Experimental and Numerical Study of RC Square Members Under Unequal Lateral Impact Load

Author(s):  
Hussein Abas ◽  
Liu Yanhui ◽  
Khalil Al-Bukhaiti ◽  
Zhao Shichun ◽  
Dong Aoran
Author(s):  
Zheng Luo ◽  
Wang Yinhui

The pendulum impact tests were carried out on one RC frame column and four RC free-standing columns. The effect of axial compression ratio and reinforcement ratio on the impact resistance of columns were compared by means of dynamic time curves of framed and freestanding columns under impact. The test results show that with the same impact load, though the presence of axial loads can play a positive role (e.g., reducing the residual displacement), it may lead to more severe local damage. Also, compared with free-standing columns, the frame column can be considered as a protective structure for its greater lateral stiffness and stronger crashworthiness. The corresponding finite element models are developed,and the influence of the axial loads on cross section force responses under impact excitation is deeply explored. The axial loads can significantly affect the distribution of the moment, the shear force, and also the damage for the column.


2020 ◽  
Vol 148 ◽  
pp. 106546
Author(s):  
Jiafeng Song ◽  
Shucai Xu ◽  
Shengfu Liu ◽  
Han Huang ◽  
Meng Zou

Author(s):  
Xiufeng Liang ◽  
Jianmin Yang ◽  
Longfei Xiao ◽  
Xin Li ◽  
Jun Li

The importance of understanding air gap response and potential deck impact is well-known in the design stage of semi-submersible platform. The highly non-linear nature of wave elevation around large structures in steep waves makes it difficult to accurately predict wave field under the deck and wave run up along the columns. Present engineering tools for the prediction of air gap response generally based on simplified models. Even the models accounting for nonlinear wave diffraction is not free of uncertainties. A method adopted here couples a Navier-Stokes solver, VOF technique capturing violent free surface and DNV/Seasam predicting motions of moored semi-submersible platform. Air gap response at different locations of the hull was evaluated in predetermined irregular wave train. Wave run up was also measured by wave probes near the columns. Load cells were mounted under the deck of the platform to trace potential deck impact. The predetermined irregular wave train was simulated in a numerical wave tank and verified against physical tank results. Analysis of the air gap response, wave run up and impact loads on the semi-submersible platform were conducted.


2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Qixiang Yan ◽  
Zhixin Deng ◽  
Yanyang Zhang ◽  
Wenbo Yang

Impact loads generated by derailed trains can be extremely high, especially in the case of heavy trains running at high speeds, which usually cause significant safety issues to the rail infrastructures. In shield tunnels, such impact loads may not only cause the damage and deformation of concrete segments, but also lead to the failure of segmental joint bolts. This paper presents a numerical study on the failure behavior of segmental joint bolts in the shield tunnel under impact loading resulting from train derailments. A three-dimensional (3D) numerical model of a shield tunnel based on the finite element (FE) modelling strategy was established, in which the structural behavior of the segmental joint surfaces and the mechanical behavior of the segmental joint bolts were determined. The numerical results show that the occurrence of bolt failure starts at the joints near the impacted segment and develops along the travel direction of train. An extensive parametric study was subsequently performed and the influences of the bolt failure on the dynamic response of the segment were investigated. In particular, the proposed FE model and the analytical results will be used for optimizing the design method of the shield tunnel in preventing the failure of the joint bolts due to the impact load from a derailed HST.


2018 ◽  
Vol 9 (2) ◽  
pp. 37
Author(s):  
Yousry B. I. Shaheen ◽  
Ghada Mousa Hekal ◽  
Ahmed Khaled Fadel

The main objective of the following work is to inspect the effect of reinforcing metal mesh on the behavior of slabs with openings under impact loadings. Based on an earlier numerical study by Shaheen et al. (2017), slabs with mid-side openings revealed the worst behavior regarding to deflection and cracked pattern when subjected to impact loading compared to other slabs with different locations of openings. Hence, the present work focuses specifically on this type of slabs and the variation in their behavior when reinforced by welded or expanded metal mesh. Seven specimens were prepared and tested in Faculty of Engineering, Menoufia University, Egypt. Moreover, a FE model for the slabs was built using Abaqus 6.14 and verified against test results. It was found that expanded metal mesh had a significant effect on reducing deflection due to impact load as well as controlling of cracks in contrast with welded metal mesh.


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