3-dimensional numerical simulations of rock bolt pullout tests of Himalayan region

Hegde Amarnath and Sitharam T.G.

This study deals with the results of the field tests and the 3-dimensional numerical simulations of the pullout tests on fully grouted rock bolts. The field pullout tests were carried out at Chenab bridge site(Jammu and Kashmir) in the Himalayan region of Northern India. 3-dimensional numerical studies were also carried out to enhance the understanding about the pullout behavior of the rock bolts. The numerical simulations were carried out using Fast Lagrangian Analysis of Continua in 3D (FLAC3D). The rock bolt was modeled using the modified pile structural element available in FLAC3D against to the conventional approach of using the cable structural element. Measured axial forces from the numerical model were within 1% of the field pullout test results. The real time measurement of the skin friction suggested that the skin friction values increase linearly with the bolt extension. The maximum skin friction and the bending moments were observed at the top portion of the bolt near to the point of application of the load. In addition, the post peak failure modes of the rock bolt namely, displacement weakening and the tensile rupture were also investigated. Results revealed that the tensile rupture results in the sudden failure of the rock bolts.

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The Stiffness Behaviour of Infilled Frames on the influence of Different Infill and Interface Materials under Static Loading

Muthukumar S., Thirumurugan V. and Satyanarayanan K.S.

The objective of this study is to investigate the behaviour of Infilled Reinforced Cement Concrete (RCC) square frames using two different infill materials namely Conventional burnt clay bricks and Autoclaved aerated concrete (AAC) blocks with two different interface materials namely cement mortar and pneumatic interface under static diagonal loading by Experimental, Theoretical and Numerical approach. The experimental results on initial stiffness, cracking and ultimate load capacities were verified using numerical and existing theoretical model. The results indicate the potential of alternate interface material like pneumatic medium for alleviation of possible earthquake disaster due to stiffness irregularity arising out of placing infills symmetrically and unsymmetrically in a typical bare frame.

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