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Wyniki wyszukiwania dla: EXCAVATIONS
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Impact of an unsecured excavation on an underground pipeline
PublikacjaThe paper presents a numerical analysis of the impact of an unsecured excavation on an underground pipeline in selected soil conditions. The research was inspired by a real-life failure of a water pipeline which was caused by a nearby unsecured excavation (Sikora et al. 2015). The failure was triggered by displacement of soil mass in the vicinity of the pipeline. The study conducted in the framework of Finite Element...
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Impact of deep excavation on nearby urban area
PublikacjaObciążenia i odciążenia gruntu wywołane są wykonaniem i obciążeniem konstrukcji. Wpływ technologii wykonawstwa powiązany jest z metodami wykonawstwa budowli i zależy od: rodzaju ścianki, sposobu jej wykonania, sztywności ścianki, sposobu obniżenia zwierciadła wody, drgań wywołanych wprowadzeniem ścianki i innych. Podano przykłady wykonania głębokich wykopów za pomocą ścianek stalowych i palisad w miejscach zurbanizowanych i różnych...
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Catamaran dynamics at irregular wave excitations
PublikacjaArtykuł dotyczy dynamiki jednostki wielokadłubowej typu katamaran poddanej wymuszeniom pochodzącym od falowania nieregularnego.Przeprowadzono analizę dynamiki jednostki wielokadłubowej przy założeniu, że jest on opisany jako model liniowy, na który działa fala nieregularna. Model matematyczny układu dynamicznego jest reprezentowany poprzez równania stanu. Zapisano równania uwzględniające napływ fali czołowej, która wywołuje ruchy...
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Multihull vessel excitations in stochastic formulation
PublikacjaPraca dotyczy określania wymuszeń wielokadłubowej jednostki pływającej w ujęciu stochastycznym. Wymuszenia ruchu jednostek pływających pochodzą od ruchu fal morskich i działania wiatru. Najczęściej jest to falowanie nieregularne i dlatego w badaniach dynamiki takich jednostek zakłada się, że proces falowania ma charakter probabilistyczny. Przeprowadzono analizę dynamiki jednostki wielokadłubowej na liniowym modelu, na który działa...
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Analysis of Excavation-induced Deformation with Different Soil Models
PublikacjaMonitorowany wykop budowlany w centrum Warszawy poddano symulacjom numerycznym z wykorzystaniem metody elementów skończonych. Wykop zrealizowany został w pre-konsolidowanych utworach spoistych z zastosowaniem ścian szczelinowych i metody stropowej. Szczególnie ważny w symulacjach tego rodzaju zagadnień jest wybór modelu zachowania się gruntu w warunkach małych odkształceń przed osiągnięciem zniszczenia. Opis aktualnej sztywności...
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Excavation induced cast iron pipeline failure – a numerical study
PublikacjaNumerical study on impact of an unsecured excavation on an underground pipeline. Analysis focused on investigation of pipeline displacement generated by soil movement caused by excavation and heavy traffic. Numerical calculations and soil parameter sensitivity analysis based on Finite Element Method. Some comparisons of results with real-life failure cases.
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Collective excitations in the hubbard model with intrasite attraction
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Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
PublikacjaIn this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable...
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Collective Excitations in the Extended Hubbard Model with Intrasite Attraction
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The results of analyses of deep excavation walls using two different methods of calculation
PublikacjaPrzedstawiono wyniki obliczeń obudowy głębokiego wykopu dwukrotnie rozpieranej i dwukrotnie kotwionej w gruncie jednorodnym niespoistym. Obliczenia numeryczne wykonano metodą podpór sprężysto-plastycznych i metodą elementów skończonych. Zwrócono uwagę na istotne różnice w wynikach obliczeń. Zaproponowano wyjaśnienie przyczyn zaobserwowanych różnic w wynikach obliczeń otrzymanych z obu metod.
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Influence of anisotropic stiffness in numerical analyses of tunneling and excavation problems in stiff soils
PublikacjaIn the stiff overconsolidated soil deposits anisotropy influences small and intermediate strain stiffness and hence it has important impact on the results of discplacement preditcions in soil-structure modelling. The authors developed a cross-anisotropic soil model which combines both stress dependent and micro-structural anisotropy. The model is based on the anisotropic hyperelastic kernel for small strain stiffness. Reference...
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Strain field of abdominal surface due to patients live excitations
PublikacjaPodano metodę opisu pola odkształceń powierzchni brzucha pacjenta podczas ruchów jego tułowia. Wyróżniono strefy brzucha o zróżnicowanej wielkości odkształceń ekstremalnych.
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Reconstruction of Ancient Lake after Peat Excavation—A Case Study about Water Quality
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Estimating Water Retention in Post-mining Excavations Using LiDAR ALS Data for the Strzelin Quarry, in Lower Silesia
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Comparison of the geophysical excitations of polar motion from the period: 1980.0–2009.0
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Pounding between Inelastic Three-Storey Buildings under Seismic Excitations
PublikacjaStructural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations....
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Spinon excitations in the quasi-one-dimensional S=12 chain compound Cs4CuSb2Cl12
PublikacjaThe spin−1/2 Heisenberg antiferromagnetic chain is ideal for realizing one of the simplest gapless quantum spin liquids (QSLs), supporting a many-body ground state whose elementary excitations are fractional fermionic excitations called spinons. Here we report the discovery of such a one-dimensional (1D) QSL in Cs4CuSb2Cl12. Compared to previously reported S=1/2 1D chains, this material possesses a wider temperature range over...
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Aerodynamic excitations generated in turbine shroud clearance determined bymeans of neural networks
PublikacjaSiły aerodynamiczne generowane w uszczelnieniach turbinowych z reguły opisywane są modelem liniowym. Przy dużych drganiach wirnika sposób ten daje niezbyt dokładne wyniki. Zaproponowano wykorzystanie sieci neuronowych do określania sił ciśnieniowych powstających w uszczelnieniu. Wyniki porównano z badaniami eksperymentalnymi.
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Dynamic analysis of temporary steel grandstand subjected to human-induced excitations due to jumping
PublikacjaSteel grandstands are structures that are frequently used during sport games and many other non-sporting events, such as festivals, music concerts, or even politicians rallies, with participation of a large number of attendees. Unfortunately, the presence of unexpected excessive dynamic loads due to unpredictable behaviour of spectators (e.g. synchronized harmonic jumping or swaying) may lead to...
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Simulation of the response of base-isolated buildings under earthquake excitations considering soil flexibility
PublikacjaThe accurate analysis of the seismic response of isolated structures requires the incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of such structures. In the present paper, seismic response time history analyses of base-isolated buildings modelled as single degree-of-freedom (SDOF) and multi degree-of-freedom (MDOF) systems with linear and nonlinear...
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UV-visible emision as a probe of core excitations applied to the furan carbon dioxide molecules
PublikacjaWykonano badania wzbudzenia wewnątrz powłokowego drobin furanu i dwutlenku węgla korzystając ze spektroskopii fluorescencyjnej w zakresie widzialnym i UV. Przeprowadzono pomiary emisji linii Hα i Hβ w pobliżu progu wzbudzenia O 1s i C 1s drobin furanu i dwutlenku węgla
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Numerical Evaluation of Dynamic Response of a Steel Structure Model under Various Seismic Excitations
PublikacjaThe present paper reports the results of the study, which was designed to perform a numerical evaluation of dynamic response of a single-storey steel structure model. The experimental model was previously subjected to a number of different earthquake ground motions during an extensive shaking table investigation. The analyzed structure model was considered as a 1-DOF system with lumped parameters, which were determined by conducting...
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Hydrological Excitations of Polar Motion Derived from Different Variables of Fgoals − g2 Climate Model
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Optimum shapes and dimensions of rubber bumpers in order to reduce structural pounding during seismic excitations
PublikacjaLarge displacement of structures observed during seismic excitations may lead to collisions between two adjacent, insufficiently-separated buildings and may result in major damages of both of them. In many building codes, appropriate equations or approximately recommended distances between structures in order to avoid pounding hazard have been introduced. Unfortunately, further, more detailed considerations show that safety situation...
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Influence of separation gap on the response of colliding models of steel structures under seismic and paraseismic excitations
PublikacjaAs a result of high urbanization, the need to erect closely-spaced buildings forces designers to consider collisions between structures taking place during ground motions. Experimental and numerical studies have confirmed that such collisions (often referred to as structural pounding) may cause serious damage to the structural elements and even lead to total collapse of colliding structures. The main reason of earthquake-induced...
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Consequences of neglecting the appropriate safety conditions of structures exposed to seismic excitations - damage examples after the Kaliningrad earthquake
PublikacjaW artykule przedstawiono przykłady uszkodzeń budowli znajdujących się w złym stanie technicznym, które powstały w wyniku trzęsienia ziemi o epicentrum w Obwodzie Kaliningradzkim. Przykłady te jednoznacznie pokazują, iż zaniedbywanie stanu technicznego konstrukcji narażonych na wstrząsy sejsmiczne może prowadzić do poważnych konsekwencji powodując znaczne straty materialne lub ofiary śmiertelne.
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Evaluation of the Construction and Investment Process of a High-Pressure Gas Pipeline with Use of the Trenchless Method and Open Excavation Method. Analytic Hierarchy Process (AHP)
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An integrated geoarchaeological approach to late Iron Age settlement at Kaštelina hillfort (Lopar, Island of Rab, Croatia) using Amplitude Data Comparison (ADC) method and trial excavation
PublikacjaGeophysical prospection and small-scale archaeological excavation were undertaken on the site of Kaštelina, a Late Iron Age hillfort settlement located on the Stolac promontory in the northern part of Rab island (Kvarner Gulf, Croatia). Within the frame of the “Archaeological topography of the island of Rab” program, a Polish–Croatian team applied a series of multidisciplinary methods to study the occupational history of the...
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Analysis of the Application of Horizontal Directional Drilling
PublikacjaConstruction works are often considered to be very intrusive for the environment. Project designers assume deep excavations, or a complete replacement of the ground within the investment, which sometimes changes the initial conditions drastically. The problem started to appear in places, where the terrain is complicated and the excavation is burdensome. Some of state authorities...
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Field measurements
PublikacjaThe article presents the scope and methodologies used in the course of geodetic measurements accompanying archaeological excavations in the area of the Wisłoujście Fortress in Gdańsk
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Analiza obudowy wykopu dla budynku z kondygnacją podziemną
PublikacjaW pracy poruszono tematykę analizy obudowy wykopu dla budynku z jedną kondygnacją podziemną, zlokalizowanego w gęstej zabudowie śródmiejskiej. Obliczenia przeprowadzono za pomocą dwóch programów obliczeniowych: GEO5 (moduł: Ściana analiza) i Autodesk Robot Structural Analysis Professional. Całość wyników podsumowano, a wnioski sformułowano w odniesieniu do obecnej sytuacji na rynku budowlanym, charakteryzującej się coraz to trudniejszymi...
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Application of Pierson-Moskowitz wave spectrum to solution differential equations of multihull vessel
PublikacjaMotion of a dynamic system can be generated by different external or internal factors. At mathematical modelling external excitation factors of the most significant effect on the system, are selected. Such external factors are usually called excitations. Response of the system to given excitations is mathematically characterized by a definite transformation called operator of a system. For a broad class of dynamic systems the...
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Wisłoujście Fortress, site 12
PublikacjaThis introductory article provides a synopsis of the range of archaeological work carried out at Wisłoujście Fortress in Gdańsk in 2013 and 2014. An outline is given of the circumstances in which this work was undertaken, the fieldwork methodology used and the technical problems encountered during excavation.
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Behaviour of Asymmetric Structure with Base Isolation Made of Polymeric Bearings
PublikacjaEarthquake-induced ground motions are the most severe and unpredictable threats to the structures all around the world. Seismic excitations cause a lot of damage in a wide variety of ways, leaving thousands of casualties in their wake. Due to randomness of earthquake occurrence, lack of visible causes and their power of destructiveness, structural engineers need to develop new technical solutions and protection systems against...
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Study of displacements of a bridge abutment using FEM
PublikacjaSteel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented...
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Stan przedawaryjny wykopu głębokiego w obudowie z pali CFA
PublikacjaW artykule przedstawiono stan przedawaryjny wykopu głębokiego w obudowie z pali CFA. Omówiono warunki geotechniczne podłoża oraz rozwiązania projektowe. Przeprowadzono analizę dwóch wersji projektów konstrukcyjnych oraz fazę wykonawstwa z wskazaniem na liczne błędy. Przedstawiono możliwe oraz przyjęte działania naprawcze. Omówiono problemy i błędy projektowe na etapie działań naprawczych. Wskazano przyczyny wystąpienia stanu przedawaryjnego.
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Turre cum capellis suis – identification of an earlier phase of the Holy Cross church at Tar – Stancija Blek (Tar-Vabriga – Torre-Abrega, Istria)
PublikacjaThe paper reports the results of the first campaign of excavations at the Church of the Holy Cross near Stancija Blek (Tar-Vabriga – Torre-Abrega municipality, Istria), which is close to the multiphase settlement of Old Tar. A trial trench behind the rear wall of the church and along its southern perimetral wall revealed an earlier building and one grave. Though the uncovered remains are scanty, several distinct architectural...
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Timber Frame Houses with Different Insulation Materials - Seismic Analysis
PublikacjaThe aim of this article is to present results of a dynamic numerical analysis focused on the response of two timber frame building structures exposed to seismic excitations. The first structure was insulated with mineral wool, while the second one with polyurethane foam. Specifications and technology involved in the models' construction are based on the previously conducted experimental study, upon which numerical structural models...
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Behaviour of asymmetric structures with base isolation made of Polymeric Bearings
PublikacjaEarthquake-induced ground motions are the most severe and unpredictable threats to the structures all around the world. Seismic excitations cause a lot of damage in a wide variety of ways, leaving thousands of casualties in their wake. During the last few years alone, the world has witnessed many major earthquakes, five of which have caused far-reaching consequences of a national scale for Haiti (January 2010), Chile (February...
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Extended Newmark method to assess stability of slope under bidirectional seismic loading
PublikacjaThe paper concerns the dynamic behavior of a simple slope model subjected to simultaneous horizontal and vertical excitations. The proposed method is based on Newmark’s sliding block concept, however, four new features are introduced. The most important assumption is that the normal component of dynamic excitations affects the resisting force both before and after the initiation of the relative slope motion, making it time-dependent....
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Dynamic tests of composite footbridge segment – experimental and numerical studies
PublikacjaExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
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Experimental study of the effect of vertical acceleration component on the slope stability
PublikacjaThe paper deals with the stability of earth dams subjected to seismic and paraseismic excitations occurring in the close distance to the dam. The Newmark’s stability approach, classified as a simplified dynamic method, has been extended for two directional dynamic loading case and the evolution of the friction coefficient. The paper is focused on the experimental verification of the proposed method for harmonic and cyclic excitations...
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Study of ultraviolet-visible fluorescence emission following resonant Auger decay of the 2p-1nl core-excited states of argon atoms
PublikacjaWe have studied the excitation and relaxation of Ar+ ions populated in resonant Auger decay from the Ar 2p−1nl core-excited states by using ultraviolet-visible fluorescence spectroscopy and photon-photon delayed coincidence technique. Fluorescence emission yields were measured in the photon energy range of 240-–255 eV for the 3s23p4(1D)5s(2D) → 3s23p4(1D)4p(2F) (393 nm) and 3s23p4(1D)4d(2F) → 3s23p4(1D)4p(2F) (335 nm) transitions...
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An ANN-Based Approach for Prediction of Sufficient Seismic Gap between Adjacent Buildings Prone to Earthquake-Induced Pounding
PublikacjaEarthquake-induced structural pounding may cause major damages to structures, and therefore it should be prevented. This study is focused on using an artificial neural network (ANN) method to determine the sufficient seismic gap in order to avoid collisions between two adjacent buildings during seismic excitations. Six lumped mass models of structures with a different number of stories (from one to six) have been considered in...
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Effective Gap Size Index for Determination of Optimum Separation Distance Preventing Pounding between Buildings during Earthquakes
PublikacjaSeismic excitations may lead to collisions between adjacent civil engineering structures causing major damage. In this paper, an effective equation for calculating the gap size index is proposed so as to provide the optimum separation distance preventing structural pounding during different earthquakes. Evaluation of the best prediction of the required separation distance between two adjacent buildings was carried out by using...
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Theoretical study of the photoelectron spectrum of ethyl formate: Ab initio and density functional theory investigation
PublikacjaThe first ionization energy and associated photoelectron spectrum of ethyl formate are investigated with quantum chemistry calculations. The geometries, harmonic vibrational frequencies and first ionization energy are computed at the Hartree-Fock (HF) and at the second order Moller-Plesset perturbation theory (MP2). Moreover, accurate ionization energies are obtained with the Coupled-Cluster theory including singles and doubles...
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Polymeric Bearings – A New Base Isolation System to Reduce Structural Damage during Earthquakes
PublikacjaBase isolators, like lead rubber bearings, high damping rubber bearings or friction pendulum systems are extensively used in practice in many seismically active regions to protect structures against earthquake forces. The present paper reports the results obtained from the experimental study aimed to determine the effectiveness of the Polymeric Bearings in suppressing structural vibrations during dynamic excitations and therefore...
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O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission
PublikacjaOxygen 1s excitation and ionization processes in the CO2 molecule have been studied with dispersed and non-dispersed fluorescence spectroscopy as well as with the vacuum ultraviolet (VUV) photon-photoion coincidence technique. The intensity of the neutral O emission line at 845 nm shows particular sensitivity to core-to-Rydberg excitations and core-valence double excitations, while shape resonances are suppressed. In contrast,...
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Possibilities of radioisotope measuring in control of an unstable solid particles hydrotransport
PublikacjaThe paper presents γ-radiation proposal to control a multiphase flow, independently from circumstances. So this method may be applied even in compound industrial or environmental processes. Moreover in many cases, it is the only method for applications for dense mixture containing coarse angular grains. The constructed equipment allows continuous measurement of density as well as solid phase for both concentration and average velocity....
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Application of the distributed transfer function method and the rigid finite element method for modelling of 2-D and 3-D systems
PublikacjaIn the paper application of the Distributed Transfer Function Method and the Rigid Finite Element Method for modelling of 2-D and 3-D systems is presented. In this method an elastic body is divided into 1-D distributed parameter elements (strips or prisms). The whole body (divided into strips or prism) is described by a set of coupled partial differential equations. Solving this equations in the state space form it is possible...