Hierarchical multiobjective optimization-based design and construction of precast concrete wall panels for a building facade

The design and construction of Precast Concrete Wall Panels (PCWP) for a building facade is a complex task. It involves several disciplines and often requires participants from different organizations to coordinate their activities in order to accomplish overall objectives of the project. To achieve an optimal design of PCWP for a building facade, this thesis presents an approach which can concurrently handle, in the decision making process, all of the related design and construction disciplines in an optimization model. The disciplines considered are: architectural design, structural design, fabrication, transportation, and erection. The optimal design model results in a multiobjective optimization problem in which some of the requirements are rule-based and the variables involved are continuous as well as discrete.; Due to the complexity and large dimension, the optimization problem for the design and construction of PCWP is decomposed hierarchically into several subproblems. Thus, a hierarchical multiobjective optimization problem is obtained. The subproblems considered are classified into multiobjective with continuous variables, single-objective with continuous variables, single-objective with discrete variables, and single-objective with rule-based requirements. The first three types of subproblems are solved by conventional hill-climbing optimization schemes. The last type of subproblem is represented and solved by the knowledge representation schemes since rule-based requirements are in general difficult to be handled by conventional hill-climbing schemes.; The solution method for each type of subproblem is discussed and an overall solution procedure is devised to coordinate the solutions for different subproblems so that an overall optimal solution can be obtained. To demonstrate the general formulation and the solution approach, typical subproblems in the optimal design of PCWP for a building facade are formulated in detail. These are the subproblems of architectural design and fabrication. In dealing with the aesthetic requirements, the concepts of proportion, balance, and symmetry are formulated in numerical terms. Three building facade design examples are solved. The objectives in these examples are to minimize the overall cost and maximize the facade aesthetic balance. For tradeoff explorations, a set of Pareto optima is obtained for each example.; The optimization model and solution approach presented in the thesis, while successfully demonstrated for PCWP of a building facade, can be extended and applied to many other engineering design problems which have similar features.