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Softver “WELL-DRAIN” za proračun trenutnog sleganja tla usled sniženja nivoa podzemne vode
No full textKorišćenje bunara za sniženje nivoa podzemne vode
(NPV) u fazi izgradnje objekta je standardna praksa, ali
se proračun trenutnog sleganja koje nastaje kao posledica
obaranje NPV često zanemaruje. Sniženje nivoa izaziva
smanjenje pornog i povećanja efektivnog pritiska, što
dovodi do zbijanja tla, odnosno sleganja. Ovakve
deformacije su mahom trajne i mogu se opisati Terzaghi-
jevim modelom koji pretpostavlja nelinearnu vezu
između efektivnih napona i deformacija, koja je rezultat
promenljive vrednosti modula stišljivosti. Pomenuti
model je integrisan u softver WELL-DRAIN koji je
razvijen na Institutu za hidrotehniku Građevinskog
fakulteta u Beogradu. Ovaj softver se sastoji iz dva
modula, gde se prvi odnosi na proračun prostornog
sniženja NPV u vremenu usled crpljenja vode iz bunara,
dok se drugi odnosi na proračun posledičnog trenutnog
sleganja tla korišćenjem rezultata sniženja NPV kao
ulaznih podataka. WELL-DRAIN je već primenjivan u
praksi, a u ovom radu su prikazani rezultati sleganja
dobijeni za jednu lokaciju u Beogradu na kojoj je za
izgradnju objekta sa tri podzemne etaže neophodno
sniziti nivo podzemne vode za 9 m. U tu svrhu je
planirana izrada 22 bunara ukupnog kapaciteta 176 L/s
koji su raspoređeni duž linije iskopa. Rezultati jasno
ukazuju na značajno sleganje tla od preko 7 cm u
neposrednoj zoni izvan iskopa, zbog čega je predloženo
alternativno rešenje kojim se ne dovode u opasnost
okolni objekti i infrastruktura
An Innovative Application of Swarm-based Algorithms for Peer Clustering
No full textIn most P2P networks, peers are placed randomly or based on their geographical position, which can lead to a performance bottleneck. This problem can be solved by using peer clustering algorithms. In this paper, we propose two innovative swarm-based metaheuristics for peer clustering, Slime Mold and Slime Mold K-Means. They are competitively benchmarked, evaluated and compared to nine well-known conventional and swarm-based algorithms: Artificial Bee Colony, Artificial Bee Colony combined with K-Means, Ant-based Clustering, Ant K-Means, Fuzzy C-Means, Genetic K-Means, Hierarchical Clustering, K-Means and Particle Swarm Optimization. The benchmarks cover parameter sensitivity analysis and comparative analysis made by using 5 different metrics: execution time, Davies-Bouldin index, Dunn index, Silhouette coefficient and Averaged Dissimilarity coefficient. Further, a statistical analysis is performed in order to validate the obtained results. Slime Mold and Slime Mold K-Means outperform all other swarm-inspired algorithms in terms of execution time and quality of the clustering solution
Izbor optimalne tehnologije izgradnje kanalizacione crpne stanice Makiš korišćenjem metode AHP-VIKOR sa FAZI pristupom
No full textAnalizirana su projektna rešenja za kanalizaciju, prečišćavanje i pumpanje atmosferskih
otpadnih voda u Kanalizacionoj pumpnoj stanici (PS) Makiš. Analiza je sprovedena u
odnosu na izgradnju sagledavajući korišćenje metode višekriterijumske optimizacije uz
razmatranje različitih načina kanalisanja, tretmana i evakuacije otpadnih voda. Analizirani
su mnogi kriterijumi prema kojima su ocenjena različita varijantna rešenja za izgradnju
kanalizacione PS Makiš. Razmatrani su različiti načini projektovanja i izgradnje objekata.
Korišćene su metode AHP, VIKOR i Fuzzy pristu
Primena metode AHP-VIKOR sa FAZI pristupom u projektovanju objekata atmosferske kanalizacije
No full textПројектована је канализација, пречишћавање и препумпавање атмосферских
отпадних вода у Канализационој пумпној станици (ПС) „Макиш“. Извршен је избор
оптималног решења у односу на изградњу коришћењем методе вишекритеријумске
оптимизације уз разматрање различитих начина каналисања, третмана и евакуације
отпадних вода. Разматрани су различити начини пројектовања и изградње објеката.
Коришћена је комбинована метода АХП-ВИКОР са Fuzzy приступом. Анализирана су
различита варијантна решења за изградњу канализационе атмосферске ПС „Макиш
Flexible joints for seismic-resilient masonry-infilled RC frames: preliminary analyses for shaking table testing
No full textMasonry infills are among the most vulnerable components of building frames, often undergoing severe damage even under minor or moderate seismic shaking. In recent years, flexible joints have emerged as a promising technique for protecting the infills from damage. To fully demonstrate the effectiveness of this technique, it is necessary to carry out full-scale tests on a structural prototype under realistic loading conditions, which can be simulated with shaking table testing. There is also a need to assess whether the joints can provide enough energy dissipation capabilities to enable a resilient-based design of infilled frames. The ERIES-FLEJOI project aims to address these gaps by investigating the performance of two promising systems based on flexible joints, one aimed at increasing the compliance of the infills, the other aimed at decoupling them from the frame. These systems, installed in two identical reinforced concrete (RC) frame prototypes, will be tested at the Dynamic Testing Laboratory of IZIIS (Skopje, N. Macedonia). This paper illustrates the two systems, the preliminary investigations, and the numerical analyses carried out to design the joint systems in order to meet the performance objectives and constraints posed by the shaking table capacity. The analyses involve two recently developed alternative modelling strategies, one based on a meso-scale description of the infill walls and the other on an equivalent discrete macro-element
Improving performance of bucket-type hydrological models in high latitudes with multi-model combination methods: Can we wring water from a stone?
Get PDFMulti-model combination (averaging) methods (MMCMs) are used to improve the accuracy of hydrological (precipitation-runoff) outputs in simulation or forecasting/prediction modes. In this paper, we examined if the application of MMCMs can improve model performance in reproducing distributions of hydrological signatures, such as annual maxima or minima of varying durations. To this end, ten MMCMs were applied to 29 bucket-type models to simulate runoff in 50 high-latitude catchments. The MMCMs were evaluated by comparing the resulting simulated flows to the reference (i.e., best-performing) individual model, considering various commonly used performance indicators, as well as model performance in reproducing the distributions of signatures. Additionally, we analysed whether (1) the selection of the candidate models, or (2) targeting specific signatures, such as annual maxima or minima, can improve performance of the model combinations. The results suggest that the application of MMCMs can improve accuracy of runoff simulations in terms of traditional performance indicators, but fails to improve performance in reproducing the distributions of signatures. Neither excluding poor-performing models nor applying the MMCMs with the targeted signatures, improves this aspect of model performance. These findings clearly reveal the need for further research aiming at enhancing model performance in reproducing the distributions of hydrological signatures, which is essential for climate-change impact studies
Numerical Modeling of Two Adjacent Interacting URM Structures
Get PDFMasonry structures in addition to their long heritage are still widely used in civil engineering practice. It should be emphasized that a lot of research has already been done on the seismic behavior of masonry structures. However, due to the nature of such a problem, its complexity and seriousness, the development of numerical models and their connection with experimental tests are always important. This is particularly significant considering their vulnerability to the action of horizontal forces generated during seismic excitations. In recent decades, many researchers have tried to capture the behavior of unreinforced masonry (URM) structures or reinforced concrete (RC) frames with masonry infills exposed to earthquakes, using different approaches. This paper tackles numerical modeling based on the finite element method (FEM) for the estimation of the dynamic response of two adjacent interacting URM units, subjected to shaking table motions. Geometrical and material properties of the specimen are provided by the Horizon 2020 project SERA-AIMS (The Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe – Seismic Testing of Adjacent Interacting Masonry Structures). The analyses of dynamic performance were executed in SAP2000 software. Obtained results on the numerical model provide useful guidelines for modeling the nonlinear seismic behavior of masonry buildings
Modulus of elasticity and compressive strength of 3D printed concrete - an experimental testing
No full textThis paper is a next part of the research on the basic physical-mechanical properties of 3D printed
concrete. The state-of-the-art present current results in experimental testing of the basic
properties of this concrete, as well as finished elements such as columns and walls. Further, it
shown current activity in the standardization process of testing methods for 3D printed concrete.
The own experimental investigation including laboratory testing of bulk density, compressive
strength, and modulus of elasticity on mold and printed samples are presented. Additionally, a
truss girder obtained by 3D concrete printing technology with dimensions of 435x240x180 mm
was tested in axial compression test. Detailed analysis of the results, conclusions, and directions
for further research on this topic are given
The ‘Umka’ landslide
No full textWe present an in-depth landslide map of the ‘Umka’ landslide near Belgrade, Serbia, at a scale of 1:5000. The map delineates elements at risk, primarily buildings and road infrastructure impacted by the landslide displacements of several cm per year, introduced during frequent reactivation stages. The Main map results from a survey of over 350 buildings and more than 7 km of state and local roads. The acquisition techniques included engineering geological field mapping, building survey, and visual interpretation of high-resolution UAV images. This is the first case of an integrated approach to mapping elements at risk within an urbanized active landslide in Serbia. Presently, over 490 people continue to reside at the site, facing daily landslide risks. This research and map hold substantial value for local authorities and decision-makers, providing a basis for conducting landslide risk analyses and implementing effective risk mitigation strategies or remedial measures
Failure modes of steel beams with web openings
No full textAs an alternative to trusses and open-web joist systems, beams with web openings
are lightweight, long-spanning structural elements that bind structural role (efficient
load distribution) and functionality in a visually acceptable way by allowing service
routes to be installed within their cross-section height. Owing to its specific
production process, this beam type has a beneficial impact on rational use of
material for low-carbon structures. In recent years, extensive scientific research has
been conducted to assess the structural behavior and ultimate capacity of beams
with web openings. Due to the presence of web openings, load transfer is
accompanied by complex stress distributions in the section web, causing failure
modes that are distinguishable from those of solid I-section beams. This paper
summarizes the different failure modes of the beams with web openings that have
been discovered and confirmed in numerous experiments of reference scientific
researches. Based on the state-of-the art in this structural area, the predictions of
different failure modes that are affected by influencing geometric parameters are
provided