👉Construction notes
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🚧What is the different between the one way slab and two way slab?
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📌One Way Slab
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▶️one way slab is supported by beams on 2 sides of longer span (rectangular).
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📌Two Way Slab
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▶️Two way slab is supported by beams on 4 sides of both span(square).
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📌One way slab
▶️In one way slab L/B>2 .here length is more than breadth
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▶️In one way slab the Main reinforcement should be provided on one direction.
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▶️The One way slab is supported by two parallel beams or walls.
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▶️In one way slab the Main bars Dia should be not less than 12 mm.
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▶️In one way slab the Distribution bars Dia should be not less than 8 mm.
📌Two way slab
▶️In two way slab L/B<2 .here length and breadth are almost equal.
▶️In two way slab the Main reinforcement should be provided on both direction.
▶️The two way slab is supported by four parallel beams or walls.
▶️Main bars Dia should be not less than 12 mm.
▶️Distribution bars Dia should be not less than 8 mm.
▶️Reinforcement of slab depends on size of room / slab.
#Constructionnotes
@etconp
.
🚧What is the different between the one way slab and two way slab?
.
📌One Way Slab
.
▶️one way slab is supported by beams on 2 sides of longer span (rectangular).
.
📌Two Way Slab
.
▶️Two way slab is supported by beams on 4 sides of both span(square).
.
📌One way slab
▶️In one way slab L/B>2 .here length is more than breadth
.
▶️In one way slab the Main reinforcement should be provided on one direction.
.
▶️The One way slab is supported by two parallel beams or walls.
.
▶️In one way slab the Main bars Dia should be not less than 12 mm.
.
▶️In one way slab the Distribution bars Dia should be not less than 8 mm.
📌Two way slab
▶️In two way slab L/B<2 .here length and breadth are almost equal.
▶️In two way slab the Main reinforcement should be provided on both direction.
▶️The two way slab is supported by four parallel beams or walls.
▶️Main bars Dia should be not less than 12 mm.
▶️Distribution bars Dia should be not less than 8 mm.
▶️Reinforcement of slab depends on size of room / slab.
#Constructionnotes
@etconp
👉Construction notes
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📌Why should construction joints in concrete slabs have slip dowels through the joint from one slab into the adjacent?
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▶️Concrete, like all other materials, expand when heated and contract when cooled.
▶️Dowels are provided between concrete pavement slabs to transfer load from one slab to the next when the wheel of the vehicle moves over the joint. If these dowels are firmly fixed in both the slabs, it will not allow slabs to contract or expand when weather turns cold or hot.
▶️This will cause temperature stresses to develop in the slabs and concrete adjacent to the joint will crack.
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▶️To allow for expansion and contraction of both the slabs while maintaining load transfer mechanism, dowels are provided which are fixed at one end and able to slide or move into a groove on the other end, along with provision of expansion joint in the slab.
#Constructionnotes
@etconp
.
📌Why should construction joints in concrete slabs have slip dowels through the joint from one slab into the adjacent?
.
▶️Concrete, like all other materials, expand when heated and contract when cooled.
▶️Dowels are provided between concrete pavement slabs to transfer load from one slab to the next when the wheel of the vehicle moves over the joint. If these dowels are firmly fixed in both the slabs, it will not allow slabs to contract or expand when weather turns cold or hot.
▶️This will cause temperature stresses to develop in the slabs and concrete adjacent to the joint will crack.
.
▶️To allow for expansion and contraction of both the slabs while maintaining load transfer mechanism, dowels are provided which are fixed at one end and able to slide or move into a groove on the other end, along with provision of expansion joint in the slab.
#Constructionnotes
@etconp
👉Construction Notes
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📌when casting beam it is not recommended to stop the casting at the mid-span, why?
*Where are they supposed to stop? What about the column?
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▶️The Construction Engineer says:-
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📌I believe that you are asking why it is not good to stop the casting of a reinforced concrete beam at mid-span.
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▶️It’s primarily because that would create a “joint” in the beam at the point that the casting was stopped and re-started. This is not a real joint, of course, but it’s a weakness that is incorporated into the beam.
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▶️Also, mid-span is precisely where one would expect the maximum bending moment, for normal loading conditions. For example, a simply-supported beam of length L and distributed load W uniformly distributed over the entire beam (W = wL) has a maximum bending moment M = WL/8 and it occurs at the center of the span.
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▶️If I were casting such a reinforced concrete beam, I would cast it at least as long as the distance between the supporting columns.
#Constructionnotes
@etconp
.
📌when casting beam it is not recommended to stop the casting at the mid-span, why?
*Where are they supposed to stop? What about the column?
.
▶️The Construction Engineer says:-
.
📌I believe that you are asking why it is not good to stop the casting of a reinforced concrete beam at mid-span.
.
▶️It’s primarily because that would create a “joint” in the beam at the point that the casting was stopped and re-started. This is not a real joint, of course, but it’s a weakness that is incorporated into the beam.
.
▶️Also, mid-span is precisely where one would expect the maximum bending moment, for normal loading conditions. For example, a simply-supported beam of length L and distributed load W uniformly distributed over the entire beam (W = wL) has a maximum bending moment M = WL/8 and it occurs at the center of the span.
.
▶️If I were casting such a reinforced concrete beam, I would cast it at least as long as the distance between the supporting columns.
#Constructionnotes
@etconp
👍1
👉Which is heavier, cement or sand?
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📌To answer this let us understand specific gravity , the specific gravity of a material gives us how much more or less dense the material is than water.
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📌Water has a specific gravity of 1.000 (near 4°C). If a material is more dense than water, then its specific gravity is greater than 1.
If it is less dense than water, then the specific gravity is less than 1.
📌Specific gravity of sand is 2.6 - 2.7 and that of cement is 3.14 - 3.15
i.e. for the same volume occupied by cement and sand , cement is “3.15/2.8 = 1.16 times”heavier than sand.
#ConstructionNotes
@etconp
.
📌To answer this let us understand specific gravity , the specific gravity of a material gives us how much more or less dense the material is than water.
.
📌Water has a specific gravity of 1.000 (near 4°C). If a material is more dense than water, then its specific gravity is greater than 1.
If it is less dense than water, then the specific gravity is less than 1.
📌Specific gravity of sand is 2.6 - 2.7 and that of cement is 3.14 - 3.15
i.e. for the same volume occupied by cement and sand , cement is “3.15/2.8 = 1.16 times”heavier than sand.
#ConstructionNotes
@etconp
👉Construction Notes
🚧Prestressed concrete with its use
.
📌Before getting into prestressed concrete, let us go back to the basics first.
.
▶️We all know that concrete is strong in compression and weak in tension.
*This is reason for providing reinforcement (in the form of steel bars) to resist tension/tensile force acting on beams columns/slabs etc.
.
▶️RCC structures under service load undergoes deflection causing the bottom of the beam (tensile zone) to elongate, causing cracks.
.
▶️Generally, steel bars are provided to limit the crack widths and resist the tensile force which the concrete lacks.
*Here, the rebar acts as ‘passive reinforcement’. Rebars (steel reinforcement) provided at the bottom of the bar, does not carry any forces until the concrete has already deflected enough to crack.
.
📌How it is used?
.
▶️This is where prestressing comes into action.
*The principle behind prestressed concrete is that compressive stresses induced by high-strength steel tendons in a concrete member before loads are applied will balance the tensile stresses imposed in the member during service.
.
▶️Simply, Permanent pre compression is produced in the areas subjected to tension using high tensile strength steel wires or alloys.
*Now, a portion of tensile stress is counteracted, thereby reducing the cross sectional area of steel reinforcement.
.
*As as result, the concrete does not crack because the pre-stressing has reduced the tensile stress in the section below cracking stress.
*hence concrete is treated as a elastic material.
.
▶️Now, the concrete is said to have two compressive force:
.
1. Internal prestressing force
2. External forces (Dead load, Live load etc.)
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▶️These two forces must counteract each other.
.
*When loads are applied, reinforcing steel takes on more stress and the compressive force in the concrete is reduced greatly, so that it doesn’t become a tensile force.
As a result the concrete is less prone to cracks or failures because it is always under compression.
📌Definition:
.
▶️Prestressed concrete is concrete that has had internal stresses introduced to counteract, to the degree desired.
*the tensile stresses that will be imposed in service. The stress is usually imposed by tendons of individual hard-drawn wires, cables of hard-drawn wires, or bars of high strength alloy steel.
.
▶️Prestressing may be achieved either by pretensioning or by post tensioning.
.
▶️Prestressed concrete structures can be classified in a number of ways depending upon the feature of designs and constructions.
.
🔹 1. Pre-tensioning:
▶️As the name says, the steel wires or tendons are tensioned first and the concrete is poured later. *Tendons are temporarily anchored and tensioned and the prestress is transferred to the concrete after it is hardened.
*Then the tendon tries to shrink back to the original length, but resisted by the bond between the concrete thereby inducing ! compressive force in it.
🔹 2. Post-tensioning:
.
▶️Post- tensioning similar to pre-tensioning, where concrete is poured first, allowed to harden and the tendons is tensioned later. Tendons are placed in sheathing at suitable places in the member before casting and later after hardening of concrete.
.
📌Uses:
▶️Longer spans constructions
▶️Unique designs: irregular shapes
▶️Shorter construction cycles
▶️Cost reduction
▶️Shorter floor-to-floor heights
▶️Superior structural performance
#ConstructionNotes
@etconp
🚧Prestressed concrete with its use
.
📌Before getting into prestressed concrete, let us go back to the basics first.
.
▶️We all know that concrete is strong in compression and weak in tension.
*This is reason for providing reinforcement (in the form of steel bars) to resist tension/tensile force acting on beams columns/slabs etc.
.
▶️RCC structures under service load undergoes deflection causing the bottom of the beam (tensile zone) to elongate, causing cracks.
.
▶️Generally, steel bars are provided to limit the crack widths and resist the tensile force which the concrete lacks.
*Here, the rebar acts as ‘passive reinforcement’. Rebars (steel reinforcement) provided at the bottom of the bar, does not carry any forces until the concrete has already deflected enough to crack.
.
📌How it is used?
.
▶️This is where prestressing comes into action.
*The principle behind prestressed concrete is that compressive stresses induced by high-strength steel tendons in a concrete member before loads are applied will balance the tensile stresses imposed in the member during service.
.
▶️Simply, Permanent pre compression is produced in the areas subjected to tension using high tensile strength steel wires or alloys.
*Now, a portion of tensile stress is counteracted, thereby reducing the cross sectional area of steel reinforcement.
.
*As as result, the concrete does not crack because the pre-stressing has reduced the tensile stress in the section below cracking stress.
*hence concrete is treated as a elastic material.
.
▶️Now, the concrete is said to have two compressive force:
.
1. Internal prestressing force
2. External forces (Dead load, Live load etc.)
.
▶️These two forces must counteract each other.
.
*When loads are applied, reinforcing steel takes on more stress and the compressive force in the concrete is reduced greatly, so that it doesn’t become a tensile force.
As a result the concrete is less prone to cracks or failures because it is always under compression.
📌Definition:
.
▶️Prestressed concrete is concrete that has had internal stresses introduced to counteract, to the degree desired.
*the tensile stresses that will be imposed in service. The stress is usually imposed by tendons of individual hard-drawn wires, cables of hard-drawn wires, or bars of high strength alloy steel.
.
▶️Prestressing may be achieved either by pretensioning or by post tensioning.
.
▶️Prestressed concrete structures can be classified in a number of ways depending upon the feature of designs and constructions.
.
🔹 1. Pre-tensioning:
▶️As the name says, the steel wires or tendons are tensioned first and the concrete is poured later. *Tendons are temporarily anchored and tensioned and the prestress is transferred to the concrete after it is hardened.
*Then the tendon tries to shrink back to the original length, but resisted by the bond between the concrete thereby inducing ! compressive force in it.
🔹 2. Post-tensioning:
.
▶️Post- tensioning similar to pre-tensioning, where concrete is poured first, allowed to harden and the tendons is tensioned later. Tendons are placed in sheathing at suitable places in the member before casting and later after hardening of concrete.
.
📌Uses:
▶️Longer spans constructions
▶️Unique designs: irregular shapes
▶️Shorter construction cycles
▶️Cost reduction
▶️Shorter floor-to-floor heights
▶️Superior structural performance
#ConstructionNotes
@etconp
👉Some Important Definitions
🚧 Water content : Ratio of the weight of water to the weight of solids.
🚧Void Ratio : Ratio of the volume of voids to the volume of solids.
🚧Porosity : Ratio of the volume of voids to the total volume of the soil.
🚧Degree of saturation : Ratio of the volume of water to the volume of voids.
🚧Air content : Ratio of volume of air voids to the volume of voids.
🚧Percentage air voids : Ratio of the volume of air voids expressed as a percentage of total volume of the soil.
🚧Unit weight : It is the weight per unit volume.
🚧Bulk Unit weight : Total weight of soil mass, per unit of total volume.
🚧Dry unit weight : Weight of solids per unit of total volume.
🚧Saturated unit weight : Ratio of total weight of a fully saturated soil, to its total volume.
🚧Submerged unit weight : Ratio of the submerged weight of soil, to its total volume.
🚧Unit weight of solids : Ratio of the weight of solids, to the volume of solids.
🚧Specific gravity : Ratio of the weight of a given volume of solids to the weight of an equivalent volume of water at 4°C.
🚧Apparent or Mass specific gravity : Ratio of the total weight of a given mass of soil to the weight of an equivalent volume of water.
#ConstructionNotes
#SoilMechanics
@etconp
🚧 Water content : Ratio of the weight of water to the weight of solids.
🚧Void Ratio : Ratio of the volume of voids to the volume of solids.
🚧Porosity : Ratio of the volume of voids to the total volume of the soil.
🚧Degree of saturation : Ratio of the volume of water to the volume of voids.
🚧Air content : Ratio of volume of air voids to the volume of voids.
🚧Percentage air voids : Ratio of the volume of air voids expressed as a percentage of total volume of the soil.
🚧Unit weight : It is the weight per unit volume.
🚧Bulk Unit weight : Total weight of soil mass, per unit of total volume.
🚧Dry unit weight : Weight of solids per unit of total volume.
🚧Saturated unit weight : Ratio of total weight of a fully saturated soil, to its total volume.
🚧Submerged unit weight : Ratio of the submerged weight of soil, to its total volume.
🚧Unit weight of solids : Ratio of the weight of solids, to the volume of solids.
🚧Specific gravity : Ratio of the weight of a given volume of solids to the weight of an equivalent volume of water at 4°C.
🚧Apparent or Mass specific gravity : Ratio of the total weight of a given mass of soil to the weight of an equivalent volume of water.
#ConstructionNotes
#SoilMechanics
@etconp
👉Terms related to Mass Haul Diagram
🚧Free haul distance
🔷Distance up to which the excavated material is hauled without any extra cost.
🚧Over haul distance
🔷Excess of haul distance beyond the free haul distance.
🚧Borrow
🔷Quantity of material ( in cubic meter) required for the embankment taken from borrow pits.
🚧Haul
🔷Sum of the products of each load by its respective haul distance.
🔷 Unit of haul is cum meter or station-meter.
🔷 1 station-meter is equal to 1 cubic meter of excavated material hauled through one station (30 meter distance)
🚧Economical Overhaul Distance or Limit of economical haul
🔷 Maximum distance to which the excavation obtained may be utilized in filing up any depression.
🔷 L = (B/O)+F
*⃣L = Economical Overhaul Distance
*⃣B = Cost of borrow per cubic meter at station
*⃣O= cost of overhaul per station-meter
*⃣F = Free haul distance
🚧Waste
🔷Material excavated from cuts but not used for embankment.
🚧Balancing line
🔷The horizontal line(base line) drawn on the mass haul diagram.
#ConstructionNotes
#HighwayEngineering
@etconp
🚧Free haul distance
🔷Distance up to which the excavated material is hauled without any extra cost.
🚧Over haul distance
🔷Excess of haul distance beyond the free haul distance.
🚧Borrow
🔷Quantity of material ( in cubic meter) required for the embankment taken from borrow pits.
🚧Haul
🔷Sum of the products of each load by its respective haul distance.
🔷 Unit of haul is cum meter or station-meter.
🔷 1 station-meter is equal to 1 cubic meter of excavated material hauled through one station (30 meter distance)
🚧Economical Overhaul Distance or Limit of economical haul
🔷 Maximum distance to which the excavation obtained may be utilized in filing up any depression.
🔷 L = (B/O)+F
*⃣L = Economical Overhaul Distance
*⃣B = Cost of borrow per cubic meter at station
*⃣O= cost of overhaul per station-meter
*⃣F = Free haul distance
🚧Waste
🔷Material excavated from cuts but not used for embankment.
🚧Balancing line
🔷The horizontal line(base line) drawn on the mass haul diagram.
#ConstructionNotes
#HighwayEngineering
@etconp
👉Superelevation (Cant) or Banking
➡️It is the transverse inclination of the pavement surface, in which the outer edge is raised with respect to the inner edge.
🚧Superelevation is provided to counteract the effect of centrifugal force and to reduce the tendency of the vehicle to overturn.
🚧Superelevation is expressed as the ratio of the height of outer edge with respect to the horizontal width.
🚧Maximum limits of Superelevation are
1⃣ For plain and rolling terrains in snow bound areas = 7.0 %
2⃣ For hill roads not bound by snow = 10 %
3⃣ For urban road stretches with frequent intersections = 4%
🚧Superelevation should not be less than the Camber of the road surface.
🚧Superelevation should be attained gradually over the full length of transition curve so that the design Superelevation is available at the starting point of the circular curve.
🚧In case where transition curve cannot be provided,2/3rd of the Superelevation may be attained at the straight portion before the start of the circular curve and the balance 1/3rd at the beginning of the circular curve.
🚧Superelevation is introduced by raising the outer edge of the pavement at a rate not exceeding 1 in 150 in plain and rolling terrains and 1 in 60 on mountainous and steep terrain.
#ConstructionNotes
#HighwayEngineering
@etconp
➡️It is the transverse inclination of the pavement surface, in which the outer edge is raised with respect to the inner edge.
🚧Superelevation is provided to counteract the effect of centrifugal force and to reduce the tendency of the vehicle to overturn.
🚧Superelevation is expressed as the ratio of the height of outer edge with respect to the horizontal width.
🚧Maximum limits of Superelevation are
1⃣ For plain and rolling terrains in snow bound areas = 7.0 %
2⃣ For hill roads not bound by snow = 10 %
3⃣ For urban road stretches with frequent intersections = 4%
🚧Superelevation should not be less than the Camber of the road surface.
🚧Superelevation should be attained gradually over the full length of transition curve so that the design Superelevation is available at the starting point of the circular curve.
🚧In case where transition curve cannot be provided,2/3rd of the Superelevation may be attained at the straight portion before the start of the circular curve and the balance 1/3rd at the beginning of the circular curve.
🚧Superelevation is introduced by raising the outer edge of the pavement at a rate not exceeding 1 in 150 in plain and rolling terrains and 1 in 60 on mountainous and steep terrain.
#ConstructionNotes
#HighwayEngineering
@etconp
👉Methods of Curing
🚧1. Curing by spraying water
➡️Spraying of water continuously on the concrete surface provides an efficient curing. It is mostly used for curing floor slabs.
▶️The concrete should be allowed to set sufficiently before sprinkling is started.
▶️The spray can be obtained from a perforated plastic box. On small jobs sprinkling of water may be done by hand.
▶️Vertical and sloping surfaces can be kept continuously wet by sprinkling water on top surfaces and allowing it to run down between the forms and the concrete. For this method of curing the water requirement is higher.
🚧2. Curing using wet Gunny bags
➡️This is a widely used method of curing, particularly for structural concrete Thus exposed surface of concrete is prevented from drying out by covering it with hessian, canvas or empty cement bags. The covering over vertical and sloping surfaces should be secured properly These are periodically wetted.
▶️The interval of wetting will depend upon the rate of evaporation of water. It should be ensured that the surface of concrete is not allowed to dry even for a short time during the curing period.
▶️Special arrangements for keeping the surface wet must be made at nights and on holidays.
🚧3. Curing by Pounding Method
➡️This is the best method of curing.
▶️It is suitable for curing horizontal surfaces such as floors, roof slabs, road and air field pavements. The horizontal top surfaces of beams can also be Pounded. After placing the concrete, its exposed surface is first covered with moist hessian or canvas. After 24 hours, these covers are removed and small ponds of clay or sand are built across and along the pavements. The area is thus divided into a number of rectangles.
▶️The water is filled between the ponds.
▶️The filling of water in these ponds is done twice or thrice a day, depending upon the atmospheric conditions. Though this method is very efficient, the water requirement is very heavy. Ponds easily break and water flows out. After curing it is difficult to clean the clay.
🚧4. Steam Curing
➡️Steam curing and hot water curing is sometimes adopted. With these methods of curing, the strength development of concrete is very rapid.
▶️These methods can best be used in pre cast concrete work. In steam curing the temperature of steam should be restricted to a maximum of 750C as in the absence of proper humidity (about 90%) the concrete may dry too soon. In case of hot water curing, temperature may be raised to any limit, ay 1000C.
▶️At this temperature, the development of strength is about 70% of 28 days strength after 4 to 5 hours. In both cases, the temperature should be fully controlled to avoid non-uniformity. The concrete should be prevented from rapid drying and cooling which would form cracks.
🚧5. Curing using chemicals
➡️Curing compounds are chemical products usually Sprayed directly over the concrete surface and allowing it to dry.
▶️The compound forms an impermeable membrane that retards the loss of moisture from the concrete.
#ConstructionNotes
#Curing
@etconp
🚧1. Curing by spraying water
➡️Spraying of water continuously on the concrete surface provides an efficient curing. It is mostly used for curing floor slabs.
▶️The concrete should be allowed to set sufficiently before sprinkling is started.
▶️The spray can be obtained from a perforated plastic box. On small jobs sprinkling of water may be done by hand.
▶️Vertical and sloping surfaces can be kept continuously wet by sprinkling water on top surfaces and allowing it to run down between the forms and the concrete. For this method of curing the water requirement is higher.
🚧2. Curing using wet Gunny bags
➡️This is a widely used method of curing, particularly for structural concrete Thus exposed surface of concrete is prevented from drying out by covering it with hessian, canvas or empty cement bags. The covering over vertical and sloping surfaces should be secured properly These are periodically wetted.
▶️The interval of wetting will depend upon the rate of evaporation of water. It should be ensured that the surface of concrete is not allowed to dry even for a short time during the curing period.
▶️Special arrangements for keeping the surface wet must be made at nights and on holidays.
🚧3. Curing by Pounding Method
➡️This is the best method of curing.
▶️It is suitable for curing horizontal surfaces such as floors, roof slabs, road and air field pavements. The horizontal top surfaces of beams can also be Pounded. After placing the concrete, its exposed surface is first covered with moist hessian or canvas. After 24 hours, these covers are removed and small ponds of clay or sand are built across and along the pavements. The area is thus divided into a number of rectangles.
▶️The water is filled between the ponds.
▶️The filling of water in these ponds is done twice or thrice a day, depending upon the atmospheric conditions. Though this method is very efficient, the water requirement is very heavy. Ponds easily break and water flows out. After curing it is difficult to clean the clay.
🚧4. Steam Curing
➡️Steam curing and hot water curing is sometimes adopted. With these methods of curing, the strength development of concrete is very rapid.
▶️These methods can best be used in pre cast concrete work. In steam curing the temperature of steam should be restricted to a maximum of 750C as in the absence of proper humidity (about 90%) the concrete may dry too soon. In case of hot water curing, temperature may be raised to any limit, ay 1000C.
▶️At this temperature, the development of strength is about 70% of 28 days strength after 4 to 5 hours. In both cases, the temperature should be fully controlled to avoid non-uniformity. The concrete should be prevented from rapid drying and cooling which would form cracks.
🚧5. Curing using chemicals
➡️Curing compounds are chemical products usually Sprayed directly over the concrete surface and allowing it to dry.
▶️The compound forms an impermeable membrane that retards the loss of moisture from the concrete.
#ConstructionNotes
#Curing
@etconp
❤1👍1
👉Construction Notes
➡️Important Points On Soil
🚧Loam Soil - is a mixture of sand, silt and clay.
🚧Peat - is a fibrous aggregate of finer fragments of decayed vegetable matter.
*⃣Peat is very compressible and one should be cautious when using it for supporting foundations of structures.
🚧Kaolin - are very pure forms of white clay used in the ceramic industry.
🚧Calcareous Soil - is a soil containing Calcium Carbonate. Such soil effervesces when tested with weak HCl.
🚧Shale - is a material in the state of transition from clay to slate.
*⃣Shale itself is sometimes considered a rock but, when it is exposed to the air or has a chance to take in water it may rapidly decompose.
🚧Normally Consolidated Clay = when the soil is currently experiencing its maximum load.
🚧Over Consolidated Clay = the soil experienced its maximum load in the past.
#ConstructionNotes
@etconp
➡️Important Points On Soil
🚧Loam Soil - is a mixture of sand, silt and clay.
🚧Peat - is a fibrous aggregate of finer fragments of decayed vegetable matter.
*⃣Peat is very compressible and one should be cautious when using it for supporting foundations of structures.
🚧Kaolin - are very pure forms of white clay used in the ceramic industry.
🚧Calcareous Soil - is a soil containing Calcium Carbonate. Such soil effervesces when tested with weak HCl.
🚧Shale - is a material in the state of transition from clay to slate.
*⃣Shale itself is sometimes considered a rock but, when it is exposed to the air or has a chance to take in water it may rapidly decompose.
🚧Normally Consolidated Clay = when the soil is currently experiencing its maximum load.
🚧Over Consolidated Clay = the soil experienced its maximum load in the past.
#ConstructionNotes
@etconp
👉Short Notes About Footing
🏷FOOTINGS
➡️Footings are mainly used to transmit the load from super structure to the underlying soil (substructure)
🚧1. Isolated footings
▶️Isolated footings are provided under each column and may be rectangular, square or circular in plan.
▶️It’s footing may be flat or tapered
🚧2. Combined Footings
▶️Combined footing supports two or sometimes three columns in a row.
▶️Combined footing is used when property lines, equipment locations, column spacing or other considerations limit the footing clearance at the column location Combined footing can be rectangular in shape if both the columns carry equal loads or Trapezoidal if there is a space limitation and they carry unequal loads.
🚧3. Strap footings
▶️Consists of two individual footings connected by a beam called strap.
▶️It’s used where the distance between the columns is so great that a trapezoidal combined footing becomes quite narrow, with resulting high bending moments.
▶️The strap beam doesn’t remain in contact with soil so a strap doesn’t transfer any pressure to the soil.
🚧4. Mat or raft foundation
▶️Is Combined footing that covers the entire area beneath a structure and supports all the columns.
▶️Foundation Engineers often considers mats when dealing with any one of the following conditions
*⃣The structural loads are so high or the soil conditions so poor that spread footings would be exceptionally large
*⃣The soil is very erratic and prone to excessive differential settlement.
*⃣The structural loads are erratic and thus increase the likelihood of excessive differential settlement.
🚧5. Pile foundations
▶️Pile foundations are the part of a structure used to carry and transfer the load of the structure to the bearing ground located at some depth below ground surface.
▶️The main components of the foundation are the pile cap and the piles.
▶️Piles are relatively long and slender members used to transmit foundation loads through soil strata of low bearing capacity to deeper soil or rock having a higher bearing capacity.
#ConstructionNotes
#Footing
@etconp
🏷FOOTINGS
➡️Footings are mainly used to transmit the load from super structure to the underlying soil (substructure)
🚧1. Isolated footings
▶️Isolated footings are provided under each column and may be rectangular, square or circular in plan.
▶️It’s footing may be flat or tapered
🚧2. Combined Footings
▶️Combined footing supports two or sometimes three columns in a row.
▶️Combined footing is used when property lines, equipment locations, column spacing or other considerations limit the footing clearance at the column location Combined footing can be rectangular in shape if both the columns carry equal loads or Trapezoidal if there is a space limitation and they carry unequal loads.
🚧3. Strap footings
▶️Consists of two individual footings connected by a beam called strap.
▶️It’s used where the distance between the columns is so great that a trapezoidal combined footing becomes quite narrow, with resulting high bending moments.
▶️The strap beam doesn’t remain in contact with soil so a strap doesn’t transfer any pressure to the soil.
🚧4. Mat or raft foundation
▶️Is Combined footing that covers the entire area beneath a structure and supports all the columns.
▶️Foundation Engineers often considers mats when dealing with any one of the following conditions
*⃣The structural loads are so high or the soil conditions so poor that spread footings would be exceptionally large
*⃣The soil is very erratic and prone to excessive differential settlement.
*⃣The structural loads are erratic and thus increase the likelihood of excessive differential settlement.
🚧5. Pile foundations
▶️Pile foundations are the part of a structure used to carry and transfer the load of the structure to the bearing ground located at some depth below ground surface.
▶️The main components of the foundation are the pile cap and the piles.
▶️Piles are relatively long and slender members used to transmit foundation loads through soil strata of low bearing capacity to deeper soil or rock having a higher bearing capacity.
#ConstructionNotes
#Footing
@etconp
👉Important concepts
🔹Which type of cement is used for underground concrete structures ?
➡️SRC (Sulphate Resisting Cement)
▶️The use of SRC is recommended for following applications:
*⃣Foundations, piles, basements and underground structures.
*⃣Sewage and Water treatment plants.
🔹What Is Roller Support
➡️Roller supports only resists perpendicular forces and they cannot resist parallel or horizontal forces & moment.
➡️It means the roller support will move freely along the surface without resisting horizontal force.
🔹What is the Concrete Temperature?
➡️Concrete temperature should not be more than 33°C & not less than 15°C in cold weather But the pumping temperature of concrete in hot weather should be 26°C.
🔹Do you know SPT ?
➡️SPT (Standard Penetration Test) is carried out to know the bearing capacity of soil.
➡️This is usually done on the foundation of bridges and the huge buildings.
#ConstructionNotes
@etconp
🔹Which type of cement is used for underground concrete structures ?
➡️SRC (Sulphate Resisting Cement)
▶️The use of SRC is recommended for following applications:
*⃣Foundations, piles, basements and underground structures.
*⃣Sewage and Water treatment plants.
🔹What Is Roller Support
➡️Roller supports only resists perpendicular forces and they cannot resist parallel or horizontal forces & moment.
➡️It means the roller support will move freely along the surface without resisting horizontal force.
🔹What is the Concrete Temperature?
➡️Concrete temperature should not be more than 33°C & not less than 15°C in cold weather But the pumping temperature of concrete in hot weather should be 26°C.
🔹Do you know SPT ?
➡️SPT (Standard Penetration Test) is carried out to know the bearing capacity of soil.
➡️This is usually done on the foundation of bridges and the huge buildings.
#ConstructionNotes
@etconp
👉Important Different Notes
🔹What is Fixed Supports
➡️Fixed supports are also known as rigid supports.
➡️Fixed supports are restrained against both rotation and translation so that they can resist any type of force or moment.
🔹Pinned / Hinged Support
➡️Pinned or hinged support can resist both vertical and horizontal forces but they cannot resist a moment.
➡️It means that hinged support is restrained against translation.
🔹What is Strip footing
➡️It is a component of shallow foundation which distributes the weight of a load bearing wall across the area of the ground.
➡️It is also known as a wall footing.
🔹What is Purpose of liquid limit test of soil
➡️Liquid limit can be determined to know shearing resistance of the soil.
🔹Difference between Earthen and Gravel Road
🚧Earthen Roads
➡️Earthen roads are lay with soil But, They are cheaper of all types of roads.
➡️Generally, This type of road is provided for less traffic areas and or for countryside areas.
➡️Good drainage system should be require which reflects good performance for longer period.
🚧Gravel Roads
➡️Gravel roads are also low quality roads but they are good when compare to earthen roads.
➡️Compacted mixture of gravel and earth is use as pavement material in this case.
#ConstructionNotes
@etconp
🔹What is Fixed Supports
➡️Fixed supports are also known as rigid supports.
➡️Fixed supports are restrained against both rotation and translation so that they can resist any type of force or moment.
🔹Pinned / Hinged Support
➡️Pinned or hinged support can resist both vertical and horizontal forces but they cannot resist a moment.
➡️It means that hinged support is restrained against translation.
🔹What is Strip footing
➡️It is a component of shallow foundation which distributes the weight of a load bearing wall across the area of the ground.
➡️It is also known as a wall footing.
🔹What is Purpose of liquid limit test of soil
➡️Liquid limit can be determined to know shearing resistance of the soil.
🔹Difference between Earthen and Gravel Road
🚧Earthen Roads
➡️Earthen roads are lay with soil But, They are cheaper of all types of roads.
➡️Generally, This type of road is provided for less traffic areas and or for countryside areas.
➡️Good drainage system should be require which reflects good performance for longer period.
🚧Gravel Roads
➡️Gravel roads are also low quality roads but they are good when compare to earthen roads.
➡️Compacted mixture of gravel and earth is use as pavement material in this case.
#ConstructionNotes
@etconp
👉Important concepts
🔹Compression failure in columns
➡️When columns are axially loaded, the concrete and steel will experience some stresses.
➡️When the loads are greater in amount compared to the cross sectional area of the column, the concrete and steel will reach the yield stress and failure will be starting without any later deformation.
➡️In this type of failure, the material fails itself, not the whole column.
➡️This type of failure mostly occurs in shorter and wider columns.
➡️To avoid this, the column should be made with sufficient cross-sectional area compared to the allowable stress.
🚧Function of stirrups in the column
➡️Stirrups are provided to handle the shear force and to hold the rebars in position.
#ConstructionNotes
@etconp
🔹Compression failure in columns
➡️When columns are axially loaded, the concrete and steel will experience some stresses.
➡️When the loads are greater in amount compared to the cross sectional area of the column, the concrete and steel will reach the yield stress and failure will be starting without any later deformation.
➡️In this type of failure, the material fails itself, not the whole column.
➡️This type of failure mostly occurs in shorter and wider columns.
➡️To avoid this, the column should be made with sufficient cross-sectional area compared to the allowable stress.
🚧Function of stirrups in the column
➡️Stirrups are provided to handle the shear force and to hold the rebars in position.
#ConstructionNotes
@etconp
👉Important Notes
🔸Important concepts in Irrigation Engineering.
🚧Duty :
➡️The term duty means the area of land that can be irrigated with unit volume of irrigation water. Duty represents the irrigating capacity of a unit.
🚧Delta:
➡️It is the total depth of the water required by a crop during the entire period the crop is in the field and is denoted by the symbol ∆.
🏷What Is Barrage Mean
➡️A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through.
➡️This allows the structure to regulate and stabilize river water elevation upstream for use in irrigation and other systems.
🔹Purpose of Barrage
*⃣1. To maintain pond level.
*⃣2. To raise the water level during low supplies. In case of higher floods, shutters are dropped down and overflow takes place while in case of gated weir, gates are raised during floods.
🏷What Are The Various Tests on Concrete with Apparatus
⏺1. Slump Cone Test
⏺2. Compressive Strength Test
⏺3. Water Absorption Test
⏺4. Water Permeability Test
⏺5. Compaction Factor Test
🏷What Is Contour map Mean
➡️A topographic map on which the shape of the land surface is shown by contour lines, the relative spacing of the lines indicating the relative slope of the surface.
🏷What Is Development length
➡️Development length is an extera length of steel, which transfer the load from one steel bar to other.
#ConstructionNotes
@etconp
🔸Important concepts in Irrigation Engineering.
🚧Duty :
➡️The term duty means the area of land that can be irrigated with unit volume of irrigation water. Duty represents the irrigating capacity of a unit.
🚧Delta:
➡️It is the total depth of the water required by a crop during the entire period the crop is in the field and is denoted by the symbol ∆.
🏷What Is Barrage Mean
➡️A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through.
➡️This allows the structure to regulate and stabilize river water elevation upstream for use in irrigation and other systems.
🔹Purpose of Barrage
*⃣1. To maintain pond level.
*⃣2. To raise the water level during low supplies. In case of higher floods, shutters are dropped down and overflow takes place while in case of gated weir, gates are raised during floods.
🏷What Are The Various Tests on Concrete with Apparatus
⏺1. Slump Cone Test
⏺2. Compressive Strength Test
⏺3. Water Absorption Test
⏺4. Water Permeability Test
⏺5. Compaction Factor Test
🏷What Is Contour map Mean
➡️A topographic map on which the shape of the land surface is shown by contour lines, the relative spacing of the lines indicating the relative slope of the surface.
🏷What Is Development length
➡️Development length is an extera length of steel, which transfer the load from one steel bar to other.
#ConstructionNotes
@etconp
👉Lets See About Structure Supports
🔹Fixed Supports
▶️Fixed supports are also known as rigid supports.
▶️Fixed supports are restrained against both rotation and translation so that they can resist any type of force or moment.
🔹Pinned / Hinged Support
▶️Pinned or hinged support can resist both vertical and horizontal forces but they cannot resist a moment.
▶️It means that hinged support is restrained against translation.
🔹Roller Support
▶️Roller supports only resists perpendicular forces and they cannot resist parallel or horizontal forces & moment.
▶️It means the roller support will move freely along the surface without resisting horizontal force.
#Structure
#ConstructionNotes
@etconp
🔹Fixed Supports
▶️Fixed supports are also known as rigid supports.
▶️Fixed supports are restrained against both rotation and translation so that they can resist any type of force or moment.
🔹Pinned / Hinged Support
▶️Pinned or hinged support can resist both vertical and horizontal forces but they cannot resist a moment.
▶️It means that hinged support is restrained against translation.
🔹Roller Support
▶️Roller supports only resists perpendicular forces and they cannot resist parallel or horizontal forces & moment.
▶️It means the roller support will move freely along the surface without resisting horizontal force.
#Structure
#ConstructionNotes
@etconp
📌Difference between working stress approach and limit state approach
🔸Working Stress Approach
➡️The service loads are used in the whole design and the strength of material is not utilized in the full extent.
➡️In this method of design, stresses acting on structural members are calculated based on elastic method and they are designed not to exceed certain allowable values.
➡️In fact, the whole structure during the life span may only experience loading stresses far below the ultimate state and that is the reason why this method is called working stress approach.
➡️Under such scenario, the most economical design can hardly be obtained by using working stress approach which is now commonly used in the design of temporary works.
🔸Limit State Approach
▶️For each material and load, a partial safety factor is assigned individually depending on the material properties and load properties.
▶️Therefore, each element of load and material properties is accurately assessed resulting in a more refined and accurate analysis of the structure.
▶️In this connection, the material strength can be utilized to its maximum value during its life span and loads can be assessed with reasonable probability of occurrence.
▶️Limit state approach is commonly used for the majority of reinforced concrete design because it ensures the utilization of material strength with the lowest construction cost input.
#ConstructionNotes
#Structure
@etconp
🔸Working Stress Approach
➡️The service loads are used in the whole design and the strength of material is not utilized in the full extent.
➡️In this method of design, stresses acting on structural members are calculated based on elastic method and they are designed not to exceed certain allowable values.
➡️In fact, the whole structure during the life span may only experience loading stresses far below the ultimate state and that is the reason why this method is called working stress approach.
➡️Under such scenario, the most economical design can hardly be obtained by using working stress approach which is now commonly used in the design of temporary works.
🔸Limit State Approach
▶️For each material and load, a partial safety factor is assigned individually depending on the material properties and load properties.
▶️Therefore, each element of load and material properties is accurately assessed resulting in a more refined and accurate analysis of the structure.
▶️In this connection, the material strength can be utilized to its maximum value during its life span and loads can be assessed with reasonable probability of occurrence.
▶️Limit state approach is commonly used for the majority of reinforced concrete design because it ensures the utilization of material strength with the lowest construction cost input.
#ConstructionNotes
#Structure
@etconp
👉HOW TO TAKE 90 DEGREE ANGLE FOR BUILDING LAYOUT
➡️How we can take the 90 degree angle in building layout so after reading this article you will be able to know how to take 90 degree angle during layout at site.
▶️In many projects many students can become the face of this problem that they are not able to take 90 angle for building or room layout at site and keep in your mind that we must take any corner of the building on 90 degree so after that our work will be fine from that.
▶️So the given formula which I am showing you now , this is the manual formula which you can do with the help of measurment tape.
🚧FORMULA TO TAKE 90 DEGREE
*⃣3 AND 4 = 5
▶️Here we have to take one side 3 meter or feet and 2nd side 4
▶️So the other side should be measure 5 meter than it will give us 90 degree angle.
🚧*NOTE:* the above formula we can not use for level machine or any other electronic machine it just used for manual work and we can complete our lay-outing with 90 degree angle with the help of measurement tape.
#ConstructionNotes
@etconp
➡️How we can take the 90 degree angle in building layout so after reading this article you will be able to know how to take 90 degree angle during layout at site.
▶️In many projects many students can become the face of this problem that they are not able to take 90 angle for building or room layout at site and keep in your mind that we must take any corner of the building on 90 degree so after that our work will be fine from that.
▶️So the given formula which I am showing you now , this is the manual formula which you can do with the help of measurment tape.
🚧FORMULA TO TAKE 90 DEGREE
*⃣3 AND 4 = 5
▶️Here we have to take one side 3 meter or feet and 2nd side 4
▶️So the other side should be measure 5 meter than it will give us 90 degree angle.
🚧*NOTE:* the above formula we can not use for level machine or any other electronic machine it just used for manual work and we can complete our lay-outing with 90 degree angle with the help of measurement tape.
#ConstructionNotes
@etconp
👉What are the advantages of piers constructed monolithically with the bridge deck over usage of bearings?
➡️Basically, piers constructed monolithically with the bridge deck are advantageous in the
following ways:
🚧(i) Movement of the bridge deck is achieved by the bending deformation of long andslender piers.
▶️In this way, it saves the construction cost of bearings by using monolithic construction between bridge deck and piers.
▶️Moreover, it is not necessary to spend extra effort to design for drainage details and access for bearing
replacement.
▶️On the other hand, in maintenance aspect substantial cost and time
savings could be obtained by using monolithic construction instead of using bearings as bridge articulation.
🚧(ii) Monolithic construction possesses the shortest effective Euler buckling length for piers because they are fixed supports at the interface between bridge deck and piers.
⚡️Note: Monolithic construction means that piers are connected to bridge decks without any joints and bearings.
#ConstructionNotes
@etconp
➡️Basically, piers constructed monolithically with the bridge deck are advantageous in the
following ways:
🚧(i) Movement of the bridge deck is achieved by the bending deformation of long andslender piers.
▶️In this way, it saves the construction cost of bearings by using monolithic construction between bridge deck and piers.
▶️Moreover, it is not necessary to spend extra effort to design for drainage details and access for bearing
replacement.
▶️On the other hand, in maintenance aspect substantial cost and time
savings could be obtained by using monolithic construction instead of using bearings as bridge articulation.
🚧(ii) Monolithic construction possesses the shortest effective Euler buckling length for piers because they are fixed supports at the interface between bridge deck and piers.
⚡️Note: Monolithic construction means that piers are connected to bridge decks without any joints and bearings.
#ConstructionNotes
@etconp
👉Some important facts
🚧1. Weight of one cement bag = 50 kg
🚧2. Minimum thickness of slab = 125 mm
🚧3. Minimum lintel thickness =15 cm
🚧4. Minimum diameter of bars used in slab= 8 mm
🚧5. Minimum diameter of bars Used in column = 12 mm
🚧6. Maximum diameter of bars in slab= 1/8x(thickness of slab )
🚧7. Maximum chair spacing = 1m
🚧8. Initial setting time of cement = 30 min
🚧9. Final setting time = 10 hrs ( 600 minutes )
🚧10. DPR = Detailed Project Report
🚧11. Unit weight
▶RCC = 25 KN/ m3
▶PCC = 24 KN/ m3
▶Steel = 7850 kg/ m3
🚧12. Minimum number of bars For square column or rectangular = 4 bars & For circular column = 6 bars
🚧13. Weight of steel = D2/162.2 kg/m.
🚧14. Slope of staircase = 25° -40° from horizontal.
🚧15. Size of concrete testing cube= (150x150x150)mm.
🚧16. Concrete cube is filled in 3 layers.
🚧17. Slump cone is filled in 4 layers.
🚧18. Cement should be used within three months of manufacturing.
🚧19. Minimum thickness of shear wall = 150 mm.
🚧20. Maximum thickness of shear wall = 400 mm.
🚧21. Universal testing machine is used for compression Test of concrete and tensile test of steel reinforcement.
🚧22. Minimum curing period of normal weather conditions is = 7 days
🚧23. Minimum curing period of dry and hot weather conditions is = 10 days
🚧24. Minimum percentage of steel in column = 0.8% of the cross section.
🚧25. Normal cover
➡️Footing = 50 mm
➡️Column = 25 mm
➡️Slab = 15 mm
➡️Beam = 25 mm
🚧26. Number Of Clear span stirrups in beam = Center to Center length /Total Length +1
🚧27. RCC is affected by water because of the corrosion of reinforcement bars.
🚧28. PCC is not affected by the water
🚧29. Maximum free fall of concrete = 1.5 m
🚧30. Air voids left in concrete is called as Honey Combing.
🚧31. The transverse reinforcement of column are called TIES.
🚧32. The transverse reinforcement in beams are called STIRRUPS.
🚧33. Cement ingredients are Burnt @ 1400°C temperature
🚧34. Short columns fail in Crushing.
🚧35. Long columns fail in Buckling.
🚧36. Intermediate columns can fail both in Buckling and Crushing.
🚧37. Strength of reinforcement shouldn't be less than 15 % of its designated strength.
🚧38. Compressive strength of bricks
▶️1st class bricks = 105 kg/cm2.
▶️2nd class bricks = 70 kg/cm2.
▶️3rd class bricks = 35 kg/cm2.
🚧39. PH value of water used concrete should not be less than 6.
🚧40. Riser = (150 - 200) mm.
🚧41. Tread = (250 - 300) mm.
🚧42. Height of parapet wall should be= 1m.
🚧43. TMT - Thermo mechanically treated bars.
🚧44. TMX - Thermax powered bars
🚧45. SDB - Super ductile bars.
#ConstructionNotes
@etconp
🚧1. Weight of one cement bag = 50 kg
🚧2. Minimum thickness of slab = 125 mm
🚧3. Minimum lintel thickness =15 cm
🚧4. Minimum diameter of bars used in slab= 8 mm
🚧5. Minimum diameter of bars Used in column = 12 mm
🚧6. Maximum diameter of bars in slab= 1/8x(thickness of slab )
🚧7. Maximum chair spacing = 1m
🚧8. Initial setting time of cement = 30 min
🚧9. Final setting time = 10 hrs ( 600 minutes )
🚧10. DPR = Detailed Project Report
🚧11. Unit weight
▶RCC = 25 KN/ m3
▶PCC = 24 KN/ m3
▶Steel = 7850 kg/ m3
🚧12. Minimum number of bars For square column or rectangular = 4 bars & For circular column = 6 bars
🚧13. Weight of steel = D2/162.2 kg/m.
🚧14. Slope of staircase = 25° -40° from horizontal.
🚧15. Size of concrete testing cube= (150x150x150)mm.
🚧16. Concrete cube is filled in 3 layers.
🚧17. Slump cone is filled in 4 layers.
🚧18. Cement should be used within three months of manufacturing.
🚧19. Minimum thickness of shear wall = 150 mm.
🚧20. Maximum thickness of shear wall = 400 mm.
🚧21. Universal testing machine is used for compression Test of concrete and tensile test of steel reinforcement.
🚧22. Minimum curing period of normal weather conditions is = 7 days
🚧23. Minimum curing period of dry and hot weather conditions is = 10 days
🚧24. Minimum percentage of steel in column = 0.8% of the cross section.
🚧25. Normal cover
➡️Footing = 50 mm
➡️Column = 25 mm
➡️Slab = 15 mm
➡️Beam = 25 mm
🚧26. Number Of Clear span stirrups in beam = Center to Center length /Total Length +1
🚧27. RCC is affected by water because of the corrosion of reinforcement bars.
🚧28. PCC is not affected by the water
🚧29. Maximum free fall of concrete = 1.5 m
🚧30. Air voids left in concrete is called as Honey Combing.
🚧31. The transverse reinforcement of column are called TIES.
🚧32. The transverse reinforcement in beams are called STIRRUPS.
🚧33. Cement ingredients are Burnt @ 1400°C temperature
🚧34. Short columns fail in Crushing.
🚧35. Long columns fail in Buckling.
🚧36. Intermediate columns can fail both in Buckling and Crushing.
🚧37. Strength of reinforcement shouldn't be less than 15 % of its designated strength.
🚧38. Compressive strength of bricks
▶️1st class bricks = 105 kg/cm2.
▶️2nd class bricks = 70 kg/cm2.
▶️3rd class bricks = 35 kg/cm2.
🚧39. PH value of water used concrete should not be less than 6.
🚧40. Riser = (150 - 200) mm.
🚧41. Tread = (250 - 300) mm.
🚧42. Height of parapet wall should be= 1m.
🚧43. TMT - Thermo mechanically treated bars.
🚧44. TMX - Thermax powered bars
🚧45. SDB - Super ductile bars.
#ConstructionNotes
@etconp
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