Reliable H∞ control for discrete-time piecewise linear systems with infinite distributed delays

In this paper, the reliable H∞ control problem is investigated for discrete-time piecewise linear systems with time delays and actuator failures. The time delays are assumed to be infinitely distributed in the discrete-time domain, and the possible failure of each actuator is described by a variable varying in a given interval. The aim of the addressed reliable H∞ control problem is to design a controller such that, for the admissible infinite distributed delays and possible actuator failures, the closed-loop system is exponentially stable with a given disturbance attenuation level γ. The controller gain is characterized in terms of the solution to a linear matrix inequality that can be easily solved by using standard software packages. A simulation example is exploited in order to illustrate the effectiveness of the proposed design procedures

A Case History of Super-Large Scale Bridge Pile Foundation in Soft Soil

The Sutong Yangtze River Bridge is the longest cable-stayed bridge in the world with main span of 1088 m. The pile cap is 113.8 m by 48.1 m by 13.3 m under each pylon and the foundation is super-long large-diameter drilled pile groups consisting of 131 piles with the length of 114/117 m and the diameter of 2.8/2.5m. This paper presents the static loading tests on single piles, centrifugal model tests on pile groups, finite element analysis, cap model tests and field monitoring for the super-large scale pile foundation. The results show that: the super-long large-diameter bored pile of Sutong Bridge is floating piles, and it is difficult for the resistance at pile bottom to play. based on the comprehensive consideration of theoretical calculation, centrifugal model tests and finite element analysis, the pile group effect coefficient of the Sutong Yangtze Bridge is 0.82. The pile-head load distribution of pile foundation under main bridge pylon presents a “W” shape, which is larger at both the edges and intermediate connection and smaller at other position of pylon. According to the results of cap model tests, the soften-coordinated spatial truss model was suitable for the stress analysis of cap. The calculated results agree well with the field monitoring results