Date of Award

Spring 2021

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Civil & Environmental Engineering

Program/Concentration

Civil Engineering

Committee Director

Ma Gangfeng

Committee Member

Navid Tahvildari

Committee Member

Jaewan Yoon

Abstract

Low-crested and submerged structures (LCS) play an integral part in the stabilization of shorelines for recreational purposes, yet there are a plethora of empirical models and gaps in the understanding of their stability and damage progression. The objectives were: i) to evaluate the present formulae, ii) explore variable importance, iii) formulate a stability model, iv) extend the current datasets and v) explore a new model for LCS. The literature points to an increasing understanding of the initiation of damage of LCS and recent exploration of the shear stress-induced erosion (van Rijn, 2019). Assessment of two existing models (Kramer, 2006 and Van der Meer and Daemen, 1994) points to reliability in predicting initiation of damage but limitations in skill in modelling progression of damage, for Re >40,000. Two analytical models (and two variations) developed herein point to difficulty (skill) in predicting damage initiation (progression) and the benefit of removing transmitted wave energy. A scale model testing programme added 124 new data points and confirms the importance of relative crest height, increased relative vulnerability of the seaward slope and crest and damage progression. Exploration of several improvements in the model was useful in deriving an LCS model that predicted damage similar to the pooled data and offered insights into the importance of i) seaward slope erosion, ii) drag and lift forces, and iii) Shield's stress relation to relative depth and stone size, Re and gradation. Importantly, damage progression is likely to be non-linear. The model is likely to be conservative and best applied for S

DOI

10.25777/d7g8-c212

ISBN

9798515227036

ORCID

0000-0002-5547-0558

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