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1

Method of settlement calculation for underlying layer of soft soil composite foundation based on load transfer mechanism

Xiao Yaoting, Wang Jing

Archives of Civil Engineering

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2024

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Vol. 70, nr 1

543--555

EN

The mechanical properties of soil in soft soil area are poor, and the settlement of the underlying layer in the composite foundation accounts for a large proportion of the total settlement. At present, most of the research focuses on the settlement of the reinforced area, and the research on the settlement of the underlying layer is of great significance for the settlement of soft soil composite foundation. The differences in load transfer modes of soil and pile are analyzed, and based on the Boussinesq solution and Mindlin solution, a calculation method for the stress and settlement of the underlying layer in flexible and rigid pile composite foundation is proposed. The relative displacement of soil and pile in flexible pile composite foundation is small, and the negative friction can be ignored, but the influence of effective pile length should be considered. The relative displacement of soil and pile in rigid pile composite foundation is large, so the negative friction should be considered. Part of soil top stress is transmitted to the pile via negative friction, and then the pile axial force is transmitted back to the soil via positive friction. In addition to effective pile length, the change of stress transfer path caused by negative friction should also be considered in settlement calculation.

2

Critical loading of pillar arrays having previously eliminated elements

Derda Tomasz

Journal of Applied Mathematics and Computational Mechanics

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2023

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Vol. 22, nr 4

18--29

EN

The paper analyzes critical loads of pillar arrays with fraction of elements removed prior to actual critical loading. Two different methods of elimination are considered. In the first case, a fraction p of weakest pillars is physically removed from the array. The second method relies on conducting a subcritical preloading. When the sudden loading is applied to the system, the destruction follows in a cascade-like manner. Subsequent cascades take place due to the redistribution of load. We explore different types of load redistribution. It turns out that the type of load transfer as well as the distribution of pillar-strength-thresholds are of crucial importance regarding the strength enhancement of critically loaded pillar arrays.

3

Experimental and theoretical research on large-diameter rock-socketed pile embedded depth

Li Yanfeng, Zhao Jihe, Xiong Ying, Wang Qinghe

Archives of Civil Engineering

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2021

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Vol. 67, nr 2

537--550

EN

A theoretical formula for large-diameter rock-socket depth is developed to support pail embedding in a large bridge pile foundation project. There is a horizontal additional stress concentration at the place where the soil around the rock-socketed pile meets the soil layer under the horizontal load. When the rock-socketed tip stress and bending moment of the pile are relatively small, the pile shows favourable embedment effect and the pile foundation can be considered safe. The function curve of soil resistance around the pile under the action of horizontal force was obtained by finite element analysis. The force characteristics reveal the depth of the largediameter rock-socketed pile under the horizontal load. As the rock-socketed pile rotates under the action of horizontal force, the rock mass resistance around the pile changes according to the cosine. The distribution of pileside soil resistance is proportional to the displacement and distributed according to the sine. A comprehensive correction coefficient of pile shaft resistance β is introduced to deduce the theoretical formula of the depth hr of the large-diameter rock-socketed pile embedded in the bedrock. It is verified through both experiments and numerical analysis.

4

Skuteczność przenoszenia obciążeń – jak mierzyć, jak wykorzystywać na nawierzchniach podatnych i półsztywnych

Janowski Andrzej, Pełczyńska Karolina

Drogownictwo

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2019

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nr 2

35--42

PL

W artykule analizowano pojęcie wskaźnika skuteczności przenoszenia obciążenia między płytami nawierzchni betonowych w zastosowaniu do pęknięć nawierzchni podatnych i półsztywnych. Omówiono potencjalne źródła błędu pomiaru i sposoby ich uniknięcia, korekty: temperaturową oraz geometryczną (ze względu na krzywiznę czaszy ugięcia nawierzchni). Jako dodatkowy parametr sterujący wyborem technologii napraw pęknięć pojedynczych zaproponowano i omówiono wskaźnik wskazujący na istnienie pustek w obszarze pęknięć.

EN

In the paper the concept of load transfer efficiency index between concrete pavement slabs in application to cracks in flexible and semi-rigid pavements was analysed. Potential sources of measurement error and ways of avoiding them i.e. temperature and geometric correction (due to the curvature of the pavement deflection) are discussed. As an additional parameter controlling the choice of repair technology for single cracks, an index revealing the existence of voids in the area of cracks was proposed and discussed.

5

Ocena nasiąkliwości i mrozoodporności pianobetonu

Kadela M., Kukiełka A., Winkler-Skalna A.

Materiały Budowlane

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2016

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nr 10

50--51

PL

Skuteczną metodą poprawy niestabilnych warunków gruntowych w przypadku nawierzchni drogowych, powierzchni parkingowych czy posadzek hal magazynowych wydaje się zastosowanie następującego układu warstw: konstrukcja nośna poddana obciążeniom powtarzającym się i/lub stałym oraz odpowiednia warstwa pianobetonu pośrednicząca w przekazywaniu obciążenia na (słabe) podłoże gruntowe. W artykule przedstawiono parametry ważne z uwagi na zastosowanie materiału w kontakcie z podłożem gruntowym, takie jak nasiąkliwość oraz mrozoodporność materiału.

EN

An effective way to improve unstable ground conditions for roads pavement, car park pavements and industrial slabs seems to be the following layered system: load-bearing layer subjected to permanent or/and cyclic loading and a suitable layer of foam concrete transferring loads to weak subsoil. The paper presents properties related to material used in contact with soil such as water absorption and freeze resistance.

6

Analysis of load transfer into composite structure

Szymczyk E., Jachimowicz J., Puchała K.

Applied Computer Science

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2014

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Vol. 10, no 3

86--94

EN

The paper presents advantages and disadvantages of metal foils insertion between composite layers. Composites are complex materials of aniso-tropic structure leading to various failure mechanisms. Mechanism of compressive load transfer into composite laminates by shear of the matrix is analysed. The method of improvement compressive strength of laminates is presented according to literature and analysed for a sele-cted case. Simplified models of a laminate structure modified using various metal foils configurations are analysed with MSC.Marc code. Axial stress in prepreg layers and shear stress in adhesive layers are studied.

7

Badania transferu danych w aplikacjach z obiektami rozproszonymi - Java RMI - w środowisku maszyn wirtualnych

Lech P., Okarma K.

TTS Technika Transportu Szynowego

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2012

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R. 19, nr 9

2635--2640, CD

PL

W artykule zbadano wpływ aplikacji rozproszonej wykonanej w technologii Java RMI na transfer danych w sieci komputerowej. Przeprowadzono badania określające transfer ładunku poprzez sieć dla technologii RMI bez wprowadzanych ograniczeń na przepustowość sieci w odniesieniu do popularnych protokołów HTTPS i TCP. Badania przeprowadzono w wirtualnym laboratorium zrealizowanym w oparciu o technologię maszyn wirtualnych.

EN

The article examines the impact of the distributed application developed using Java RMI technology on the data transfer over a computer network. The objective of the conducted tests was determining the load transfer through the network for the RMI technology without restrictions related to the capacity of the network in comparison to the popular protocols such as HTTPS and TCP. The experiments were conducted in a virtual laboratory implemented using virtual machines technology.

8

Significance of rivet flexibility for load transfer in lap joints

Skorupa M., Machniewicz T., Skorupa A., Korbel A.

Mechanics and Control

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2010

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Vol. 29, no. 2

63-69

EN

Presented in this paper are results of an experimental investigation on the rivet flexibility and load transmission in a riveted lap joint representative for the aircraft fuselage. The test specimens consisted of two aluminium alloy Alclad sheets joined with three rows of rivets. Rivet flexibility measurements have been performed under constant amplitude fatigue loading using several methods including two novel optical techniques developed by the present authors. The axial forces in the sheets required to determine the rivet flexibility have been derived from strain gauge measurements. In order to eliminate the effect of sheet bending the strain gauges have been bonded at the same locations on the outside and faying surface of the sheet. Variations of the rivet flexibility during the fatigue loading as well as the dependence of the rivet flexibility and load transmission on the rivet squeeze force have been studied. The experiments enabled to evaluate the usefulness of various techniques to determine the rivet flexibility. It was observed that although the measured flexibility was identical for both outer rivet rows, the load transfer through either of these rows was different. Previous experimental results of the authors suggest that the non-symmetrical load transfer distribution through the joint is associated with large differences between the rivet hole expansion in the sheet adjacent to the driven rivet head and the sheet under the manufactured head. It has been concluded that commonly used computation procedures according to which the load transfer is only related to the rivet flexibility may lead to erroneous results.

PL

Przedstawiono wyniki pomiarów podatności nitów oraz transferu obciążenia przez poszczególne rzędy nitów w zakładkowym połączeniu typowym dla konstrukcji lotniczych. Blachy ze stopu aluminium D16CzATW łączono trzema rzędami nitów zakuwanych z dwoma różnymi siłami. Prowadzone przy stałej amplitudzie obciążenia pomiary podatności nitów pozwoliły na porównanie i określenie użyteczności różnych technik pomiaru, w tym dwóch oryginalnych metod optycznych zaproponowanych przez Autorów. Konieczne do określenia podatności nitów osiowe siły działające w poszczególnych przekrojach poprzecznych łączonych blach wyznaczano przy użyciu tensometrów oporowych. Zbadano wpływ siły zakuwania na transfer obciążenia przez poszczególne rzędy nitów oraz na podatność nitów na różnych etapach trwałości zmęczeniowej połączenia. Stwierdzono nieco mniejszą podatność nitów w środkowym rzędzie połączenia w porównaniu z rzędami skrajnymi. Chociaż w obu skrajnych rzędach podatności nitów były takie same, to transfer obciążenia przez każdy z nich był inny. Wynika stąd, że zwykle stosowane procedury obliczeniowe uzależniające transfer obciążenia od samej tylko podatności nitów prowadzić mogą do zafałszowanych wyników.

9

Rivet flexibility and load transmission for a riveted lap joint

Skorupa M., Machniewicz T., Korbel A., Skorupa A.

Archive of Mechanical Engineering

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2010

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Vol. LVII, nr 3

235-245

EN

Presented in this paper are results of an experimental investigation on the rivet flexibility and load transmission in a riveted lap joint representative for the aircraft fuselage. The test specimens consisted of two aluminium alloy Alclad sheets joined with 3 rows of rivets. Two different squeeze forces were applied to install the rivets. Rivet flexibility measurements have been performed under constant amplitude fatigue loading using several methods including two original optical techniques developed by the present authors. The axial tractions in the sheets required to determine the rivet flexibility have been derived from strain gauge measurements. In order to eliminate the effect of secondary bending the strain gauges have been bonded at the same locations on the outside and faying surface of the sheet. The experiments enabled an evaluation of the usefulness of various techniques to determine the rivet flexibility. It was observed that, although the measured flexibility was identical for both end rivet rows, the load transfer through either of these rows was different. Previous experimental results by the present authors suggest that behind the non-symmetrical load transfer distribution through the joint are large differences between the rivet hole expansion in the sheet adjacent to the driven rivet head and the sheet under the manufactured head. It has been concluded that commonly used computation procedures according to which the load transfer is only related to the rivet flexibility may lead to erroneous results.

PL

W artykule zaprezentowano wyniki eksperymentalnych badań podatności nitów oraz transferu obciążenia w nitowanych połączeniach zakładkowych, typowych dla kadłuba samolotu. Badania prowadzono przy stałej amplitudzie obciążenia, na blachach z lotniczego stopu aluminium D16 połączonych trzema rzędami nitów przy dwóch różnych siłach ich zakuwania. Do pomiaru podatności nitów zastosowano kilka różnych metod w tym zaproponowane przez autorów dwie oryginalne metody optyczne. Porównywanie uzyskanych dzięki nim wyników umożliwiło ocenę użyteczności poszczególnych technik do wyznaczenia podatności nitów. Udział poszczególnych rzędów nitów w przenoszeniu obciążenia określony został na drodze pomiarów tensometrycznych. Celem uwzględnienia zjawiska wtórnego zginania tensometry oporowe mocowane były w rejonie zakładki parami tj. na wewnętrznej i zewnętrznej powierzchni jednej z łączonych blach. Stwierdzono nieco mniejszą podatność nitów w środkowym rzędzie połączenia w porównaniu z rzędami skrajnymi. Jakkolwiek w obu skrajnych rzędach podatności nitów były takie same, to transfer obciążenia przez każdy z nich był inny. Wyniki wykonanych wcześniej badań wskazują, że ten brak symetrii w transferze obciążenia może mieć związek ze znacznie większą ekspansją otworu nitowego w blasze po stronie zakuwki niż po stronie głowy fabrycznej. Wynika stąd, że zwykle stosowane procedury obliczeniowe uzależniające transfer obciążenia od samej tylko podatności nitów, prowadzić mogą do zafałszowanych wyników.

10

Load transfer in ship wave analysis

Skeie G., Damhaug A. C.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, no 1

245-265

EN

We discuss structural response analysis of vessels subjected to hydrodynamic loads. The response analyses are performed in order to assess vessel strength either through quasi-static ultimate strength analyses (ULS) or stochastic fatigue analyses (FLS). We focus on consistency in modeling with emphasis on accurate load transfer between the fluid- and structure domains. In wave analysis the dynamic pressure- and inertia forces are generated through a linear ship, where the vessel is treated as a rigid body. The calculated pressure forces are distributed on the fluid panel interface while the inertia forces (accelerations) are represented on the rigid body structure. The final strength assessment is carried out on a finite element model (FEM). The FEM interface model and the panel interface model are assumed to be incompatible both in geometry and field representation.

11

Mechanical and medical aspects of an implant-bone connection in the femur: A three-dimensional photoelastic study of the load transfer mechanism using gamma radiation for fixing the experimental information. Comparison of two solutions of femur prosthesi

Beer R. J, Eberhardsteiner J., Kodvanj J., Grienauer W., Gottsauner-Wolf F., Skrbensky G.

Acta of Bioengineering and Biomechanics

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2000

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Vol. 2, nr 2

25-31

EN

The investigation of the implant-bone connection is of significant surgical interest as the postoperative course is influenced by the primary stability of the connection. It is necessary to achieve primary stability, so that the patient can be mobilized as soon as possible without any additional orthopaedic treatment. The achievement of the so-called secondary (longtime) stability through an ingrowth of bone is only possible if a perfect fixation of the implant is reached during surgical treatment. In this paper two different types of prosthesis, called Viennese and Bologna models are investigated. The reason for this investigation is given by the fact that these two types present two different fixing techniques developed for long bones. The main difference between the two solutions is given by the kind of implantation and its influence on the stress distribution in the load transfer area. In suitable models the stresses in the close vicinity of the load transfer areas are compared in both implant types using suitable photoelastic models.