Optimum Design of Reinforced Concrete Columns

In the design of reinforced concrete (RC) columns, ductility is provided by allowing yielding of steel in the part of section under tensile stresses. This situation cannot be provided for RC columns since sections of columns are generally under compressive stresses resulting from axial loading including weight of all upper stories, flexural moments, and shear forces. To practically provide ductility, axial force is limited, and stirrups are densely designed. These rules are given in design regulations and must be checked during optimization. In this chapter, an optimum design methodology for biaxial loaded column is presented. Uniaxial loaded column methodology is given with the computer code. Finally, the slenderness effects are presented via ACI 318: Building code requirements for structural concrete and optimum results are given for several numerical cases using various metaheuristic algorithms.

Optimum Design of Post-Tensioned Axially-Symmetric Cylindrical Reinforced Concrete Walls

In this chapter, an optimization methodology for design of post-tensioned axially symmetric cylindrical reinforced concrete (RC) walls is presented. The objective of optimization is the minimization of total material cost of the wall including concrete, reinforced bars, post-tensioned cables, and form work required for wall and application of the post-tensioning. The optimized values are wall thickness, compressive strength of the concrete, locations and intensities of the post-tensioned loads, the diameter of the reinforcement bars (rebars), and distance between rebars. The optimization process employs the superposition method (SPM) for the analyses of the wall, and the design constraints are defined according to ACI-318: Building code requirements for structural concrete.

Optimum Design of Carbon Fiber-Reinforced Polymer for Increasing Shear Capacity of Beams

For reinforced concrete (RC) structures, retrofit of structures are needed to be done for several situations. These situations include the renovation of structure by adding new components (floors or extension) and elimination of safety risks (resulting from unforeseen effects - forces and durability). Most retrofit methods for RC structures need destruction of existing members and hard work on increasing of existing section dimension and reinforcements. Whereas, using carbon fiber reinforced polymer (CFRP) strips is an easy option to increase the flexural moment or shear capacity of RC members without destruction. In that case, the use of the structure is provided during the application. In this chapter, the optimum design of CFRP strips is presented for increasing the insufficient shear capacity of RC beams. The design constraints are provided according to ACI-318: Building code requirements for structural concrete and ACI-440: Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structure.

Optimum Design of Reinforced Concrete Retaining Walls

In this chapter, the optimization of reinforced concrete (RC) retaining walls is presented. RC retaining walls are one of the structural types that are constructed on land and used for retaining soil backfill. Because of this reason, both structural and geotechnical limits are in progress in the optimization process. Additionally, the stability conditions against pressure of soils are the key constraints in the optimum design of RC retaining walls. The presented methodology in this chapter considers both static and dynamic soil pressures resulting from earthquakes. A computer code employing teaching-learning-based optimization algorithm is also given.

Brief Information About Metaheuristic Methods

First, the reasons of using metaheuristic algorithms are listed for optimum design of reinforced concrete (RC) structures and members. The main reason is the non-linear formulation of RC design problems including various types of design constraints. The basic terms and formulation of optimization methods are presented. A general process of metaheuristic-based optimization methods is presented. This process is summarized as three stages: pre-optimization, analysis, and optimization. Details of several metaheuristic algorithms effectively used in structural engineering problems are summarized by giving all formulations according to the inspiration of algorithms. The flowcharts for the optimization processes are also included.

Introduction and State-of-the-Art Review of Optimum Design of Reinforced Concrete Structures

This first chapter of the book presents an introduction and review study. The necessity of optimization in engineering design is discussed. The nonlinear behavior of problems plays an important role in the usage of metaheuristic methods because of complexity resulting from design constraints considering safety and utilization rules. Design factors in analysis and design of structures are given. A brief history about optimization of structures is presented, including the first early attempts of Galilei Galileo. As the main scope of the book, the review of studies considering optimization of reinforced concrete (RC) structures and members via metaheuristic methods are given. The optimized RC members include beams, columns, slabs, frames, bridges, footings, shear walls, retaining walls, and cylindrical walls.

Metaheuristic Optimization of Reinforced Concrete Frames

In this chapter, an optimum design methodology for reinforced concrete (RC) frames are presented. In the optimum design of frames, both beams and columns are optimized. In addition to that, internal forces can be modified according to rigidity of members for statically indetermined frames. In the presented methodology, the optimization of RC frame is done according to dynamic seismic loads and the design is done according to time-history analysis. As a metaheuristic algorithm, a modified harmony search is used, and the design constraints are provided according to ACI 318: Building code requirements for structural concrete. The optimum results of two span-two story symmetric RC frames and three span-three story RC frame are presented.

Optimum Design of Reinforced Concrete Beams

The design of reinforced concrete (RC) beams need special conditions to provide a ductile design. In this design, the maximum amount of tensile reinforcement must be limited to singly reinforced design. After the singly reinforced limit, the cost of doubly reinforced RC beam rapidly increases, and it may not be an optimum design. To consider this nonlinear behavior and other rules used in RC structures according to regulations such as ACI 318: Building code requirements for structural concrete and Eurocode 2: Design of concrete structures, an algorithmic and iteration optimization method is needed. In this chapter, two examples are presented, and optimum results are shared for methodologies employing several metaheuristic algorithms. The importance of using metaheuristic algorithms can be seen in this chapter.

Metaheuristic Optimization of Reinforced Concrete Footings

Footings are one of the structural members, which is one of the complex engineering problems to optimize. Differently from the other reinforced concrete member designs such as beams and columns, geotechnical limit states are also needed to consider in addition to structural state limits. In this chapter, the optimum design of RC footing is presented according to ACI 318: Building code requirements for structural concrete. The optimum results of methodologies employing different algorithms including Harmony Search (HS), Teaching-Learning-Based Optimization algorithm (TLBO), and Flower Pollination Algorithm (FPA). In the methodologies, the design variables are values about dimensions of the footing, the orientation of the supported columns and reinforcements. Also, a simplified methodology is also presented with a design code employing HS.