Optimized Foundation Design in Geotechnical Engineering

The design of foundations constitutes a major step for each civil engineering structure. Indeed, the stability of those structures relies on cost-effective and adequately designed foundation solutions. To come up with an optimized design of a foundation, the geotechnical study passes several steps: the geotechnical survey including in situ and laboratory tests, the synthesis of geotechnical parameters to be considered for the design, and the suggestion of foundation solution avoiding over estimated cost and ensuring suitable method of execution. In this chapter, the three currently practiced categories of foundation are briefly introduced. Then, two illustrative Tunisian case histories are analyzed to explain, first, when the practiced foundation solution was inadequately chosen how a non-cost-effective solution can be avoided, and second, why an unsuitable foundation solution can lead to the stopping of the structure functioning and then how to proceed for the design of retrofit solution to be executed for restarting the functioning of the structure.

Earthquake Resistant Design

In the long history of mankind's existence, nature's forces have influenced human existence to a great extent. Of all natural disasters, the least understood and most destructive are earthquakes. Their claim of human lives and material losses constantly force people to search for better protection, still a great challenge for engineers and researchers worldwide. Although important progress has been done in understanding seismic activity and developing buildings technology, a better way of protecting buildings on large scale is still in search. The essential features of earthquake resistance structure are stable foundation design, regularity, ductility, adequate stiffness, redundancy, and ruggedness. The chapter focuses on increasing the knowledge dictum of earthquake resistant design and discusses the various sorts of issues and challenges. It also presents a wide view on optimization techniques that are required to be done in the latest technology currently in practice so as to achieve the optimum design techniques.

Wind Loads on Structures, and Energy Dissipation Systems Optimization

Wind has a great impact on civil structures. It is considered a dynamic and random phenomena and it plays an important role in the design of tall structures. Existing buildings with certain height must resist wind effect. Many researchers have developed theories and schemes that consider more thoroughly wind components and the influence of its turbulence on buildings. It is known that any structure inherently dissipates and absorbs energy due to external loads thanks to its inherent damping. In order to improve this capacity and limit structural damage, fluid viscous dampers are commonly used for structural protection; they have confirmed their efficiency and reliability. Many researchers have investigated their effect by inserting them in the structure; some of the optimization methods for the design of these dampers previously used will be discussed. Finally, an effective method for optimal design of additional dampers will be illustrated by an example and discussion.

Improvement of Continuity Between Industrial Software and Research One by Object-Oriented Finite Element Formulation of Shell and Plate Element

This chapter shows, through the example of the addition of a plate and shell element to freeware FEM-object, an object-oriented (C++) finite element program, how object-oriented approaches, as opposed to procedural approaches, make finite element codes more compact, more modular, and versatile but mainly more easily expandable, in order to improve the continuity and the compatibility between software of research and industrial software. The fundamental traits of object-oriented programming are first briefly reviewed, and it is shown how such an approach simplifies the coding process. Then, the isotropic shell and orthotropic plate formulations used are given and the discretized equations developed. Finally, the necessary additions to the FEM-object code are reviewed. Numerical examples using the newly created plate membrane plate element are shown.

Using Diffusion Model for Prediction and Optimization of Drying Process of Building Material

The aim of this chapter is to confirm the possibility of using the simple diffusion model to predict the behavior of a building material during the application of drying process under variable operating conditions. This approach can be considered as a simulation of the effect of the variable climatic conditions on the building material. During this research, the thermo-physical properties of the tested material as well as the drying air are considered as variable and changing with the operating conditions. Accordingly, diffusion coefficient is determined experimentally and is considered as variable with the temperature and the humidity and represented as function of the wet bulb temperature. Two sorts of conditions are tested: constant flux and convective flux. Furthermore, two types of changes are also tested: sudden changes and progressive changes of the drying conditions. The results of the study are mainly represented by the drying curves or the drying kinetics.

Optimization of Soil Structure Effect by the Addition of Dashpots in Substratum Modelization

Soil structure interaction can significantly affect the behavior of buildings subjected to seismic attacks, wind excitation, and other dynamic loading types. Different researches were developed in the last decade demonstrating the importance of taking account of soil properties and its effect in changing the behavior of the structures. It is common practice to analyze the structures assuming a fixed base, but this approach is not appropriate for the reason that neglecting the soil parameters such as the stiffness and the damping affect the behavior of the structure. Therefore, the nonlinear static approach provided the nonlinear response behavior of a structure for different types of soil. In this chapter, the authors will discuss some proposed methods in taking account of soil-structure interaction that must be considered from the very beginning of the design process and its impact on the structural behavior optimization by adding springs and dashpots to reproduce the soil behavior.

Optimization of Condensed Stiffness Matrices for Structural Health Monitoring

This chapter aims to develop a system identification methodology for determining structural parameters of linear dynamic systems, taking into consideration practical constraints such as insufficient sensors. Based on numerical analysis of measured responses (output) due to known excitations (input), structural parameters such as stiffness values are identified. If the values at the damaged state are compared with the identified values at the undamaged state, damage detection and quantification can be carried out. To retrieve second-order parameters from the identified state space model, various methodologies developed thus far impose different restrictions on the number of sensors and actuators employed. The restrictions are relaxed in this study by a proposed method called the condensed model identification and recovery (CMIR) method. To estimate individual stiffness coefficient from the condensed stiffness matrices, the genetic algorithms approach is presented to accomplish the required optimization problem.

Offshore Structures

Fire will always be a major threat to the offshore structure as oil and gas always passes through the installation. The design against accidental fire situation should be included in the structural design of offshore structures in collaboration with safety engineers. The design of offshore structures for fire safety involves considering fire as a load condition, assessment of fire resistance, use of fire protection materials, and so on. This chapter presents a methodology that will enable an engineer to design an offshore structure to resist fire. It aims to highlight the major requirements of design and to establish a common approach in carrying out the design.

Optimization of Single Row Layout in Construction Site Planning

Several heuristics algorithms can be employed to solve single row layout in construction site planning. Firstly, this chapter builds Tabu Search to deal with the problem. Other heuristics methods which are genetic algorithm (GA) and estimation distribution algorithm (EDA) are also developed against Tabu Search. A comparative study is performed to test the effectiveness and efficiency of the algorithms. The statistical test, ANOVA followed by the t-test, compares the results of the three algorithms. Then, the pros and cons of using the algorithms are stated.