Bending moment

About: Bending moment is a research topic. Over the lifetime, 14577 publications have been published within this topic receiving 158834 citations. The topic is also known as: bending moment.

Numerical modelling of centrifuge tests on tunnel–soil systems

Abstract: The number of tunnels in seismic regions has grown significantly in recent decades. It has usually been assumed that tunnels perform better than surface structures during seismic events. However, recent cases have shown that tunnels can be significantly damaged by seismic events. Thus, an evaluation of their response to earthquakes has become increasingly necessary. This paper presents a FEM blind prediction of centrifuge tests on a reduced scale tunnel. The main objective of the paper is to evaluate the numerical model that reproduces the response recorded in the centrifuge. The centrifuge tests involved a tunnel in dry sand. The numerical simulation was performed on the physical-scale model of the transverse direction of the tunnel, which is of prime importance, as it can show large stress–strain levels in the tunnel lining. The tunnel behaviour was assumed to be visco-linear-elastic, while the soil behaviour was assumed to be visco-elastic-perfectly plastic. The soil model parameters were calibrated on the basis of laboratory tests performed on the sand used for the test. The comparison between the experimental and numerical results is presented in terms of acceleration in the time and frequency domains. The experimental and numerical settlements of the sand surface and displacements of the sand-tunnel system, as well as the bending moments and hoop forces acting in the tunnel are also compared. Increments of the bending moments and hoop forces are also evaluated using the closed-form solution proposed by Wang (Seismic design of tunnels: a simple state-of-the-art design approach. Parson Brinckerhoff, New York, 1993) and Penzien (Earthq Eng Struct Dyn 29:683–691, 2000). A very good agreement between the experimental and numerical results is achieved in terms of horizontal acceleration time-histories and their Fourier spectra, as well as in terms of vertical displacements of the sand surface. Moderate differences exist between the experimental and numerical bending moments and hoop forces; experimental, numerical and analytical increments of the bending moments and hoop forces are in a quite good agreement with each other.

Shear wall with outrigger trusses on wall and column foundations

Abstract: A graphical method of analysis is presented for preliminary design of outrigger truss-braced high-rise shear wall structures with non-fixed foundation conditions subject to horizontal loading. The method requires the calculation of six structural parameters: bending stiffness for the shear wall, bending and racking shear stiffnesses for the outrigger, an overall bending stiffness contribution from the exterior columns, and rotational stiffnesses for the shear wall and column foundations. The method of analysis employs a simple procedure for obtaining the optimum location of the outrigger up the height of the structure and a rapid assessment of the influence of the individual structural elements on the lateral deflections and bending moments of the high-rise structure. It is concluded that all six stiffnesses should be included in the preliminary analysis of a proposed tall building structure as the optimum location of the outrigger as well as the reductions in horizontal deformations and internal forces in the structure can be significantly influenced by all the structural components. Copyright © 2004 John Wiley & Sons, Ltd.