Development and Validation of Simulation Protocols for Assessing Stresses in a Network Tied Arch with a Posttensioned Tie Girder

Date of Award

8-2023

Degree Name

Doctor of Philosophy

Department

Civil and Construction Engineering

First Advisor

Upul Attanayake, Ph.D., P.E.

Second Advisor

Xiaoyun Shao, Ph.D., P.E.

Third Advisor

William W. Liou, Ph.D.

Keywords

Concrete tie girders, finite element simulation, network tied arch, posttensioning, prestress losses

Abstract

Posttensioned concrete members; especially the posttensioned tie girders, are critical load resisting elements in network tied arch bridges. The stresses in the structure are influenced by the prestress losses that depend on the posttension force magnitude, time-dependent concrete modulus of elasticity, and concrete creep and shrinkage. The use of performance-based, high-strength, ternary mixes to promote the carbon neutral concrete and the need for executing multiple construction stages challenge the assessment of the state of stress in a completed bridge. The primary objective of this study is the development and validation of simulation protocols for assessing stresses in a network tied arch with a posttensioned concrete tie girder. The scope of the study included (a) selecting shrinkage and creep models for a high-strength concrete mix with a high dosage of supplementary cementitious materials, (b) developing simulation protocols for assessing posttensioned member stresses in a network tied arch, and (c) validating the protocols using data from an instrumented bridge. The strains in the posttensioned members of the 2nd Avenue network tied arch bridge in Detroit, Michigan, were measured using embedded vibrating wire strain gauge sensors. A three-dimensional finite element model of the network tied arch located on the west side of the bridge was developed using ABAQUS and validated using measured strains. In addition, the time-dependent modulus of elasticity and the creep and shrinkage characteristics of the concrete mix was evaluated in the laboratory. The field and laboratory measured creep and shrinkage strains were compared with those calculated using existing empirical models. Accordingly, the CEB-FIP 2010 model was selected to represent the creep and shrinkage behavior of the posttensioned members using user subroutines. The simulation results closely matched the data collected from the instrumented bridge and validated the developed simulation protocols. The findings support the use of developed protocols for simulating posttensioned members with complex geometries and time-dependent material properties. Further, the developed protocols can be implemented to establish the final state of stress in the completed bridge.

Access Setting

Dissertation-Abstract Only

Restricted to Campus until

8-1-2025

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