摘要:

A heuristic approach is presented for interactive analysis of statically determinate and indeterminate bridge trusses subjected to moving loads such as the American Association of State Highway and Transportation Officials (AASHTO) specifications live loads. These loads consist of two‐axle truck loading, two‐axle truck plus one‐axle semitrailer loading, and uniform lane loading. The procedure is based on using the information about the shape of the influence line diagrams (ILDs) for members of a truss. This information may be obtained through numerical experimentation for any given type of truss. A methodology is presented for classifying the ILDs for member axial forces of a bridge truss. The procedure is applied to Pratt trusses. Heuristic rules are developed for finding the maximum compression and tensile forces in the members of a Pratt truss based on its characteristic influence line diagrams and the type of the AASHTO live load. The procedure presented in this article results in substantial savings in structural analysis computations, and is specially suitable on microcomputers in an interactive enviro

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00240.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

This paper presents the development of an interface between an expert system and a data base management system. The flexibility provided by such interface is shown to be very useful for civil engineering applications. An example application is developed in this paper that applies this interface to the management of retaining walls. The different relational data bases store most of the required information. The inventory data base stores identification information, the inspection data base stores historical condition data gathered by inspections, and the replacement data base stores information needed to perform a replacement cost analysis for a retaining wall. The expert system, on the other hand, is used to diagnose the possible reasons for the failure of a retaining wall. The development of the data base management system, the expert system, and the interface between them is discussed, along with the restrictions imposed by the software chosen for this example application.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00241.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

An analytical model for dynamic response analysis of low‐rise steel frame buildings on microcomputers is described. The model consists of an assemblage of planar frames with either braced or moment resisting connections. All but the frame lateral degrees of freedom are removed using static condensation prior to assemblage of the overall model. Floor diaphragms are modeled as either flexible or completely rigid in their own planes. Linear elastic behavior is assumed in the model and time‐history dynamic analysis is performed using the mode‐acceleration method. A FORTRAN computer program was written to implement the model on a microcomputer and a sample analysis of an actual building is presented to illustrate its use. The program was envisioned as a simplified analysis and design tool which could aid a designer in investigating a proposed structure or in rehabilitating an existing one for lateral f

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00242.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Sanitary landfills are common facilities for waste disposal. The process of designating a location as a landfill requires extensive studies of biogeochemical and hydrologic characteristics of all potential sites. This process demands a considerable amount of empirical inputs, expert opinions, and heuristic rules. A site selection process can be modeled only by incorporating the available empirical and expert rules into our decision making process. This task can be accomplished in the framework of knowledge‐based expert systems. A prototype expert system for site selection is presented. The rules are based on U.S. EPA documents for ranking of uncontrolled hazardous waste sites for remedial actions. They include rules concerning ground water routes, local climate, waste characteristics, planned features of the proposed landfill facility, and targets at risk. The above model is programmed with the aid of Insight 2+, which is a microcomputer shell progra

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00243.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

An input system is presented which has been tailored for engineering data. The system makes use of a problem‐oriented language organized as a tree structure. Input data is parsed line by line and placed in appropriate queues. The application program then extracts this queued data using logical functions. A sample finite element problem is included to demonstrate the use of the input system. The input system requires only 17 Kb of memory and operates very efficiently. The system is ideal for microcomputer applications and provides input methods that were once only available in extremely large applications program

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00244.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

A computer program is presented to show the algorithm that is used to give the buckling load factor and the effective lengths of all columns in a multistory building frame when these columns are subjected to a set of primary axial forces. Since the buckling load factor is the lowest multiplier of the primary axial forces that makes the determinant of the global stiffness matrix equal to zero, it has to be found by trial and error. It is found that the determinant of the global stiffness matrix is the product of the pivots used in the piecewise small inversions within the earlier one on bifurcation analysis lies in the way by which the determinant is computed. Significant amount of computer time is saved because of the need of repetitive computations of the determinant at many trial values of the buckling load factor.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00245.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

An innovative approach is reported for teaching structural steel design in a civil engineering undergraduate curriculum. It is based on the interactive environment and graphic capabilities of inexpensive microcomputers. Ten BASIC interactive microcomputer‐aided design programs have been developed and used in a senior‐level structural steel design course at the Ohio State University. The approach of interactive design and the interactive microcomputer‐aided design programs make the learning of structural steel design more exciting and result in more effective training of future designers. Students can gain experience and develop insight in structural design while they are still in an academic enviro

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00246.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00247.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY