scholarly journals Distributed Fiber Optic Shape Sensing of Concrete Structures

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6098
Author(s):  
Christoph M. Monsberger ◽  
Werner Lienhart
Keyword(s):  
Fiber Optic ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Sensing Systems ◽  
Aging Infrastructure ◽  
Load Tests ◽  
Bending Behavior ◽  
Shape Sensing ◽  
Real Scale ◽  
Comprehensive Study

Civil structural health monitoring (CSHM) has become significantly more important within the last decades due to rapidly growing construction volume worldwide as well as aging infrastructure and longer service lifetimes of the structures. The utilization of distributed fiber optic sensing (DFOS) allows the assessment of strain and temperature distributions continuously along the installed sensing fiber and is widely used for testing of concrete structures to detect and quantify local deficiencies like cracks. Relations to the curvature and bending behavior are however mostly excluded. This paper presents a comprehensive study of different approaches for distributed fiber optic shape sensing of concrete structures. Different DFOS sensors and installation techniques were tested within load tests of concrete beams as well as real-scale tunnel lining segments, where the installations were interrogated using fully-distributed sensing units as well as by fiber Bragg grating interrogators. The results point out significant deviations between the capabilities of the different sensing systems, but demonstrate that DFOS can enable highly reliable shape sensing of concrete structures, if the system is appropriately designed depending on the CSHM application.

scholarly journals Effects of nano-modified polymer cement-based materials on the bending behavior of repaired concrete beams

2021 ◽  
Vol 10 (1) ◽  
pp. 292-303
Author(s):  
Tao Meng ◽  
Songsong Lian ◽  
Xiufen Yang ◽  
Ruitan Meng
Keyword(s):  
Concrete Beams ◽  
Concrete Structures ◽  
Bending Moment ◽  
Average Width ◽  
Modified Polymer ◽  
Steel Bars ◽  
Cement Based Materials ◽  
Bending Behavior ◽  
The Moment

Abstract As the use time of concrete structures increases, defects such as concrete cracks, corrosion and exposure of steel bars gradually appear, resulting in additional repair of concrete structures to increase their durability and life. In this article, the effects of nano-modified polymer cement-based materials as repair material on the bending behavior of repaired concrete beams were studied. Based on the moment, deflection, strain, surface quality and cracking development monitor of repaired concrete beams, the bending behavior of repaired beams with polymer, nano-modified polymer and fibers was compared and the failure mechanism of the beams was analyzed. The results showed that the nano-modified polymer cement-based materials are helpful in improving the performance of repaired beams, manifested by the increase in the ultimate bending moment and the significant improvement in the quality of the interface between repair and matrix concrete. Compared with polymer cement-based materials, nano-modified polymer cement-based materials result in a 27% increase in ultimate bending moment of the repaired beam and a 58% increase in cracking moment, while reducing the total number of cracks by 23% and the average width of cracks by 17% in the repaired beam. This article demonstrated the availability of nanomaterials for improving the loading behavior of structural components with polymer-modified cement-based materials.

scholarly journals A study on the numerical modelling of UHPFRC-strengthened members

2018 ◽  
Vol 199 ◽  
pp. 09001
Author(s):  
Renaud Franssen ◽  
Serhan Guner ◽  
Luc Courard ◽  
Boyan Mihaylov
Keyword(s):  
Numerical Modelling ◽  
High Performance ◽  
Concrete Structures ◽  
Concrete Members ◽  
High Durability ◽  
Tension Tests ◽  
The World ◽  
Aging Infrastructure ◽  
New Generation ◽  
Modelling Approach

The maintenance of large aging infrastructure across the world creates serious technical, environmental, and economic challenges. Ultra-high performance fibre-reinforced concretes (UHPFRC) are a new generation of materials with outstanding mechanical properties as well as very high durability due to their extremely low permeability. These properties open new horizons for the sustainable rehabilitation of aging concrete structures. Since UHPFRC is a young and evolving material, codes are still either lacking or incomplete, with recent design provisions proposed in France, Switzerland, Japan, and Australia. However, engineers and public agencies around the world need resources to study, model, and rehabilitate structures using UHPFRC. As an effort to contribute to the efficient use of this promising material, this paper presents a new numerical modelling approach for UHPFRC-strengthened concrete members. The approach is based on the Diverse Embedment Model within the global framework of the Disturbed Stress Field Model, a smeared rotating-crack formulation for 2D modelling of reinforced concrete structures. This study presents an adapted version of the DEM in order to capture the behaviour of UHPFRC by using a small number of input parameters. The model is validated with tension tests from the literature and is then used to model UHPFRC-strengthened elements. The paper will discuss the formulation of the model and will provide validation studies with various tests of beams, columns and walls from the literature. These studies will demonstrate the effectiveness of the proposed modelling approach.

Anchorages of stirrups under transverse tension in concrete - development of a design model

2019 ◽  
Author(s):  
Mirhat Medziti ◽  
Daia Zwicky
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Tensile Force ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Reinforced Concrete Beams ◽  
Design Model ◽  
Hook Effect ◽  
Internal Forces ◽  
Negative Bending

<p>According to Swiss code SIA 262 "Concrete structures", stirrups of reinforced concrete beams must "surround the tensile longitudinal reinforcement" and must "be anchored to mobilize the static height of internal forces". For existing concrete structures, Swiss code SIA 269/2 provides stirrup detailing requirements while limiting these directives for stirrup anchorage to the compression zone. In zones of negative bending, these requirements are often not satisfied for execution reasons. This question is addressed in a largely experimental Ra&amp;D project. Anchorage tests were performed and analyzed, with a total of 144 tests on 9 concrete beams. These underwent a longitudinal tensile force up to 1’000 kN to simulate transverse cracking at stirrup anchorages in negative flexure zones. The study parameters are crack width (0, 0.4 and 0.9 mm), stirrup diameter (10 and 14 mm), bar ribbing (smooth and ribbed) and hook angle (90°, 135°, 180° and straight bars). A design model based on the "tension chord model" (TCM) developed at ETH Zurich is proposed. This simple and practical design model has proved ist effectiveness to consider bond effects. Reduction factors for bar diameter (k<sub>Ø</sub>), relative bar ribbing (k<sub>fR</sub>), hook effect (k<sub>θ</sub>) and crack width (k<sub>w</sub>) were taken into account for calibration. Results of analytical calculations are coherent with experimental tests.</p>

An optical soft-sensor based shape sensing using a bio-inspired pattern recognition technique to realise fly-by-feel capability for intelligent aircraft operation

2018 ◽  
Vol 122 (1257) ◽  
pp. 1734-1752
Author(s):  
M. Basu ◽  
S. K. Ghorai
Keyword(s):  
Support Vector Regression ◽  
Time Lag ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Support Vector ◽  
Wing Model ◽  
Sensing Systems ◽  
Structural Failures ◽  
Training Methodologies ◽  
Shape Sensing

ABSTRACTInformation regarding deformations in large and complex systems is necessary in the prediction of structural failures caused by un-natural flexural occurrences. Sensing systems which are used to predict shapes, in order to develop a global surface picture require high precision and lower time lag. In this work, a unique bio-inspired training mechanism for support vector regression is presented for shape sensing in structures mounted with Fiber Bragg Gratings. Experimental validation was carried out on a simply supported beam, loaded at different positions and an aircraft wing model for different types of bending. The resulting deflections at specified locations along the length of the beam and on both surfaces of the wing were interpreted from the wavelength shifts of the corresponding Fiber Bragg Gratings through the specially modified Support Vector Regression. The method has shown high accuracy, low computational requirements and enhanced prediction times. The proposed bio-inspired training method has also been compared with two conventional training methodologies.

scholarly journals Qualification of a truly distributed fiber optic technique for strain and temperature measurements in concrete structures

2011 ◽  
Vol 12 ◽  
pp. 03004 ◽  
Author(s):  
J.M. Henault ◽  
J. Salin ◽  
G. Moreau ◽  
S. Delepine-Lesoille ◽  
J. Bertand ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Concrete Structures ◽  
Temperature Measurements

scholarly journals Numerical and experimental investigations of steel-concrete beams with thin-walled section

Vestnik MGSU ◽  
2019 ◽  
pp. 22-32
Author(s):  
Farit S. Zamaliev
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Strain State ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Numerical Studies ◽  
Field Samples ◽  
Thin Walled

Introduction. Conducted is to the evaluation of the stress-strain state of the steel-concrete beams with thin-walled section. In recent times, steel-reinforced concrete structures have become widely used in civilian buildings (beams, slabs, columns). Thin-walled section have not found wide application in steel concrete structures, unlike steel structures. Presents the results of numerical studies of beams consisting of concrete, anchors and steel beams. Two investigating of the location of anchors are given. Numerical investigations are presented of steel-concrete beams with thin-walled section based on numerical studies. Testing procedure and test result are given. Results of calculations, comparison of numerical and experimental studies are presented. Materials and methods. For full-scale experiments, steel I-beams with filling of side cavities with concrete were adopted, screws are used as anchor ties, with varied both the lengths and their location (vertically and obliquely). As steel curved C-shaped steel profiles were used steel profiles from the range of the company “Steel Faces”. ANSYS software package was used for computer modeling. A total of 16 steel concrete beams were considered, for which the results of strength and stiffness evaluation were obtained in ANSYS. Results. The data of the stress-strain state of beams on the basis of computer simulation are obtained. The results are used for the production of field samples. Data of computer simulation are compared with the indicators of field experiments. Conclusions. The stress-strain state of steel-concrete structures was studied on the basis of numerical and experimental data. The proposed calculation method gives good convergence with the experimental data. Anchor connections made from self-tapping screws can be used in studies for modeling in steel-concrete beams structures and other anchor devices, ensuring the joint operation of concrete and steel profiles in structures.

Shape sensing using distributed fiber optic strain measurements

2004 ◽  
Author(s):  
Gary A. Miller ◽  
Charles G. Askins ◽  
E. Joseph Friebele
Keyword(s):  
Fiber Optic ◽  
Strain Measurements ◽  
Shape Sensing

Fiber optic sensors in concrete structures: a review

1999 ◽  
pp. 1-24 ◽  
Author(s):  
C. I. Merzbacher ◽  
A. D. Kersey ◽  
E. J. Friebele
Keyword(s):  
Fiber Optic ◽  
Concrete Structures ◽  
Fiber Optic Sensors
Sign in / Sign up

Export Citation Format

Share Document