Damage Evolution of Underground Structural Reinforced Concrete Small-Scale Static-Loading Experiments
Small-scale RC models of both piles and tunnel duct s were produced as mockups of reality and loaded under soil confinement conditionsto investigate the damage evolution of structural RC interacting with soil. Experimental v erifications usinga 3D nonlinear FE analysis program called COM3D, which was developed at the University of Tokyo, are introduce d. This analysis has been used in practice for seismic performance a ssessment of underground ducts and in-ground LNG storage tanks in consideration of soil-structure interactionunder static and dynam ic loading. Varying modes of failure of RCpilessubjected to different m agnitudes of soil confinement were successfully reproduced in the proposed small-scale experiments and numerically simulated as well. Analytical simulation was applied to RC tunnel mockups under a wide variety of depth and soil confinement conditions, and reasonable matchin g was confirmed.
RC pile–soil interaction analysis using a 3D‐finite element method with fibre theory‐based beam elements
To evaluate the overall response of a structural system including its foundation and surrounding soil, an equivalent finite element model with reduced degrees of freedom using fibre theory‐based beam element was proposed. The proposed model was based on investigations of the subgrade soil reaction of a single‐layer model, and was verified for the cyclic behaviour of a laterally loaded single RC pile in terms of the load–displacement relationship, pile deformation, and soil pressures on the pile surface. Also investigated was the effect of the interfacial element between pile and soil on the behaviour of the laterally loaded pile. Copyright © 2006 John Wiley & Sons, Ltd.
MECHANICAL BEHAVIOR OF PILE FOUNDATIONS SUBJECTED TO CYCLIC LATERAL LOADING UP TO THE ULTIMATE STATE
Pile foundations in a soft ground will usually be subjected to lateral cyclic loading during earthquakes. In a major earthquake, it is reasonable to think that the mechanical behavior of the pile foundation and the surrounding ground is nonlinear. In recent years, the limit state design method has become predominant in the design of foundations for railway bridges and other structures. Investigations of the mechanical behavior of pile foundations subjected to lateral cyclic loading up to the ultimate state, therefore, are very important in providing evidence for the design method. In this paper, field tests on a pile foundation, composed of cast-in-place reinforced concrete piles and subjected to oneside cyclic lateral loading up to the ultimate state, are simulated with the three-dimensional elasto-plastic finite element analysis (DGPILE-3D). In the numerical analysis, particular attention is paid to the stress-strain relation of the soil which, to the author's point of view, plays a dominant role in the mechanical behavior of the pile foundation. Such constitutive models as the Drucker-Prager model, Cam-clay model, and tij model are adopted for the analysis in order to find the differences in the results due to the application of different constitutive models. Based on the analysis, the authors try to provide an applicable numerical way of evaluating the mechanical behavior of a pile foundation subjected to cyclic lateral loading at the ultimate state.