The introduction of new products is a critical aspect for the survival, growth, and rentability of enterprises. Mass customization has aided to decreasing the production costs and the time to reach the final consummator. But, the rapid change in technology and in social and individual expectative, as well as, the explosion of the concurrence demand new and efficient methods for products development. In order to assume these challenges, products lines approach looks for the reuse of common characteristics of products and the harnessing of the variability of other characteristics useful to satisfy exigencies of customers. The features model, widely used in the development of products lines, has limitations to treat the complexity of domains, to adopt standard guides to construction and segmentation of domain models. In our research, domain knowledge is organized in different ways, in order to represent tangible and intangible realities using mathematical, conceptual, and physical models. Traditional engineering, as mechanical, civil, materials, and hydraulic has important applications in automotive, and aerospace industry, and in the construction of ships, buildings, railways, roads, among others. There, it is easy to appreciate the common use of ideal, conceptual, and physical models in projects development. In civil engineering, for example, new structural elements, their conceptual representations, mathematical models, software systems for analysis and design, and physical models use concepts of a domain model, which depict common and variable characteristics of a products line. In this work, we model domain in terms of goals and characteristics, highlighting the reusable part of products and the variability. This domain model allows the application of products line concepts to the analysis, design and construction of structural elements in civil engineering. We apply proposed products lines models in the analysis and design of coupled structural walls.