Join TheConstructor to ask questions, answer questions, write articles, and connect with other people. When you join you get additional benefits.
Log in to TheConstructor to ask questions, answer people’s questions, write articles & connect with other people. When you join you get additional benefits.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
What are the construction practices used to avoid differential settlement in foundation?
Which type of foundation is best for black cotton soil?
Depending on the structural needs one can choose shallow, deep as well as mat foundation. The thing that matters is which type of structure is going to be built. Thank you!
Depending on the structural needs one can choose shallow, deep as well as mat foundation. The thing that matters is which type of structure is going to be built.
Thank you!
See lessDuring manual concreting of a raft footing which was designed for M25 grade concrete, the estimated cement required was 240 bags, while the laborers due to sheer negligence have added only 140 bags. The Soil conditions are good. There was ...
Effect of cement content on strength of footing: The result reveals that the strength of concrete Foundation increases with increasing cement content in it. However, for concrete with cement content more than 150 kg per metre cube then the strength increases with the increase in the size of coarse aRead more
The result reveals that the strength of concrete Foundation increases with increasing cement content in it.
However, for concrete with cement content more than 150 kg per metre cube then the strength increases with the increase in the size of coarse aggregate up to 25 mm and decreases as the aggregate size increases beyond 25mm.
Without a proper range of cement in the mixture then low strength development or excessive shrinkage may occur leading to premature deterioration.
Thank you. Â
See lessWhat are the bearing capacity values of different types of soils such as clay, sand, gravel, rocks etc.?
Follwoing are the values of safe bearing capacity as per IS:1904–1978 - Rocks - a) hard sound rock - 330 t/m2 or 3240 KN/m2 b) leminated rock - 165 t/m2 or 1620 KN/m2 c) residual deposit of shattered and broken rocks- 90 t/m2 or 880 KN/m2 d) soft rock - 45 t/m2 or 440 KN/m2 Non Cohesive Soil (sandRead more
Follwoing are the values of safe bearing capacity as per IS:1904–1978 –
Rocks –
a) hard sound rock – 330 t/m2 or 3240 KN/m2
b) leminated rock – 165 t/m2 or 1620 KN/m2
c) residual deposit of shattered and broken rocks- 90 t/m2 or 880 KN/m2
d) soft rock – 45 t/m2 or 440 KN/m2
Non Cohesive Soil (sand & gravel ) –
a) compact gravel, sand and gravel – 45 t/m2 or 440 KN/m2
b) compact and dry coarse sand – 45 t/m2 or 440 KN/m2
c) compact and dry medium sand – 25 t/m2 or 245 KN/m2
d) find sand – 15 t/m2 or 150 KN/m2
e) loose gavel or sand – 25 t/m2 or 245 KN/m2
f) loose and dry fine sand – 10 t/m2 or 100 KN/m2
Cohesive soil –
a) hard or stiff clay, soft shale – 45 t/m2 or 440 KN/m2
b) medium clay – 25 t/m2 or 245 KN/m2
c) moist clay and sand clay mixture – 15 t/m2 or 150 KN/m2
d) soft clay – 10 t/m2 or 100 KN/m2
e) very soft clay – 5 t/m2 or 50 KN/m2
f) black cotton soil , peat – by soil investigation
This is bit difficult to state like this. Generally, in fields, we deal with layered soil systems where in you need to work out settlement of each layer and then compare the same to allowable settlement of the subject structure. The allowable settlement for each structure in different and hence the criterion changes all the time.
More than shear criteria, the settlement criteria generally governs the safe bearing capacity of a soil. So, it is difficult to standardize the bearing capacity values in case of soils. May be, in the case of rock, you can standardize the values as the rock does not settle more than 3–4 mm.
See lessWhat is the difference between gray water and black water in sewage? How can we differentiate between them in a sewer?
Difference between Black Water and greywater: Black Water: Blackwater is the best water from bathrooms and toilets that contains faecal matter and urine. Waterproof kitchens and dishwashers are also considered Black Water due to the contamination of pathogens. It is also referred to as she waits forRead more
Black Water:
Treatment of blackwater:
Greywater:
Treatment of Greywater
Thank you.
See lessWhat is the step by step procedure for construction of foundation for a building? How the foundation construction is carried out at site?
Step by Step procedure for construction of building foundation on an organised construction site can be as below: First step is to write a method statement involving scope of work, references, count and type equipments and labour required and requirements . Ensure you have  approved drawings good foRead more
Step by Step procedure for construction of building foundation on an organised construction site can be as below:
Hope this helps.
See less
How many-legged stirrups do I have to provide in Footing if shear stress exceeds 5 kg/cm2?
2 legged vertical stirrups are to be provided when shear stress increases more than 5kg/cm2. The footing undergoes punching shear due to which its stability.One-way shear has to be checked across the full width of the base slab on a vertical section located from the face of the column, pedestal or wRead more
2 legged vertical stirrups are to be provided when shear stress increases more than 5kg/cm2. The footing undergoes punching shear due to which its stability.One-way shear has to be checked across the full width of the base slab on
a vertical section located from the face of the column, pedestal or wall at a distance equal to
(i) effective depth of the footing slab in case of footing slab on soil.
2) half the effective depth of the footing slab if the footing slab is on
Two-way or punching shear (cls.31.6 and 34.2.4)
Two-way or punching shear shall be checked around the column on a
perimeter half the effective depth of the footing slab away from the face of the column or pedestal
The permissible shear stress, when shear reinforcement is not provided, shall not exceed ks c τ , where ks = (0.5 + β c ), but not greater than one, β c being the ratio of short side to long side of the column, and c τ = 0.25(fck) 1/2 in limit state
method of design, as stipulated in. Normally, the thickness of the base slab is governed by shear. Hence, the necessary thickness of the slab has to be provided to avoid shear reinforcement.
See less
When should we opt for continuous footing?
A continuous footing is the one which supports more than two columns. This footing is also called as strip footing and is analogous to the strip footing for wall. The loads from the individual columns are transferred either directly to the footing slab, or through a longitudinal beam running longituRead more
A continuous footing is the one which supports more than two columns. This footing is also called as strip footing and is analogous to the strip footing for wall. The loads from the individual columns are transferred either directly to the footing slab, or through a longitudinal beam running longitudinally when the loads are heavy.
See less
Komal Bhandakkar
Differential settlement in foundation: Usually, due to poor compaction, lower bearing capacity of the soil, high depth of hard strata, various changes in water content in soil are the basic reason behind the differential settlement of soil. Apart from that, trees & vegetation is not good for fouRead more
Differential settlement in foundation:
Usually, due to poor compaction, lower bearing capacity of the soil, high depth of hard strata, various changes in water content in soil are the basic reason behind the differential settlement of soil.
Apart from that, trees & vegetation is not good for foundation safety.
Soil consolidation is the main reason for differential settlement of the foundation.
Foundation push piers & foundation underpinning also harms the foundation, which leads to a differential settlement.
Thank you.
See less