Experimental and Analytical Study on Ultimate Load Capacity of RC Columns in the Subway Stations Under High-Temperature Gas Fume Effects

2016 ◽  
Vol 16 (2) ◽  
pp. 147-154
Author(s):  
S. Q. Lian ◽  
Z. R. Wang ◽  
Q. S. Wang ◽  
L. Wang ◽  
J. J. Jiang
Keyword(s):  
High Temperature ◽  
Analytical Study ◽  
Ultimate Load ◽  
Load Capacity ◽  
Ultimate Load Capacity ◽  
Rc Columns ◽  
Subway Stations ◽  
High Temperature Gas

scholarly journals Enhancing Stability of Thin-Walled Short Steel Channel Using CFRP under Eccentric Compression

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Hongyuan Tang ◽  
Canjun Wang ◽  
Ruijiao Wang
Keyword(s):  
Analytical Study ◽  
Ultimate Load ◽  
Load Capacity ◽  
Local Buckling ◽  
Fiber Reinforced Polymer ◽  
Actual Behavior ◽  
Thin Wall ◽  
Ultimate Load Capacity ◽  
Reinforced Polymer ◽  
Global Buckling

This paper presents the experimental and analytical results of eccentrically loaded short cold-formed thin-wall steel channels strengthened with transversely oriented carbon fiber reinforced polymer (CFRP) strips around their web and flange. Seven specimens, each 750 mm long, were fabricated; the main parameters were the number of CFRP plies (one or two) and the space between the CFRP strips (50, 100, or 150 mm). The application of the CFRP strips results in increases in ultimate load capacity and, with the exception of the most heavily reinforced (2 plies at 50 and 100 mm), local buckling was observed prior to global buckling. To extend and better understand the experimental work, a companion analytical study was conducted. Comparisons between experimental observations and computed results show that the analyses provided good correlation to actual behavior. In addition, the numerical results explained the observed phenomenon that flange local buckling was constrained to regions between the CFRP strips.

scholarly journals Experimental Behavior of Cracked Reinforced Concrete Columns Strengthened with Reinforced Concrete Jacketing

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2832 ◽  
Author(s):  
Ahmed Mohamed Sayed ◽  
Mohamed Mohamed Rashwan ◽  
Mohamed Emad Helmy
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Ultimate Load ◽  
Load Capacity ◽  
Ultimate Load Capacity ◽  
Rc Columns ◽  
Material Efficiency ◽  
Strengthening Technique ◽  
New Variables ◽  
Safety Limit

Reinforced concrete (RC) columns often need to be strengthened or rehabilitated to allow them to carry the loads applied to them. In previous studies, RC columns have been strengthened by jacketing, without considering the occurrence of cracking. In this study, the behavior of RC columns strengthened externally by jacketing after cracking is analyzed. The accuracy of the existing models was verified by analyzing the performance of fifteen RC columns with different cross-sections to determine the effect of new variables, such as the column size, amount of steel reinforcement, and whether the column was cracked or not, on the effectiveness of strengthening. The analysis demonstrated that this strengthening technique could effectively improve both the ductility and strength of RC column cross-sections. The results indicate that the model suggested by the ACI-318 code can predict the ultimate load capacity of RC columns without strengthening, or strengthened by RC jacketing before or after cracking, with higher accuracy and material efficiency. The RC columns without strengthening met the safety limit of the ACI-318 model. However, for strengthened columns, a reduction coefficient must be used to enable the columns to meet the safety limit, with values of 94% and 76% for columns strengthened before and after cracking, respectively. Furthermore, strengthening after cracking affects the ultimate load capacity of the column, with 15.7%, 14.1%, and 13.5% lower loads for square, rectangular, and circular columns than those strengthened before cracking, respectively.

Analysis on Ultimate Load Capacity of Cylinder With Local Discontinuity Under High Temperature Gradient

2014 ◽  
Author(s):  
Yuebing Li ◽  
Jianwei Zhu ◽  
Shiyi Bao ◽  
Zengliang Gao
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Ultimate Load ◽  
Load Capacity ◽  
Severe Accident ◽  
Ultimate Load Capacity ◽  
High Temperature Gradient ◽  
Accident Management ◽  
Cylinder Model ◽  
Local Discontinuity

A severe accident management concept, known as ‘in-vessel retention (IVR)’, is widely used in advanced pressurized water reactor, such as AP600, AP1000, and so on. The severe accident management strategy is to flood the reactor cavity, submerging the reactor pressure vessel (RPV). In such condition, the temperature on the inside of RPV may exceed the melting point (about 1327 °C) of RPV material, and results in the localized wall thinning. On the outside, the temperature is remained at about 127 °C, by assuming the flow regime is kept to be nucleate boiling. So it will form a high temperature gradient on the wall, and caused high thermal stress. It will bring about the local discontinuity on the PRV wall because of the wall molten under the elevated temperature. A cylinder model is established to simulate the local discontinuity. The model is composed of the cylinder with the same external radius, but different wall thickness in the local discontinuity zone. Two elastic perfectly plastic models are used to analyze the stress and strain distributions on the wall and ultimate load capacity, based on the hot tensile curves and isochronous stress-strain curves at 100 hour with the change of temperature. The effect of local discontinuity is discussed, under the case of high temperature gradient and internal pressure. The results show that the Mises stress on the whole wall-thickness in the region of local discontinuity will achieve yield stress, under the high thermal stress. Appling internal pressure, the stress decreases in the zone of local discontinuity. The weakest link takes place in the thin segment of the cylinder model, and the ultimate pressure is obtained.

scholarly journals Flexural Behavior of Unbounded Pre-stressed Beams Modified With Carbon Nanotubes under Elevated Temperature

2019 ◽  
Vol 5 (4) ◽  
pp. 856-870 ◽  
Author(s):  
Amr H. Badawy ◽  
M. S. El-Feky ◽  
Ahmed Hassan ◽  
Hala El-kady ◽  
L. M. Abd-El Hafez
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
Elevated Temperature ◽  
Prestressed Concrete ◽  
Ultimate Load ◽  
Load Capacity ◽  
Test Method ◽  
Flexural Behavior ◽  
Tension Zone ◽  
Ultimate Load Capacity

Since fire is one of the common reasons for rehabilitation and reconstructions during the service life of a building, it is necessary to assess the elements structural and technical conditions. The objective of the present paper is to investigate the flexural behavior in bending for unbounded full pre-stressed beams with and without the incorporation of carbon nanotubes (CNTs) under the exposure to elevated temperature in comparison with non-pre-stressed beams. The test Method was divided into two major stages where the principal stage’s goal was considering the flexural behavior of fully and non-prestressed concrete beams containing CNT of 0 and 0.04% as cement replacement at ambient temperature. In the second stage, a typical group of beams was prepared and the flexural behavior was explored under the exposure to temperature of 400ºC, for 120 minutes. The major findings upon monitoring the failure mechanisms, ultimate load capacity, and deflection at critical sections, was that the CNT had shown a significant impact on the behavior and extreme resistance of fully and non-prestressed normal concrete. With CNT beams also exhibited higher imperviousness to high-temperature than that of the normal beams. Finally the significant Improvement was that the ultimate load of the non-pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 13%, while the ultimate load of the fully pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 21% as compared to the same beam without CNT, respectively. For the non-pre-stressed beams, the load capacity of the beam with CNT after exposure had a similar load capacity as the beam without CNT before exposure to high temperature.

Discussion of “Ultimate Load Capacity of Arch Dams”

1967 ◽  
Vol 93 (3) ◽  
pp. 259-267
Author(s):  
Marek Janas ◽  
Lance A. Endersbee ◽  
M.L. Juncosa ◽  
K.V. Swaminathan ◽  
A. Rajaraman
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
Ultimate Load Capacity ◽  
Arch Dams

Performance of Reinforced Concrete Beams with Multiple Openings

2020 ◽  
Vol 857 ◽  
pp. 162-168
Author(s):  
Haidar Abdul Wahid Khalaf ◽  
Amer Farouk Izzet
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Ultimate Load Capacity ◽  
Concentrated Load ◽  
Simply Supported ◽  
Group I

The present investigation focuses on the response of simply supported reinforced concrete rectangular-section beams with multiple openings of different sizes, numbers, and geometrical configurations. The advantages of the reinforcement concrete beams with multiple opening are mainly, practical benefit including decreasing the floor heights due to passage of the utilities through the beam rather than the passage beneath it, and constructional benefit that includes the reduction of the self-weight of structure resulting due to the reduction of the dead load that achieves economic design. To optimize beam self-weight with its ultimate resistance capacity, ten reinforced concrete beams having a length, width, and depth of 2700, 100, and 400 mm, respectively were fabricated and tested as simply supported beams under one incremental concentrated load at mid-span until failure. The design parameters were the configuration and size of openings. Three main groups categorized experimental beams comprise the same area of openings and steel reinforcement details but differ in configurations. Three different shapes of openings were considered, mainly, rectangular, parallelogram, and circular. The experimental results indicate that, the beams with circular openings more efficient than the other configurations in ultimate load capacity and beams stiffness whereas, the beams with parallelogram openings were better than the beams with rectangular openings. Commonly, it was observed that the reduction in ultimate load capacity, for beams of group I, II, and III compared to the reference solid beam ranged between (75 to 93%), (65 to 93%), and (70 to 79%) respectively.

scholarly journals Experimental Study on the Effect of Heel Plate Length on the Structural Integrity of Cold-formed Steel Roof Trusses

2018 ◽  
Vol 65 ◽  
pp. 08010
Author(s):  
Je Chenn Gan ◽  
Jee Hock Lim ◽  
Siong Kang Lim ◽  
Horng Sheng Lin
Keyword(s):  
Ultimate Load ◽  
Structural Integrity ◽  
Load Capacity ◽  
Local Buckling ◽  
Ultimate Capacity ◽  
Ultimate Load Capacity ◽  
Plate Length ◽  
Roof Truss ◽  
Cold Formed Steel ◽  
Structural Failures

Applications of Cold-Formed Steel (CFS) are widely used in buildings, machinery and etc. Many researchers began the research of CFS as a roof truss system. It is required to increase the knowledge of the configurations of CFS roof trusses due to the uncertainty of the structural failures regarding the materials and rigidity of joints. The objective of this research is to investigate the effect of heel plate length to the ultimate load capacity of CFS roof truss system. Three different lengths of heel plate specimens were fabricated and subjected to concentrated loads until failure. The highest ultimate capacity for the experiment was 30 kN. The results showed that the increment of the length of the heel plate had slightly increased the ultimate capacity and strain. The increment of the length of the heel plate had increased the deflection of the bottom chords but decreased the deflection of the top chords. Local buckling of top chords adjacent to the heel plate was the primary failure mode for all the heel plate specimens.

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