ORCID Identifier(s)

0000-0003-2751-539X

Graduation Semester and Year

2019

Language

English

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

First Advisor

Xinbao Yu

Abstract

Ever since their advent in the 1800s, corrugated metal pipes (CMPs) have played a vital role in this nation’s infrastructure. The wide range of options on diameter and span have made these culverts more preferable over traditional concrete culverts. However, compared to concrete culverts, CMPs have a shorter design life and are only expected to last 10 to 30 years even under ideal conditions. Over the course of years, different open-cut and trenchless methods have been used to rehabilitate existing old and damaged culverts. In recent years, trenchless methods like sliplining, CIPP, spray-applied pipe linings, etc. have been gaining popularity over open-cut methods as they are quicker, easier to install and prevent economic costs incurred from having to block road traffic over the duration of repairs. In addition to this, rehabilitation methods like CIPP and spray applier linings can benefit significantly from the residual capacity of host pipes. However, this residual capacity is usually ignored when designing such repair methods. One of the reasons for this is because of the difficulty in determining the residual capacity of a damaged culvert. Therefore, if this residual capacity could be properly defined, it can be used to design more efficient and economic rehabilitation methods. In this thesis, laboratory tests and finite element modeling are used to identify the residual capacity of a damaged CMP. Damage to the culvert’s invert due to corrosion and abrasion was found to be the most common form of damage among CMPs. There have been studies in the past that have tried to simulate damaged culverts by reducing the wall thickness in finite element (FE) models or testing deteriorated culverts exhumed from field. However, due to the varying degree and distribution of corrosion in tested culverts, the data cannot be reliably used to quantify the residual capacity of a damaged CMP. Because of this difficulty in maintaining the same degree of control over the damage parameters, CMPs with removed invert are tested to obtain the residual capacity of damaged culverts. This is considered as the worst-case scenario and the base line data obtained from this test can be conservatively used to design suitable repair and rehabilitation practices. To obtain the measure of the residual capacity, an intact CMP is tested for baseline data. Both the CMPs are analyzed under a shallow cover to reduce iii the load distribution provided by the soil and hence further simulate rare but critical field condition. The laboratory test on intact CMP showed that under shallow cover, with a standard AASHTO H20 truck’s footprint sized load pad, the failure mode is local buckling in pipe. The failure of cover soil was seen prior to buckling. However, the system easily handled the H20 service load of 16,000 lbs. without significant deformations to CMP. The finite element model of the test mimicked the test’s response fairly well up to the point of soil failure. Once failure of soil occurred, further response could not be modeled as the numerical solutions did not converge beyond this state. For invert-cut CMP, the failure mode was excessive deformation. This deformation was highest at the location of the removed invert (haunch), with the CMP moving inwards to reduce the gap. The invert-cut CMP was significantly weaker than the intact CMP and the maximum pressure capacity was reduced by over 91%.

Keywords

Corrugated metal pipes, Finite Element Modeling (FEM), Invert removed, Deteriorated culvert, Residual capacity

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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