Date of Publication

7-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Subject Categories

Civil and Environmental Engineering | Civil Engineering | Engineering

College

Gokongwei College of Engineering

Department/Unit

Civil Engineering

Honor/Award

Br. Andrew Gonzalez FSC Award for Student Researchers (Doctorate Level)

Thesis Advisor

Lessandre O. Garciano

Defense Panel Chair

Andres Winston C. Oreta

Defense Panel Member

Jonathan R. Dungca

Gerardo Augusto

Mario de Leon

Renan Tanhueco

Abstract/Summary

Water distribution networks (WDN) are expected to perform its function even after seismic events as its service is essential, not only in keeping the welfare of the consumers, but also in performing disaster risk and management, and emergency operations. Hence, it is important that its service is uninterrupted even during and after a seismic event. To ensure uninterrupted service, WDN must adhere to resilient quality and standards. However, measuring the performance of WDN also poses a challenge as the structure of nodes and links that are interconnected, yet, responding independently to hazards.

As observed in developed countries, water distribution networks adhere to resiliency parameters such as robustness, redundancy, resourcefulness, and rapidity. Though no specific resiliency parameters are in place, several guidelines are established by the American Lifeline Alliance (ALA) and Japan Water Works Association (JWWA). For rank A facilities (such as main water distribution, transmission lines, distribution main lines), JWWA sets no light damage; or with light damage but functional; to light damage and may not be functional but can quickly recover its service as its target performance. ALA, on the other hand, sets low rate damage throughout the water system ensuring 90% of customers recover its water service within three days from a seismic event damage, and an amount of damage of 0.03 to 0.06 breaks per 1000 feet for 6-inch diameter pipes as its target performance.

Researchers, engineers, and field experts are also pushing for resilient water networks. Frameworks on resiliency and methodologies were presented to aid in quantifying the resiliency of water infrastructures. However, there is still a gap in measuring resiliency based on a framework that considered resiliency to be defined by robustness, redundancy, rapidity, and resourcefulness (4Rs). Though many have established resiliency quantification considering robustness, rapidity, and resourcefulness, there is a limited methodology that considers redundancy and its influence on WDN resiliency. It is critically important to include the influence of redundancy in WDN’s resiliency as the availability of a backup system can help ensure the continuity of functionality. Hence, this study focuses on measuring resiliency considering all 4Rs with emphasis on the influence of redundancy on it. Moreover, there is also a need for a continuous search for a tool to measure redundancy, as existing tools were shown to be not sensitive to parameters known to highly influence redundancy such as pipe capacity, number of alternative paths, and sources.

This study aimed to contribute in quantifying resiliency in water distribution networks by developing a novel method to measure resiliency. The method incorporates all 4Rs (i.e. robustness, redundancy, rapidity, and resourcefulness) in the resiliency quantification. Available tools are employed to measure robustness (e.g. PSHA, measurement of critical damage rate), rapidity (e.g. minimum spanning tree, and maximum slope method), and resourcefulness (accomplished through a survey). However, in measuring redundancy, due to the shortcoming of existing tools, a method is proposed to measure redundancy. The method involves measuring the probability of relative isolation of a demand node from a source node as links (or pipes) may

fail during a seismic event and the chance of maintaining connectivity is influenced by the backup capacity or alternative paths. Similarly, since resiliency quantification based on existing tools excludes redundancy, this study proposed a tool to measure resiliency with effects due to redundancy considered. Hence, a resiliency quantification that includes robustness, rapidity, resourcefulness, and redundancy can now be utilized as an output of this study.

The redundancy analysis, utilizing the method developed, was applied to 3 case study areas. It was shown that redundancy is highly influenced by the performance of links. Link’s performance (pipe capacity), expressed in terms of probability of failure, determines whether a path that leads to a node (connecting it from a source) may fail or not, rendering the node isolated if it fails. Another factor that affects redundancy is the availability of alternative paths, and strategic placement of additional source. Analysis results, however, showed that number of paths and links, are not as strongly as pipe capacity’s influence to connectivity.

Resiliency analysis was performed utilizing the method developed by the author/s that incorporates robustness, redundancy, rapidity, and resourcefulness. It was shown that better redundancy performance greatly improves the resiliency performance of a water distribution network as characterized by a resiliency index. Through the developed method to measure resiliency via resiliency index, it was shown that water distribution networks with good redundancy feature can improve the resiliency index of a water distribution network.

Abstract Format

html

Language

English

Format

Electronic

Keywords

Redundancy (Engineering); Water-supply engineering

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1-17-2028

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