FPInnovations provides practical advice on installing culverts./Culvert construction forest road.jpg)
Loggers are always searching for ways to make their road budgets stretch further, while still protecting the environment. A technical note from FPInnovations provides a few practical examples of cost effective culvert foundations that are currently being tested. Inadequate culvert foundations, especially on soft soils, can result in the structure shifting or sinking, and even having pipes sag in the centre. The information is intended for smaller culvert structures that foresters or their contractors construct, and not major structures where engineering consultants are required. The following designs are presented:
Loggers are always searching for ways to make their road budgets stretch further, while still protecting the environment. A technical note from FPInnovations provides a few practical examples of cost effective culvert foundations that are currently being tested. Inadequate culvert foundations, especially on soft soils, can result in the structure shifting or sinking, and even having pipes sag in the centre. The information is intended for smaller culvert structures that foresters or their contractors construct, and not major structures where engineering consultants are required. The following designs are presented:
- Using a geogrid under the pipe and extended into the road base.
- Using a geogrid in the same manner as above, but also placing gravel or coarse soil material over the geogrid. The gravel can also assist in lifting the culvert foundation to the desired elevation.
- A single layer of corduroy is placed into the excavated trench parallel to the pipe direction. The corduroy is then covered by a geotextile and gravel in a method similar to the design above.
- A design similar to the above, but two layers of corduroy are used with the geotextile and gravel, with the lower layer being parallel to the pipe and the upper layer being perpendicular to the pipe.
- The trench is excavated until more stable soil is located. The trench is then lined with a geotextile layer and a deep backfill of gravel is used above this.
- EPS (expanded polystyrene) foam blocks are placed in a shallow trench and lined with a geotextile. A gravel bedding is placed over this.
- Log piles are driven into the subsoil at the bottom of the trench, with a timber or log mat placed over this. This is covered with the geotextile and gravel fill.