Analysis of stress-strain state of hydrotechnical structure in operation modes

Abstract

In complex conditions of open sea and in areas with increased seismic activity, hydrotechnical structures must ensure stable and reliable operation throughout their entire operation. The stress-strain analysis is very important component of the design, the reconstruction and the operation of hydrotechnical structures, as it determines the reliability and the durability of their bearing elements, timely detection of critical areas can extend the operation of the object, and optimize repair costs. This is why the problem of analyzing the stress-strain state of bearing elements of hydrotechnical structures is of particular relevance in the modern engineering practice. The purpose of this analysis is to determine the maximum values of internal forces and displacements that arise in elements and joints of the hydrotechnical structure, taking into account real operating conditions. The object of this research is the hydrotechnical structure that represents the offshore stationary oil-production platform on piles, installed at the depth of 11 meters.The analysis was performed for two variants of the discrete idealized model of the platform: with the grillage foundation rigidly attached to a perfectly rigid support surface and with consideration of the elastic soil base and pile foundation. The analysis showed: the largest internal forces in both models occur in elements of upper sections of piles, spatial column trusses, and connections of columns with the superstructure;the localization of the largest displacements in both models occurs in nodes of the flambeau console and the communication mast, among nodes of main bearing structures – in nodes of the superstructure; in elements of the «rigid» model, the decrease in bending and torsional moments, shear forces, and the variable nature of the longitudinal force are observed compared to the corresponding elements of the «flexible» model;taking into account the foundation flexibility affects the stress-strain state of the structure significantly.