Procter & Gamble (United Kingdom)
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Possibilities for measuring the thickness of the water film on the road surface
Get PDFU projektu RESAFE (Road and Environmental Safety related to water – pavement interactions) koji se realizuje u okviru nacionalnog programa PRIZMA, jedan od ciljeva je izrada alata REST (Road and Environmental Safety Toolkit) za procenu sigurnosti puteva tokom kišnih epizoda u pogledu akvaplaninga kao i uticaj te vode na životnu sredinu. Važan element projekta je i eksperimentalna provera uticaja padavina na uslove na putu u laboratorijskim uslovima kao i u kontrolisanim terenskim uslovima. Pored poznavanja intenziteta padavina, debljina vodenog filma je jedna od ključnih veličina. Merenjima treba detektovati granicu akvaplaninga od oko 0,8 mm. Potreban opseg merenja debljine vodenog filma od 0,1 – 0,2 do 4 mm, sa rezolucijom boljom od 0,1 mm što isključuje mogućnosti primene „klasičnih“ sistema za merenje nivoa vode. U radu se daje pregled mogućih metoda za merenje debljine vodenog filma na površini kolovoza: optičke, radarske i kapacitivne. Pored fizičkog principa merenja, u radu se za svaku od metoda navode i njena ograničenja, faktori koji utiču na pouzdanost merenja (temperatura, prisustvo soli tokom zimskog perioda, zamrzavanje vodenog filma, uticaj saobraćaja i slično) kao i okvirna cena. Na kraju rada se predlaže i metoda koja će se primenjivati u projektu RESAFE, s obzirom na striktna ograničenja budžeta.In the RESAFE project (Road and Environmental Safety related to water-pavement interactions) implemented within the national PRIZMA program, one of the objectives is to develop the REST tool (Road and Environmental Safety Toolkit) for assessing road safety during rainy episodes, regarding aquaplaning and the impact of this water on the living environment. An important element of the project is the experimental verification of the impact of precipitation on road conditions at laboratory experimental rig as well as in controlled field conditions. In addition to knowing the intensity of precipitation, the thickness of the water film is one of the key parameters. The measurements should detect the aquaplaning threshold at around 0.8 mm. The required range of water film thickness measurement is from 0.1 - 0.2 to 4 mm, with a resolution better than 0.1 mm, which excludes the possibility of using traditional water level measurement systems. The paper provides an overview of possible methods for measuring water film thickness on road surfaces: optical, radar, and capacitive. In addition to the physical measurement principle, the paper also lists the limitations of each method, factors affecting measurement reliability (temperature, presence of salts during winter, freezing of the water film, traffic impact, etc.), as well as approximate cost. Finally, a method applicable to the RESAFE project and strict budget constraints is proposed
Lessons learned from reconnaissance missions of SUZI-SAEE in recent earthquakes
No full textSerbian Association for Earthquake Engineering (SUZI-SAEE) is a national non-governmental (NGO) technical association with a mission to enhance awareness among professionals and general public related to the earthquakes and their consequences. SUZI-SAEE has several technical committees, including the Learning from Earthquakes (LFE) Committee, which is engaged in compiling and disseminating lessons from significant earthquakes in the country and the region. The activities include physical and/or virtual visits to earthquake-affected areas. The overarching goal is to reduce earthquake losses, increase community resilience and speed up post-earthquake recovery process in Serbia and other countries in the Balkans. The committee is also working on the development and application of advanced field reconnaissance tools, such as drone footage, data collections app, etc. In the last four years, SUZI-SAEE has dispatched expert teams to assess the impact of the November 26, 2019, Durres, Albania earthquake, the December 29, 2020, Petrinja, Croatia earthquake, and February 2023 Kahramanmaras, Turkey earthquake sequence. Several members were also involved in virtual reconnaissance visits after the 2021 Nippes, Haiti earthquake, the November 2022 Indonesia Earthquake, and November 2022 Duzce, Turkey Earthquake. Activities of the LFE committee are relevant for individuals and organizations responsible for education, seismic design, post-earthquake damage assessment, as well as for state authorities responsible for enacting laws and programs related to earthquake risk mitigation. The committee is making efforts to cooperate and share experience with similar committees around the world as well as jointly work on future reconnaissance missions, building on the past successfully accomplished collaborations
Progressive failure analysis of laminar composites under compression using smeared crack-band damage model and full layerwise theory
No full textThis paper presents an original finite element (FE) model that integrates the smeared crack band (SCB) approach and full layerwise plate theory (FLWT). The model enhances the computational efficiency of progressive failure analysis (PFA) of laminar composites in compression, by utilizing the layerwise approach which reduces a 3D model to a 2D one. The model distributes damage throughout the FE domain, with fracture mechanisms represented by material stiffness degradation controlled by damage variables (based on equivalent strains specifically defined for each failure mode). Mesh dependency issues are addressed by scaling fracture energy using a characteristic element length, and failure initiation and modes are determined using the 3D Hashin failure criterion.
Accurately describing lamina response in fiber direction under compression requires linear-brittle softening with a stress plateau. The study showed that a model considering 30% of residual stress accurately predicts maximum stress regardless of mesh refinement, demonstrating results' minor dependence from the selected element size.
The model accuracy has been confirmed by comparing the obtained results against experimental and benchmark data from the literature. The size effect study demonstrated a decrease in maximum stress of the open-hole laminates in compression with increasing specimen in-plane size. This trend is consistent with experimental and reference numerical observations, confirming the model accuracy and applicability even for relatively coarse meshes. Therefore, computational efficiency is improved, with preserved accuracy of conventional solid finite element models
Nonlinear Modeling and Machine Learning for Interstorey Damage State Classification in 10-Story RC Frame Building
No full textThis study introduces a methodology combining nonlinear numerical modeling and machine learning for damage state assessment of a 10-story reinforced concrete (RC) frame building. The structure, tested at the E-Defense laboratory in 2015, was subjected to the triaxial ground motion record of the 1995 JMA Kobe earthquake. Nonlinear analysis using OpenSeesPy software was performed to obtain interstorey drift ratios (IDRs). After rigorous model calibration, the building prototype was subjected to additional 19 far-field ground motion records, extracted from FEMA P695. Damage states were specified using FEMA P-58 methodology based on derived fragility curves. Each seismic record was adjusted to four intensity levels, expanding the dataset to 800 samples. A decision tree (DT) algorithm was trained using twelve input parameters to identify the damage state (DS) of each story, demonstrating notable accuracy and efficiency with low compu-ting and time requirements
The application of demountable connector with mechanical coupler and rebar anchor in steel-reinforced concrete connections
No full textNepovoljan uticaj građevinske industrije na životnu sredinu može se smanjiti primenom principa cirkularne ekonomije, što predstavljaja korak ka održivom građevinarstvu. Spregnute i mešovite konstrukcije od čelika i betona imaju veliki potencijal sa stanovišta ponovne upotrebe na kraju tzv. „prvog upotrebnog veka“.
Primena tradicionalnih demontažnih spojeva omogućava ponovnu upotrebu čeličnih elemenata, ali je ponovna upotreba armiranobetonskih elemenata, odnosno spojeva, i dalje upitna. Jedno od mogućih rešenja je upotreba demontažnih konektora sa mehaničkom spojnicom. Konektor se sastoji od tri elementa: (1) demontažnog zavrtnja, (2) ubetonirane mehaničke spojnice, i (3) elementa kojim se konektor sidri u okolni beton – armaturnog ankera ili drugog, ubetoniranog zavrtnja. Glavni izazov pri primeni ovakvog tipa konektora predstavlja adekvatna analiza svih komponenata spoja.
U ovom radu su prikazani prethodni rezultati eksperimentalne i numeričke analize konektora sa mehaničkom spojnicom pri čistom smicanju i pri čistom zatezanju. Dobijene nosivosti upoređene su sa prediktivnim nosivostima iz evropskih tehničkih normi i smernica, kao i predlozima iz naučnih istraživanja. Za komercijalno dostupne konektore sa mehaničkom spojnicom i armaturnim ankerom određene su nosivosti pri interakciji smicanja i zatezanja. Pravilnim oblikovanjem spoja može se postići da demontažni zavrtanj bude „najslabija“ komponenta, čime se u potpunosti iskorišćava potencijal ovog konektora u smislu ponovne upotrebe svih konstruktivnih elemenata veze.The negative impact of construction industry on environment can be decreased via principles of circular economy concept, as a step towards sustainable design. Composite and mixed steel-concrete structures have a great potential in terms of reuse at the “end-of-life” scenario.
The application of traditional demountable connections enables the reuse of steel elements, whereas the reuse of reinforced concrete elements, i.e., connections, is still questionable. One of the possible solutions is to use demountable connectors with mechanical couplers. This type of the connector consists out of three parts: (1) demountable bolt, (2) mechanical coupler embedded in concrete, and (3) element for anchoring of the connector to concrete – rebar anchor or second, embedded bolt. The main challenge for application of this type of the connector is adequate analysis of connection components.
In this paper, the results of previous experimental and numerical research of the connector with mechanical coupler in pure shear and in pure tension are presented. The obtained shear and tension resistances are compared to predicted resistances from European technical codes and guidelines, as well as from scientific research. For commercially available demountable connectors with mechanical coupler and rebar anchor, the resistance under combined shear and tension loads were determined. It has been shown that demountable bolt can be the “weakest link” in the connection, which would fulfill the connectors potential in terms of reuse of all structural elements in joint
Modelovanja transporta toplote u višeslojnim strukturama u nestacinarnom režimu korišćenjem Grin-ove funkcije i ekvivalnentnih električnih RC kola
No full textPredstavljena je analiza transporta toplote kroz višeslojne građevinske pregrade u nestacionarnom slučaju u vremenskom domenu. Razamatrani su pristupi bazirani na Grin-ovim funkcijama i konvoluciji kao i modelovanje nestacinarnih termičkih procesa korišćenjem ekvivlaentnog RC kola. Pokazano je da je sa praktičnog stanovišta, pri analizi termalnih gubitaka u građevinskim objektima, metod baziran na Grin-ovim funkcijama i konvolucionom integralu u vremenskom domenu pogodoniji za određivanje fluksa toplotnih gubitaka kroz višeslojne pregrade u slučajevima kada su poznate vemenski promenljive temperature vazduha sa spoljašne i unutrašnje strane posmatrane strukture, dok je modelovanje bazirano na ekvivalentnom električnom RC kolu pogodnije u slučajevima
kada su poznate vremenski zavisna spoljašnja temperatura vazduha i snaga unutrašnjih grejnih tela. U modelu baziranom na RC kolu moguće je uzeti u obzir i toplotne gubitke kroz pod kao i
toplotni kapacitet prostorije, što je u slučaju pristupa baziranog na Grin-ovim funkcijama u vremenkom domenu znatno složenije. Na osnovu razvijenog numeričkog RC modela dobijene su
toplotne dinamičke karakteristike posmatranog višeslojnog zida u vidu vremenskih konstanti za različite delove konstrukcije
Support in Achieving SDG6 for Sustainable Water Supply and Wastewater Management in Southeastern Europe
No full textTo assist three Southeastern Europe (SEE) countries, namely Albania, Bosnia and Herzegovina, and Montenegro, in meeting their SDG 6 targets while simultaneously enhancing their environment and advancing sustainable development, two UNESCO Water Centres from SEE were assigned a collaborative project, the findings of which are summarized in this paper. The paper offers an integrated strategy for achieving SDG6 focusing among others to objective 6B, which concerns stakeholder engagement, and specifically targets indicator 6.B.1. This indicator evaluates the extent to which local administrative units have established and operationalized policies and mechanisms for involving local communities in water and sanitation management. A combination of in-person interviews, site visits, data collecting and analysis from literature, and a standardized questionnaire directed at local and regional water agencies to describe and analyse the current state of water resource management in the three SEE countries. The more pressing needs related to drinking water and wastewater security were investigated. Subsequently, a thorough evaluation encompassing water and wastewater services, water infrastructure, policy issues, funding, and management aspects was conducted to provide a comprehensive review. Key areas of focus include the identification of priority needs, the need for water conservation plans/policies, the detection of areas where the capacity-building efforts needs strengthening, and the examination of potential barriers to the financial sustainability of the water utilities. The results highlight the shortcomings of the target countries in developing and executing a comprehensive water strategy that will facilitate the timely and effective fulfilment of SDG 6.A series of recommendations were suggested to support the achievement of SDG6 in the three countries
Layer wise finite element for mechanical buckling of FGM plates under non-uniform edge loading
No full textIn many engineering handbooks and texts, the dependence of buckling loads on in-plane loads are given for uniform type of in-plane loading. However, plates are usually part of complex structural systems and in-plane load may not be always linear. These are the cases of structures like I-beams or wide flange beam subjected to bending moments at the end or lateral loads on the flange, while the web of the beam is under non-uniform in-plane loads. Over the last decades, due to the advance properties of functionally graded materials (FGM), when compared to the laminated composites, the demand for buckling analysis of FGM plates subjected to in‐plane loads is increased. Therefore, in this paper, the elastic stability analysis of functionally graded material (FGM) plate under non-uniform mechanical in–plane load is analysed. The displacement model based on Generalized Laminate Plate Theory (GLPT) assumes piece–wise linear variation of in–plane displacements, constant transverse displacement, non–linear strain–displacement relations (in von Karman sense) and linear material properties. The properties of FGMs are assumed to be constant in xy–plane and vary through thickness by a power law function in terms of volume fraction of the constituents. The mathematical model includes the quadratic variation of transverse shear stresses within each layer of the plate. The principle of virtual displacements (PVD) is used to derive the weak form of linearized buckling problem. Linearized buckling problem is solved using Finite element method (FEM). In-plane plate is discretized using nine node Lagrangian isoparametric finite element or 2D quadratic in-plane interpolation, while 1D Lagrangian interpolation is used for discretization through the thickness. The original MATLAB computer program is coded for the FEM numerical solution. The solutions are verified by comparison with the results from the literature. The results are shown that the effects of in-plane load distribution, side–to–thickness ratio b/h and power–low index had significant effect on critical buckling loads of FGM plates, and should be used when designing safe FGM plate like structures
Mineral carbonation of industrial wastes for application in cement-based materials
No full textMineral carbonation is a way to permanently store carbon dioxide (CO2) in cementbased materials. Demolished concrete waste and other types of alkaline industrial wastes, like iron and steel slags, fly ash, concrete slurry waste and cement kiln dust are prospective candidates for accelerated carbonation application. This paper presents CO2 sequestration potentials, impacts of the accelerated carbonation on the selected properties of wastes and their possible applications in cement-based materials. Based on the analysis of published research in the area it was concluded that porosity, volume stability and heavy metals leaching of different waste types are improved after accelerated carbonation pre-treatment. This increases the effectiveness and broadness their application as substitutes for aggregates and binders in mortar and concrete. The research is however still very limited in the area of the application of the carbonated wastes with highest CO2 sequestration potential, namely recycled concrete powders and iron/steel slags. Besides, for proper conclusions on the environmental benefits, an LCA (Life Cycle Assessment) which includes all the phases of the life cycle must be performed, which is also lacking in the published research
Buckling strengths of Cold-Formed Built-up Cruciform Section Columns under axial compression
No full textThis paper describes experiments addressing the buckling and collapse behaviour of cold-formed stainless steel cruciform section columns. Doubly symmetrical flanged cruciform section columns were built using six individual press-braked plain channels made of austenitic grade EN 1.4307 assembled back-to-back. Three different column lengths were tested – namely, short (600 mm), intermediate (1200 mm) and long (2400 mm) lengths, and two channel geometries were used in all tests – with cross-section depths of 200 mm and 100 mm. Tests were carried out under pure axial compression and with fixed end support conditions. Tests were repeated two times for each length. It was observed that the buckling patterns were affected both by the global slenderness and by the spacing between the fasteners. Stocky columns experienced local buckling of the individual channel sections. The plastic failure mechanism was dependent on the fasteners spacing. Intermediate slenderness columns were characterised by interaction between global torsional buckling and local buckling whereas more slender columns failed predominantly through torsional buckling. For the latter, the spacing between the fasteners had a minor influence on the ultimate capacity