The aim of the project was to test the mechanical performance of the piles. For this purpose, it was decided to perform pushdown, pullout and flexion full-scale on-site tests.
The new semi-conductor production facility in Tainan Scientific Park, Taiwan, was to be built on soil with low mechanical properties. Since proper functioning of such a facility is possible only if a high stability of foundation is assured it was estimated that approximately 3000 piles were necessary. All the piles had the same dimensions, a diameter of 1.20m and length of 35 m, and were constructed to have the same mechanical properties.
Aim of monitoring:
The aim of the project was to test the mechanical performance of the piles. For this purpose, it was decided to perform pushdown, pullout and flexion full-scale on-site tests. SOFO sensors were used to monitor the behavior of the piles during the tests. Two sets of piles, the first on the east side and the second on the west side of the facility’s foundations, were tested. Each set consisted of three piles and each set was tested to a single influence: compression, traction or horizontal force. The sensors were installed on rebar cages before the pouring of the concrete. The position of the sensors for each test is presented in Figure 1 and their installation on the rebar cages in Figure 2.
|
NSTALLATION PERIOD |
TYPE OF SENSOR |
NUMBER OF SENSORS |
|
2000 |
SOFO |
72 |
Main results:
The load was applied step-by-step by using hydraulic jacks while respecting the prepared schedule. The intensity of the load was monitored on the scale of the loading set-up. Each step of load was maintained during the period (length is dependent on load level). After the maximal load is applied, the piles were unloaded, step-by-step again. Important information is obtained from the test and the results are resumed in Figure 3. For example, the distribution of normal forces in pile and frictional stresses in the soil are presented in Figure 4 for bearing capacity load (480 t) and for maximum applied load (840 t) for the pushdown test. A zone of soil with a poor quality is distinguished in Figure 4.
Related Papers:
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Fibre Optic Methods for Structural Health Monitoring, Branko Glisic and Daniele Inaudi, John Wiley & Sons, Ltd – 2007
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Piles monitoring using topologies of long-gauge fiber optic sensors, B. Glisic, D. Inaudi, S. Vurpillot, E. Bu, C.-J. Chen, First International Conference on Structural Health Monitoring and Intelligent Infrastructure, Tokyo, November 13-15 – 2003
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Field Applications of Fiber Optic Strain and Temperature Monitoring Systems, D. Inaudi, B. Glisic, Opto-electronic Sensor-based Monitoring in Geo-engineering,Nanjing, P.R.China, November 23-24 – 2005
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Finite Element Structural Monitoring Concept, Glisic B., Inaudi D., The 2nd fib International Congress June 5-8, 2006, Naples, Italy – (on conference CD, ID 17-18) – 2006
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Piles monitoring during the axial compression, pullout and flexure test using fiber optic sensors, Branko Glisic, Daniele Inaudi, Claire Nan, 81st Annual Meeting of the Transportation Research Board (TRB), on CD – (02-2701) – 2002
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Structural Monitoring of Concrete Structures, B. Glisic, D. Inaudi, S. Vurpillot, Third World Conference on Structural Control, 7-12.4.2002, Como, Italy – (Vol 2, p 729-238) – 2002
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Crack monitoring in concrete elements using long-gauge fiber optic sensors, B. Glisic, D. Inaudi, Structural Health Monitoring Workshop, ISIS Canada, 19-20 September 2002, Winnipeg, Canada – 2002
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Long-gauge fiber optic sensors for global structural monitoring, B. Glisic, D. Inaudi, Structural Health Monitoring Workshop, ISIS Canada, 19-20 September 2002, Winnipeg, Canada – 2002
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Long-gauge sensor topologies for strucutral monitoirng, D. Inaudi, B. Glisic, Fisrt fib world congress, 14-18 October 2002, Osaka Japan – 2002
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Strain, deformation and crack monitoring in bended structural members using long-gauge fiber optic sensors, B. Glisic, D. Inaudi, Test 2003, 13-15 May 2003, Nurenberg, Germany – (paper A3.4 on conference CD) – 2003
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Components of structural monitoring process and selection of monitoring system, Branko Glisic, Daniele Inaudi, Daniele Inaudi, 6th International Symposium on Field Measurements in GeoMechanics (FMGM 2003), September 15-18, 2003, Oslo, Norway – (pages 755-761) – 2003
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A method for piles monitoring using long-gauge fibre optic sensors, Branko Glisic, Daniele Inaudi, Samuel Vurpillot, Claire Nan, 6th International Symposium on Field Measurements in GeoMechanics (FMGM 2003), September 15-18, 2003, Oslo, Norway – (pages 499-506) – 2003
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Overview of Fiber Optic Sensing Technologies for Geotechnical Instrumentation and Monitoring, Daniele Inaudi, Branko Glisic, Geotechnical News – (Volume 25, Number 3, Pages 4-8) – 2007
Pile dimensions, sensor networks and sequences of installation on rebar cage
Photos taken during installation of sensors on the rebar cage
Foundation performances determined using SOFO sensors
Distributions of normal force in the pile, friction stress and different zones of soil
