A THESIS SUBMITTED TO THE FACULTY OF CIVIL ENGINEERING, INSTITUTE OF TECHNOLOGY, SCHOOL OF GRADUATE STUDIES, ARBA MINCH UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN STRUCTURAL ENGINEERING

Abstract

Slabless reinforced concrete staircases have gained popularity in recent years due to their aesthetic appeal, space-saving, reduced weight rapid construction, and cost-effectiveness. Slabless staircases are also known as sawtooth or ortho-polygonal staircases. However, slabless reinforced concrete (RC) stairs are typically thinner and lack the structural support provided by a landing or step tread, which means they are more susceptible to bending and cracking. The main objective of the present study is to investigate the flexural performance of slabless reinforced concrete staircase using numerical approach. The experimental result presented in the literature was used to validate the FE analysis using the ANSYS software program. A total of 24 specimens were modeled, considering the various parameters such as the effect of planar reinforcement, the effect of compressive strength of concrete, and the effect of thickness of carbon fiber reinforced polymer sheet. The finite element analysis results show that planar reinforcement increase the load resistance capacity of slabless staircase 5.87%, compared to the control specimen, and decrease stress concentration by 6.61%. As the compressive strength of concrete increases from 50MPa to 90MPa, the load resistance capacity increases by 46.00 % and reduces cracking by 11.99 %. Change in Carbon fiber reinforced polymer sheet thickness from 7mm to 11mm, improves the ultimate strength by 16.31% and the Von Mises stress concentration is reduced by 21.47%.