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.

Microcomputer applications are continually expanding into new fields, including the area of concrete construction. The dissemination of information concerning these applications promotes their growth and development and benefits the construction industry. When the Bureau of Reclamation began planning Upper Stillwater Dam, the largest roller-compacted concrete (RCC) dam to date in the U.S., due consideration was given to the management of the myriad of concrete test data that would be generated during this rapid method of construction. Using a microcomputer system to facilitate proper treatment of these data would serve several important purposes: 1) provide an overall view of quality control of the RCC, and act as a quality assurance tool; 2) provide a quick method for updating mix design quantities based on variations in materials; and 3) provide access to the data for a comprehensive review of this state-of-the-art method of construction. Both the programming structure and the capabilities of the program will be discussed. The qualifications for developing an RCC quality control system required that the program be user friendly so that it could be readily used by construction inspectors and laboratory technicians. The system provides record keeping for all RCC tests and RCC materials tests, including concrete unit weight, concrete consistency measurements by vibrating table, nuclear density readings, cylinder compressive brake strengths, and aggregate gradations and moisture contents. The program also calculates adjusted mix proportions based on moisture content and clean separation of the aggregate. The RCC quality control system is written in dBASE III, and the host is an IBM-XT microcomputer. The system is connected to a mainframe computer in Denver via modem so that data can be periodically reviewed by designers and for long-term storage.

The microcomputer and associated digital technology has changed the way things are done both in the structural laboratory and in the field. The impact of microcomputers on the science of field measurement is mainly with regard to cost and time. The many benefits of field monitoring of structures are now available at an acceptable cost. Cost is reduced due to automatic recording rather than manual methods. This paper discusses the benefits of field monitoring during construction and the life of the structure. Two proven measuring systems are described in detail. The paper also describes a system for dynamic analysis of structures. The reduced cost of determining the behavior of buildings and bridges is not the only benefit of these three new measuring systems. Data returned for analysis are in a form that can be quickly reduced and evaluated by computer. A short turn-around time means that the behavior data are available when needed.

A large amount of specialized factual and heuristic knowledge on the relations between the design of concrete mixtures, including the constituents, and the durability of concrete has been gained through research and field experience. Effective dissemination of this knowledge should result in fewer incidents of premature deterioration of concrete. Expert systems appear to be an effective means for transferring the knowledge on the durability of concrete obtained through laboratory and field studies and experiences to engineers and designers responsible for the design, construction, and maintenance of concrete structures. Durcon is a prototype expert system being developed to give recommendations on the selection of constituents for durable concrete. The purpose of developing Durcon is to demonstrate the application of expert systems to improve the process of selecting construction materials. Four major deterioration problems are covered by Durcon: freezing and thawing, corrosion of reinforcing steel, sulfate attack, and alkali-aggregate reactions. This report discusses the approach being followed and the progress being made in developing Durcon. In addition, model systems for recommendations for concrete exposed to corrosive environments and for preventing alkali-aggregate reactions are presented.

Presents an algorithm for a program code for the analysis of concrete columns reinforced with nonprestressed reinforcement, prestressed reinforcement, or both. The algorithm can be used to generate the coordinates of the load-moment interaction diagram for the section chosen in terms of shape; material properties; and type, amount and location of nonprestressed and prestressed reinforcement. Three shapes--namely rectangular, T, and I--can be analyzed. Hollow-core wall panels can be analyzed by converting them to equivalent I-sections. The lateral reinforcement could be ties, spirals, or none. The program can also be coded to reanalyze the section for revised partial input. This capability aids the designer in generating the loads and moment for, say, a different compressive strength of concrete without reinputting the entire design data. The load-moment values can be printed to look like the load-moment interaction diagram. The various assumptions involved, the equations, and the sequence of calculations are explained using a number of flow charts. A procedure is outlined for using the program for design purposes. Example problems are provided to illustrate the input-output variables. The program code, written in BASIC for Apple desktop computer, can be obtained from the author. The algorithm deals with only the strength aspect. The serviceability aspect, especially for prestressed columns, should be checked separately.