Provides comprehensive guidelines for the design and construction of well foundations, primarily used for bridges and heavy structures across riverbeds. It covers the estimation of scour depth, design of well components like steining and bottom plug, and safe sinking practices including pneumatic methods and tilt/shift limits.
Lays down provisions for the design and construction of well foundations, commonly used for major bridges, covering sinking, and founding levels.
Quick Reference Values
Permissible tilt during sinking1 in 80
Permissible shift during sinking150 mm
Minimum vertical reinforcement in steining0.12% of gross cross-sectional area
Minimum hoop reinforcement in steining0.04% of gross volume
Key Formulas
d = 0.473 * (Q/f)^(1/3) — Normal depth of scour using Lacey's formula
Practical Notes
Continuous monitoring of tilts and shifts is critical during the open dredging/sinking process to ensure they do not exceed the 1-in-80 and 150mm limits.
Kentledge loading must be applied symmetrically to prevent eccentric stresses and unwanted tilting during well sinking.
The bottom plug must be designed and cast underwater carefully to resist upward hydrostatic pressure before the well can be safely dewatered.