Moshe A. Adin

Analysis of beams on nonlinear winkler foundation

Abstract The analysis of beams on Winkler foundations is very common in engineering. In many practical problems nonlinear foundation behavior should be considered. Based on an exact solution for a finite beam on a linear elastic foundation an iterative procedure for a piecewise linear foundation is formulated. The approach is implemented in a continuous beam computer program and demonstrated in two examples.

Resistance Mechanism Model for Reinforced Concrete FlatSlab-Column Frame Connections

Results of an analytical and theoretical study on reinforced concrete flat slab-column frames connections, subjected to lateral and vertical loads from earthquake and gravity, are presented. The study investigates the plastic behavior, and load transfer and final failure mechanisms. An idealized model of the response is presented, based on observations of tests reported in literature, and particularly on tests carried out by the authors and followed by detailed postmortem dissections of the failure zones. Based on the idealized resistance mechanism model, an analytical method is presented for graphically predicting the entire moment-rotation response envelope of a connection during the different loading stages, detailing the varying relative fractions of the resistance components. The numerical solutions are compared with current calculation methods on full-subassemblage experimental results.

Beams on nonlinear winkler foundation with gaps

Abstract The analysis of beams on a Winkler foundation is very common in engineering. In many practical problems nonlinear foundation behavior should be considered. In some cases a gap may exist between the beam and the nonlinear foundation. Based on an exact solution for a finite beam on linear elastic foundation, an iterative procedure for a piecewise linear foundation is formulated. The approach is implemented in a continuous beam computer program and demonstrated in numerical examples.

Analysis of beams on BI-moduli elastic foundation

Abstract The analysis of beams on elastic foundation using the Winkler model is very common in engineering. When an elastic foundation is incapable of exerting tensile reactions, or when it has different stiffnesses in compression and tension, the simple Winkler model leads to a set of nonlinear equations which are complicated even for simple cases. Using exact stiffness matrices for beams on elastic foundation the problem is solved in an iterative technique, in which secondary nodes are inserted at transition points. Comparisons are made with simple case results in literature and the efficiency of the proposed procedure is demonstrated for a complex loading system.

Mathematical Model for Bond-Slip Behavior Under Cyclic Loading

This paper models the bond-slip behavior of a reinforcing steel bar embedded in concrete and subjected to monotonic cyclic loading. In this paper, the typical cyclic bond stress-slip relationsip is represented by 3 major resistance components that appear to control the behavior and act, changing their influence, at various loading stages. The model is developed according to experimental bond-slip tests for well-confined concrete reported in the literature and is based on their observations. Results predicted by that model are compared with experimental results and show good correspondence.

Analysis of lateral load transfer by internal slab-column joints

Abstract The results of an analytical study examining the behavior and load transfer mechanism of 16 interior flat slab-column joint models, transferring lateral load, are presented. Predictions of the connection response were calculated using a professional finite element computer program, utilizing three-dimensional, elasto-plastic, concrete elements. Currently, various analytical methods are suggested for calculating the load transfer. The assume that the slab sections carry the external unbalanced moment by developing a bending moment on the front and back faces, and a torsional moment on the side faces. Several studies have tried to determine the relative contribution of the bending and torsional moments. Slots or cutting through the slab, made along the respective column faces, were introduced in an attempt to isolate the components that resist the external moment. According to the present analysis, the various types of connections have a minor effect on the response. They display very similar deformations and stress distributions in the slab, except for very local stress concentrations, almost ignoring the slots and cuttings. As a result of this analysis, the attempts to isolate appear to be unsuitable since the slabs bending and torsional mechanisms are highly coupled.