scholarly journals Geodetic monitoring of bridge deformations occurring during static load testing

2015 ◽  
Vol 10 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Tarvo Mill ◽  
Artu Ellmann ◽  
Martti Kiisa ◽  
Juhan Idnurm ◽  
Siim Idnurm ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Static Load ◽  
Terrestrial Laser Scanning ◽  
Deformation Monitoring ◽  
Load Test ◽  
Load Testing ◽  
Static Load Test ◽  
Study Results ◽  
Extreme Load ◽  
Load Tests

Terrestrial laser scanning technology has developed rapidly in recent years and has been used in various applications but mainly in the surveying of different buildings and historical monuments. The use for terrestrial laser scanning data for deformation monitoring has earlier been tested although conventional surveying technologies are still more preferred. Since terrestrial laser scanners are capable of acquiring a large amount of highly detailed geometrical data from a surface it is of interest to study the metrological advantages of the terrestrial laser scanning technology for deformation monitoring of structures. The main intention of this study is to test the applicability of terrestrial laser scanning technology for determining range and spatial distribution of deformations during bridge load tests. The study presents results of deformation monitoring proceeded during a unique bridge load test. A special monitoring methodology was developed and applied at a static load test of a reinforced concrete cantilever bridge built in 1953. Static loads with the max force of up to 1961 kN (200 t) were applied onto an area of 12 m² in the central part of one of the main beams; the collapse of the bridge was expected due to such an extreme load. Although the study identified occurrence of many cracks in the main beams and significant vertical deformations, both deflection (–4.2 cm) and rising (+2.5 cm), the bridge did not collapse. The terrestrial laser scanning monitoring results were verified by high-precision levelling. The study results confirmed that the TLS accuracy can reach ±2.8 mm at 95% confidence level.

scholarly journals TLS Measurement during Static Load Testing of a Railway Bridge

2019 ◽  
Vol 8 (1) ◽  
pp. 44 ◽  
Author(s):  
Pelagia Gawronek ◽  
Maria Makuch
Keyword(s):  
Laser Scanning ◽  
Static Load ◽  
Vertical Displacement ◽  
Load Test ◽  
Load Testing ◽  
Railway Bridge ◽  
Static Load Test ◽  
3D Data ◽  
Steel Railway Bridge ◽  
White Target

Terrestrial laser scanning (TLS) technology has become increasingly popular in investigating displacement and deformation of natural and anthropogenic objects. Regardless of the accuracy of deformation identification, TLS provides remote comprehensive information about the measured object in a short time. These features of TLS were why TLS measurement was used for a static load test of an old, steel railway bridge. The results of the measurement using the Z+F Imager 5010 scanner and traditional surveying methods (for improved georeferencing) were compared to results of precise reflectorless tacheometry and precise levelling. The analyses involved various procedures for the determination of displacement from 3D data (black & white target analysis, point cloud analysis, and mesh surface analysis) and the need to pre-process the 3D data was considered (georeferencing, automated filtering). The results demonstrate that TLS measurement can identify vertical displacement in line with the results of traditional measurements down to ±1 mm.

A Load-Testing Program on Large-Diameter (66-Inch) Open-Ended and PSC-Instrumented Test Piles to Evaluate Design Parameters and Pile Setup

2018 ◽  
Vol 2672 (52) ◽  
pp. 291-306 ◽  
Author(s):  
Md. Nafiul Haque ◽  
Murad Y. Abu-Farsakh ◽  
Chris Nickel ◽  
Ching Tsai ◽  
Jesse Rauser ◽  
...  
Keyword(s):  
Static Load ◽  
Large Diameter ◽  
Load Test ◽  
Design Parameters ◽  
Soil Conditions ◽  
Load Testing ◽  
Static Load Test ◽  
Testing Program ◽  
Tip Resistance ◽  
Load Tests

This paper presents the results from a pile load testing program for a bridge construction project at Chalmette, Louisiana. The load testing includes three 66-in. spun-cast post-tensioned open-ended cylinder piles and one 30-in. square prestressed concrete (PSC) pile driven at four different locations along the bridge site in clayey-dominant soil. Both cone penetration tests and soil borings/laboratory testing were used to characterize the subsurface soil conditions. All test piles (TP) were instrumented with strain gauges to measure the load distribution along the length of the TPs and to measure the side and tip resistances, separately. Dynamic load tests (DLT) were performed on all TPs at different waiting periods after pile installations to quantify the amount of setup (i.e., increase in pile resistance with time). Case Pile Wave Analysis Program (CAPWAP®) analyses were performed on the DLT data to calculate the resistance distributions along the TPs. A static load test was performed only on the PSC pile and statnamic load tests (SNLT) were conducted on both pile types. Design parameters such as the total stress adhesion factor, α, and the effective stress coefficient, β, were back-calculated. The α values ranged from 0.41 to 0.86, and the β values ranged from 0.13 to 0.29. The load test results showed that SNLT overestimated the tip resistance as compared with dynamic and static load tests. Moreover, the pile tip resistance was almost constant during the testing period, and setup was mainly attributed to increase in pile side resistance with time.

scholarly journals Accuracy Assessment of Semi-Automatic Measuring Techniques Applied to Displacement Control in Self-Balanced Pile Capacity Testing Appliance

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4067 ◽  
Author(s):  
Zbigniew Muszyński ◽  
Jarosław Rybak ◽  
Paulina Kaczor
Keyword(s):  
Laser Scanning ◽  
Static Load ◽  
Accuracy Assessment ◽  
Reference Beam ◽  
Load Test ◽  
Static Load Test ◽  
Automatic Measuring ◽  
Measuring Techniques ◽  
Vertical Displacements ◽  
Load Tests

Static load tests of foundation piles are the basic method for the designing or verification of adopted design solutions which concern the foundation of a building structure. Preparation of a typical test station using the so-called inverted beam method is very expensive and labor-intensive. The settlement values of the loaded pile are usually recorded using accurate dial gauges. These gauges are attached to a reference beam located in close proximity to the pile under test, which may cause systematic errors (difficult to detect) caused by the displacement of the adopted reference beam. The application of geodetic methods makes it possible to maintain an independent, external reference system, and to verify the readouts from dial gauges. The article presents an innovative instrumentation for a self-balanced stand for the static load test made from a closed-end, double steel pipe. Instead of typical, precise geometric leveling, the semi-automatic measuring techniques were used: motorized total station measurement and terrestrial laser scanning controlled by a computer. The processing of the acquired data made it possible to determine the vertical displacements of both parts of the examined pile and compare displacements with the results from the dial gauges. On the basis of the excess of the collected observations, it was possible to assess the accuracy, which confirmed the usefulness of measuring techniques under study.

scholarly journals First results of pipe pile static load test in small laboratory scale

2018 ◽  
Vol 251 ◽  
pp. 04038 ◽  
Author(s):  
Michal Baca ◽  
Jaroslaw Rybak
Keyword(s):  
Static Load ◽  
Axial Loading ◽  
Laboratory Scale ◽  
Load Test ◽  
Scale Model ◽  
Small Scale ◽  
Small Laboratory ◽  
Static Load Test ◽  
First Results ◽  
Load Tests

Presented laboratory testing program of tubular steel piles is a part of a bigger research program which contained static load tests in full scale and numerical simulations of conducted research. The main goal of the research is to compare static load tests with different working conditions of a shaft. The presented small scale model tests are the last part of the research. The paper contains the testing methodology description and first results of model pile axial loading. The static load tests in a small laboratory scale were conducted in a container filled with uniformly compacted medium sand (MSa). The first results of the investigation are presented in this paper, with the comparison of two pile capacities obtained for different roughness of the pile shaft (skin friction). The results are presented as load-displacement curves obtained by means of the Brinch-Hansen 80% method.

scholarly journals Calculation of Pile Side Friction by Multiparameter Statistical Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zhijun Zhou ◽  
Yaqin Dong ◽  
Peijun Jiang ◽  
Dandan Han ◽  
Tong Liu
Keyword(s):  
Statistical Analysis ◽  
Static Load ◽  
Load Test ◽  
Load Testing ◽  
Analysis Method ◽  
Static Load Test ◽  
Statistical Analysis Method ◽  
Loess Region ◽  
Side Friction ◽  
Static Load Testing

In this paper, a static load test and a multiparameter statistical analysis method are used to study the value of pile side friction in different soil layers in a loess region. Currently, static load testing is the most commonly used method to determine the bearing capacity of pile foundation. During the test, a vertical load is applied at the top of the pile, the data under each load level are recorded, and a Q-S curve is drawn to obtain the ultimate bearing capacity of a single pile. Reinforcement stress gauges are installed at different sections of the pile body, and then the axial force and the pile side friction of each section are calculated. Few studies have investigated the calculation of pile side friction in different soil layers using the multiparameter statistical analysis method. Obtaining accurate results using this method will provide an important supplement to the calculation of pile side friction and will also be conducive to the development of theoretical calculation of pile side friction. Therefore, taking Wuding Expressway project in loess region as an example, the lateral friction resistance of six test piles is studied through static load testing and multiparameter statistical analysis. The multiparameter statistical analysis method is compared with the static load test results, and the error is controlled within 20%. The results show that the calculation results of multiparameter statistical analysis essentially fulfill engineering requirements.

scholarly journals Skin and Toe Resistance Mobilisation of Pile During Laboratory Static Load Test

2018 ◽  
Vol 40 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Zygmunt Meyer ◽  
Krzysztof Żarkiewicz
Keyword(s):  
Skin Friction ◽  
Laboratory Experiments ◽  
Static Load ◽  
Load Test ◽  
Static Load Test ◽  
New Approach ◽  
Two Factors ◽  
Load Tests ◽  
Friction Curve ◽  
The Relationship

Abstract 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.

scholarly journals Static Load Test on Instrumented Pile – Field Data and Numerical Simulations

2017 ◽  
Vol 39 (3) ◽  
pp. 17-25 ◽  
Author(s):  
Adam Krasiński ◽  
Mateusz Wiszniewski
Keyword(s):  
Static Load ◽  
Real Data ◽  
Load Test ◽  
Force Distribution ◽  
Static Load Test ◽  
Reliable Determination ◽  
Static Tests ◽  
Load Tests ◽  
Engineering Practices

Abstract 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.

scholarly journals Application of Geodetic Measuring Methods for Reliable Evaluation of Static Load Test Results of Foundation Piles

2021 ◽  
Vol 13 (16) ◽  
pp. 3082
Author(s):  
Zbigniew Muszyński ◽  
Jarosław Rybak
Keyword(s):  
Inverse Analysis ◽  
Laser Scanning ◽  
Static Load ◽  
Test Site ◽  
Load Test ◽  
Static Load Test ◽  
Displacement Control ◽  
Secondary Importance ◽  
Measuring Methods

Geodetic measuring methods are widely used in the course of various geotechnical works. The main purpose is usually related to the location in space, geometrical dimensions, settlements, deflections, and other forms of displacements and their consequences. This study focuses on the application of selected surveying methods in static load tests (SLTs) of foundation piles. Basic aspects of the SLT are presented in the introductory section, together with the explanation of the authors’ motivation behind the novel (but already sufficiently tested) application of remote methods introduced to confirm, through inverse analysis, the load applied to the pile head under testing at every stage of its loading. Materials and methods are described in the second section in order to provide basic information on the test site and principles of the SLT method applied. The case study shows the methodology of displacement control in the particular test, which is described in light of a presented review of geodetic techniques for displacement control, especially terrestrial laser scanning and robotic tacheometry. The geotechnical testing procedure, which is of secondary importance for the current study, is also introduced in order to emphasize the versatility of the proposed method. Special attention is paid to inverse analysis (controlling of the pile loading force on the basis of measured deflections, and static calculations by means of standard structural analysis and the finite element method (FEM)) as a tool to raise the credibility of the obtained SLT results. The present case study from just one SLT, instrumented with various geodetic instrumentation, shows the results of a real-world dimensions test. The obtained variability of the loading force within a range of 15% (depending on real beam stiffness) proves good prospects for the application of the proposed idea in practice. The results are discussed mainly in light of the previous authors’ experience with the application of remote techniques for reliable displacement control. As only a few references could be found (mainly by private communication), both the prospects for new developments using faster and more accurate instruments as well as the need for the validation of these findings on a larger number of SLTs (with a very precise definition of beam stiffness) are underlined in the final remarks.

scholarly journals Static load test curve (Q–s) conversion in to pile of different size

2018 ◽  
Vol 50 (2) ◽  
pp. 171-182
Author(s):  
Zygmunt Meyer ◽  
Kamil Stachecki
Keyword(s):  
Mathematical Description ◽  
Static Load ◽  
Load Capacity ◽  
Limit Load ◽  
Load Test ◽  
Static Load Test ◽  
Load Curve ◽  
Load Tests ◽  
Different Diameters ◽  
Calculation Analysis

Abstract In the work authors analysed possibility of obtaining static load tests curve for a pile in case of changed diameter, using load curve based on results of static load tests for given diameter. In calculation analysis authors used Meyer–Kowalów (M-K) method. A mathematical description was shown of determining new M-K curve for a pile with changed diameter, taking as a basis original M-K curve obtained from static load tests. Then an example of calculations is presented in which parameters of M-K model for a new curve were determined. Simulation calculations were carried out in the original computer program, the results of which includes load curves for piles with different diameters and relations between diameter changes, limit load capacity and settlement of a pile.

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