USF Tampa Graduate Theses and Dissertations

2018

Thesis

M.S.C.E.

Degree Name

MS in Civil Engineering (M.S.C.E.)

Degree Granting Department

Civil and Environmental Engineering

Rajan Sen, Ph.D.

Committee Member

Gray Mullins, Ph.D.

Committee Member

Michael J. Stokes, Ph.D.

Keywords

force distribution, force flow, openings, refined method, rigidity

Abstract

Shear walls are the primary lateral load resisting elements in bearing wall systems used in masonry construction. Horizontal loads due to wind or earthquake are transferred to vertical walls by diaphragms that are rigid such as concrete floor slabs or flexible such as wood floors. With rigid diaphragms, loads are apportioned to the supporting walls based on their relative rigidity. Walls with openings accommodating doors and windows (“perforated walls”) have reduced rigidity that can be determined using available hand calculation methods. These methods primarily focus on analysis procedures, not on the visualization of the load path that is critically important in structural engineering practice.

The analogy of springs in series or parallel is used to determine the equivalent stiffness of elastic systems in structural dynamics. This thesis uses this analogy to develop a method that can help visualize load flow in perforated shear walls connected to rigid diaphragms. Rigidities are calculated using existing methods and combined as springs in series or parallel to represent a perforated wall. Loads taken by the wall segments correspond to the electrical current flowing through this imaginary “circuit”. To help visualize the load path, the line drawing representation of springs in series or parallel and the applied lateral load are deliberately oriented in the vertical direction. The application of the analogy is illustrated by several numerical examples of varying complexity taken from text books. Finite element solutions are included in the comparisons to provide a measure of the relative accuracy of hand calculation methods.

The analogy can be extended to refine existing hand calculation methods though this increases computational effort. It improves accuracy but only for cases where the aspect ratio of the wall segments is such that shear effects are dominant.

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