Tower Foundation Design
1. Designing Factors
GBT – Soil test of the site. Important factors governing foundation design are SBC, angle of repose, soil density, water table, filled up soil depth if any.
RTT – Physical check of existing bars in building column, size of building column, layout.
2. IS Codes and Foundation Design
All steel reinforcement shall be high yield strength cold deformed bars confirming to IS-1786-1985 with min. yield stress of 0.2% proof stress of 415 N/sq mm (grade Fe 415).
Concrete for all RCC work shall be of Grade M20 as per IS:456:2000
Water for construction work shall confirm to clause of IS:456
All lap/development length for reinforcement shall be 47xdia of bar.
Welding of bars shall be done as per IS:2751:1979
Clear cover to main reinforcement shall be as per IS:456
TNS has expert structure consultant team to carry out design work. Emphasis is given on optimization of foundation. Special software tools are used to carry out this task. Apart from raft and isolated footing foundation designs, pile foundation is also designed. Integrated team of design and soil testing helps to get desired output in short span and better efficiency.
Soil Testing is mandatory requirement to bring any ground base site. This is carried out to know soil bearing capacity of the soil where foundation needs to be designed for ground base tower. The bearing capacity is one of most important factor for designing the tower foundation for GBT site. TNS has competent teams to carry out this activity with own tools and laboratory to analyze and generate report. In order to establish the sub-soil characteristic at the area marked for tower, the investigation is carried out in two parts:
Part I: Field Test, which comprises
Collection of samples for detailed laboratory analysis
Carrying out standard penetration tests.
Part II: Laboratory Test, which comprises:
Grain size analysis
Liquid limit and plastic limit
Natural moisture contents
Bulk density and dry density
Direct sheer test
Tri axial shear test in unconsolidated un drained condition Consolidation test