Timber vs. composite/plastic pile fender systems in Pearl Harbor maintenance cost comparison

Abstract

The Navy has traditionally used treated timber materials for fender systems for piers and wharves in Pearl Harbor. In recent years, the costs associated with the use of timber have escalated and the Navy has begun to use plastic piles at installations around the world to replace timber fender systems. Plastic fender systems are more expensive, but have greater energy absorption capabilities and are more resilient to environmental decay. To determine whether plastic piles are a cost saving alternative to treated timber, the present study compiled and evaluated existing technical data, maintenance/ construction records and inspection reports from various Navy staff civil engineer offices and at the Navy Public Works Center Pearl Harbor (PWC). Since records at these various locations were not designed to present associated cost/ maintenance data in a format suitable for an economic analysis, field surveys of over 3 miles of waterfront in Pearl Harbor and interviews with staff civil engineers and wharf building branch managers at PWC were conducted to supplement existing historical data. Through the gathered data, the maintenance costs of timber pile fenders are estimated and compared to those of composite plastic piles using manufacturers' quotes and from reports compiled by the Navy Civil Engineering Laboratory (NCEL). For the expected life cycles of timber piles observed in Pearl Harbor this analysis shows the proposed plastic system to be more cost effective for shore facilities with remaining service lives of greater than ten years