Study on Normal Section Bearing Capacity of Stone Arch Rib Enclosed by Reinforced Concrete

2012 ◽  
Vol 594-597 ◽  
pp. 1565-1568
Author(s):  
Jing Zhang ◽  
Yong Jiu Qian
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Analytical Method ◽  
Influence Factors ◽  
Test Results ◽  
Normal Section ◽  
Stress States

The mechanical behavior and failure mechanism of stone arch rib enclosed by reinforced concrete under different existed stress state is obtained by the failure test. Normal section bearing capacity effect of different stress states is studied by test results. Then an analytical method considering the influence factors is proposed to count normal section bearing capacity of stone arch rib enclosed by reinforced concrete.

Mechanical Study on Short Timber Columns Reinforced by Different Methods of FRP under Axial Compression

2013 ◽  
Vol 405-408 ◽  
pp. 968-971
Author(s):  
Wei Liang ◽  
Jiang Feng Dong ◽  
Qing Yuan Wang
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Compressive Stress ◽  
Axial Compression ◽  
Mechanical Behaviour ◽  
Test Results ◽  
Mechanical Study ◽  
Strain Relationship ◽  
Lateral Deformations

In this paper, the effect of different enwrapping methods on the mechanical behaviour of short timber columns were presented and analysed.Five timber columns reinforced by CFRP and AFRP with two enwrapping forms (hoop and spiral) were tested under the axial compressive.The failure mechanism of specimens, the load-displacement relationship and the load-strain relationship were analyzed. Test results showed that the reinforcement with FRP can obviously improve the compressive bearing capacity of the columns and the highest improve ratio is 57.5%. The compressive stress of specimens reinfoced with hooped FRP sheets is much higher than the ones with spiral method. And the lateral deformations of reinforced specimen is greatly constrained by FRP. In addition, the knags of the wood will affect the mechanical behavior of columns on a large extent.

scholarly journals Analysis and Modification of Methods for Calculating Axial Load Capacity of High-Strength Steel-Reinforced Concrete Composite Columns

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6860
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Yifan Wang ◽  
Xinran Wang ◽  
Qi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Slenderness Ratio ◽  
High Strength ◽  
Confinement Effect ◽  
Test Results ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Modified Formula

To investigate the applicability of the methods for calculating the bearing capacity of high-strength steel-reinforced concrete (SRC) composite columns according to specifications and the effect of confinement of stirrups and steel on the bearing capacity of SRC columns. The axial compression tests were conducted on 10 high-strength SRC columns and 4 ordinary SRC columns. The influences of the steel strength grade, the steel ratio, the types of stirrups and slenderness ratio on the bearing capacity of such members were examined. The analysis results indicate that using high-strength steel and improving the steel ratio can significantly enhance the bearing capacity of the SRC columns. When the slenderness ratio increases dramatically, the bearing capacity of the SRC columns plummets. As the confinement effect of the stirrups on the concrete improves, the utilization ratio of the high-strength steel in the SRC columns increases. Furthermore, the results calculated by AISC360-19(U.S.), EN1994-1-1-2004 (Europe), and JGJ138-2016(China) are too conservative compared with test results. Finally, a modified formula for calculating the bearing capacity of the SRC columns is proposed based on the confinement effect of the stirrups and steel on concrete. The results calculated by the modified formula and the finite element modeling results based on the confinement effect agree well with the test results.

Investigation of the effect of stress states on hydro-mechanical behaviors of reservoir rock under fluid injection

2021 ◽  
Author(s):  
Qi Li ◽  
Miao He ◽  
Michael Kühn ◽  
Xiaying Li ◽  
Liang Xu
Keyword(s):  
Stress State ◽  
Mechanical Behavior ◽  
Triaxial Compression ◽  
Reservoir Rock ◽  
Fluid Injection ◽  
Differential Stress ◽  
Mechanical Coupling ◽  
Injection Process ◽  
The Difference ◽  
Stress States

<p>Injecting fluid into the formation is an effective solution for improving the permeability and production of a target reservoir. The evaluation of economy and safety of injection process is a challenging issue faced in reservoir engineering [1-2]. As known, the relative magnitude and direction of the principal stresses significantly influence the hydro-mechanical behavior of reservoir rock during fluid injection. However, due to the limitations of current testing techniques, it is still difficult to comprehensively conduct laboratory injection tests under various stress conditions, e.g. triaxial extension stress states [3]. To this end, a series of numerical simulations were carried out on reservoir rock to study the hydro-mechanical changes under different stress states during fluid injection. In this modelling, the saturated rock is first loaded to the target stress state under drainage conditions, and then the stress state is maintained and water is injected from the top end to simulate the reservoir injection process. Particular attention is paid to the difference in hydro-mechanical changes under triaxial compression and extension stresses. This includes the difference of the pore pressure propagation, mean effective stress, volumetric strain, and stress-induced permeability. The numerical results demonstrate that the differential stress will significantly affect the hydro-mechanical behavior of target rock, but the degree of influence is different under the two triaxial stress states. The hydro-mechanical changes caused by the triaxial compression stress states are generally greater than that of extension, but the difference decreases with increasing differential stress, indicating that the increase of the differential stress will weaken the impact of the stress state on the hydro-mechanical response. This study can deepen our understanding of the stress-induced hydro-mechanical coupling process in reservoir injection engineering.</p><p>Keywords: Reservoir injection; Subsurface flow; Hydro-mechanical coupling; Stress state; Triaxial experiment modelling</p><p>[1] Li, X., Lei, X. & Li, Q. 2016. Injection-induced fracturing process in a tight sandstone under different saturation conditions. Environmental Earth Sciences, 75, 1466, http://doi.org/10.1007/s12665-016-6265-2</p><p>[2] Yang, D., Li, Q. & Zhang, L. 2016. Propagation of pore pressure diffusion waves in saturated dual-porosity media (II). Journal of Applied Physics, 119, 154901, http://doi.org/10.1063/1.4946832</p><p>[3] Xu, L., Li, Q., Myers, M., Tan, Y., He, M., Umeobi, H.I. & Li, X. 2021. The effects of porosity and permeability changes on simulated supercritical CO<sub>2</sub> migration front in tight glutenite under different effective confining pressures from 1.5 MPa to 21.5 MPa. Greenhouse Gases: Science and Technology, http://doi.org/10.1002/ghg.2043</p>

Analysis and Prospect of Size Effect on Normal Section Bearing Capacity of Reinforced Concrete Column

2013 ◽  
Vol 351-352 ◽  
pp. 422-426
Author(s):  
Yong Ping Xie ◽  
Lei Jia ◽  
Gang Sun
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Theoretical Analysis ◽  
Size Effect ◽  
Bearing Capacity ◽  
Concrete Column ◽  
Concrete Compressive Strength ◽  
Reinforced Concrete Column ◽  
Normal Section

With the development of modern constructional technique, more attention on the size effect is paid by academics and engineers. The normal section bearing capacity of Reinforced Concrete Column is analyzed by eccentrically compressed theory firstly. The size effect on normal section bearing capacity of reinforced concrete column is obtained by theoretical analysis and experimental summary. The size effect formula of concrete compressive strength is proposed. Finally, a research thinking of size effect on bearing capacity is suggested.

scholarly journals FLEXURAL REINFORCED CONCRETE ELEMENTS NORMAL SECTION BEARING CAPACITY EVALUATION IN FRACTURE STAGE

2017 ◽  
Vol 9 (2) ◽  
pp. 70-78 ◽  
Author(s):  
Justas SLAITAS ◽  
Zbynek HLAVAC ◽  
Arnoldas ŠNEIDERIS
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Crack Depth ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Assessment Process ◽  
Reinforced Concrete Structures ◽  
Compression Zone ◽  
Normal Section

This article examines flexural reinforced concrete structures condition assessment process in existing buildings on the stage where the reinforcement stress is between the yield and the tensile strength. The research is made on V. Jokūbaitis proposed methodology directly measuring the compression zone height, allowing us to evaluate the behavior of reinforced concrete beam fracture sufficiently precisely. This paper confirms the hypothesis that, when reinforcement reaches yielding stress, elastic strain dominates in concrete‘s compression zone and it is reasonable to use triangular concrete compression zone diagram, without tensile concrete above crack evaluation. The methodology of reinforced concrete structures bearing capacity assessment according to limit normal section crack depth is proposed. There is established connection between bending moments, when reinforcement achieve yielding stress and tensile strength, which allows us to decide about structures bearing capacity reserve. The results are confirmed with experimental studies and calculated values obtained by methodologies based on different reduced stress diagrams of concrete‘s compressive zone.

Test Analysis for RC Beams Strengthened with Externally Bonded Prestressed CFRP Laminates

2008 ◽  
Vol 385-387 ◽  
pp. 41-44 ◽  
Author(s):  
Shi Qi Cui ◽  
Jin Shan Wang ◽  
Zhao Zhen Pei ◽  
Zhi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Test Results ◽  
Test Analysis ◽  
Cfrp Laminates ◽  
Cfrp Sheet ◽  
Externally Bonded

Reinforced concrete beams strengthened with externally bonded CFRP sheet and prestressed CFRP are analyzed in this paper. Crack developments and displacements with curvatures for different beams are analyzed. Test results show that prestressed CFRP are able to control the development of macro cracks in concrete and prestressed CFRP is an effective method to improve the toughness of concrete, reduce strengthening cost and meanwhile enhance bearing capacity of concrete beams.

Ultimate Bearing Capacity of Headed Studs in Tensile Concrete Slab

2010 ◽  
Vol 163-167 ◽  
pp. 11-15
Author(s):  
Wen Qi Hou ◽  
Mei Xin Ye ◽  
Ye Zhi Zhang
Keyword(s):  
Bearing Capacity ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Influence Factors ◽  
Ultimate Bearing Capacity ◽  
Test Method ◽  
Test Results ◽  
Steel Girder ◽  
Push Out ◽  
Main Influence

Abstract. In the presented paper, reverse push-out test method was put forward and applied in the ultimate bearing capacity experiments of studs with concrete slab in tension. Ultimate bearing capacity experiments were carried out on 22 reverse push-out specimens composed of C50 or C40 concrete, 14MnNbq steel girder and Φ22studs. Results showed that ultimate bearing capacity of studs, pu, in tensile concrete slab is controlled by concrete failur, concrete strength, studs arragement and reinforcement ratio are the main influence factors of pu. Compared with that in compressive concrete, pu of Φ22 studs in tensile concrete is reduced about 30% averagely. According to the test results, a fitted load-slip relationship curve and a regression formula of pu for studs in tensile concrete were put forward, calculated results were in good agreement with the test results.

Experimental Study of Mechanical Behavior of Concrete Filled Steel Tubular Short Columns after Fire

2010 ◽  
Vol 168-170 ◽  
pp. 674-678 ◽  
Author(s):  
Ming Zhou ◽  
Xin Tang Wang ◽  
Wan Zhen Wang
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Test Results ◽  
Fire Load ◽  
Ordinary Concrete ◽  
Short Column ◽  
Short Columns ◽  
Maximum Value ◽  
Bearing Load ◽  
Strength And Ductility

Mechanical behavior and bearing capacity of ordinary concrete filled steel tubular short column (NCSSC) and ceramsite concrete filled steel tubular short column (CCSSC) subjected to fire load are experimentally investigated. Effect of the parameters, such as the maximum value of fire temperatures, fire duration on the strength and ductility of the two types of specimens were especially discussed. The test results show that both of the specimens of NCSSC and CCSSC after fire have higher bearing capacity and better ductility, there was no descent segment in load-displacement curves of the most specimens after the fire load was subjected, and even the case that bearing load increased again after descent segment arose. It was concluded that the maximum response temperature of specimens and fire duration time has great effect on the axial bearing capacity of concrete-filled steel tubular short columns subjected to fire, and there is a turning point of temperature for the influence.

Experimental Study on Strengthening with Bonded Steel Angles for Reinforced Concrete Columns after Fire

2013 ◽  
Vol 639-640 ◽  
pp. 1120-1126
Author(s):  
Guo Feng Wang ◽  
Kai Yu ◽  
Jun Hua Li ◽  
Dong Liang Qiu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Fire Damage ◽  
Tension Zone ◽  
Test Results ◽  
Reinforced Concrete Columns ◽  
Standard Fire ◽  
Eccentric Compression ◽  
Steel Angles

The mechanical properties of fire-damage reinforced concrete columns strengthened with bonded steel angles were studied. Nine specimens were tested, including three normal temperature controlled columns, six heated under ISO834 standard fire. After exposure to fire, three of the six were rehabilitated with the bonded steel angles. It was shown by test results that the destructive properties of reinforced concrete columns with bonded steel angles may change and the small eccentric compression specimens may become large eccentric compression due to the steel angles increased the amount of steel in the tension zone of the specimen. In this research, compared with these under normal temperature, the bearing capacity of specimens which were exposure to fire was only ranged from 0.25 to 0.37 times. But the bearing capacity of specimens rehabilitated by the bonded steel angles can increase to 2.86 to 4.04 times of the originals and it can reach to the level of that in normal temperature.

Low Cycle Fatigue Crack Initiation of Rotating Structures Under Biaxial Stress States

2009 ◽  
Author(s):  
Chao Zhang
Keyword(s):  
Stress State ◽  
Crack Initiation ◽  
Low Cycle Fatigue ◽  
Cyclic Stress ◽  
Biaxial Stress ◽  
Test Results ◽  
Primary Stress ◽  
Biaxial Stress State ◽  
Fatigue Characteristics ◽  
Stress States

Rotating structures can experience biaxial stress states with a wide range of biaxiality ratios on structure surfaces. Low cycle fatigue (LCF) crack initiation in such conditions demonstrates different fatigue characteristics in terms of crack orientation, fatigue life, etc. The biaxial stress states can be categorized into two types: in-phase and out-of-phase under which fatigue characteristics can be significantly different according to rig test results. This paper presents an investigation of LCF crack initiation under in-phase and out-of-phase biaxial stress states based on rig test results of a nickel alloy. The crack orientations are reviewed and discussed at different stress states. Relations of biaxial LCF life debit factor vs biaxiality ratio are derived (the debit factor is defined as a ratio of the LCF life at a biaxial stress state to the LCF life at corresponding uniaxial stress state which has same cyclic and mean stresses as the primary cyclic and mean stressees of the biaxial stress state). The rig test results showed that the crack orientation is usually normal to the primary stress vector under in-phase biaxial stress states but is inclined to the primary stress vector under out-of-phase stress states. As per the derived biaxial LCF life debit factors, the LCF life was found to be slightly reduced with increasing biaxiality ratios under in-phase biaxial stress states but significantly reduced under out-of-phase biaxial stress states compared with corresponding uniaxial primary stress states. The equivalent cyclic stress fatigue criterion is also employed to theoretically model the biaxial LCF life debit factor under in-phase biaxial stress states. The hydrostatic cyclic stress is included in the equivalent cyclic stress in order to take into account the hydrostatic cyclic pressure effects. The equivalent cyclic stress in the criterion can physically reflect the materials’ ductility reduction under in-phase multiaxial stress states.

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