A guideline for the installation of culverts on forest roads

Abstract

There are many culverts installed in forest roads each year that fail prematurely, due to improper installation techniques. This report presents a general guideline for the proper installation of culverts on forest roads. The guideline is based on eleven common modes of failure identified from forty-two case studies. This study was carried out from May to September, 2000. It was concluded from this study that vertical deflection, collapse and erosion were the most frequent failure modes. It was also determined that the main causes to all the failures found were inadequate compaction and improper depth placement of the culvert. These to types of causes resulted in 38 of the 42 cases. These results were then used for the formulation of a installation guideline to avoid the failures observed. The culvert installation guideline presented at the end of this report is a concise step by step guide to installing culverts. There is an additional laminated field guide which highlights the two most problematic steps, inadequate compaction and improper depth placement of the culvert. Information concerning basic soil mechanics, and culvert structures are also presented in this manual as background information, that is vital for road builders to know when performing culvert installations . The installation guideline will help lower road construction and maintenance costs.