International Concrete Abstracts Portal

With the aid of modern digital computers and sophisticated computational techniques such as the finite element method, it is now possible to simulate the structural behavior of an arbitrary reinforced concrete shell structure under general loading through its elastic, cracking, inelastic, and ultimate load ranges, taking into account nonlinear material, nonlinear geometry and time-dependent effects of creep and shrinkage. In this paper, a method of analysis and a computer program based upon a composite layered finite element displacement model are briefly described. The analysis recognizes the nonlinearities due to cracking, nonlinear stress-strain behavior in concrete, yielding of the steel reinforcement and the tension stiffening between cracks. The effects of the countinuously changing structural geometry are taken into account by an updated Lagrangian formulation. The time dependent effects of creep and shrinkage are also included by an initial strain procedure. Numerical results for reinforced concrete shells obtained with the computer program are presented which indicate that in some cases an increase and in other cases a large reduction in the calculated ultimate load occurs as each of the nonlinear factors is included in the computer analysis.

Presents a new computer design environment that allows the designer complete freedom in choosing design options. It combines three common tools--analysis, graphics, and a spreadsheet--into a completely integrated system. The environment allows the designer to take results directly from the analysis database, display them graphically, choose the values to be used for design, and then insert those values automatically into the spreadsheet environment. The spreadsheet can be customized, through the use of templates, to fit any design scheme. A template for the design of singly reinforced concrete beams is presented.

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.

Spreadsheet programming is presented as a new programming alternative for solving daily calculations in the engineering design office. Two spreadsheet programs with different applications are used to introduce the reader to this technique. A retaining wall template demonstrates the advantage of altering one design parameter and seeing the results propagate instantly, thus leaving the engineer with a very responsive tool. A prestressed bridge template organizes in separate windows the engineering design process involved in the prestress design. The template is written according to the design requirements of AASHTO. It allows the engineer to verify different alternatives in the design of the concrete girder, hence leading to a manually optimized section.