Damage Detection with FBG Sensors for Pre-Stress Concrete Girders

2017 ◽  
Vol 737 ◽  
pp. 454-458 ◽  
Author(s):  
Seong Cheol Lee ◽  
Kyung Joon Shin ◽  
Jae Min Kim ◽  
Hwan Woo Lee
Keyword(s):  
Prestressed Concrete ◽  
Shear Failure ◽  
Experimental Program ◽  
Test Results ◽  
Strain Variation ◽  
Concrete Members ◽  
Concrete Girders ◽  
Drastic Increase ◽  
Fbg Sensors ◽  
Tendon Strain

In this paper, possibility to detect damage on post-tensioned concrete girders was investigated through an experimental program with 6 m long specimens containing smart tendons where FBG (Fiber Bragg Grating) sensors were embedded. Total six specimens were fabricated and tested, and test variables were prestressing tendon’s profile and web thickness. All the specimens were subjected to 3-points loading, and they exhibited shear failure. Through the test, it was observed that tendon strains were successfully measured through FBG sensors regardless of the test variables. It was also observed that tendon strains within the pure span significantly increased while ones nearby the anchors beyond the pure span were constant. When the specimen was cracked, FBG sensors nearby cracks showed relatively drastic increase on tendon strain. Since strain variation along tendons cannot be detected by conventional equipment such as a load-cell, the test results indicated that actual tendon strains can be easily measured with FBG sensors. These results showed that FBG sensors can be useful to check whether prestressed concrete members were significantly damaged. In addition, it is expected that FBG sensors can be helpful on more reasonable maintenance of PSC girders.

scholarly journals Pullout Behavior of GFRP Anti-Floating Anchor Based on the FBG Sensor Technology

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ming-yi Zhang ◽  
Zheng Kuang ◽  
Xiao-yu Bai ◽  
Xiao-yu Chen
Keyword(s):  
Axial Force ◽  
Shear Failure ◽  
Distribution Functions ◽  
Sensor Technology ◽  
Force Distribution ◽  
Test Results ◽  
Glass Fiber Reinforcement ◽  
Promising Solution ◽  
Service Conditions ◽  
Fbg Sensors

Building anti-floating anchors have been increasingly used in recent years, but conventional steel anchors under service conditions are easily subjected to chemical erosion. Glass fiber reinforcement polymer (GFRP) is a promising solution to this problem. In this study, field pullout tests were conducted on three full instrumented GFRP anti-floating anchors in weathered granite. Specifically, the GFRP anchors during pultrusion were innovatively embedded with bare fiber Bragg grating (FBG) sensors to monitor the axial force distribution along depth. It was found that the embedded FBG could reliably monitor the axial force distribution of GFRP anchors. The ultimate pullout force of a GFRP anchor with diameter of 28 mm and anchorage length of 5 m was up to 400 kN. The GFRP anchor yielded at 0.8 m underground. Force distribution and field photos at failure indicated shear failure occurred at the anchor/bolt interface at the end of the tests. The feasibility of the GFRP anti-floating anchor was also verified in civil engineering. Finally, an elastic mechanical model and Mindlin’s displacement solution are used to get distribution functions of axial force and shear stress along the depth, and the results accord with the test results.

Shear Behavior of CFRP Prestressed Concrete Beams without Stirrups

2011 ◽  
Vol 266 ◽  
pp. 126-129 ◽  
Author(s):  
Zuo Hu Wang ◽  
Xiu Li Du ◽  
Jing Bo Liu
Keyword(s):  
Prestressed Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Shear Span ◽  
Compression Failure ◽  
Concrete Members ◽  
Prestressed Beams

Five beams were tested up to failure to study the shear behavior of concrete beams prestressed with fiber reinforced polymer (FRP). Different factors were taken into consideration: the type of prestressing tendons and the shear span ratio. The shear failure modes and the influence of different factors on shear behavior were investigated in details. The test results showed that FRP prestressed beams without stirrups had two shear failure modes: diagonal compression failure and shear compression failure; the shear span ratio was the most important factor to determine the failure mode and shear capacity of the prestressed beams. The shear capacity of concrete members prestressed with FRP tendons was lower than that of concrete beams prestressed with steel cables.

scholarly journals Parametric Study on Mixed Torsional Behavior of U-Shaped Thin-Walled RC Girders

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Jianchao Xu ◽  
Bo Diao ◽  
Quanquan Guo ◽  
Yinghua Ye ◽  
Y. L. Mo ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Test Results ◽  
Height Ratio ◽  
Calculating Method ◽  
Concrete Girders ◽  
Flexural Failure ◽  
Parametric Studies ◽  
Thin Walled ◽  
Shear Failures

Nowadays, U-shaped thin-walled concrete girders have been widely applied in the urban construction of rail viaducts in China as well as worldwide. However, the mixed torsional behaviors of these structures are not well understood. In this paper, the mixed torsional behaviors of the U-shaped thin-walled RC girders are theoretically analyzed, and a method predicting failure modes and ultimate torques is proposed. Nonlinear FE models based on ABAQUS to simulate the mixed torsional behaviors are built and calibrated with the test results. Parametric studies considering three crucial parameters (boundary condition, span length-section height ratio, and ratio of longitudinal bars to stirrups) are conducted based on both the above suggested calculating method and the FE modeling. The calculated and the simulated results agree well with each other and with the test results. It is found that the failure modes of the U-shaped thin-walled RC girders under torsion are influenced by all the three parameters. Three kinds of failure modes are observed: flexural failures dominated by warping moment, shear failures caused by warping torque and circulatory torque, and flexural-shear failures in the cases where flexural failure and shear failure appear almost at the same time.

scholarly journals Behavior of Strengthened Composite Prestressed Concrete Girders under Static and Repeated Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Abbas AbdulMajeed Allawi
Keyword(s):  
Prestressed Concrete ◽  
Experimental Tests ◽  
Full Scale ◽  
Repeated Loading ◽  
Test Results ◽  
Concrete Girders ◽  
Load Carrying ◽  
Prestressed Concrete Girders ◽  
Aashto Lrfd ◽  
Analysis Models

The use of external posttensioning technique for strengthening reinforced concrete girders has been considerably studied by many researchers worldwide. However, no available data are seen regarding strengthening full-scale composite prestressed concrete girders with external posttensioned technique under static and repeated loading. In this research, four full-scale composite prestressed I-shape girders of 16 m span were fabricated and tested under static and repeated loading up to failure. Accordingly, two girders were externally strengthened with posttensioned strands, while the other two girders were left without strengthening. The experimental tests include deflection, cracking load, ultimate strength and strains at midspan, and loading stages. Test results were compared with the design expressions mentioned in AASHTO LRFD specifications and ACI 318-2014 code. Also, a nonlinear analysis was conducted using the finite element method (FEM). The presented analysis models were verified by comparing the model results with test results. The general theme abstracted from both experimental tests and numerical analysis reflects that the performance and procedure of strengthening with external prestressing of girders were found to be effective in increasing the load carrying capacity of the strengthened girders.

Experimental Research on Crack Width of Retard-Bonded Partially Prestressed Concrete Beams

2013 ◽  
Vol 639-640 ◽  
pp. 211-215 ◽  
Author(s):  
Xin Feng ◽  
Xian Yan Zhou
Keyword(s):  
Experimental Research ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Test Results ◽  
Paper Test ◽  
Concrete Members ◽  
Maximum Crack ◽  
The Relationship

Retard-bonded prestressed concrete which has appeared in recent twenty years is a new and distinctive prestressed system. For the research on mechanical behavior and service property of retard-bonded prestressed concrete members, retard-bonded prestressed strands were made by manual work in this paper. Experimental research and theoretical analysis of three retard-bonded partially prestressed concrete T-beams were carried out under static loadings. The law of crack development and distribution both with the relationship between load and maximum crack width were studied in the paper. Test results were contrasted with experimental studies of two traditional partially prestressed concrete T-beams, and the characters and merits of retard-bonded partially prestressed concrete T-beams were obtained. It provides theoretical reference for the actual project application of the new retard-bonded prestressed concrete system.

A review of cracking of partially prestressed concrete members

1985 ◽  
Vol 12 (3) ◽  
pp. 645-652 ◽  
Author(s):  
B. deV. Batchelor ◽  
M. El Shahawi
Keyword(s):  
Key Words ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Sparse Data ◽  
Simple Expression ◽  
Test Results ◽  
Strong Case ◽  
Concrete Members ◽  
Maximum Crack ◽  
Prestressed Reinforcement

A selective review of cracking of partially prestressed concrete members is presented. The main studies, together with the resulting methods for calculating maximum crack width, are critically examined. From an analysis of published test results it is shown that, in the light of the sparse data available, there is no point in using a complicated crack width formula for partially prestressed members. A simple expression for calculating crack width is proposed, which involves only the calculation of stress in the non-prestressed reinforcement. A strong case is made for further research in this area so that effects of the controlling parameters may be considered, where necessary. Key words: concrete (prestressed), cracking, crack width, partial prestressing.

The Influence of Concrete Cover, Type of Wire Indentation and Concrete Mix on Bond between Steel and Concrete in Prismatic Prestressed Concrete Members

2021 ◽  
Vol 39 ◽  
pp. 103-126
Author(s):  
Adrijana Savić ◽  
Aref Shafiei Dastgerdi ◽  
Terry Beck ◽  
Robert J. Peterman ◽  
Aaron Robertson
Keyword(s):  
Prestressed Concrete ◽  
Concrete Cover ◽  
Concrete Mixture ◽  
Test Results ◽  
Cover Type ◽  
Minimum Value ◽  
Concrete Members ◽  
Material Characteristics ◽  
Splitting Test ◽  
Concrete Mix

This research was focused on evaluating the influence of the different variables that affectsplitting in prestressed concrete members, particularly prestressed concrete ties. These include the thickness of concrete cover, release strength of concrete, and the type of wire indentation. Different combinations of these variables can affect splitting. This research was focused on finding the best possible material characteristics to avoid potential failures in the field. The objective of this research was to set the minimum value of the thickness of concrete cover, for different wire types used in manufacturing having given types of aggregate for concrete mixture. The importance of this research was to identify the best materials and the best system (concrete, wire, cover) designs before the production of prestressed concrete ties. Splitting test results presented in this research were focusedon three different thicknesses of concrete cover, three different concrete mixes, a 4500psi concrete release strength, and seven different indented wire types.

Inspection and Analysis of Prestressed Concrete Girders Deteriorated by Alkali-Silica Reaction

2006 ◽  
Vol 302-303 ◽  
pp. 131-137
Author(s):  
Ting Yu Hao
Keyword(s):  
Prestressed Concrete ◽  
North China ◽  
Alkali Silica Reaction ◽  
Test Results ◽  
Railway Bridge ◽  
Alkali Content ◽  
Concrete Girders ◽  
The Future ◽  
Prestressed Concrete Girders

In-situ inspection and lab study were combined to analyze the prestressed concrete girders of an existing railway bridge built in 1976 in North China. The reactive components in aggregates and the alkali content of concrete were investigated. Typical reaction product was found in site and was analyzed in lab. Residual expansion of concrete cores drilled from some girders was measured. From test results, it can be deducted that alkali silica reaction had affected the concrete girders and would continue to cause expansion in the future.

scholarly journals Experimental Study on Seismic Behavior of Masonry Walls Strengthened by Reinforced Mortar Cross Strips

2019 ◽  
Vol 11 (18) ◽  
pp. 4866 ◽  
Author(s):  
Dong ◽  
Sui ◽  
Jiang ◽  
Zhou
Keyword(s):  
Seismic Performance ◽  
Cyclic Load ◽  
Failure Modes ◽  
Shear Failure ◽  
Constant Load ◽  
Shear Capacity ◽  
Experimental Program ◽  
Test Results ◽  
Reinforced Masonry ◽  
Key Factor

Due to the poor seismic performance, strengthening of masonry structures is always a significant problem worthy to study. It has been proven that the bearing capacity of existing masonry buildings can be enhanced greatly with efficient strengthening measures. An experimental program was conducted to investigate seismic performance of un-reinforced masonry (URM) walls strengthened b,y reinforced mortar (RM) cross strips. Eleven walls were tested under horizontal low-cyclic load, simultaneously with a vertical constant load on the top face. Three URM walls were tested as reference. The other eight walls were externally strengthened with 40 and 60 mm thick of RM cross strips on one or both faces. Test results showed that externally strengthening with RM cross strips was an efficient way to enhance the seismic performance of URM walls. The failure modes were divided into shear failure and shear-compression failure. All the tested walls did not collapse until the test ended, while many diagonal cracks and few vertical cracks appeared on mortar strips. After strengthening, the shear capacity of the strengthened walls increased by at least 38.2%, and the reinforcement ratio was noted to be the key factor to influence the shear capacity with positive correlation. Besides, RM cross strips did improve deformation capacity greatly.

scholarly journals Experimental Study on Lateral-Load-Resisting Capacity of Masonry-Infilled Reinforced Concrete Frames

2021 ◽  
Vol 11 (21) ◽  
pp. 9950
Author(s):  
Minjae Kim ◽  
Eunjong Yu
Keyword(s):  
Shear Failure ◽  
Masonry Wall ◽  
Experimental Program ◽  
Test Results ◽  
Concrete Frames ◽  
Masonry Infill ◽  
Proposed Model ◽  
Current Code ◽  
Adequate Method ◽  
Good Agreement

In this study, an experimental program was performed on masonry-infilled frame specimens with varied construction precision and masonry thickness. A total of five portal frame specimens, which consist of four masonry-infilled frames and a bare frame, were tested, and the results were analyzed to investigate the effects of construction precision and interaction between the masonry infill and the frame. The test results indicated that the gap in the masonry infill decreased strength by 75% to 80% and stiffness by 55% to 70%. A comparison between the measured and predicted peak strength using the current code shows that the code equations underestimate the strength by up to 70%. This is due to the fact that the contribution of friction in shear resistance of the masonry wall is actually ignored in the current code since no adequate method for estimating the normal force is provided. In addition, reflecting the observation that the failure mode of the columns changed to shear failure when thick masonry walls were used, a mechanical model that can explain the shear failure and enables the estimation of maximum strength was proposed. The maximum strengths of the specimens calculated using the proposed model were in good agreement with the experimental results.

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