E 670 Retaining Walls and Bulkheads

In the process of street design, particularly on hillside projects, the use of bulkheads or retaining walls must sometimes be considered.  The need for such structures may be due wholly or in part to some of the following requirements:

  1. To correct or alleviate unstable side slope conditions.
  2. To avoid exceeding the allowable maximum cut or fill on side slopes.
  3. To reduce the amount of earthwork (cut or fill).
  4. To reduce excessive right of way costs.
  5. To prevent undermining or burying existing improvements.

Based on the above conditions, if it is decided that structural support is necessary, a choice must be made as to the use of bulkheads or retaining walls. Some of the factors that might influence this decision are treated here only briefly, since the decision may be based in part on the advice of the Geology and Soils Engineering Section or the Street Opening and Widening Division and is normally a function of the Bridge and Structural Design Division.