Wyniki wyszukiwania - Biblioteka Nauki

1

Experimental and theoretical research on large-diameter rock-socketed pile embedded depth

100%

Li Y. , Zhao J. , Xiong Y. , Wang Q.

Archives of Civil Engineering

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2021

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tom Vol. 67, nr 2

537--550

EN

A theoretical formula for large-diameter rock-socket depth is developed to support pail embedding in a large bridge pile foundation project. There is a horizontal additional stress concentration at the place where the soil around the rock-socketed pile meets the soil layer under the horizontal load. When the rock-socketed tip stress and bending moment of the pile are relatively small, the pile shows favourable embedment effect and the pile foundation can be considered safe. The function curve of soil resistance around the pile under the action of horizontal force was obtained by finite element analysis. The force characteristics reveal the depth of the largediameter rock-socketed pile under the horizontal load. As the rock-socketed pile rotates under the action of horizontal force, the rock mass resistance around the pile changes according to the cosine. The distribution of pileside soil resistance is proportional to the displacement and distributed according to the sine. A comprehensive correction coefficient of pile shaft resistance β is introduced to deduce the theoretical formula of the depth hr of the large-diameter rock-socketed pile embedded in the bedrock. It is verified through both experiments and numerical analysis.

2

Flexural behavior of square hollow steel-reinforced concrete members

100%

Ren Q. , Ding J. , Wang Q. , Liang H.

Archives of Civil and Mechanical Engineering

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2022

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tom Vol. 22, no. 1

art. no. e34, 2022

EN

This paper presents an experimental investigation on the flexural behavior of the square hollow steel-reinforced concrete (HSRC) members. A total of six specimens with different hollow ratios and steel tube ratios were prepared, and their failure modes, strain distributions, the mid-span deflection, and bending moment were recorded. The obtained results showed that the HSRC specimen fails in a ductile mode and no local buckling occurs in the inner steel tube. The increase of steel tube ratio leads to the improvements of the ultimate bending moment, the flexural stiffness and the ductility coefficient. The ultimate bending moment can be increased by 52.8% when the steel tube ratio increases from 0 to 2.96%. To expand the ranges of parameters, a finite element model (FEM) was developed and benchmarked against the test results from this study. Then, a parametric study was conducted to quantify various influential factors on the flexural behavior of the square HSRC members, and the key influential factors were further determined. Based on the parametric investigation, a simplified design method on the prediction of the ultimate bending moment for the square HSRC members was provided to account for the contribution of the incompletely full-section yielded steel tube, and the predicted results from the simplified design method were satisfactorily in accordance with the experimental and numerical results.

3

Seismic performance of concrete columns confined by high‑strength stirrups

88%

Hou C. , Zheng W. , Liu P. , Wang Q. , Qi S.

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2023

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tom Vol. 23, no. 2

art. no. e69, 2023

EN

The concrete columns confined by high-strength stirrups exhibited higher bearing capacity and better deformation ability. Based on the test results of concrete columns confined by high-strength stirrups under lateral cyclic loading, it is found that stirrup yield strength could not be used directly in calculating bearing capacity, because the high-strength stirrup could not yield at the peak point. Moreover, according to the seismic performance of a total of 49 sets of confined concrete columns from this paper and other 5 research papers, an easy-to-use model of skeleton curve is proposed by using a set of empirical equations to calculate the characteristic points of skeleton curve. Furthermore, based on the proposed model of skeleton curve, hysteretic rules are developed for the unloading and reloading stages by providing calculating formula of unloading stiffness and ignoring the effect of strength degradation. Finally, the proposed model of skeleton curve and hysteretic rules are verified and evaluated by comparing the calculated curves and experimental curves.

4

Numerical and theoretical research on spatial shear lag effect of self-anchored suspension bridge steel box girder

88%

Li Y. , He Y. , Bao L. , Sun B. , Wang Q.

Archives of Civil Engineering

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2021

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tom Vol. 67, nr 2

631--651

EN

The shear lag effect of the steel box girder section in a self-anchored suspension bridge was investigated in this study. Finite element analysis software Midas Civil was used to discretize the girder under analysis into space plate elements and establish a plate element model. The law of shear lag in the longitudinal direction of the girder in the construction and completion stages was determined accordingly. The shear lag coefficient appears to change suddenly near the side support, middle support, side cable anchorage area, and near the bridge tower support of the steel box girder under the imposed load. The most severe shear lag effect is located near the side support and near the side cable anchorage area. Steel box girder sections are simulated before and after system conversion to analyze the shear lag coefficient in the bridge construction stage. The results show that the shear lag coefficient markedly differs before versus after system conversion due to the different stress mechanisms. The finite element analysis results were validated by comparison with the results of an analysis via analogous rod method.