Prem Egade

ORCID Identifier(s)

0000-0001-8380-671X

Graduation Semester and Year

2018

Language

English

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

First Advisor

Nur Yazdani

Abstract

Construction defects are common and are difficult to avoid completely. This arises due to improper workmanship, inspection, drawing and specification. On bridge decks, achieving the desired cover is necessary since inadequacy can cause accelerated corrosion in steel and for the most part spalling and delamination which ultimately led to failure. Tolerance provided by different standards and specification also restrict the amount of rebar. So, construction is more focused on increasing cover undermining the loss of strength as consequence. The objective of this research is to check the safety of decks by analyzing bridges for reduction in capacity due to cover variation. The investigation was conducted on two old and two new bridges using Ground Penetration Radar (GPR) for possible rebar cover variation. Data were collected with ground coupled high-frequency 2.6GHz antenna for high accuracy. The dielectric constant for depth calculation was estimated using migration and ground truth method with minimum error. The hyperbolic signatures were detected and plotted in form of contours and percent distribution was calculated. For 0.5 in. (13mm) and 1 in. (25.4mm) increase in rebar cover, the deck capacity is reduced by 9% and 18%, respectively for 8.5 in. (216mm) thickness of the slab. It was found that on average the rebar cover distribution of 40% and 77% varied +1/2 inch and +1 inch, respectively. The reduced negative moment capacity followed by decreased effective depth is compared with design moments. Finally, the load on rebar cage is modeled and deflection and stresses are calculated different bar sizes and distance of rebar supports. The smaller size rebar with less spacing deflected more than larger size rebars.

Keywords

Ground penetrating radar, Non-destructive technique, Variable cover, Bridge deck, Rebar deflection

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

Download

Share

COinS