International Concrete Abstracts Portal

A series of procedures and utility programs have been developed to assist structural engineers in the development of highly graphical and interactive applications. The procedures are callable from FORTRAN-based programs. They perform such tasks as menu control, on-screen data input and verification, selection of entities from screen, control help facility, and provide a model for graphical representation of information on the screen. The programming environment is available in the DOS operating system, and it is viewed as an alternative to spreadsheet-based programming tools.

An automatic quantitative image analysis (AQIA) software system has been developed to quantify constituents in multiple phase materials, such as hardened cement and concrete. Some major features of AQIA are presented. The applications of AQIA to cement and concrete research are explored. The system is expected to provide a more versatile, and more reliable means than the manual microscope examination. It is much less expensive than existing hardware-type image analyzers, and specially designed for materials use.

Design and construction of bridges composed of simple-span, pretensioned girders made continuous for composite dead and live loads have become widespread. The design of these structures in the U.S. has been generally based on the procedure outlined in "Design of Continuous Highway Bridges with Precast, Prestressed Concrete Girders," published by the Portland Cement Association (PCA) in 1969. Although existing bridges designed by this procedure are generally performing well, it is believed that this method may not accurately predict the true behavior of these structures. One of the major uncertainties in the design of these structures is prediction of positive and negative moments in the cast-in-place connections at the piers. This uncertainty is due to the different loading and construction stages, time-dependent effects, and details used to make the connection. To resolve such uncertainties, an analytical study was conducted to develop guidelines for more rational design of the continuity connections. Paper summarizes results of an extensive parametric study to consider the effects of 1) construction sequence, including simple span behavior before and continuous behavior after casting the deck and diaphragms; 2) time-dependent behavior, including concrete creep and shrinkage, and steel relaxation; 3) live load applied at any stage of service life; 4) cracking resulting from both positive and negative moment, including "tension stiffened" stress-strain relationships for reinforcement; and 5) closing of cracks when combined dead load plus time-dependent moments are reversed by application of live loads.

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