07/1571 - Response to Information Request [As Published] · 142007.1571

Project 305-2325

 

February, 2006 ; Page 12
Underground Services

Where footings are located adjacent to existing structures, revetment walls etc. the
footings should extend to base a minimum of 200mm below the base level for a distance
of 1m out from the trench. Beyond 1m, the footings should be taken a minimum of

200mm below an imaginary line drawn up at 30 degrees from the base level. Figure 1
refers.

These requirements do not override minimum footing base levels.

 

 

 
     

 

 

 

 

Service
0 Trench
All footings 200mm
below this line 30°
1.0
‘ FIGURE 1
Pile Groups

Where higher column loads are involved, pile groups may need to be used to achieve the
required load bearing capacities.

Where pile groups are required, a pile spacing of not less than 2.5 times the pile diameter
is recommended. Larger pile spacing can be used if the efficiency of the pile groups
needs to be increased. Table 5 indicates the relationship between pile spacing and group
efficiency (after Tomlinson 1969).

TABLE 5 PILE GROUP EFFICIENCY

 

 
    

 

 

4%
2 x Pile Diameter 0.7
4 x Pile Diameter 0.8

 

 

 

 

 

2% SOIL SURVEYS ENGINEERING