Aaltodoc Repository :: Browsing by Department "Department of Civil Engineering"

Browsing by Department "Department of Civil Engineering"

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3-D segmentation of concrete spalling in point cloud using unsupervised clustering and plane fitting
(2023) Zhang, Y.; Xia, B.; Department of Civil Engineering; Biondini, Fabio; Frangopol, Dan M.; Structures – Structural Engineering, Mechanics and Computation; Silo AI Oy
Spalling is one of the typical damage types of concrete structures. Concrete spalling occurs with local concavity and volume loss, leading to a certain range of load capacity reduction. Recently, with the rapid development of structural health monitoring and non-destructive inspection technologies, it becomes possible to perform high-resolution measurements and capture rich details of civil structures. By using laser scanners, Lidar scanners, or photogrammetry techniques, dense point clouds of structural faces can be reconstructed. Those dense point cloudscan describe both global and local geometries of structures in detail, which can be further used for damage assessment. However, the researches on identifying and localizing structural damage on concrete structures based on PC processing are still limited. Therefore, in the article, we propose a method to segment concrete spalling in 3-D point clouds of concrete structures. Unsupervised clustering methods are used to segment the point cloud into several classes that represent different faces of the target structure or structural member. Then a plane is fitted to each class of the point cloud using the Least Squares method. Based on the distances from the points to the corresponding fitted plane, a threshold can be determined, and the points that are far off the plane can be identified and localized. Those identified points can be used to present concrete spalling damage. To validate the proposed method, an experiment was conducted on a reinforced concrete beam. The result shows that the volume loss of the concrete beam was successfully identified and localized. Using a distance threshold, the points of damage can be segmented from the point cloud. Therefore, the feasibility of the proposed method was fully demonstrated.
3D dataset of a twisted bending-active beam element digitized using structure-from-motion photogrammetry
(Elsevier, 2024-06) Janiszewski, Mateusz; Elmas, Serenay; Markou, Athanasios A.; Jaaranen, Joonas; Filz, Günther H.; Department of Civil Engineering; Department of Architecture; Mineral Based Materials and Mechanics; Structures – Structural Engineering, Mechanics and Computation
The current work presents the generation of a comprehensive spatial dataset of a lightweight beam element composed of four twisted plywood strips, achieved through the application of Structure-from-Motion (SfM) - Multi-view Stereo (MVS) photogrammetry techniques in controlled laboratory conditions. The data collection process was meticulously conducted to ensure accuracy and precision, employing scale bars of varying lengths. The captured images were then processed using photogrammetric software, leading to the creation of point clouds, meshes, and texture files. These data files represent the 3D model of the beam at different mesh sizes (raw, high-poly, medium-poly, and low-poly), adding a high level of detail to the 3D visualization. The dataset holds significant reuse potential and offers essential resources for further studies in numerical modeling, simulations of complex structures, and training machine learning algorithms. This data can also serve as validation sets for emerging photogrammetry methods and form-finding techniques, especially ones involving large deformations and geometric nonlinearities, particularly within the structural engineering field.
3D Object Detection Algorithm Based on the Reconstruction of Sparse Point Clouds in the Viewing Frustum
(Hindawi Publishing Corporation, 2022-10-15) Xu, Xing; Wu, Xiang; Zhao, Yun; Lü, Xiaoshu; Aapaoja, Aki; Zhejiang University of Science and Technology; Department of Civil Engineering; Solita Oy
In response to the problem that the detection precision of the current 3D object detection algorithm is low when the object is severely occluded, this study proposes an object detection algorithm based on the reconstruction of sparse point clouds in the viewing frustum. The algorithm obtains more local feature information of the sparse point clouds in the viewing frustum through dimensional expansion, performs the fusion of local and global feature information of the point cloud data to obtain point cloud data with more complete semantic information, and then applies the obtained data to the 3D object detection task. The experimental results show that the precision of object detection in both 3D view and BEV (Bird's Eye View) can be improved effectively through the algorithm, especially object detection of moderate and hard levels when the object is severely occluded. In the 3D view, the average precision of the 3D detection of cars, pedestrians, and cyclists at a moderate level can be increased by 7.1p.p., 16.39p.p., and 5.42p.p., respectively; in BEV, the average precision of the 3D detection of car, pedestrians, and cyclists at hard level can be increased by 6.51p.p., 16.57p.p., and 7.18p.p., respectively, thus indicating the effectiveness of the algorithm.
3D Simulations of Deep Mixed Columns under Road Embankment
(Rakenteiden mekaniikan seura ry, 2021) Abed, Ayman; Korkiala-Tanttu, Leena; Forsman, Juha; Koivisto, Kirsi; Chalmers University of Technology; Mineral Based Materials and Mechanics; Ramboll Finland Oy; Department of Civil Engineering
When column stabilisation is meant to function as a ground improvement under an embankment, the design cases to be considered consist of overall stability, compression resistance of the column heads, arching of the embankment on the columns and settlements. This paper focuses on the compression resistance of the columns. The proper geotechnical design of deep mixed (deep stabilised) columns under road embankment requires good estimation of the stress- strain behaviour of the columns and the surrounding soil under the embankment and traffic loading. Earlier Finnish design approaches relied on an even traffic load of 10 kN/m2 on the road surface. The dimensioning methods for column stabilised soil are also based on the idea of an even traffic load. Due to Eurocode recommendations a more realistic scenario is introduced, which remarkably increases the magnitude of the traffic loading. After deriving suitable material properties and stiffness parameters for static and dynamic traffic loading, three-dimensionalfinite element calculations are performed to achieve better understanding of the mechanical interaction between the embankment, columns and soil under the new loading configuration. Even though more investigations are needed before delivering a final statement, the calculations show that, for the considered case in this paper, the new loading scenario has no relevant consequences on the design compared to the earlier design approach.
3D strain gradient elasticity : Variational formulations, isogeometric analysis and model peculiarities
(Elsevier Science, 2022-02-01) Hosseini, S. B.; Niiranen, J.; Department of Civil Engineering; Mineral Based Materials and Mechanics
This article investigates the theoretical and numerical analysis as well as applications of the three-dimensional theory of first strain gradient elasticity. The corresponding continuous and discrete variational formulations are established with error estimates stemming from continuity and coercivity within a Sobolev space framework. An implementation of the corresponding isogeometric Ritz-Galerkin method is provided within the open-source software package GeoPDEs. A thorough numerical convergence analysis is accomplished for confirming the theoretical error estimates and for verifying the software implementation. Lastly, a set of model comparisons is presented for revealing and demonstrating some essential model peculiarities: (1) the 1D Timoshenko beam model is essentially closer to the 3D model than the corresponding Euler-Bernoulli beam model; (2) the 3D model and the 1D beam models agree on the strong size effect typical for microstructural and microarchitectural beam structures; (3) stress singularities of reentrant corners disappear in strain gradient elasticity. The computational homogenization methodologies applied in the examples for microarchitectural beams are shown to possess disadvantages that future research should focus on. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
Achieving a 4-Hour Takt Time – and Driving Change With It
(2023-07-31) Riekki, Jaakko; Rannisto, Jukka; Lehtovaara, Joonas; Seppänen, Olli; Peltokorpi, Antti; Performance in Building Design and Construction; Haahtela-rakennuttaminen Oy; Department of Civil Engineering
This study seeks to validate the hypothesis that takt production can be used as a driver for implementing several lean construction concepts together and for making them work as a system. This is done by studying a single case project where takt production with a 4-hour takt time was a core element of the operating system. In studying the case, a set of lean construction concepts found present in the project are extracted and analysed. It is concluded that takt production and in particular the short takt time worked to integrate the stakeholders and enabled the individual lean construction concepts to work in a tight relationship. Future case studies could be more explicitly designed to further validate the hypothesis.
Actual energy performance and indoor climate in Finnish NZEB daycare and school buildings
(Elsevier BV, 2022-09-15) Ahmed, Kaiser; Hasu, Tero; Kurnitski, Jarek; Department of Civil Engineering; Structures – Structural Engineering, Mechanics and Computation; Kouvola Innovation Oy
The study addressed the improvement of building energy performance along with a good thermal comfort and indoor air quality (IAQ) in newly built Finnish daycare and school buildings. Indoor Environmental Quality (IEQ), calculated and actual energy performance, investment and life cycle cost (LCC) were monitored. Ventilation airflow rates, temperature, and CO2 were measured onsite in five daycare and school buildings during summer and winter, and an occupant questionnaire survey was conducted in parallel with onsite measurements. Energy performance was evaluated based on an energy performance certificate (EPC) and actual metered consumption to figure out possible performance gaps. Simulations were conducted to calibrate models and analyse improvements in ventilation system operation, which showed energy-saving potential while ensuring good thermal comfort and IAQ. The thermal comfort and IEQ of all buildings were excellent and were in line with the results of the questionaries survey except in 'School 3', which had specific odour and noise problems. The measured energy use of all buildings except 'School 3' was increased by a factor of 2.1-2.6 compared to the EPC value, caused by poor control of a ventilation system and the presence of some non-regulated uses such as hot kitchens, washing machines, and dryers. LCC considerably depended on actual energy use stressing the importance of accurate energy prediction. It was shown that the reduction of energy use by a factor of 1.9-3.1 is possible without compromising indoor climate by adjustment of correct operation hours, improving ventilation system control, and limiting excessive outdoor airflows in some cases.
Adapted FLASHCAT methodology to model horizontal cable tray fires using computational fluid dynamics
(Elsevier Science Ltd., 2023-07) Verma, N.; Hostikka, S.; Vaari, J.; Korhonen, T.; Department of Civil Engineering; Performance in Building Design and Construction; VTT Technical Research Centre of Finland
Nuclear power plants (NPPs) have an extensive network of electrical cables and associated trays to support daily operations. As electrical cables have combustible mass, their presence adds to the fire load in such plants. Thermal stress from cable fires can cause cable failures and spread fire to other redundant cables or other equipment, jeopardizing the safe operation of NPPs. Assessing the heat release rates (HRR) of cable fires is critical for the nuclear industry as HRR regulates the thermal stress in the surrounding of a fire and other fire products that can damage the facility. This paper presents a computational fluid dynamics-based method to model the HRR of such cable fire. The method is partly based on the FLASHCAT model (modified and adapted here) and the surface temperature ignition model of the Fire Dynamics Simulator (FDS) software. The simulation set up with validation objective replicates an experiment of OECD PRISME 3 program in which cables arranged over two horizontal trays are burnt. HRR obtained from the simulation had peak HRR underestimated by 4%, and the time to reach peak HRR overestimated by 5%. The result is encouraging as it provides confidence in using the method outlined in the paper.
Additive Manufacturing in the Construction Industry: The Comparative Competitiveness of 3D Concrete Printing
(Springer International Publishing AG, 2021-05-01) Haghighat Khajavi, Siavash; Tetik, Müge; Mohite, Ashish; Peltokorpi, Antti; Li, Minyang; Weng, Yiwei; Holmström, Jan; Department of Industrial Engineering and Management; Department of Civil Engineering; Department of Architecture; Structures – Structural Engineering, Mechanics and Computation; Nanyang Technological University
The construction industry is facing increasing pressure to improve productivity and decrease its environmental impact. Additive manufacturing (AM) technologies, especially three-dimensional concrete printing (3DCP) technology, have provided many benefits for construction. However, holistic comparative studies of the competitiveness of 3DCP and conventional methods, from cost and time perspectives, are lacking. Choosing between the methods is difficult for practitioners. In this study, we investigated the current state of 3DCP in the construction industry using seven distinct scenarios. Our analysis was performed to illustrate the impact of design and supply chain configurations on performance. The results prove the notable competitiveness of 3DCP. In contrast to the conventional construction method, the more complex round design had a positive impact on the cost and process time in 3DCP scenarios. Additionally, we show that on-site 3DCP using a robotic arm was more cost-effective than off-site 3DCP.
Advancement of highly environmentally sustainable business management concepts with contexts embedded in construction markets
(Institute of Physics Publishing, 2019-09-02) Huovinen, P.; Department of Civil Engineering
Sustainable is defined to be capable of, relating to, or designating forms of human economic activity and culture that do not lead to environmental degradation, especially avoiding the long-term depletion of natural resources. Herein, the aim is to advance the design of business management (BM) concepts with contexts embedded in construction markets along the environmental sustainability dimension. The paper is part of the on-going reviewing of research on construction-related BM. The reviewing has resulted in the identification of 79 construction-related BM concepts published between 1990 and 2017. Thereof, only 16 (20%) authors have designed their concepts along the environmental sustainability dimension. There are 3 (4%) high-sustainability BM concepts including sustainable business goals, offerings, advantages, synergies, competitiveness, processes, organizations, and/or project portfolios, followed by 1 (1%) medium-sustainability and 12 (15%) low-sustainability BM concepts. In the future, the design of high-sustainability BM concepts could be advanced by (i) creating and distributing value in sustainability for all stakeholders, (ii) re-designing strategies and leveraging knowledge about and competences in sustainability through value chains, (iii) making sustainability a priority for decision makers, (iv) empowering middle managers, experts, and employee teams, and (v) redefining businesses and public services as well as collaborating inside and across borders.
Air Distribution and Air Handling Unit Configuration Effects on Energy Performance in an Air-Heated Ice Rink Arena
(Multidisciplinary Digital Publishing Institute (MDPI), 2019-02-20) Taebnia, Mehdi; Toomla, Sander; Leppä, Lauri; Kurnitski, Jarek; Department of Civil Engineering; Structures – Structural Engineering, Mechanics and Computation
Indoor ice rink arenas are among the foremost consumers of energy within building sector due to their exclusive indoor conditions. A single ice rink arena may consume energy of up to 3500 MWh annually, indicating the potential for energy saving. The cooling effect of the ice pad, which is the main source for heat loss, causes a vertical indoor air temperature gradient. The objective of the present study is twofold: (i) to study vertical temperature stratification of indoor air, and how it impacts on heat load toward the ice pad; (ii) to investigate the energy performance of air handling units (AHU), as well as the effects of various AHU layouts on ice rinks’ energy consumption. To this end, six AHU configurations with different air-distribution solutions are presented, based on existing arenas in Finland. The results of the study verify that cooling energy demand can significantly be reduced by 38 percent if indoor temperature gradient approaches 1 ◦ C/m. This is implemented through air distribution solutions. Moreover, the cooling energy demand for dehumidification is decreased to 59.5 percent through precisely planning the AHU layout, particularly at the cooling coil and heat recovery sections. The study reveals that a more customized air distribution results in less stratified indoor air temperature.
The air temperature change effect on water quality in the Kvarken Archipelago area
(ELSEVIER SCIENCE B.V., 2023-05-20) Girgibo, N.; Lü, X.; Hiltunen, E.; Peura, P.; Dai, Z.; Department of Civil Engineering; Performance in Building Design and Construction; University of Vaasa; Jilin University
The Kvarken Archipelago is Finland's World Heritage site designated by UNESCO. How climate change has affected the Kvaken Archipelago remains unclear. This study was conducted to investigate this issue by analyzing air temperature and water quality in this area. Here we use long-term historical data sets of 61 years from several monitoring stations. Water quality parameters included chlorophyll-a; total phosphorus; total nitrogen; coliform bacteria thermos tolerant; temperature; nitrate as nitrogen; nitrite-nitrate as nitrogen, and Secchi depth and correlations analysis was conducted to identify the most relevant parameters. Based on the correlation analysis of weather data and water quality parameters, air temperature showed a significant correlation with water temperature (Pearson's correlations = 0.89691, P < 0.0001). The air temperature increased in April (R2 (goodness-of-fit) = 0.2109 & P = 0.0009) and July (R2 = 0.1207 & P = 0.0155) which has indirectly increased the chlorophyll-a level (e.g. in June increasing slope = 0.39101, R2 = 0.4685, P < 0.0001) an indicator of phytoplankton growth and abundance in the water systems. The study concludes that there might be indirect effects of the likely increase in air temperature on water quality in the Kvarken Archipelago, in particular causing water temperature and chlorophyll-a concentration to increase at least in some months.
Airborne and aerosol pathogen transmission modeling of respiratory events in buildings : An overview of computational fluid dynamics
(Elsevier BV, 2022-04) Sheikhnejad, Yahya; Aghamolaei, Reihaneh; Fallahpour, Marzieh; Motamedi, Hamid; Moshfeghi, Mohammad; Mirzaei, Parham A.; Bordbar, Hadi; Department of Civil Engineering; Structures – Structural Engineering, Mechanics and Computation; University of Aveiro; Dublin City University; Tarbiat Modares University; University of Nottingham; Sogang University
Pathogen droplets released from respiratory events are the primary means of dispersion and transmission of the recent pandemic of COVID-19. Computational fluid dynamics (CFD) has been widely employed as a fast, reliable, and inexpensive technique to support decision-making and to envisage mitigatory protocols. Nonetheless, the airborne pathogen droplet CFD modeling encounters limitations due to the oversimplification of involved physics and the intensive computational demand. Moreover, uncertainties in the collected clinical data required to simulate airborne and aerosol transport such as droplets’ initial velocities, tempo-spatial profiles, release angle, and size distributions are broadly reported in the literature. There is a noticeable inconsistency around these collected data amongst many reported studies. This study aims to review the capabilities and limitations associated with CFD modeling. Setting the CFD models needs experimental data of respiratory flows such as velocity, particle size, and number distribution. Therefore, this paper briefly reviews the experimental techniques used to measure the characteristics of airborne pathogen droplet transmissions together with their limitations and reported uncertainties. The relevant clinical data related to pathogen transmission needed for postprocessing of CFD data and translating them to safety measures are also reviewed. Eventually, the uncertainty and inconsistency of the existing clinical data available for airborne pathogen CFD analysis are scurtinized to pave a pathway toward future studies ensuing these identified gaps and limitations.
Algorithmic Advancements in Drive-by Inspection Methods Towards Intelligent Bridge Monitoring
(Aalto University, 2023) Lan, Yifu; Rakennustekniikan laitos; Department of Civil Engineering; Bridge Engineering; Insinööritieteiden korkeakoulu; School of Engineering; Lin, Weiwei, Assoc. Prof., Aalto University, Department of Civil Engineering, Finland
Since conventional vibration-based structural health monitoring (SHM) methods typically require the installation of numerous sensors directly onto the bridge, the substantial costs associated with on-site sensor installation and maintenance have long rendered such technology an expensive option. Recently, an alternative approach referred to as the "drive-by bridge inspection method" has attracted scholarly attention. This method necessitates no instrumentation on the bridge; instead, it uses a few sensors positioned on the vehicle traversing the bridge, with the vehicle functioning as both an exciter and a receiver. It offers the possibility to efficiently monitor groups of bridges (particularly small and medium-sized ones), presenting an economically efficient solution to bridge health monitoring problems. While previous research on the drive-by method has yielded promising results, there are still some challenging problems and ample room for improvement before its engineering application. This thesis aims to propose algorithmic solutions to address the challenges faced by the current drive-by methods, successfully extracting bridge modal parameters and identifying damage. In terms of bridge modal parameters, two algorithms are proposed. Algorithm 1 extracts the bridge frequency as a common signal component in the responses of multiple sensors mounted on the vehicle. This method does not require specially designed vehicles or multiple cars, as in earlier studies, but instead utilizes a single ordinary vehicle, providing a practical solution. Algorithm 2 employs the Coherence-PPI (Prominent Peak Identification) method, which extracts the bridge frequency from the common vibrational components of multiple passes of the same vehicle. Rather than seeking to minimize differences, it encourages variability in drive-by measurements (e.g., varying vehicle parameters, avoiding traversing the same road surface) to filter bridge frequencies. It is particularly suitable for vehicles passing the same bridge multiple times (such as buses). In terms of damage identification, a data-driven algorithm based on an optimized AdaBoost-linear SVM is proposed (Algorithm 3), which accurately indicates bridge damage using only the raw vibration signals received from vehicles passing the bridge. To further improve damage identification accuracy and address certain limitations of drive-by measurements, such as noise and data redundancy, a time-domain signal processing algorithm for the raw vehicle accelerations is also proposed (Algorithm 4). The proposed algorithms have been validated through numerical simulations, laboratory experiments, and field tests on simply supported and continuous beam bridges using truck and bus models. The ultimate goal is to achieve a practical and intelligent bridge health monitoring system.
Ämmässuon kaatopaikan laajennusalueen huoltotunneli ja sen geotekninen mitoitus
(Aalto University, 2008) Winqvist, Fredrik; Forsman, Juha; Rakennustekniikan laitos; Department of Civil Engineering; Insinööritieteiden korkeakoulu; School of Engineering; Vepsäläinen, Pauli
Pääkaupunkiseudun yhteistyövaltuuskunnan jätteenkäsittelykeskuksessa Ämmässuolla vastaanotetaan pääkaupunkiseudun yhteensä yli miljoonan asukkaan ja 50 000 yrityksen jätteet. Ämmässuon jätteenkäsittelykeskus on pohjoismaiden suurin yhdyskuntajätteen kaatopaikka. Jätteenkäsittelykeskuksen vanha jätetäyttöalue oli suljettava viranomaispäätösten (VNp 861/97 ja 1049/99) määräyksiin perustuen viimeistään 1.11.2007. Vanhan täyttöalueen länsipuolelle sijoittuvan laajennusalueen suunnittelu on aloitettu vuonna 1990 ja sen ensimmäinen täyttöalue vihittiin käyttöön 30.10.2007. Laajennusalueelle tuleva jätetäyttö eristetään ympäristöstään tiivisterakenteiden avulla. Tiivisterakenteeseen kuuluu kaatopaikan pohjan kuivatuskerros, joka koostuu vettä hyvin läpäisevästä materiaalista ja suotoveden keräilyputkista. Tehokkaan kuivatuksen varmistamiseksi on Ämmässuolla päädytty ratkaisuun, jossa pohjarakenteet salaojineen kallistetaan alueen keskiosaan päin viettäviksi. Keskiosaan on rakennettu täytön alle jäävä teräsbetoninen huoltotunneli, jossa sijaitsevaan kokoojaputkistoon salaojat yhdistetään. Kokoojaputkien avulla salaojavedet johdetaan täyttöalueen eteläpuolelle, josta ne edelleen siirretään käsittelyyn. Koska Suomessa ei ole aikaisempia kokemuksia vastaavan huoltotunnelirakenteen suunnittelusta ja toteutuksesta, suunnittelun lähtöaineiston keräämiseksi selvitettiin olemassa olevat huoltotunnelikohteet maailmanlaajuisesti. Kaikki 13 todettua huoltotunnelikohdetta sijaitsevat Euroopassa, joista pääosa Saksassa. Ämmässuon huoltotunnelin poikkileikkauksen dimensiot määritettiin huonetila- ja rakennemitoituksen avulla. Muotoa valittaessa huomioitiin myös käytössä oleva muottitekniikka. Rakennemitoituksen lähtökohdaksi tehtiin maapainelaskelmia, joilla selvitettiin huoltotunnelin rakenteisiin kohdistuva maanpaine jätteen tilavuuspainon vaihdellessa välillä 12...15 kN/m3. Käytetty jätetäyttösyvyys perustuu ympäristöluvan asettamiin reunaehtoihin. Jätetäyttösyvyytenä laskelmissa käytettiin 70 metriä. Huoltotunnelin suunnittelussa käytetty mitoitusikä oli 200 vuotta. Maanpainelaskentojen lisäksi tarkasteltiin siirtymärakenteiden tarvetta painumaerojen aiheuttaessa lisärasituksia suoto- ja tarkkailusalaojiin sekä geomembraaniin huoltotunnelin seinälinjalla. Ämmässuon huoltotunnelin 1. rakennusvaiheen työt käynnistyivät kesäkuussa 2006 ja valmistuivat lokakuussa 2007. Huoltotunnelin ensimmäisen vaiheen pituus on 450 metriä.
Analysing entrapped pores in concrete via x-ray computed tomography : Influence of workability and compaction time
(Elsevier Science Ltd., 2024-02-23) Ahmed, Hassan; Kuva, Jukka; Punkki, Jouni; Department of Civil Engineering; Mineral Based Materials and Mechanics; Department of Civil Engineering; Geological Survey of Finland
Understanding the attributes of entrapped pores in compacted concrete is crucial for improving mechanical and durability properties of concretes. This research investigates how compaction time and workability affect entrapped pores characteristics. Using X-ray Computed Tomography, concrete specimens, with different workability classes, were analysed after being compacted for different times. Results show that increased workability and vibration time significantly reduce entrapped porosity, especially in the 2.7–4.6 mm diameter range, but this effect lessens at extended durations. Higher workability results in less spherical pores, potentially leading to stress concentrations. Additionally, concentrations of entrapped pores up to 5% were observed along specimen heights. These insights contribute to our understanding of pore properties, indicating potential adverse impacts on the performance of concrete.
Analysing Film Plastic Waste in Residential Construction Project
(2023-07-31) Chauhan, Krishna; Peltokorpi, Antti; Seppänen, Olli; Performance in Building Design and Construction; Department of Civil Engineering
Sustainability and lean construction are closely interrelated topics to consider. However, sustainability issues in construction projects are rarely discussed in International Group for Lean Construction (IGLC) community. The major aim of this research is to analyze the film plastic waste in residential construction project. For the analysis, three cases were selected, where the amount and quality of film plastic waste were investigated from the beginning of project to the end. According to the results, 1009–1710 kg of film plastic waste was separately collected (about 0.5–1.0% of total waste). In addition, the generated pattern of film plastics was approx. 0.34 kg/m2 and each apartment generated approx. 26.20 kg. The most film plastic is generated in the interior phase of the work stage, which includes tasks such as partition work, furniture installation and home appliance installation. Furthermore, based on the results of this research, we have developed a preliminary web modelling tool: kalvomuovi.fi, which could be adopted for estimating the amount of film plastic waste in a residential construction project. Future research could further develop the web model tool for other type of construction projects, such as, schools, hospitals, and shopping centers. Also, future research is necessary to develop better recycling technology of film plastic waste.
Analysis of key thermal coupled factors in modelling of bentonite barriers
(2021-10-12) Gupta, Abhishek; Abed, Ayman; Sołowski, Wojciech Tomasz; Department of Civil Engineering; Mineral Based Materials and Mechanics
Bentonite is a material considered to be used as a component of a barrier in deep geological repositories for nuclear waste. Its behaviour is affected by temperature, humidity and chemical composition of water saturating its pores. Reproduction of bentonite behaviour in such thermo-hydro-mechanical (THM) conditions involves extensive use of empirical and physical coupled relationships. This paper investigates parameters, which influence the bentonite behaviour in THM experiments relevant to the conditions in the repositories. For the study, a numerical investigation is performed based on test simulation computed with the finite element code Thebes (Abed and Sołowski 2017). A numerical simulation by Abed and Sołowski (2017) of a non-isothermal infiltration experiment (Villar and Gomez-Espina 2009) has been taken as a basis for the investigation. The results of this simulation were compared with a series of 7 other simulations that are set up by inactivating the selected thermally coupled variables, one at a time. Presented results identify the key parameters the simulation is sensitive to and provide insights on the relevance of the underlying coupled processes.
Analysis of Modulus Properties of High-Modulus Asphalt Mixture and Its New Evaluation Index of Rutting Resistance
(MDPI AG, 2023-05) Huang, Guojing; Zhang, Jiupeng; Hui, Bing; Zhang, Hongfei; Guan, Yongsheng; Guo, Fucheng; Li, Yan; He, Yinzhang; Wang, Di; Department of Civil Engineering; Mineral Based Materials and Mechanics; Chang'an University; Jiangsu Sinoroad Engineering Research Institute Co., Ltd.
High-modulus asphalt mixture (HMAM) is one of the most effective materials to enhance the rutting resistance of asphalt pavement and upgrade pavement sustainability. The objectives of this study are to investigate the modulus properties of different HMAMs and their correlation with the rutting resistance, to propose reasonable modulus evaluation indicators, and to analyze the rutting resistance mechanisms of different materials (hard asphalt, polyethylene, dissolved polyolefin). The effect of three HMAMs and two styrene-butadiene-styrene (SBS) modifiers on asphalt mixtures’ rutting resistance were evaluated by dynamic modulus test and wheel track test, and the results were simulated and further analyzed via ABAQUS. The results indicate that the dynamic modulus of the mixtures showed a gradual increase and decrease with the increase of loading frequency and testing temperature, respectively. The ratio of dynamic modulus in low frequency to that in high frequency correlates well with dynamic stability under high-temperature conditions, and the wider the frequency coverage, the higher the correlation between this ratio and dynamic stability. The rutting resistance of asphalt pavements can be improved by reducing the frequency sensitivity of HMAMs under high temperatures or by increasing the modulus’ absolute value of the pavement structural layer. Therefore, two indicators, the absolute value of the modulus and the ratio of 0.1 Hz dynamic modulus to 25 Hz dynamic modulus at 55 °C, are recommended for the evaluation of rutting resistance of HMAMs. Based on the evaluation indexes proposed in this paper, a comparative analysis of the rutting resistance mechanism of HMAMs prepared with different materials was carried out, and it was concluded that the mixture with high-modulus agents had the best rutting resistance, which is consistent with the test road observations, thus verifying the feasibility of the modulus evaluation indexes recommended in this paper for the evaluation of the rutting resistance of different types of HMAMs.
Analysis of multi-layers insulated sandwich panel with flexible shear connectors
(TAYLOR & FRANCIS, 2022-12-16) Chen, An; Bazroun, Mohammed; Yossef, Mostafa; Department of Civil Engineering; Structures – Structural Engineering, Mechanics and Computation; Beijing Jiaotong University; Iowa State University
Insulated sandwich panel consists of face layers separated by foam insulation cores. Existing studies are mainly focused on two-layers sandwich panel. Multiple layers can also be used to increase the panels’ strength and improve their energy performance. This article presents an analytical solution for multi-layers insulated sandwich panels with flexible shear connectors, such as Fiber-Reinforced Polymer (FRP) shear connectors. For flexible shear connectors, the slip between layers leads to partial Degree of Composite Action (DCA), which is considered in the analytical solution. The analytical results are verified with Finite Element (FE) analyses. Finally, a multi-layers sandwich panel application is presented.

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