scholarly journals Ultimate Bearing Capacity Analysis of CFRP-Strengthened Shield Segments Using Bonding Slip Behavior Experiments

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4200
Author(s):  
Hong-bin Nie ◽  
Shuan-cheng Gu
Keyword(s):  
Bearing Capacity ◽  
Bending Strength ◽  
Ambient Pressure ◽  
Ultimate Bearing Capacity ◽  
Compression Tests ◽  
Confined Compression ◽  
Layer System ◽  
Reinforced Plastics ◽  
Bonding Performance ◽  
Hygrothermal Environment

Shield segments of subway tunnels are often exposed to the combined actions of several hygrothermal factors that could lead to accidents such as water seepage and tunnel collapse. Further, they often break and deform owing to formation pressure. In addition, uncertainties related to the stress relaxation characteristics and bonding performance of carbon-fiber-reinforced plastics (CFRPs) under a hygrothermal environment make their application in subway systems difficult. This study analyzes the effects of the slip-on-bending strength of CFRP-strengthened shield segments in a hygrothermal environment. In the study, the shield segments are damaged at ambient pressure under a combination of humidity (0%, 5%, and 10%) and temperature (20 °C, 25 °C, 30 °C, and 40 °C). An experimental procedure is designed to evaluate a CFRP-reinforced concrete arch. The method predicts the load–slip relationship and maximum shearing stress and strain. Moreover, confined compression tests are conducted on a tunnel segment lining strengthened with CFRP to evaluate the bearing capacity of the CFRP-strengthened shield segments. An equation for the latter’s ultimate bearing capacity is developed based on the elastic layer system theory, stress boundary condition, and bending stress characteristics of axisymmetric elements. It was found that the results from the developed model are compared with the experimental values of CFRP-strengthened shield segments under different humidity values (0%, 5%, and 10%) and a constant temperature. The ultimate strength—the debonding deflection of the CFRP-strengthened shield segment—can be predicted using the proposed ultimate bearing capacity equation with sufficient accuracy.

Experimental Research on Steel-High Performance Concrete Composite Bridge Towers and Piers

2011 ◽  
Vol 255-260 ◽  
pp. 1303-1306
Author(s):  
Chun Sheng Wang ◽  
Xin Xin Wang ◽  
Qian Wang
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultimate Bearing Capacity ◽  
Bridge Engineering ◽  
Good Prospect ◽  
Compression Tests ◽  
Composite Bridge ◽  
Bridge Tower

Steel-concrete composite bridge towers have the advantages of steel and concrete, they have a good prospect in bridge engineering. However, the applications and related researches of composite bridge towers in China are rare. Therefore, in this article, two types of steel-high performance concrete composite bridge tower and pier models, which had none and one row of longitudinal stud connectors, were designed. The axial compression tests were practiced on the two specimens, in order to study the influence of connectors on the mechanical properties of the composite bridge towers and piers. From the tests, the ultimate bearing capacity and failure mode were obtained, and the regularities of strains and deformations were also analyzed. The results show that setting up stud connectors on the composite towers and piers can improve the ductility and the ultimate bearing capacity obviously.

scholarly journals An Investigation of Bearing Capacity of High-Strength SRC Columns under Eccentric Axial Load

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 639
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Wenze Sun ◽  
Xinyu Yi
Keyword(s):  
Bearing Capacity ◽  
High Strength ◽  
Ultimate Bearing Capacity ◽  
Parameter Analysis ◽  
Test Results ◽  
Compression Tests ◽  
Steel Ratio ◽  
Eccentric Compression ◽  
Steel Strength ◽  
Relative Eccentricity

This paper investigates the eccentric compression performance of high-strength steel reinforced concrete (SRC) columns. In addition, the feasibility of the calculation codes used for the load-carrying capacity of these columns is verified by eccentric compression tests on 10 high-strength SRC columns with Q460 and Q690 steels and two normal SRC columns with Q235 steel. Moreover, the influence of the steel strength, relative eccentricity, steel ratio, and stirrup spacing on the bearing capacity and ductility of the specimens is analyzed. It was found that the bearing capacity and ductility of the specimens significantly increases when the steel strength increases from 276.5 MPa to 774.2 MPa; the bearing capacity of the Q690 SRC column is slightly higher than that of the Q460 SRC column. In addition, the ductility coefficient of the Q690 SRC columns is significantly higher than that of the Q460 SRC columns. It was also found that increasing the eccentricity and steel ratio can improve the ductility of the specimens and the smaller stirrup spacing can enlarge the contribution of Q690 steel under the ultimate bearing capacity. It is demonstrated that Eurocode 4-2004 and AISC360-16 codes significantly underestimate the test results. In contrast, JGJ138-2016 slightly underestimates the test results when the relative eccentricity is 0.2 but overestimates the test results when the relative eccentricity is 0.6. Furthermore, in order to maximize the contribution of Q690 steel under ultimate bearing capacity, the expanded parameter analysis is carried out using a finite element model. Following the analysis results, the suggestions for designing high-strength SRC columns under eccentric load are provided.

scholarly journals Study on the flexural performance of RC beams anchored with CFRP plates under secondary load

2021 ◽  
Vol 233 ◽  
pp. 03024
Author(s):  
Xiangrui Feng ◽  
Xian Cui ◽  
Haikun Luo
Keyword(s):  
Bearing Capacity ◽  
Bending Strength ◽  
Concrete Beams ◽  
Ultimate Bearing Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Flexural Performance ◽  
Cfrp Plate ◽  
Secondary Load ◽  
Structural Indicators

In order to explore the influence of length and width of CFRP as well as anchor spacing on the reinforcement effectiveness of CFRP plates on reinforcement concrete beams (RC beams) under secondary load, 7 anchored damaged FRP reinforced concrete beams are used as test beams, 1 unanchored beam is used as a control beam, and structural indicators such as ultimate load and bending strength are analyzed in the result. The conclusion is that composite CFRP plate can effectively prevent the early peeling and failure of carbon plates and improve the ultimate bearing capacity of the beam. When the width of the CFRP plate decreases, the thickness increases and the steel plate anchor spacing increases appropriately, the ultimate bearing capacity and ductility of the beam are significantly improved.

scholarly journals Study on the ultimate bearing capacity of a strip footing influenced by an irregular underlying cavity in karst areas

2021 ◽  
Author(s):  
Lianheng Zhao ◽  
Shan Huang ◽  
Zhonglin Zeng ◽  
Rui Zhang ◽  
Gaopeng Tang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Strip Footing ◽  
Karst Areas

Experimental Investigation for Horizontal Ultimate Bearing Capacity and Target Ductility Factor Improvement Results of the RC Column Reinforced by AFL with Damages

2014 ◽  
Vol 488-489 ◽  
pp. 497-500
Author(s):  
You Lin Zou ◽  
Pei Yan Huang
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Test Results ◽  
Rc Columns ◽  
Static Test ◽  
Rc Column ◽  
Ductility Factor ◽  
Secant Stiffness ◽  
Function Relationship ◽  
Reversed Cyclic

Deem test results from the low reversed cyclic loading quasi-static test with 2 RC columns as the basic information of secant stiffness damage of the reference column and take use of the TMS instrument in the test to artificially make the damage percentage of secant stiffness of the RC column as 33%, 50% and 66%, 6 damaged columns in total; reinforce the 6 damaged columns and 2 undamaged ones under the same conditions with AFL, through quasi-static contrast test. Test results show that it is able to effectively boost horizontal ultimate bearing capacity and ductility deformability of the RC columns with AFL for reinforcement; besides, there is a linear function relationship between horizontal ultimate bearing capacity, target ductility factor, and damage percentage of secant stiffness.

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