Because of the presence of lateral loads and high-end eccentricities, the ACI 318-83 empirical design method cannot be used for design of tilt-up walls. Analysis must be performed during design to account for the P-{delta} effects. To confirm various design concepts and to evaluate the slenderness limitations, a series of tests on concrete wall panels was conducted. Several simplified design procedures were used to compare analytical results to test observations of slender load-bearing walls. Results of computer program TILT for IBM-PC (or compatible) computers were compared with the results of simplified design procedure calculations and test observations. Investigations show that the actual strength of load-bearing tilt-up walls are considerably higher than predicted by simplified analysis. The paper briefly discusses the theory of geometrical and material nonlinearities and presents methods for solutions that are incorporated in the program TILT. Conclusions and effectiveness of the TILT computer program for analyses of tilt-up load-bearing walls are shown.

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.

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.

Presents the results from a study of modeling concrete in the postcracking range using a three dimensional finite element analysis. The analytical work was based on an experimental study of concrete foundations which were loaded through bearing plates. The discrete cracking model was used, resulting in cracking which closely followed that in the tests. Comparisons have been made for different meshes, variable concrete material properties, and variable foundation dimensions. Failure occurred when the concrete foundation broke into segments, with a resulting loss in load-carrying capacity. The approach used is conceptually straightforward, lying between three-dimensional elastic analyses used in the past for concrete foundations and highly rigorous theoretical ones which have been used only for very limited applications.

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.