Clark Public Utilities Reduces Casing Diameters and Minimizes Road Closures on SR 502 Utility Project using Fusible PVC® Pipe

Clark County, one of the fastest growing counties in Southwest Washington, has faced a multitude of unique challenges as the local population has skyrocketed. One specific challenge has involved the acquisition and distribution of potable water to new residents while simultaneously limiting construction impact to local roadways and the environment.

PTo achieve these goals as effectively and efficiently as possible Clark Public Utilities, which owns the Clark County potable water distribution system, has embraced a broad assortment of construction materials and methodologies. Bidding multiple options ensures that the utility receives the most optimal and economical engineered solution on each project.

This innovative approach was recently used on the State Route (SR) 502 Water Main Installation Project. The purpose of the project was to upgrade and link components of the utility's distribution network in the northwest service area of the County. Based on their intimate knowledge of the existing distribution system and considerable experience with an array of utility construction materials and methodologies, the utility contracted with Harper Houf Peterson Righellis, Inc. (HHPR) to evaluate and design the necessary system improvements.

Ultimately the project scope included approximately 23,000 LF of new 16-inch water main along the SR 502 corridor, as well as short extensions of 8-inch through 16-inch distribution lines to intersecting streets and connection points. Rob VanderZanden with HHPR noted, "Project construction was completed under heavy traffic conditions and was further complicated by environmental constraints and challenging soil conditions. The utility's pipeline installation had to be coordinated with the work of multiple other utility organizations and the project success can be attributed to the collaborative approach of all involved parties."

Pipeline Details and Project Summary
Project: SR 502 Water Main Installation
Location: Clark County, WA
Pipe Size: 1,560 LF of 16" DR25, 12" DR18, and 8" DR18 Fusible PVC® Pipe
Owner: Clark Public Utilities
Engineer: Harper Houf Peterson Righellis, Inc.
Contractor: Tapani, Inc

One of the most challenging elements of the project was that SR 502 is a critical traffic corridor between I-5 and Battle Ground, WA. As a result, minimal disruptions to existing traffic flow were allowed. With thirteen cased highway crossings required on the project, HHPR and general contractor Tapani, Inc. (Tapani) turned to Fusible PVC® pipe to help minimize construction time, traffic impact, and overall material cost. By utilizing Fusible PVC® pipe as the carrier pipe, Tapani was able to preload fused sections of Fusible PVC® carrier pipe into the steel casings and then lift the entire pre-assembled pipe system quickly and efficiently into place during controlled lane closures. Also, due to the favorable OD/ID relationship of Fusible PVC® pipe, its zero profile joint, and the lack of casing spacer requirements (Uni-Bell Handbook of PVC Pipe Design and Construction) Tapani was able to minimize material cost by reducing the size of the steel casings.

Russ Knutson of Clark Public Utilities stated, "HHPR put together a great design, accommodating an assortment of materials and innovative construction methods to take full advantage of the competitive local construction market. On the construction side, Tapani did a tremendous job on the project and teamed well with Underground Solutions to ensure the SR 502 road crossings were completed efficiently and with minimal disruption to traffic."

Darren Cahoon, Senior Project Manager with Tapani, added, "With the high profile nature of the project we expected our fair share of headaches. With the attentiveness of the Owner and Engineer and the flexibility of Underground Solutions, the project proceeded rather smoothly."