11-03-2010, 09:23 AM
![[Image: 92057790394408774449.png]](https://pic.civilea.com/images/92057790394408774449.png)
Here's quotes from Ed. Wilson,
Quote:Many engineers believe that the creation of a two-dimensional finite element mesh, as shown in Figure 7.7b (above), is the best approach to evaluate the displacements and stresses within the shear wall. In the author’s opinion, this approach may not be the best for the following reasons:
1. As previously illustrated, the use of four-node plane elements for frame analysis does not accurately model linear bending. The approximation of constant shear stress within each element makes it very difficult to capture the parabolic shear distribution that exists in the classical frame element.
2. If a very fine mesh is used, the linear finite element solution will produce near infinite stresses at the corners of the openings. Because the basic philosophy of reinforced concrete design is based on cracked sections, it is not possible to use the finite element results directly for design.
3. Using common sense and a physical insight into the behavior of the structure, it is possible to use frame elements to create a very simple model that accurately captures the behavior of the structure and directly produces results that can be used to design the concrete elements.