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1

Skin and toe resistance mobilisation of pile during laboratory static load test

Meyer Z., Żarkiewicz K.

Studia Geotechnica et Mechanica

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2018

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Vol. 40, nr 1

1--5

EN

This article shows the mathematical method to determine the lateral stress on the shaft and toe resistance of pile using the new approach. The method was originally invented by Meyer and Kowalow for the static load test. The approximation curve was used for the estimation of both settlement curve and toe resistance curve of the pile. The load applied at the head of the pile is balanced by the sum of two components: the resistance under the toe of the pile and the skin friction. Therefore, the settlement curve is compilation of two factors: the skin friction curve and the resistance under toe curve. The analysis was based on the verification of the methods using laboratory experiments, that is, static load tests. The results of the research allowed to determine the relationship between parameters of the Meyer-Kowalow curve. On the basis of the relationships, it was possible to determine the skin friction and the toe resistance of the pile. Mathematical analysis of curve parameters allowed to determine the influence of the toe resistance on the settlement.

2

Static load test on instrumented pile – field data and numerical simulations

Krasiński A., Wiszniewski M.

Studia Geotechnica et Mechanica

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2017

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Vol. 39, nr 3

17--25

EN

Static load tests on foundation piles are generally carried out in order to determine load – the displacement characteristic of the pile head. For standard (basic) engineering practices this type of test usually provides enough information. However, the knowledge of force distribution along the pile core and its division into the friction along the shaft and the resistance under the base can be very useful. Such information can be obtained by strain gage pile instrumentation [1]. Significant investigations have been completed on this technology, proving its utility and correctness [8], [10], [12]. The results of static tests on instrumented piles are not easy to interpret. There are many factors and processes affecting the final outcome. In order to understand better the whole testing process and soil-structure behavior some investigations and numerical analyses were done. In the paper, real data from a field load test on instrumented piles is discussed and compared with numerical simulation of such a test in similar conditions. Differences and difficulties in the results interpretation with their possible reasons are discussed. Moreover, the authors used their own analytical solution for more reliable determination of force distribution along the pile. The work was presented at the XVII French-Polish Colloquium of Soil and Rock Mechanics, Łódź, 28–30 November 2016.

3

Influence of installation effects on pile bearing capacity in cohesive soils – large deformation analysis via Finite Element Method

Konkol J., Bałachowski L.

Studia Geotechnica et Mechanica

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2017

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Vol. 39, nr 1

27--38

EN

In this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs have been performed in highly overconsolidated clay (OCR ≈ 12). The results of numerical analysis are compared with corresponding field tests and with so-called “wish-in-place” numerical model of pile, where no installation effects are taken into account. The advantages of using large deformation numerical analysis are presented and its application to the pile designing is shown.

4

Możliwości monitorowania konstrukcji mostowych z zastosowaniem czujników światłowodowych

Grzywa A., Kania J.

Materiały Budowlane

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2016

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nr 9

128--129

PL

W artykule przedstawiono możliwość zastosowania innowacyjnego systemu monitorowania konstrukcji mostowych bazującego na czujnikach światłowodowych. W badaniach zastosowano czujniki światłowodowe FBG. Czujniki zamocowano do wieszaków mostowych, a pomiaru odkształcenia tych elementów dokonywano podczas próbnego obciążenia statycznego mostu. Uzyskane wartości odkształceń przekształcono w wartości sił osiowych w badanych elementach.

EN

The paper presents the possibility of applying an innovative monitoring system into a bridge structure based on fiber-optic sensors. During the test FBG sensors were used. The FBG sensors were installed to bridge hangers and the elongation of this elements were monitored during a static load test of the bridge. The attained strains were converted into the axial forces occurring in this elements.

5

Badania pełnowymiarowego mostowego dźwigara hybrydowego typu „kompozyt FRP – beton” pod obciążeniem statycznym

Rajchel M., Siwowski T.

Materiały Budowlane

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2016

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nr 8

79--81

PL

W artykule przedstawiono nowy rodzaj dźwigarów mostowych, w których kompozyt FRP ( fibre reinforced polymer) jest połączony z betonem, co pozwala na optymalne wykorzystanie zalet obu materiałów konstrukcyjnych. Dźwigary hybrydowe charakteryzują się dużą wytrzymałością, sztywnością i trwałością oraz dobrymi parametrami dynamicznymi i bezpieczną, pseudoplastyczną postacią zniszczenia. Celem badań pełnowymiarowego dźwigara hybrydowego była ocena jego zachowania pod obciążeniem statycznym w warunkach 4-punktowego zginania oraz wyznaczenie nośności doraźnej i postaci zniszczenia. Badania wykazały dużą nośność i sztywność dźwigara oraz pozwoliły na ocenę charakteru zniszczenia kompozytu. Potwierdziły także wymaganą nośność projektową i odpowiedni zapas bezpieczeństwa (w aspekcie wykorzystania dźwigara do budowy prototypowego mostu drogowego).

EN

The new hybrid bridge girder has been presented, in which FRP composite and concrete are composed together in order to optimize the efficient utilization of the advantages of both structural materials. Hybrid girders characterize high strength, stiffness and durability as well as good dynamic behavior and safe, pseudo-plastic failure mode. The main testing goal of the full-scale hybrid bridge girder has been the evaluation of its static behavior under the 4-point bending and the assessment of ultimate carrying capacity and failure modes. The test results revealed the high load bearing capacity and stiffness of the girder and allowed to assess the local failures in the composite body. They confirmed also required load bearing capacity design and adequate safety margin (regarding to girder’s utilization in prototype road bridge construction).

6

Validation of numerical models of concrete box bridges based on load test results

Bień J., Kużawa M., Kamiński T.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 4

1046--1060

EN

A Results of experimental load tests are used for the validation of numerical models applied in analyses of the concrete box bridges by means of the Finite Element Method. Six different models were used in the analyses: two created of 1-dimensional finite elements in a 2- and 3-dimensional space and four hybrid models composed of 1- and 2-dimensional elements in a 3-dimensional space. Validation of the theoretical models was based on the case of a cable-stayed bridge structure (max. span length 256 m) and a continuous multi-span beam structure (max. span length 60 m). Details of the numerical models, results of static and dynamic analyses as well as the procedure and effects of static and dynamic load tests are presented, compared and discussed.