. The basic mechanical characteristics were measured using the Basic QS Trapezoid quasi-static mode. Time-dependent properties of the sealants were assessed by the indentation creep method. The results have confirmed that microindentation technique offers a suitable methodology for assessing changes in the basic mechanical time-dependent properties of the tested sealants due to photo-degradation processes and climatic effects.

Thermal Induced Climatic Loads of Insulated Glazed Units in Energy Efficient Facades

Climatic loads on Insulated Glazed Units (IGU) have been investigated since the early 1990s. Beginning in 1996 a German technical guideline defined the procedure to respect climatic loads in static design of IGUs. Furthermore the required values of climatic changes and thermal changes of Double Glazed Units (DGU) have been determined. In practice, those values have been applied to other systems like Triple Glazed Units (TGU) as well as Double Skin Facades (DSF). In the last two decade’s those values haven not changed. This paper presents the results of a study on IGU’s in summer conditions, evaluating the thermal performance recent constructions. The upgrade from DGU to TGU causes a significant change of the thermal behavior. By adding a third glass layer, the middle glass gets insulated on both sides. In case of solar radiation the middle glass layer absorbs energy and is disabled to release energy. As a result, higher temperatures can be reached on TGU. By considering ventilated or not ventilated DSF’s, external or internal shading devices can influence further changes in the thermal behavior. This paper shows the development of an iterative calculation model by including present European standards. The model is able to deal with factors mentioned above. The results of different facade studies are shown and compared to the DIN 18008 standard. Furthermore the ongoing changes through European prestandards were discussed. Over all the study shows that a more sophisticated approach is necessary to determine correct temperature and climatic loads.

Field Test for Polymeric Collector Models in Different Climatic Locations

Polymeric collectors have been exposed on outdoor testing sites in three distinct climatic locations and the climatic loads and collector temperatures have been monitored by the minute. The obtained data was analyzed with focus on the frequency and extend of the thermal loads, which the different components of the collector were exposed to. As a result this data can be correlated to accelerated aging tests.

Gas loss of insulating glass units under load: internal pressure controlled permeation test

The edge-seal is the most important part of an insulating glass unit regarding the loss of insulating gases from the inter-pane space. Its long-term behavior is mainly defined by climate loads. Here, increasing stresses on the polymer sealants lead to chain-orientation. This introduces anisotropic materials properties. The strain causes macroscopic deformation of the edge-seal. Both effects might enhance the permeation rate, yet are not considered by the established testing standards. Therefore, the standard test to measure the gas loss rate under climate conditions has to be refined and extended. In this work, a new test setup is introduced which correlates the stress-strain behavior within the edge-seal with the gas loss rate of insulating glass units. Three different concepts are evaluated by means of the stress-strain state within the edge-seal as well as the needed dimensions and the manufacturing complexity of the test stand. As a result, the internal pressure controlled permeation test method appears to be the most suited. Finally, the measurement setup is realized as a prototype and optimized.

Climate loads in insulating glass units: comparison of theory and experimental results

The verification of insulating glass units in ultimate limit state often gives rise to the question of how to take into account the edge seal in the design of the glass panes. Usually the edge seal is calculated as immovable, as this is a more conservative assumption. A flexible edge seal, as to be expected under realistic conditions, leads to a lower climate load and therefore to lower stresses in the glass. In order to determine the influence of a flexible support on the verification of the ultimate limit state under the applicable standards in Germany, various setups of insulating glass units were subjected to cyclically recurring temperatures of $$-$$ 18 to $$+53\,^{\circ }\hbox {C}$$ in a climate chamber. In this procedure, the atmospheric pressure was measured as well as the pressure in the cavity, as were the deformations of the edge seal orthogonally to the glass panes. Based on these, a comparison of analytical calculations of the climate load and the experimentally determined climate load is conducted. By means of the experimentally determined pressure difference in the cavity and the measured deformations of the edge seal, an effective spring stiffness in tension of the edge seal under the climatic test conditions was calculated using a finite element (FE) model. On the basis of an effective spring stiffness in tension assumed in a FE simulation, the influence of a flexible edge seal on the design of the glass panes is determined and discussed.

Adaptation of NCHRP Project 1-41 Reflection Cracking Models for Semirigid Pavement Design in AASHTOWare Pavement ME Design

Semirigid pavements are composite pavements that comprise a surface asphalt concrete (AC) layer overlying a cement stabilized base, granular subbase, and subgrade foundation. When subjected to traffic and climate loading, semirigid pavements provide good performance through resistance to rutting or deformation of base and subgrade, moisture damage, and AC fatigue. However, semirigid pavements can develop fatigue and transverse shrinkage cracks in the underlying cement stabilized base layer, which ultimately propagates through the surface AC thickness with repeated applications of axle loads and temperature cycles (i.e., reflection cracking). Although new semirigid pavements have been designed and constructed in the United States since the 1960s, a new semirigid pavement design methodology was not included in Version 1.0 of AASHTOWare Pavement ME Design software. This methodology was omitted because developers and researchers at that time concluded that there were no suitable existing mechanistic-based fatigue or transverse reflection cracking models available to be adapted and included in the design procedure. Under NCHRP Project 1-41—Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays, mechanistic-based AC fatigue and transverse reflection cracking models were developed. The models were developed to be compatible and thus easily adaptable into the AASHTOWare Pavement ME Design framework. Work done to adapt the NCHRP Project 1-41 reflection cracking models for the design of new semirigid pavement in AASHTOWare Pavement ME Design is presented.

Numerical Modelling of Bubbles Formation in the Bridge Asphalt Pavement Under Gas Pressure Impact

One of the major issues of concrete bridges pavement design and maintenance is bonding between flexible bituminous layers and the deck. Any bonding failure can lead to the development of local delamination areas, which are formed as a result of the separation of the membrane sheets (insulation) from the concrete deck. This is caused by high pressure of gases accumulated between the layers leading to the formation of gas-filled bubbles. This paper discusses the research carried out in order to better understand this process of distress between pavement, insulation and concrete deck. The main objective of the presented study is the detailed structural modeling under the influence of climatic and mechanical loading. Numerical solution was obtained using Finite Element Analysis (FEA) and the calculations were performed applying Abaqus system. The ability to determine of the stress and deformation states of the bridge structure pavement opens a new way to better understand the phenomenon and to carry out the optimization of detailed technological solutions.

Complex Optimization of Heavy Duty Asphalt Pavement Types in DURABROADS Project

DURABROADS, an EU FP7 financed project launched in 2013, and led by the University of Cantabria (Spain) aims at providing a sustainable growth through the development of innovative, cost-effective and more durable pavements. The new generation of pavement is based on innovative eco-friendly nanotechnology-enhanced asphalts as well on the optimization of procedures to build and rehabilitate durable, safer and greener road infrastructure more adapted to climate change and freight corridor traffic loads. One of the objectives of this project is to identify and evaluate the existing constraints concerning currently used road materials of heavily trafficked roads (TEN-T routes) to withstand current road challenges. Due to different traffic and climate features, four European regions (Northern, Central, Western and Southern Europe) were differentiated. The climate change elements critical to various road types were identified, reviewing the pavement deterioration forms they accelerate. The traffic loads on freight corridors were evaluated considering their accelerated pavement deterioration forms. The synergistic effect of extreme climatic and mechanical loads to pavement surface was scrutinised. A comprehensive quantification methodology for extreme traffic and climatic load combinations was suggested including technical (functional), economic, environmental and social-human aspects with appropriate weighing. Then the European region-specific “optimal” asphalt wearing course types and road rehabilitation techniques for TEN-T routes were identified. The region-specific material and procedure optimization utilizes – in addition to the processing of a comprehensive literature survey – the answers coming from 81 experts of 52 European institutions to targeted questionnaire. These data were used to develop a decision support model based on AHP and TOPSIS models to facilitate the selection of asphalt pavement types. The results suggested Stone Mastic Asphalt (SMA) as the most suitable alternative in different climate change scenarios evaluated by a sensitivity analysis.

Assessing the Vulnerability of Irish Rail Network Earthworks

The Irish Rail network was largely constructed in the mid-1800s. As a result of this, a significant proportion of the network is comprised of aged cuttings and embankments the construction of which predate modern design standards. Although most of the networks have remained stable for over a hundred and fifty years, a significant proportion of the network has slope angles in excess of those recommended in current design standards. Climate change predictions expect increased rainfall levels across Europe that will deteriorate these slopes further and increase incidence of failure.Current practice when populating earthwork asset databases is to conduct a technical walkover survey. Data obtained in this way is susceptible to bias errors and involve subjective approximations. This is particularly evident in slope geometry attributes such as slope height and angle. Remote sensing data is able to improve precision while reducing bias substantially, while being a much faster alternative than visual assessments on a network scale. Having precise and reliable data over the entire network is a fundamental prerequisite when conducting relative risk assessments of assets. In this paper, post-processed findings from an airborne LiDAR survey of the entire Irish Rail network are presented and compared to walkover assessment data. The current state of assets will also be discussed in light of modern design codes, together with the implications on infrastructure performance.Slope vulnerability to shallow planar type failures is expected to increase with predicted changes in climate such as increased environmental loading (rainfall events are predicted to be more intense and of longer duration, with longer dry periods in between). This type of failure is already the dominant failure mode across Irish Rail network. Typically these failures are instigated by rainwater percolating into the slope to a given depth, filling available pore space thus reducing in-situ soil suctions. This in turn reduces the shear strength of the soil. When the percolating water reaches some critical depth failure occurs.Fragility curves, a particular type of asset vulnerability assessment, provide a connection between triggering actions (such as rainfall) and expected damage to infrastructure assets. They can therefore be potentially useful in estimating a slope's response to predicted future climate loading. An example of a fragility curve applied to a typical slope on the Irish Rail network is presented in this paper.

Advances in the monitoring of geo-structure subjected to climate loading

The paper presents results achieved within the project MAGIC, a project funded by the European Commission under the Marie-Curie Industry Academia Partnerships and Pathways (IAPP) scheme. The project MAGIC aims to advance the state-of-the art in the monitoring of geo-structures subjected to climate loading by filling some of the gaps in current monitoring technologies. The project involves a partnership between academic and industrial partners to boost knowledge transfer and promote the development of 'industrial' instruments and services. The paper presents developments concerning the measurement of pore-water tension (suction in excess of 100 kPa) and the integration of geotechnical and geophysical monitoring.

Handling Interdependencies in Climate Change Risk Assessment

Typically, a climate change risk assessment focuses on individual sectors or hazards. However, interdependencies between climate risks manifest themselves via functional, physical, geographical, economic, policy and social mechanisms. These can occur over a range of spatial or temporal scales and with different strengths of coupling. Three case studies are used to demonstrate how interdependencies can significantly alter the nature and magnitude of risk, and, consequently, investment priorities for adaptation. The three examples explore interdependencies that arise from (1) climate loading dependence; (2) mediation of two climate impacts by physical processes operating over large spatial extents; and, (3) multiple risks that are influenced by shared climatic and socio-economic drivers. Drawing upon learning from these case studies, and other work, a framework for the analysis and consideration of interdependencies in climate change risk assessment has been developed. This is an iterative learning loop that involves defining the system, scoping interaction mechanisms, applying appropriate modelling tools, identifying vulnerabilities and opportunities, and assessing the performance of adaptation interventions.

에너지 자립섬을 위한 신재생복합발전시스템의 최적용량 설계에 관한 연구

The recent trend is that diesel power generation on islands where its prime cost for power generation is high is replaced by new and renewable energy. Therefore, south Jeolla province is progressing the construction project of self-sufficient islands for the areas where power is supplied by depending on diesel generators, which is the project that power is supplied through eco-friendly energy source using sunlight, wind power and energy storage device etc. However, it is difficult to construct new and renewable energy source with the capacity to respond to the load perfectly due to its environmental and geographical conditions regarding capacity design of new and renewable energy. Besides, Microgrid design considering appropriate capacity design of the system components and efficient operation is required through the analysis of climate conditions and load patterns from the design stage for optimal composition of a hybrid system with economic feasibility. Therefore, this study is aimed to conduct a research on optimal combination, capacity calculation and economic feasibility by comprising a hybrid power generation system which will replace 40% of power generation by diesel as new and renewable energy source for Geomun Island where has more than 300 households and requires expansion of the facility among islands located in southwest coast.

Moisture dependent thermal properties of hydrophilic mineral wool: application of the effective media theory

Thermal properties of mineral wool based materials appear to be of particular importance for their practical applications because the majority of them is used in the form of thermal insulation boards. Every catalogue list of any material producer of mineral wool contains thermal conductivity, sometimes also specific heat capacity, but they give only single characteristic values for dry state of material mostly. Exposure to outside climate or any other environment containing moisture can negatively affect the thermal insulation properties of mineral wool. Nevertheless, the mineral wool materials due to their climatic loading and their environmental exposure contain moisture that can negatively affect their thermal insulation properties. Because the presence of water in mineral wool material is undesirable for the majority of applications, many products are provided with hydrophobic substances. Hydrophilic additives are seldom used in mineral wool products. However, this kind of materials has a good potential for application for instance in interior thermal insulation systems, masonry desalination, green roofs, etc. For these materials, certain moisture content must be estimated and thus their thermal properties will be different than for the dry state. On this account, moisture dependent thermal properties of hydrophilic mineral wool (HMW) are studied in a wide range of moisture content using a pulse technique. The experimentally determined thermal conductivity data is analysed using several homogenization formulas based on the effective media theory. In terms of homogenization, a porous material is considered as a mixture of two or three phases. In case of dry state, material consists from solid and gaseous phase. When moistened, liquid phase is also present. Mineral wool consists of the solid phase represented by basalt fibers, the liquid phase by water and the gaseous phase by air. At first, the homogenization techniques are applied for the calculation of solid matrix thermal conductivity. Subsequently, the thermal conductivity dependence on moisture content is evaluated by means of several mixing formulas. To verify the obtained results, Wiener’s and Hashin-Shtrikman’s bounds are used. The results show that the application of homogenization techniques can provide useful estimates of measured data and can be successfully used for much less time consuming thermal conductivity evaluation even for the highly inhomogeneous fibrous material such as mineral wool. The data on thermal properties can find use in building practice, especially in the design of thermal insulation building envelopes. DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7334

Tensile behaviour of unsaturated compacted clay soils — A direct assessment method

This paper presents a new method for testing the behaviour of soils placed under tensile load and demonstrates its suitability for testing a number of soil types under various conditions including saturation, compaction and stabilisation. Validation of the results obtained for the soils at relatively low saturation has been conducted using the established Brazilian (indirect) test for measuring the tensile strength of brittle materials. A fair comparison has been found and the results highlight the limited applicability of the Brazilian method to soils at very low water contents at which the tensile failure criterion has been assumed using this methodology. Optical characterisation of the performance of both testing methods has also been conducted using Digital Image Correlation. The consistent, accurate measurement of directly induced tensile strains using the proposed new method has been confirmed, verifying its capability to apply a direct tensile stress in the absence of shearing, a problem commonly associated with other tensile testing methods. The developed technique has then been used to investigate the water content–tensile strength relationship for compacted, unsaturated soils and offers significant advantages in the characterisation of clay soils subjected to variable climatic loading.