Document Type

Dissertation - Open Access

Award Date

2018

Degree Name

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

First Advisor

Mostafa Tazarv

Keywords

buckling restrained reinforcement, innovative connection

Abstract

A new moment-resisting precast connection is developed in the present work through experimental and analytical studies to accelerate construction of bridges and buildings, to improve their seismic performance, and to quickly repair them through replacement of exposed reinforcement. The new precast joint detailing incorporates (1) detachable external reinforcing steel bars restrained against buckling, which is referred to as buckling restrained reinforcement (BRR), to develop plastic bending moments, (2) a steel pipe connecting the precast members through a pin connection to resist plastic shear forces, and (3) detachable mechanical bar splices to assemble and disassemble BRR at any time specifically after server event as a quick repair method. Feasibility and performance of a new type of BRR that can be used as detachable external reinforcing steel bars, were experimentally investigated. Furthermore, a simple design method for BRR with or without a section modification (e.g. dog-bone) is presented to further help engineers with the design of external reinforcement and energy dissipaters. The seismic performance of the proposed repairable precast connections was investigated through cyclic testing of four half-scale beam-column specimens detailed based on a nine-story building designed for Los Angeles, which is a high seismic region. A reference cast-inplace beam-column specimen was also included for comparison. The test results showed that the repairable precast connections can withstand more than fourteen times the design level earthquake with insignificant damage and ability to be repaired afterward. Furthermore, a comprehensive analytical study including pushover and nonlinear response history analyses was performed to investigate the seismic performance of three-, six-, and nine-story repairable precast and cast-in-place (CIP) buildings, and repairable precast bridge columns. It was found that the stiffness of the proposed precast system is 60% of conventional cast-in-place structures but the displacement capacity of the proposed precast structures can be four times higher than that in the conventional structures. The increase in the displacement demands of the precast systems due to lower initial stiffness is usually within the design limits and there is no need to increase the member sizes. Based on the construction, and experimental and analytical studies, it can be concluded that the proposed precast connection detailing is expected to improve the seismic performance of bridges and buildings, to expedite the construction, and to eliminate the need of structure total replacement after severe earthquakes since the repair is done by replacement of exposed bars.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

278

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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