NAS TRANSITION ENGINEERING SERVICES | PROVIDING ALL CIVIL ENGINEERING SOLUTION
About Geotechnical Engineering
Speciality of Sub Soil Investigation team of NAS:
NAS has its own geotechnical laboratory equipped with necessary routine testing facilities. If some specialized testing is required by client or consultancy necessary that is not available in NAS laboratory, NAS provides that test result performed by BRTC, BUET. NAS’s equipments are manufactured as per specification of American Society for Testing and Materials (ASTM). In Bangladesh SPT is usually performed by labours which has following limitations.
SPT boring team is not aware of importance of height of fall. Most of the cases height of fall is more than that specified in ASTM.
SPT spoon is usually does not comply with ASTM. Most of the cases, driving shoe of SPT spoon is sharper than that specified in ASTM.
Undisturbed sampling by Shelby tubes are disturbed significantly because of use of very low quality Shelby tube samplers.
SPT N value is an indicator of shear strength of soil. Larger value of N means more shear strength of soil. Due to above mentioned limitations SPT N value we get is less than actual value. That means we are getting less strength of soil than it actually have. As a result foundation designs become expensive.
For considering the above mentioned limitations, NAS is providing the auto hammer for SPT N value in field. Auto hammer is manufactured as per specification of American Society for Testing Materials. NAS is collecting undisturbed soil sample by using ASTM standard Shelby tube which is first one for Bangladesh. This type of Shelby tube is manufactured first by NAS for Bangladesh & now BUET also using this.
Most of the structures in Bangladesh are failing for only foundation problem. NAS foundation designer always respect the client requirement which is the “Minimum cost with proper design”.
SPT boring team is not aware of importance of height of fall. Most of the cases height of fall is more than that specified in ASTM.
SPT spoon is usually does not comply with ASTM. Most of the cases, driving shoe of SPT spoon is sharper than that specified in ASTM.
Undisturbed sampling by Shelby tubes are disturbed significantly because of use of very low quality Shelby tube samplers.
SPT N value is an indicator of shear strength of soil. Larger value of N means more shear strength of soil. Due to above mentioned limitations SPT N value we get is less than actual value. That means we are getting less strength of soil than it actually have. As a result foundation designs become expensive.
For considering the above mentioned limitations, NAS is providing the auto hammer for SPT N value in field. Auto hammer is manufactured as per specification of American Society for Testing Materials. NAS is collecting undisturbed soil sample by using ASTM standard Shelby tube which is first one for Bangladesh. This type of Shelby tube is manufactured first by NAS for Bangladesh & now BUET also using this.
Most of the structures in Bangladesh are failing for only foundation problem. NAS foundation designer always respect the client requirement which is the “Minimum cost with proper design”.
Geotechnical Engineering Services
Consultancy
Foundation Design
Liquefaction Analysis
Design, Installation & Development of Wells/ Deep Tube Wel
Geotechnical Investigation
Field Tests:
Standard Penetration Test -rotary drilling and percussion drilling method
Dynamic Cone Penetration Test (DCP)
California Bearing Ratio (CBR) In Situ
Field Vane Shear Test
Electrical Resistivity Test of Soil
Thermal Resistivity Test of Soil
Plate Load Test
Field Density Test by Sand Replacement Method
In Situ Permeability Test
Perculation Test
Laboratory Tests:
Liquid limit, plastic limit and shrinkage limit
Grain size distribution or sieve analysis
Hydrometer analysis
Unconfined compression test
Direct shear test
One Dimensional Consolidation Test
Triaxial test of Soil (UU, CU and CD)
Specific gravity
Natural moisture content
California Bearing Ratio- Laboratory (Soaked CBR Test
Relative density
Laboratory Permeability Test of Soil
Engineering Classification of Soil
Maximum Density of Soil
Pile Test:
Static Axial Compressive Pile Load Test
Static Axial Lateral Load Test
Static Axial Uplift Load Test
High Strain Pile Testing / Pile Dynamic Analyser (PDA) / Pile Load Test
