Fences are very commonly found above retaining walls. If a fence is going to be added to the wall during or after the wall’s construction several things need to be considered.
Impact structures or fence posts should be positioned a minimum of 3 ft (0.9 m) from the back of top course to allow a properly designed load for local overturning.
If fence posts must be placed within 3 ft (0.9 m) of the back of the wall facing, the designer must consider the localized top of wall overturning force into their design.
Common post footings are formed by using construction tubes placed at desired on-center locations during construction. If posts are placed after construction is complete, holes must be hand dug as using a power auger will cause severe damage to the geogrid layers.
If the post design calls for an engineered product to solve localized overturning forces, a product such as the (ref. BP, Chapter 12.2) can be specified. Sleeve-IT is a Stratagrid product designed for use in segmental retaining walls to resist top of wall overturning forces from fences and railing.Allan Block is working to achieve our industry initiative of Zero Wall Failures. With our Best Practices Manual and experience in the industry we are trying to expand the knowledge base for the design of segmental retaining walls (SRW's) by communicating and educating the professionals in the industry. To see the full Best Practices Manual, visit allanblock.com to download today and keep an eye out for more industry Best Practice recommendations here.