Date of Award

8-23-2024

Publication Type

Dissertation

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

Keywords

Decked I-beam;High strength A1035 rebar;Link slab;Prestressed UHPC pile;Sustainable ECC;UHPC

Supervisor

Sreekanta Das

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

The performance of some of bridge components with new designs and innovative materials is investigated. These components are link slab, decked I-beam (DIB), pile and its splice joint. Link slabs serve as an alternative to expansion joints in bridge structures, aiming to reduce maintenance costs and mitigate corrosion issues associated with premature failure of expansion joints. However, link slabs must be deformable enough to accommodate girder end rotation while also ensuring narrow flexural cracks to prevent water and salt infiltration. Hence, choice of material is crucial for the link slab. This study compared structural performance of different link slabs made from various materials, including ultra-high performance concrete (UHPC), sustainable engineered cementitious composites (ECCs), and normal concrete (NC). A high amount of PC, which is responsible for a large amount of greenhouse gases, is used in conventional ECC. Hence, use of two eco-friendly ECC materials in which a significant portion of PC was replaced with fly ash or slag was considered. Additionally, this study employed the finite element method (FEM) to examine the structural behavior of these link slabs when reinforced with different types of rebars. Results showed that the link slab made of high-volume fly ash ECC provided the highest deformability. UHPC link slab demonstrated superior performance in controlling crack width, followed by high-volume fly ash ECC link slab and then high-volume slag ECC link slab. Another component investigated in this study was UHPC decked-I beam (DIB). This beam was designed to align with the objectives of accelerated bridge construction (ABC) approach. The lateral bending strength of the web of UHPC DIB is a concern, particularly regarding its resistance to applied forces during shipping, erection, and construction activities. Hence, the lateral bending strength of the web of UHPC DIB specimens was assessed through experimental tests when they were unreinforced or vertically reinforced either with high-strength A1035 or conventional 400W steel reinforcements. Additionally, finite element method (FEM) was employed to model and analyze DIB sections with different dimensions and UHPC materials. This study also showed that unreinforced UHPC specimen exhibited an acceptable service lateral bending capacity when compared with reinforced web component. Specimens reinforced with A1035 rebar exhibited smaller crack widths at service limit state. Additionally, this study investigated the behavior of rectangular UHPC sections reinforced with either A1035 or 400W rebars, considering various parameters through fiber technique analysis. The findings revealed that loss of ductility can be minimized by utilizing a UHPC material that possesses a higher ultimate tensile strain. Pile is another component which can affect the service life of a bridge. The significant cost of repairing and replacing deep foundations has prompted interest in finding alternative materials for pile foundations to attain a minimum 75-year service life with minimal maintenance. UHPC stands out as a promising candidate due to its exceptional strength and durability properties. Hence, a prestressed UHPC pile with a new geometry was investigated and its bending and shear strength were evaluated through experimental tests. Additionally, the moment-curvature relationship of this prestressed UHPC pile under different values of axial compression forces was determined using the fiber technique analysis. Additionally, this study focused on the splice joints designed for the mentioned UHPC pile. The shear and bending capacities of the spliced piles were assessed through experimental tests. Findings revealed that compression crushing was the leading cause of bending failure in UHPC piles without splice (unspliced) due to the prestressing. The ultimate bending moment about the strong axis of spliced piles was at 86% of ultimate bending moment of unspliced piles, while ultimate shear load in both directions in spliced piles exceeded that of UHPC unspliced piles.

Available for download on Saturday, August 23, 2025

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