Segelsen Ridge Project

Segelsen Ridge was a tremendously challenging project for PTS, involving the design and construction of a Verizon Wireless Cellular Facility in the Mt. Baker National Forest at an elevation of 4,400 feet above sea level.

Site access for construction and maintenance to the site is impassable 5 months out of the year, as there is an average snow pack of over 15 feet between November and April. There is no electrical service to the site due to the costs and hazards of routing utilities to the location. As a result of these factors, the project required that the facility be powered locally with on-site generation that must sustain all radio and support systems through the 5 month period without refueling.

On-site fuel capacity is limited to 1,000 gallons of propane by the US Forest Service. Typical genset systems providing primary power for a facility of this size have a maximum runtime of 2-3 months based upon a 1,000 gallon fuel reserve. In order to extend runtime by a factor of 100%, creative approaches to power management, energy conservation and thermal efficiency were applied. In close working conjunction with the genset, dc power plant, air conditioning and general contractor, many innovative approaches to passive and active energy conservation and control resolved the extension of runtime spanning the 5 month period.

Resolution of design and permitting was compressed due to the limited construction window ending in November. Complex development and programming of black box systems orchestrating optimal operating synergies between the generator and dc plant systems were committed to early in project planning. US Forest Service requirements dictated a design reflecting alpine architecture, while the harsh environmental conditions drove the hardening of both architectural and structural systems. These factors complicated constructability, allowing a very short construction window of time.

A 150' self supporting lattice tower and 3 separate building structures were required to support RF and support systems across a limited area constrained by a sheer cliffside location. Granite subsurface conditions further complicated the planning and design of foundation and grounding systems. Ice canopies spanning the roofs of all buildings were designed to protect the structures from falling ice. A multi-staged air conditioning system relies partly upon direct air cooling through the use of an economizer cycle that is precisely synchronized with indoor and outdoor temperatures along with genset and dc plant operations which were all carefully analyzed to project thermal curves in order to minimize parasitic heat loss and maximize benefit from heat recycling between all systems. The wall mounted air conditioners are protected by deep eaves and snow fences to ensure operation and optimum efficiency during periods when snow accumulation exceeds the height of the units.

Out of the box strategies were employed throughout the project and team effort was extreme. One example illuminating this teamwork was the loss of the primary equipment building that was under fabrication midstream of the project. The shelter was two weeks from completion at a fabrication facility on the Louisiana coast when hurricane Katrina destroyed the fabrication plant and the shelter. Through tremendous team effort on our client's part, an existing shelter earmarked for another market was re-assigned to our project. Rapid assessments and redesign of the original system design and site layout were made to address the different design constraints of this new shelter. Without the flexible attitude and fluid design approach committed by all project team members, this remedial design effort would never have been attempted.