| 1. |
- Abbu, Muthanna, et al.
(författare)
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The mechanical properties of lightweight (volcanic pumice) concrete containing fibers with exposure to high temperatures
- 2023
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Ingår i: Journal of the Mechanical Behavior of Materials. - : Walter de Gruyter. - 2191-0243. ; 32:1
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Tidskriftsartikel (refereegranskat)abstract
- Fires are considered one of the main risks leading to building collapse. Lightweight concrete comprises a variety of components, each of which has a distinct behavior under the effect of temperature change. A total of sixteen concrete mixtures were investigated in this paper. A reference mix of concrete comprising simply ordinary Portland cement and ten mixes having varying percentages of fine and coarse lightweight aggregates (pumice), which were replaced gravel and sand by fine pumice and coarse aggregates pumice by 20%, 40%, 60%, 80%, and 100%, respectively. In addition, the study focused on the effects of adding fibers to lightweight aggregate concrete mixtures. Polypropylene fibers, carbon fibers, and steel fibers were employed as fiber additions. The binary mixture had higher density than the remaining mixtures containing one substitute. The behavior of six concrete mixes in addition to the reference mix of ordinary concrete after exposure to temperatures 100, 250, 350 and 450 °C for two hours and then cooled in two ways (water and air) as well as examined directly and the results showed that the concrete mixes containing fiber better behavior compared to other mixtures, especially at high temperature. If left to cool in the air, the lightweight concrete containing Volcanic Pumice can recover its compression strength after being exposed to high temperatures.
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| 2. |
- Ibrahim, Mohammed Khaleel, et al.
(författare)
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3D FE modeling of cable-stayed bridge according to ICE code
- 2022
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Ingår i: Open Engineering. - : Walter de Gruyter. - 2391-5439. ; 12:1, s. 1126-1133
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the performance of a cable-stayed bridge by representing a model using the ANSYS program under the influence of a concentrated load and then comparing the results with the experimental results. One model used in the analysis was the Harp type 1, which used the length of the girder (4500mm), the height of the pylon (1480mm), and the depth of the flange on the girder (40mm). If cable-stayed bridges are constructed using the balanced cantilever method, the stability problem of the girder is more significant during the construction stage than at the initial state. In this study, to investigate the ultimate behavior of cable-stayed bridges, experimental and analytical studies were conducted for one model: Harp Type 1. At the limit state, several plastic hinges occurred, and the girders buckle along the entire span. Numerical analysis was conducted for the experimental model, the results of which showed good agreement with the experimental results. The influence of such effects on the analysis and the structural role of cable-stayed bridges has been detailed and examined in the study. The dimensions of the model were also compared with the ICE Code in terms of the height of the tower to the main space, and the back span to the main span ratio. It was close to standard specifications. A finite element procedure for the nonlinear analysis of cable-stayed bridges first set up and then detailed for the static deflection analysis of such bridges is carried out.
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