scholarly journals Experimental Study on the Mechanics Characteristics of CFRP Strengthening of Highway Tunnels at Different Damage States

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xuezeng Liu ◽  
Yunlong Sang ◽  
Shuang Ding ◽  
Guiliang You ◽  
Wenxuan Zhu ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Structural Deformation ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Scaled Model ◽  
Term Operation ◽  
Cfrp Sheets ◽  
Secondary Load ◽  
Load Carrying ◽  
Damage States

Cracks and other diseases may occur in the long-term operation of highway tunnels and reduce the structural load-carrying capacity. Strengthening using carbon fiber reinforced polymer (CFRP) sheets and other materials could extend the service time of the tunnels. However, the process of strengthening tunnels is remarkably different from the process of strengthening aboveground structures because of the secondary load. In order to understand the development of stress and deformation of strengthened tunnels under secondary load, a 1 : 10 scaled model was tested to simulate the tunnel strengthened with CFRP under different damage states. The test results show that CFRP strengthening improved the stiffness of the structure and inhibited the propagation of the existing cracks. The peeling of the CFRP sheets made the strengthened structure quickly lose its load-carrying capacity, causing the instability of the structure. The failure loads of the structures strengthened at different damage states were essentially the same, with an average value of 184% of the original failure load. Nevertheless, the early strengthening helped control the structural deformation. The test results also demonstrate that the bonding strength between the CFRP and the lining is essential for strengthening effectiveness. This study provides a theoretical basis for similar engineering reinforcement designs.

scholarly journals Effect of Preload Level on Flexural Load-carrying Capacity of RC Beams Strengthened by Externally Bonded FRP Sheets

2015 ◽  
Vol 9 (1) ◽  
pp. 426-434 ◽  
Author(s):  
Guibing Li ◽  
Aihui Zhang ◽  
Yugang Guo
Keyword(s):  
Carrying Capacity ◽  
Concrete Strength ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Test Results ◽  
Damage Level ◽  
Cfrp Sheets ◽  
Flexural Performance ◽  
Load Carrying ◽  
Externally Bonded

Most of the laboratory tests investigated the flexural performance of un-preloaded or undamaged RC beams strengthened with CFRP composites. However, in engineering applications, the structural member must carry a certain load or damage. There is a lack of systematical investigations on the effects of preload or damage level on the flexural load-carrying capacity of CFRP-strengthened RC beams. This paper tested 22 RC beams to investigate the influence of preload level on flexural load-carrying capacity of CFRP-strengthened RC beams. The test variables are preload level, amount of CFRP sheets, tension rebar ratio, and concrete strength. The test results show that if the preload level is not more than 80% of the yielding strength of the original beam, the preload or damage level does not influence the flexural load-carrying capacity of CFRP-strengthened RC beams. However, the ultimate flexural load-carrying capacity is significantly poor than that of RC beam strengthened under a preload level not more than 80% of the yielding strength, if the RC beams are strengthened under a preload level more than 90% of the yielding strength.

Load-Carrying Capacity of Second-Growth Douglas-Fir Stump Anchors

1987 ◽  
Vol 2 (3) ◽  
pp. 77-80 ◽  
Author(s):  
Marvin R. Pyles ◽  
Joan Stoupa
Keyword(s):  
Carrying Capacity ◽  
Deformation Behavior ◽  
Ultimate Load ◽  
Douglas Fir ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Tree Diameter ◽  
Second Growth ◽  
Load Carrying ◽  
Load Tests

Abstract In order to quantify the stump anchor capacity of small second-growth Douglas-fir (Pseudotsuga menziesii [Mirb]. Franco) trees, load tests to failure were conducted on 18 stumps from trees 7 to 16.5 in dbh. The tests produced ultimate loads that varied as the square of the tree diameter. However, the ultimate load typically occurred at stump system deformations that were far in excess of that which would be considered failure of a stump anchor. A hyperbolic equation was used to describe the load-deformation behavior of each stump tested and was generalized to describe all the test results. West. J. Appl. For. 2(3):72-80, July 1987.

Evaluation on ultimate load-carrying capacity of concrete-filled steel tubular arch structure with preload

2019 ◽  
Vol 22 (13) ◽  
pp. 2755-2770
Author(s):  
Fuyun Huang ◽  
Yulong Cui ◽  
Rui Dong ◽  
Jiangang Wei ◽  
Baochun Chen
Keyword(s):  
Finite Element ◽  
Initial Stress ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Arch Bridge ◽  
Load Carrying ◽  
Arch Structure ◽  
Ultimate Load Carrying Capacity

When casting wet concrete into hollow steel tubular arch during the construction process of a concrete-filled steel tubular arch bridge, an initial stress (due to dead load, etc.) would be produced in the steel tube. In order to understand the influence of this initial stress on the strength of the concrete-filled steel tubular arch bridge, a total of four single tubular arch rib (bare steel first) specimens (concrete-filled steel tubular last) with various initial stress levels were constructed and tested to failure. The test results indicate that the initial stress has a large influence on the ultimate load-carrying capacity and ductility of the arch structure. The high preloading ratio will reduce significantly the strength and ductility that the maximum reductions are over 25%. Then, a finite element method was presented and validated using the test results. Based on this finite element model, a parametric study was performed that considered the influence of various parameters on the ultimate load-carrying capacity of concrete-filled steel tubular arches. These parameters included arch slenderness, rise-to-span ratio, loading method, and initial stress level. The analysis results indicate that the initial stress can reduce the ultimate loading capacity significantly, and this reduction has a strong relationship with arch slenderness and rise-to-span ratio. Finally, a method for calculating the preloading reduction factor of ultimate load-carrying capacity of single concrete-filled steel tubular arch rib structures was proposed based on the equivalent beam–column method.

scholarly journals Influence of ties on the behavior of short reinforced concrete columns strengthened by external CFRP

2018 ◽  
Vol 162 ◽  
pp. 04005
Author(s):  
Kaiss Sarsam ◽  
Raid Khalel ◽  
Mohammed Hadi
Keyword(s):  
Carrying Capacity ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Load Carrying Capacity ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
The Difference ◽  
Normal Strength

An experimental study was carried out to investigate the behavior of normal strength reinforce concret (RC) circular short column strengthned with “carbon fiber reinforced polymer (CFRP) sheets”. Three series comprising totally of (15) specimens loaded until failure under concentric compresion load. Strengthening was varied by changing the number of CFRP strips, spacing and wrapping methods. The findings of this research can be summarized as follows: for the columns without CFRP, the influence of the tie spacing was significant: compared with 130 mm tie spacing, dropping the spacing to 100 mm and 70 mm increased the load carrying capacity by 18% and 26%, respectively. The columns with less internal confinement (lesser amount of ties) were strengthened more significantly by the CFRP than the ones with greater amount of internal ties. As an example of the varying effectiveness of the fully wrapped CFRP, the column with ties at 130 mm was strengthened by 90% with the CFRP. In contrast, the ones with 70 mm spaced ties only increased in strength with CFRP by 66%. Compared with the control specimen (no CFRP), the same amount of CFRP when used as hoop strips led to more strengthening than using CFRP as a spiral strip- the former led to nearly 9% more strengthening than the latter in the case of 130 mm spaced internal steel ties. In the case of 100 mm internal steel ties, the difference (between the hoops & spiral CFRP strengthening) is close to 4%. In contrast, there is no difference between the two methods of strengthening in the heavily tied columns (70 mm tied spacing).

Load-Carrying Capacity of Corroded Gusset Plate Connection and Its Repair Using CFRP Sheets

2021 ◽  
Vol 147 (6) ◽  
Author(s):  
Ngoc Vinh PHAM ◽  
Takeshi Miyashita ◽  
Kazuo Ohgaki ◽  
Yusuke Okuyama ◽  
Yuya Hidekuma ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Gusset Plate ◽  
Cfrp Sheets ◽  
Load Carrying ◽  
Plate Connection

Extracting Load Research of Taper Interference Fit Made of Glass and Ceramics Parts Using a Servo Press

2015 ◽  
Vol 816 ◽  
pp. 461-468 ◽  
Author(s):  
Pavel Lekomtsev ◽  
Pavol Božek ◽  
Alexander Romanov ◽  
Andrey Abramov ◽  
Ivan Abramov ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Axial Loading ◽  
Thermal Method ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Interference Fit ◽  
Servo Press ◽  
Load Carrying ◽  
Technical Ceramics ◽  
Axial Shift

Test results of axial shift of “technical ceramics - glass” parts in taper interference fit joint under axial loading are presented. The load-carrying capacity was tested under normal conditions; a servo press was used to load the test samples. The tested samples were assembled by thermal method.

Load Carrying Capacity and Ductility of CFRP-Reinforced Earthquake Waste Filled Circular Steel Tube Columns

2012 ◽  
Vol 463-464 ◽  
pp. 234-238 ◽  
Author(s):  
Dong He ◽  
Jiang Feng Dong ◽  
Shu Cheng Yuan ◽  
Qing Yuan Wang
Keyword(s):  
Carrying Capacity ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Load Carrying Capacity ◽  
Aggregate Concrete ◽  
Cfrp Sheets ◽  
Circular Steel Tube ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

In order to significantly increase not only the load carrying capacity but also the ductility of the steel tube columns filled with recycled aggregate concrete from the earthquake waste, two different strengthening methods by using externally bonded of carbon fibre reinforced polymer (CFRP) to strengthened the columns was proposed. Composite columns of CFRP reinforced and steel circular steel tube columns are studied in this study. The aims were to study the contribution of the CFRP sheets applied in enhancing the load carrying capacity and ductility of the steel tube columns with different concrete type, normal concrete and recycled aggregate concrete. The results demonstrate that the ultimate load carrying capacity and ductility of the steel tube columns filled with recycled aggregate concrete can be increased satisfactorily by full wrapping and partial wrapping arrangement of CFRP sheets. Moreover, stiffness of the columns strengthened was also increased greatly due to the restraining effect offered by CFRP and the full wrapping arrangement is better than the partial wrapping arrangement in enhancing the stiffness and the load carrying capacity.

Test Analysis of Stiffened T-Stub Connections

2015 ◽  
Vol 744-746 ◽  
pp. 319-322
Author(s):  
Chang Chun Dong ◽  
Wei Zhao
Keyword(s):  
Free Boundary ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Test Analysis ◽  
Deformation Curves ◽  
Load Carrying

To investigate the effect of stiffener on the stiffness and strength of T-stubs, 3 T-stub connections without stiffeners and 6 stiffened T-stub connections with varied shape and thickness of stiffeners were tested monotonically. The load carrying capacity, relative deformations of endplates and strains on the stiffeners and endplates were measured. The load-deformation curves of the connections and load-strain curves were presented. The test results showed that the commonly used stiffeners in current Chinese practice often yield or/and buckle prematurely. And the stiffener designed by the method can meet the requirement in CECS102-2002, which demands that the stiffener should be able to force the extended portion of endplates from clamped-free boundary to plates fixed on two adjacent boundaries.

Effect of MoS2 Films on Scoring Resistance of Gears

1986 ◽  
Vol 108 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Y. Terauchi ◽  
H. Nadano ◽  
M. Kohno
Keyword(s):  
Molybdenum Disulfide ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Wear Characteristics ◽  
Load Carrying ◽  
Mos2 Film ◽  
Scoring Resistance ◽  
Gear Machine

In trying to clarify the effect of molybdenum disulfide film on the scoring resistance and the wear characteristics of gears, various tests on balls and gears coated with MoS2 film have been run. From the test results obtained with a four-ball machine and a power-circulating gear machine it was found that the effect of the MoS2 film was small on the seizure load of the balls. In contrast, the effect of the MoS2 film on the scoring resistance of the gears was significant, and the development of the gears of which the load-carrying capacity against scoring is considerably large could be made.

scholarly journals Push-Out Tests on Various Steel Anchors with Partial-Length Welding in Steel–Concrete Composite Members

2020 ◽  
Vol 11 (1) ◽  
pp. 105
Author(s):  
In-Rak Choi ◽  
Chang-Soo Kim
Keyword(s):  
Carrying Capacity ◽  
Peak Load ◽  
Steel Beams ◽  
Load Reduction ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Partial Length ◽  
Load Carrying ◽  
Ductile Behavior ◽  
Push Out

To investigate the behavior of various steel anchors, push-out tests were performed for 13 test specimens. Test parameters included the geometry of beams (wide-flange beams and composite beams) and the type of steel anchors (stud anchors and Z- and C-channel anchors with full- or partial-length welding). Test results showed that the performance of test specimens strongly depends on the types of steel anchors rather than the geometry of steel beams. The specimens with C-channel anchors showed the highest load-carrying capacity but the most drastic load reduction after the peak load. The specimens with Z-channel anchors showed a similar behavior to those with C-channel anchors but the load reduction occurred at a slightly slower rate. The load-carrying capacity was increased with the length of the Z- and C-channel anchors. The specimens with stud anchors reached the peak load at a slow rate and showed the most ductile behavior. The test results were compared with predictions by various design equations for steel anchors available in the literature, and the existing design equations for channel anchors with partial-length welding were considered applicable to design.

Sign in / Sign up

Export Citation Format

Share Document