International Concrete Abstracts Portal

The computer-aided design field is expanding rapidly. There is an abundance of commercial and public domain software that is available. It is no longer necessary to write programs to introduce students to computer-aided design. The availability of spreadsheet programs has added a new dimension to computer-aided design. The principal advantage of a spreadsheet program is that it allows a series of relational steps to be programmed without having to know a programming language or having to write formal program statements. In addition, if a change is made in a particular step of a program, changes are automatically made in steps affected by that change. This can be a significant advantage in teaching reinforced concrete design. Students can use the templates created by the spreadsheet programs to answer "what if" questions about design. In this paper, several programs for the flexural design and shear design of reinforced concrete beams are described. These programs are not written in a programming language but are formulated with a spreadsheet program. The programs were run on a mainframe computer. The basic formulation of a spreadsheet program is described. Advantages of using spreadsheet programs in computer-aided design and their application in undergraduate courses in reinforced concrete design are discussed.

A model for the design of a computer system to support decision making for the design of reinforced concrete structures is proposed. The process of analysis-design-drafting is transformed into a series of integrated operations performed upon a relational database. The computer tools used in structural engineering today are evaluated, and a model for planning their data integration has been developed. Databases are the backbone for the process of systematically storing and retrieving data to accumulate knowledge and support decisions. The focus of the paper is on identifying the requirements of databases suitable for structural analysis and design of reinforced concrete structures. A primer objective for such a database structure is to include data from engineering codes to provide information throughout the design. The importance of incorporating the ACI 318 Code and Commentary is emphasized and its implementation through a relational database is proposed.

SP-98 Because the design of concrete structures and proportioning concrete mixtures can be complex, you need state-of-the-art knowledge when selecting structural systems and construction materials. Computer Applications in Concrete Technology has been especially prepared to aid designers and engineers in all facets of concrete design and technology. Providing a source of "know-how" for the entire civil engineering community, this symposium volume of 13 papers covers a broad spectrum of computer applications. Some of the subjects include: expert systems for selecting concrete constituents, analysis of reinforced concrete shear walls, analysis and design of load-bearing tilt-up walls, decision support systems for design, and spreadsheet programming for structural design. Other topics include: monitoring construction with microcomputers as you build, analysis and design of reinforced and prestressed concrete compression members using desktop computers, and integrated design environment for concrete structures.

A finite element procedure is presented for the analysis of reinforced concrete shearwalls. The wall is idealized as a two-dimensional structure, and the global behavior of the wall under static loading conditions is emphasized. A combination of a new family of higher-order quadrilateral elements and beam elements is employed in the finite element discretization of the wall. Constitutive models of material behavior are based on the nonlinear elasticity. The main material nonlinear effects accounted for in the analysis are the tensile cracking, the biaxial compressive response of concrete, and the yielding of steel reinforcement. A smeared approach is used in the representation of concrete cracking and steel bars. Simplified uniaxial and biaxial material models for reinforced concrete are developed and presented in detail. The incremental-iterative nonlinear solution techniques employ both constant and variable stiffness with the option of selective updating of the stiffness matrix in the load increment. Numerical examples are presented and compared with other existing solutions.

Presents the results from a study of modeling concrete in the postcracking range using a three dimensional finite element analysis. The analytical work was based on an experimental study of concrete foundations which were loaded through bearing plates. The discrete cracking model was used, resulting in cracking which closely followed that in the tests. Comparisons have been made for different meshes, variable concrete material properties, and variable foundation dimensions. Failure occurred when the concrete foundation broke into segments, with a resulting loss in load-carrying capacity. The approach used is conceptually straightforward, lying between three-dimensional elastic analyses used in the past for concrete foundations and highly rigorous theoretical ones which have been used only for very limited applications.