International Concrete Abstracts Portal

At the 1986 winter Meeting in Fort Worth, Texas, the National Society of Professional Engineers, decided to study the possibility of an electronic bulletin board system (BBS) being installed at our headquarters in Alexandria, Virginia. The purpose of the board was to provide a national communication link for the engineers in the society, who number around 75,000. The project manager of construction of computer applications was given the task of further defining the goals of the system evaluating alternative systems, making the selection, and following the project through installation and complete implimentation. In order to learn more about how bulletin boards functioned, a commodore 64 was taken from the office and fitted with a modem (an acronym for modulator/demodular) a device which concerts digital data into audio tones suitable for transmission over regular telephone lines and bulletin boards in south Florida area were called. Whyat was found out there was quite interesting for the most part, it's like the work of the Cber's with a lot of chatter, exotic names (handles), jokes, meaningless messages, and just general fun, but upon further explanation a more serious element was found. A few of the boards contacted were doing real work, some dedicated to a particular computer system, such as a heathkit IBM, commodore, etc. and others dedicated to such objects as computer communications, radio and television graphics, music, religion, and serious discussion of just about everything imaginable. The seboard shadusersand sysops (System Operators) that were helping each other in a way we had never envisioned before

The knowledge contained in Computer Applications in Concrete Technology will prove invaluable. This symposium volume of 10 papers will provide you with the information you need to build high-quality, cost efficient structures. Presenting various practical applications of computer technology, the topics covered include: computer analysis of time-dependent behavior of continuous precast prestressed bridges; substructure modeling of two-way slab systems; an automatic quantitative image analysis system for cement and concrete research; maintenance and implementation of an expert system for durable concrete; and prediction of shear failure in concrete structures using nonlinear finite element analysis. Other subjects covered include: a three-dimensional stability analysis/ design computer program for concrete monolithic structures; and a programming environment for structural engineering applications based on interactive computer graphics." Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP106

The complex factors that influence behavior and strength of concrete components failing in shear pose serious obstacles to the use of traditional linearly elastic analysis techniques. However, recent developments in the application of nonlinear finite element methods and in modeling nonlinear material properties have allowed the development of a computer model to effectively analyze complex nonlinear situations. The model includes material laws representing the full inelastic response of concrete cracking and crushing (including effects of triaxial confinement) and the yielding of reinforcing steel bars. This computer model is verified using data from a test program involving nine reinforced concrete shear-sensitive beams of varying dimensions and span-to-depth ratios. Calculated and measured failure modes, deflection and cracking patterns, and ultimate capacities corresponded well in all of the beams compared. A computer program based on the verified model has been used by the authors in several applications to predict ultimate capacity and failure modes for complex systems of walls, beams, and slabs. One such application, the prediction of shear strength in the reinforced concrete ice walls of an offshore concrete gravity-based structure, is discussed in detail.

A substructuring technique to analyze equivalent frames according to ACI 318-83 is presented. A more consistent implementation of the equivalent frame method is formulated. The width of the column strip and the percentage of torsional stiffness required are studied. A program that will analyze a building system subjected to gravity as well as lateral loads is developed.

Describes an expert system with a knowledge base consisting of freeze-thaw, sulfate, alkali-aggregate, and corrosion aspects of concrete durability. The system was developed on a microcomputer using an expert-system shell facility. This paper discusses knowledge acquisition, knowledge representation, issues relating to the maintenance of expert systems, and recommendations for field implementations.