Architectural Engineering and Construction, Durham School of

 

First Advisor

Ece Erdogmus

Second Advisor

Jay Puckett

Date of this Version

5-2020

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Architectural Engineering, Under the Supervision of Professor Ece Erdogmus and Professor Jay Puckett. Lincoln, Nebraska: May 2020

Copyright 2020 Tyler Sondag

Abstract

Vibration serviceability of staircases has been a growing challenge for structural engineers due to changing materials and structural forms. In order to prevent or correct serviceability problems due to structural vibrations, structural engineers should be able to predict the dynamic performance of a staircase structure. However, there are few technical guides available for designing steel staircases, and the ones that do exist are often limited in their applications. Currently, there is a lack of research on staircases that are less prone to vibrations, such as staircases with concrete filled pans that are composed of face and wall stringers. Therefore, the goal of this thesis is to improve the understanding and accuracy of the overall vibration response (natural frequencies and mode shapes) predictions of concrete filled pan tread stairs. In order to determine the vibration response, experimental data was collected on two types of staircases and used to create and update finite element models. Using the experimentally updated finite element models, various parameters such as railing mass and boundary conditions were altered, demonstrating the staircases’ response to changes in these parameters. This study also demonstrated different methods for modeling the unknown boundary condition stiffness contributions in the staircase structure. In addition, this thesis evaluated the potential limitations of the AISC design guide equation that quickly calculates a prediction of the first mode frequency of a staircase. This thesis also suggested an empirical factor to be applied to the AISC equation that would allow the equation to be used for staircases with a boundary condition created by a wall stringer. Finally, this thesis work has created suggestions for designers on how to model these types of staircases.

Advisors: Ece Erdogmus and Jay Puckett

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