1. The document discusses various aspects of constructing substructures or foundations, including site clearance, job layout, excavation methods, timbering and strutting, and different types of foundations.
2. Shallow foundations discussed include stepped foundations, wall footings, reinforced concrete footings, isolated and combined column footings, and raft foundations.
3. Deep foundations include different types of piles as well as well foundations and cofferdams. Piles are further classified based on their function as bearing, friction, sheet, anchor, batter, and fender piles.
The document provides information on the basics of civil engineering foundations. It discusses the objectives and types of foundations, including shallow foundations like isolated and combined footings, and deep foundations such as pile and pier foundations. Pile foundations can be friction piles or load bearing piles. Factors that determine the size and bearing capacity of foundations are also covered. The document contains diagrams to illustrate foundation components and construction methods.
Deep foundations are used when the bearing stratum is located at a significant depth below the surface. The most common types of deep foundations are pile foundations, cofferdams, and caisson foundations. Pile foundations support structures using vertical piles that transfer loads either through end bearing or skin friction. Piles can be made of timber, concrete, steel, or a composite. Cofferdams are temporary structures used to exclude water from a construction site to allow work below the water level. Common types include earthfill, rockfill, single-walled, and cellular cofferdams. Caissons are watertight structures that become part of the permanent foundation. Types are open caissons, box caissons
The document discusses retaining walls and includes:
- Definitions of retaining walls and their parts
- Common types of retaining walls including gravity, semi-gravity, cantilever, counterfort and bulkhead walls
- Earth pressures like active, passive and at rest pressures
- Design principles for stability against sliding, overturning and bearing capacity
- Drainage considerations for retaining walls
- Theories for analyzing earth pressures like Rankine and Coulomb's theories
- Sample design calculations and problems for checking stability of retaining walls
This document discusses deep foundation types used in construction. It provides details on pile foundations, well foundations, and caisson foundations. For pile foundations, it describes different pile types including end bearing piles, skin friction piles, anchor piles, compaction piles, driven piles, and auger cast piles. It also discusses advantages and disadvantages of different deep foundation methods like drilled pier foundations, augered piles, driven concrete piles, and driven wooden piles.
This document provides an overview of foundations for building construction. It discusses the importance of foundations in distributing building loads to the ground. There are two main types of foundations - shallow foundations and deep foundations. Shallow foundations include spread footings, grillage foundations, raft foundations, stepped foundations, and mat/slab foundations. Deep foundations transfer loads deep into the earth and include drilled caissons, driven piles, and precast concrete piles. Foundation design considers factors like soil type, structural requirements, construction requirements, site conditions, and cost. The document also discusses waterproofing, drainage, and underpinning foundations.
This document discusses raft/mat foundations, including:
- A raft foundation is a thick reinforced concrete slab that supports columns and transmits loads into the soil. It is used for structures with large or uneven column loads.
- Types of raft foundations include flat plate, thickened under columns, beam and slab, box structures, and mats on piles.
- Construction involves soil testing, excavation, reinforcement placement, forming, concrete pouring, and curing. Raft foundations are economic and reduce differential settlement but require treatment for point loads.
Joints are easy to maintain and are less detrimental than uncontrolled or uneven cracks. Concrete expands & shrinks with variations in moisture and temp. The overall affinity is to shrink and this can cause cracking at an early age. Uneven cracks are unpleasant and difficult to maintain but usually do not affect the integrity of concrete.
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This document discusses different types of braced excavation systems used to support deep excavations, including soldier beams with lagging, sheet piles, and slurry trenches. It describes the design process for braced cuts, which involves analyzing stability, ground movements, and structural elements like sheet piles and struts. Methods for determining loads on structural elements using tributary area and equivalent beam approaches are presented. Factors affecting stability like heaving in soils are discussed. Design of structural components like struts, wales, and sheet piles is also covered.
The document provides information on the basics of civil engineering foundations. It discusses the objectives and types of foundations, including shallow foundations like isolated and combined footings, and deep foundations such as pile and pier foundations. Pile foundations can be friction piles or load bearing piles. Factors that determine the size and bearing capacity of foundations are also covered. The document contains diagrams to illustrate foundation components and construction methods.
Deep foundations are used when the bearing stratum is located at a significant depth below the surface. The most common types of deep foundations are pile foundations, cofferdams, and caisson foundations. Pile foundations support structures using vertical piles that transfer loads either through end bearing or skin friction. Piles can be made of timber, concrete, steel, or a composite. Cofferdams are temporary structures used to exclude water from a construction site to allow work below the water level. Common types include earthfill, rockfill, single-walled, and cellular cofferdams. Caissons are watertight structures that become part of the permanent foundation. Types are open caissons, box caissons
The document discusses retaining walls and includes:
- Definitions of retaining walls and their parts
- Common types of retaining walls including gravity, semi-gravity, cantilever, counterfort and bulkhead walls
- Earth pressures like active, passive and at rest pressures
- Design principles for stability against sliding, overturning and bearing capacity
- Drainage considerations for retaining walls
- Theories for analyzing earth pressures like Rankine and Coulomb's theories
- Sample design calculations and problems for checking stability of retaining walls
This document discusses deep foundation types used in construction. It provides details on pile foundations, well foundations, and caisson foundations. For pile foundations, it describes different pile types including end bearing piles, skin friction piles, anchor piles, compaction piles, driven piles, and auger cast piles. It also discusses advantages and disadvantages of different deep foundation methods like drilled pier foundations, augered piles, driven concrete piles, and driven wooden piles.
This document provides an overview of foundations for building construction. It discusses the importance of foundations in distributing building loads to the ground. There are two main types of foundations - shallow foundations and deep foundations. Shallow foundations include spread footings, grillage foundations, raft foundations, stepped foundations, and mat/slab foundations. Deep foundations transfer loads deep into the earth and include drilled caissons, driven piles, and precast concrete piles. Foundation design considers factors like soil type, structural requirements, construction requirements, site conditions, and cost. The document also discusses waterproofing, drainage, and underpinning foundations.
This document discusses raft/mat foundations, including:
- A raft foundation is a thick reinforced concrete slab that supports columns and transmits loads into the soil. It is used for structures with large or uneven column loads.
- Types of raft foundations include flat plate, thickened under columns, beam and slab, box structures, and mats on piles.
- Construction involves soil testing, excavation, reinforcement placement, forming, concrete pouring, and curing. Raft foundations are economic and reduce differential settlement but require treatment for point loads.
Joints are easy to maintain and are less detrimental than uncontrolled or uneven cracks. Concrete expands & shrinks with variations in moisture and temp. The overall affinity is to shrink and this can cause cracking at an early age. Uneven cracks are unpleasant and difficult to maintain but usually do not affect the integrity of concrete.
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This document discusses different types of braced excavation systems used to support deep excavations, including soldier beams with lagging, sheet piles, and slurry trenches. It describes the design process for braced cuts, which involves analyzing stability, ground movements, and structural elements like sheet piles and struts. Methods for determining loads on structural elements using tributary area and equivalent beam approaches are presented. Factors affecting stability like heaving in soils are discussed. Design of structural components like struts, wales, and sheet piles is also covered.
This document discusses different types of foundations, including shallow and deep foundations. Shallow foundations include spread footings, combined footings, strap footings, and raft/mat foundations. Deep foundations include pile foundations, pier foundations, and caisson/well foundations. It also discusses considerations for foundations on expansive black cotton soil, recommending methods like strip foundations, pier foundations, and under-reamed pile foundations.
Shoring is the construction of a temporary structure to support an unsafe or unstable structure. There are three main types of shoring: raking shores, flying shores, and dead shores. Raking shores use inclined members called rakers to provide lateral support to walls. Flying shores provide temporary support between party walls when an intermediate building is demolished. Dead shores provide vertical support to walls and structures when the lower part of a wall is removed, such as to add an opening.
Retaining walls are used to retain earth in a vertical position where there is an abrupt change in ground level. There are several types of retaining walls including gravity, cantilever, counterfort, and buttress walls. Cantilever walls are the most common type for heights up to 8 meters. They consist of a vertical stem and base slab that behave like one-way cantilevers. Counterfort walls include transverse supports called counterforts to reduce bending moments in the stem and slabs. Proper design of the stem, heel slab, toe slab, and foundation depth is required to resist overturning, sliding, soil pressure, and bending failure.
The document provides specifications for lime mortar and excavation and foundation work. It discusses the properties and types of lime mortar, including non-hydraulic and hydraulic lime mortar. It also outlines the process of excavation, including depth, methods such as open cut and braced excavation, and backfilling. Measurements for excavation work and appropriate equipment for different soil conditions are also specified.
It is used as a mould for a structure in which fresh concrete is poured only to harden subsequently.
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Definition,
functions,
types of foundations,
foundation loads,
selection criteria for foundations based on soil conditions,
bearing capacity of soil,
methods of testing,
method of improving bearing capacity of soil,
settlement of foundations,
precautions against settlement,
shallow and deep foundations,
different types of foundations – wall footing (strip footing), isolated footing, combined footing, raft foundation, pile foundation etc.
This document provides an overview of concrete, including its composition, properties, production process, and testing. Some key points:
- Concrete is a composite material made of cement, fine and coarse aggregates, and water. It can be classified based on its cementing material, mix proportions, performance specifications, grade, density, and place of casting.
- The production of concrete involves batching, mixing, transporting, placing, compacting, curing, and finishing. Proper batching and mixing are important to ensure uniform strength. Compaction removes entrapped air for maximum strength. Curing maintains moisture for proper hardening.
- Concrete properties depend on water-cement ratio, with maximum theoretical
This document discusses pile foundations. It begins by listing the topics that will be covered, including types of piles, pile spacing, pile caps, load testing, and failures. It then defines a pile foundation as using slender structural members like steel, concrete or timber that are installed in the ground to transfer structural loads to deeper, stronger soil layers. The document goes on to classify piles based on their function, material, and installation method. It describes common pile types such as precast concrete, driven steel, and cast-in-place piles. The document provides details on pile uses, selection factors, and installation procedures.
The document discusses different types of foundations for buildings. It describes shallow foundations, which transfer loads to depths of less than 3 meters, including spread footings, strip foundations, mat foundations, and combined footings. It also describes deep foundations, which transfer loads to depths greater than 3 meters, including pile foundations and caisson foundations. Key factors for determining the appropriate foundation type include the soil bearing capacity and required load capacity of the structure.
Pile foundations transmit structural loads to deeper, more stable soil strata when surface soils have insufficient bearing capacity. Piles are classified by load transfer method and installation technique. Common pile types include timber, precast concrete, cast-in-place concrete, composite, and steel piles which are installed using methods like driving, vibrating, jetting, boring, or jacking. Drilled pier foundations are large-diameter bored piles that may transfer load through end bearing, side friction, or both. Caisson foundations are prefabricated enclosed structures that can be sunk to provide dry working areas below water or soft soils.
This document defines and describes different types of foundations. It begins by defining shallow and deep foundations based on their depth. Shallow foundations discussed include isolated spread footings, wall footings, combined footings, cantilever or strap footings, raft or mat foundations, and grillage foundations. Deep foundations discussed are pile foundations and pier foundations. Pile foundations are further classified as load-bearing, friction, or load-bearing cum friction piles. The document provides diagrams and detailed descriptions of the characteristics and uses of each foundation type.
This document discusses different types of foundations. It describes shallow foundations, which are placed immediately below the structure and distribute loads over a wide area near the surface. Spread footings, combined footings, and mat/raft foundations are types of shallow foundations. Spread footings are used to support columns and walls. Combined footings support two or more closely spaced columns. Mat foundations consist of a thick concrete slab covering the entire bottom of the structure. The document also outlines some limitations and advantages of shallow foundations.
Piles are deep foundations used to transfer structural loads through weak soil layers to stronger soil strata below. There are different types of piles based on function (load bearing, non-load bearing), material (concrete, timber, steel), and installation method (driven, cast-in-place). Load bearing piles can be end bearing piles that rest on a hard layer or friction piles that transfer load through side friction. Factors like soil conditions, water table, and cost determine the suitable pile type for a given foundation. Load capacity is estimated through testing, soil parameters, or dynamic/static formulas.
The document discusses different types of shallow foundations. It describes spread footings, combined footings, strap footings, and mat or raft foundations. For spread footings, it provides details on single, stepped, sloped, wall, and grillage footings. Foundations are also discussed for black cotton soils, including strip footings, pier foundations, and under-reamed pile foundations. Finally, potential causes of foundation failure are listed such as unequal settlement, subsoil moisture movement, and lateral soil pressures.
The document discusses underpinning, which is strengthening and stabilizing an existing building's foundation. Reasons for underpinning include an insufficient original foundation, changed building usage or soil properties, or nearby construction requiring soil excavation. Underpinning extends the foundation deeper or wider to bear on stronger soil or distribute load. Common methods are micropiles, jet grouting, and soil grouting. Types of underpinning include mass concrete, beam and base, and mini-piled underpinning. Mass concrete involves digging boxes and pouring concrete sequentially. Beam and base uses a reinforced concrete beam supported by mass concrete bases. Mini-piles are used for deep foundations on variable soils.
Deep foundations are used when the bearing capacity of soil near the surface is insufficient or space is restricted for shallow foundations. Deep foundations extend below the shallow soil layers to reach stronger soil at depth. Common types include pile foundations, caisson foundations, and cofferdams. Pile foundations transmit structural loads to the ground through end bearing on a hard layer or side friction along the pile. Piles can be made of timber, concrete, steel, or a composite of materials. The type of pile used depends on factors like soil conditions, structural loads, material availability, and cost.
This document discusses shoring and underpinning methods used to provide temporary or permanent support to structures. Shoring provides temporary stability during construction or repairs using techniques like raking, flying, or dead shores made of timber or steel. Underpinning supports existing foundations by strengthening soils using pit, pile, or chemical methods to allow additions without disturbing the structure. Proper design, installation, and precautions are needed for both techniques.
This document discusses different types of foundations, focusing on pile foundations. It defines foundations and classifies them as either shallow or deep. Pile foundations are described as deep foundations that transfer loads to deeper, stronger soils using piles. The main types of piles - displacement, replacement, and installation techniques - are outlined. Specific pile types are then detailed, including pre-cast concrete, pre-stressed concrete spun, steel H, bored, and wood piles. The document concludes by describing end bearing piles, friction piles, settlement reducing piles, and piles in fill.
The document discusses different types of well foundations used in construction. It describes the key components of well foundations including the cutting edge, steining, bottom plug, top plug, and well cap. It explains the process of sinking well foundations, which involves excavating material inside the well curb to allow the well to sink vertically into the ground. Precautions like maintaining verticality and limiting tilt and shift are important during well sinking.
This document discusses different types of well foundations used in construction. It describes three main types: open caissons, which have open tops and bottoms; pneumatic caissons, which use air pressure; and box caissons, which are closed at the bottom. It provides details on each type, including advantages and disadvantages. Open caissons can be built to greater depths but inspection of the bottom is not possible. Pneumatic caissons allow work under water but require complex machinery. Box caissons have a lower construction cost but the foundation base cannot be inspected.
This document provides information on foundations for buildings. It defines foundations as the lowest part of a structure that transfers loads to the soil. Foundations have several functions, including distributing weight over a large area to prevent overloading the soil. Proper site investigation is important to determine soil properties and suitable foundation type. Investigation methods include test pits, auger borings, and deep borings. Bearing capacity refers to the load a soil can support without excessive settlement. Shallow foundations suitable for stronger soils include strip, raft, and pad foundations. Deep foundations using piles are used for weaker soils.
This document provides information about setting out foundation trenches and excavation procedures for building foundations. It discusses the basic steps for setting out trenches, including marking building corners, laying centerlines, and using triangles or instruments to mark perpendicular lines. It then describes various methods for supporting trench walls during excavation, such as stay bracing, box sheeting, vertical sheeting, runner systems, and sheet piling, and provides diagrams to illustrate each technique. Sheet piling is noted as the preferred method for deep, wide excavations or those with loose soil or groundwater.
This document discusses different types of foundations, including shallow and deep foundations. Shallow foundations include spread footings, combined footings, strap footings, and raft/mat foundations. Deep foundations include pile foundations, pier foundations, and caisson/well foundations. It also discusses considerations for foundations on expansive black cotton soil, recommending methods like strip foundations, pier foundations, and under-reamed pile foundations.
Shoring is the construction of a temporary structure to support an unsafe or unstable structure. There are three main types of shoring: raking shores, flying shores, and dead shores. Raking shores use inclined members called rakers to provide lateral support to walls. Flying shores provide temporary support between party walls when an intermediate building is demolished. Dead shores provide vertical support to walls and structures when the lower part of a wall is removed, such as to add an opening.
Retaining walls are used to retain earth in a vertical position where there is an abrupt change in ground level. There are several types of retaining walls including gravity, cantilever, counterfort, and buttress walls. Cantilever walls are the most common type for heights up to 8 meters. They consist of a vertical stem and base slab that behave like one-way cantilevers. Counterfort walls include transverse supports called counterforts to reduce bending moments in the stem and slabs. Proper design of the stem, heel slab, toe slab, and foundation depth is required to resist overturning, sliding, soil pressure, and bending failure.
The document provides specifications for lime mortar and excavation and foundation work. It discusses the properties and types of lime mortar, including non-hydraulic and hydraulic lime mortar. It also outlines the process of excavation, including depth, methods such as open cut and braced excavation, and backfilling. Measurements for excavation work and appropriate equipment for different soil conditions are also specified.
It is used as a mould for a structure in which fresh concrete is poured only to harden subsequently.
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beam formwork
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types of formwork
formwork for concrete
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Definition,
functions,
types of foundations,
foundation loads,
selection criteria for foundations based on soil conditions,
bearing capacity of soil,
methods of testing,
method of improving bearing capacity of soil,
settlement of foundations,
precautions against settlement,
shallow and deep foundations,
different types of foundations – wall footing (strip footing), isolated footing, combined footing, raft foundation, pile foundation etc.
This document provides an overview of concrete, including its composition, properties, production process, and testing. Some key points:
- Concrete is a composite material made of cement, fine and coarse aggregates, and water. It can be classified based on its cementing material, mix proportions, performance specifications, grade, density, and place of casting.
- The production of concrete involves batching, mixing, transporting, placing, compacting, curing, and finishing. Proper batching and mixing are important to ensure uniform strength. Compaction removes entrapped air for maximum strength. Curing maintains moisture for proper hardening.
- Concrete properties depend on water-cement ratio, with maximum theoretical
This document discusses pile foundations. It begins by listing the topics that will be covered, including types of piles, pile spacing, pile caps, load testing, and failures. It then defines a pile foundation as using slender structural members like steel, concrete or timber that are installed in the ground to transfer structural loads to deeper, stronger soil layers. The document goes on to classify piles based on their function, material, and installation method. It describes common pile types such as precast concrete, driven steel, and cast-in-place piles. The document provides details on pile uses, selection factors, and installation procedures.
The document discusses different types of foundations for buildings. It describes shallow foundations, which transfer loads to depths of less than 3 meters, including spread footings, strip foundations, mat foundations, and combined footings. It also describes deep foundations, which transfer loads to depths greater than 3 meters, including pile foundations and caisson foundations. Key factors for determining the appropriate foundation type include the soil bearing capacity and required load capacity of the structure.
Pile foundations transmit structural loads to deeper, more stable soil strata when surface soils have insufficient bearing capacity. Piles are classified by load transfer method and installation technique. Common pile types include timber, precast concrete, cast-in-place concrete, composite, and steel piles which are installed using methods like driving, vibrating, jetting, boring, or jacking. Drilled pier foundations are large-diameter bored piles that may transfer load through end bearing, side friction, or both. Caisson foundations are prefabricated enclosed structures that can be sunk to provide dry working areas below water or soft soils.
This document defines and describes different types of foundations. It begins by defining shallow and deep foundations based on their depth. Shallow foundations discussed include isolated spread footings, wall footings, combined footings, cantilever or strap footings, raft or mat foundations, and grillage foundations. Deep foundations discussed are pile foundations and pier foundations. Pile foundations are further classified as load-bearing, friction, or load-bearing cum friction piles. The document provides diagrams and detailed descriptions of the characteristics and uses of each foundation type.
This document discusses different types of foundations. It describes shallow foundations, which are placed immediately below the structure and distribute loads over a wide area near the surface. Spread footings, combined footings, and mat/raft foundations are types of shallow foundations. Spread footings are used to support columns and walls. Combined footings support two or more closely spaced columns. Mat foundations consist of a thick concrete slab covering the entire bottom of the structure. The document also outlines some limitations and advantages of shallow foundations.
Piles are deep foundations used to transfer structural loads through weak soil layers to stronger soil strata below. There are different types of piles based on function (load bearing, non-load bearing), material (concrete, timber, steel), and installation method (driven, cast-in-place). Load bearing piles can be end bearing piles that rest on a hard layer or friction piles that transfer load through side friction. Factors like soil conditions, water table, and cost determine the suitable pile type for a given foundation. Load capacity is estimated through testing, soil parameters, or dynamic/static formulas.
The document discusses different types of shallow foundations. It describes spread footings, combined footings, strap footings, and mat or raft foundations. For spread footings, it provides details on single, stepped, sloped, wall, and grillage footings. Foundations are also discussed for black cotton soils, including strip footings, pier foundations, and under-reamed pile foundations. Finally, potential causes of foundation failure are listed such as unequal settlement, subsoil moisture movement, and lateral soil pressures.
The document discusses underpinning, which is strengthening and stabilizing an existing building's foundation. Reasons for underpinning include an insufficient original foundation, changed building usage or soil properties, or nearby construction requiring soil excavation. Underpinning extends the foundation deeper or wider to bear on stronger soil or distribute load. Common methods are micropiles, jet grouting, and soil grouting. Types of underpinning include mass concrete, beam and base, and mini-piled underpinning. Mass concrete involves digging boxes and pouring concrete sequentially. Beam and base uses a reinforced concrete beam supported by mass concrete bases. Mini-piles are used for deep foundations on variable soils.
Deep foundations are used when the bearing capacity of soil near the surface is insufficient or space is restricted for shallow foundations. Deep foundations extend below the shallow soil layers to reach stronger soil at depth. Common types include pile foundations, caisson foundations, and cofferdams. Pile foundations transmit structural loads to the ground through end bearing on a hard layer or side friction along the pile. Piles can be made of timber, concrete, steel, or a composite of materials. The type of pile used depends on factors like soil conditions, structural loads, material availability, and cost.
This document discusses shoring and underpinning methods used to provide temporary or permanent support to structures. Shoring provides temporary stability during construction or repairs using techniques like raking, flying, or dead shores made of timber or steel. Underpinning supports existing foundations by strengthening soils using pit, pile, or chemical methods to allow additions without disturbing the structure. Proper design, installation, and precautions are needed for both techniques.
This document discusses different types of foundations, focusing on pile foundations. It defines foundations and classifies them as either shallow or deep. Pile foundations are described as deep foundations that transfer loads to deeper, stronger soils using piles. The main types of piles - displacement, replacement, and installation techniques - are outlined. Specific pile types are then detailed, including pre-cast concrete, pre-stressed concrete spun, steel H, bored, and wood piles. The document concludes by describing end bearing piles, friction piles, settlement reducing piles, and piles in fill.
The document discusses different types of well foundations used in construction. It describes the key components of well foundations including the cutting edge, steining, bottom plug, top plug, and well cap. It explains the process of sinking well foundations, which involves excavating material inside the well curb to allow the well to sink vertically into the ground. Precautions like maintaining verticality and limiting tilt and shift are important during well sinking.
This document discusses different types of well foundations used in construction. It describes three main types: open caissons, which have open tops and bottoms; pneumatic caissons, which use air pressure; and box caissons, which are closed at the bottom. It provides details on each type, including advantages and disadvantages. Open caissons can be built to greater depths but inspection of the bottom is not possible. Pneumatic caissons allow work under water but require complex machinery. Box caissons have a lower construction cost but the foundation base cannot be inspected.
This document provides information on foundations for buildings. It defines foundations as the lowest part of a structure that transfers loads to the soil. Foundations have several functions, including distributing weight over a large area to prevent overloading the soil. Proper site investigation is important to determine soil properties and suitable foundation type. Investigation methods include test pits, auger borings, and deep borings. Bearing capacity refers to the load a soil can support without excessive settlement. Shallow foundations suitable for stronger soils include strip, raft, and pad foundations. Deep foundations using piles are used for weaker soils.
This document provides information about setting out foundation trenches and excavation procedures for building foundations. It discusses the basic steps for setting out trenches, including marking building corners, laying centerlines, and using triangles or instruments to mark perpendicular lines. It then describes various methods for supporting trench walls during excavation, such as stay bracing, box sheeting, vertical sheeting, runner systems, and sheet piling, and provides diagrams to illustrate each technique. Sheet piling is noted as the preferred method for deep, wide excavations or those with loose soil or groundwater.
This is useful for civil engineering students in their subject Building construction offered by GTU. This presentation includes Timbering of trenches, Scaffolding, Shoring 7 underpinning techniques used in construction of building for temporary period of time.
The document discusses different types of foundations for buildings. It describes shallow foundations, which are near the surface, and deep foundations, which are deeper. Shallow foundations include spread footings, combined footings, strap footings, and mat/raft foundations. Deep foundations include pile foundations, which transfer load through friction or end bearing, and pier foundations. The document provides details on different types of piles based on material, function, and construction method.
This document provides an overview of mat foundations. It defines a mat foundation as a substructure that transmits structural loads across its entire bottom area to the soil below. The document outlines different types of mat foundations and notes they are suitable when settlements may occur due to compressible or irregular soil. It describes the design, construction process, and concludes that mat foundations help reduce overall settlement by distributing loads uniformly over a large area.
Civil types of foundations for different soil characteristics (2) - copyVenkatesh D
This document summarizes different types of soil classifications and foundations. It describes how soils are classified based on particle size into coarse-grained or fine-grained soils. The engineering properties and index properties of soils that influence foundation design are discussed. Shallow foundations like footings and rafts as well as deep foundations like piles are introduced. Factors affecting bearing capacity and different types of footings for varying soil conditions are summarized.
This document discusses excavation and basement construction. It begins by defining excavation as loosening and removing materials to create space above or below ground. It then discusses the advantages and disadvantages of using mechanical plants for excavation work. The document goes on to describe 10 common excavation plants including backhoes, bulldozers, loaders, dump trucks, and clamshell excavators. It also discusses government regulations for controlling excavation work. Finally, it describes two methods for deep excavation: the dumpling method and diaphragm walling method.
Raft foundations are large concrete slabs laid on the ground to support buildings. They spread the building load over a wide area, lowering pressure on the soil. This makes raft foundations suitable for unstable soils, areas with soil movement, and buildings with high loads or closely spaced supports. Raft foundations can serve as both the foundation and floor slab. They are used for heavy commercial buildings, in low bearing soils, and where footing overlap would otherwise occur. Advantages include reduced excavation needs and differential settlement.
Prof. Karan S. Chauhan discusses different types of shallow foundations that can be used for building construction, including spread footings, combined footings, strap footings, and raft/mat foundations. Some key considerations for foundations are distributing structural loads across a large area, providing stability, and minimizing settlement. In expansive black cotton soil, deeper foundations of 1.5 meters or removal and replacement of the soil are recommended to prevent cracking from swelling and shrinkage. Specific foundation options for black cotton soil include strip footings, pier foundations, and under-reamed pile foundations.
Foundations transmit loads from buildings to the ground below. There are different types including shallow foundations like spread footings and deep foundations like piles. Spread footings support individual columns on isolated slabs while combined footings link two columns. Strap footings connect isolated footings with a beam. Mat foundations are large slabs supporting many columns. Pile foundations transfer loads to deeper soils through friction or bearing. Foundations can fail due to unequal settlement, subsoil moisture movement, lateral pressures, or weathering effects. Proper design and construction seeks to prevent these failures.
The document discusses site investigation methods for determining appropriate foundation types. It describes various types of shallow and deep foundations. Site investigation involves soil exploration through methods like boreholes, test pits, and geophysical surveys to understand soil properties and water levels. Different sampling techniques are used to collect disturbed and undisturbed soil samples for analysis. Findings are documented in a bore log report making recommendations on foundation design.
Foundation underpinning involves transferring structural loads to deeper, more stable soils or bedrock when the existing foundation is inadequate. It is done by excavating pits under the foundation and installing concrete piers that the foundation is wedged up onto. Helical piers are also used, which are screwed into the ground to support the foundation. Shoring involves installing a structural system like metal or timber to support the sides of an excavation and prevent collapse, and is needed when excavating under an existing foundation, repairing a foundation, or where loose soil or water are present. The main underpinning and shoring methods were discussed.
This document provides information on different types of foundations used in construction, including shallow foundations and deep foundations. It describes various shallow foundation types such as wall footings, isolated footings, combined footings, inverted arch footings, continuous footings, cantilever footings, grillage footings, and raft foundations. It also discusses different types of deep foundations including basements, buoyancy rafts, caissons, cylinders, shaft foundations, and pile foundations. Special foundation techniques like caisson foundations and cofferdam foundations are explained in detail.
This document discusses different types of foundations used in multi-storey building construction projects. It describes surface excavation to remove vegetation and compressible soils. Shoring and timbering is required for trenches over 2 meters deep. Foundations must not exceed the safe bearing capacity of the soil and include spread, stepped, pad, ring, and raft foundations. Pile foundations transfer load through friction and end bearing, and include driven cast-in-situ concrete piles, bored precast concrete piles, under-reamed piles, and Franki piles. Foundations are chosen based on subsoil conditions and load characteristics.
The document discusses different types of foundations used in construction. It describes shallow foundations including spread footings, grillage foundations, combined footings, strap footings, raft/mat foundations. It also describes deep foundations including pile foundations, piers, caissons. It provides details on the functions, materials, and installation methods for various foundation types. The key functions of foundations are to distribute load evenly and provide stability. Foundations need to sustain and transmit loads while minimizing differential settlement.
This document discusses different types of shallow foundations that can be used to transfer structural loads from buildings to the soil or earth very near the surface. It describes spread footing foundations, mat-slab foundations, slab-on-grade foundations, and rubble trench foundations. Spread footing foundations consist of strips or pads of concrete that transfer loads from walls and columns to the soil. Mat-slab foundations distribute loads across the entire building area to lower pressure on the soil. Slab-on-grade foundations are commonly used in areas with expansive clay soils. Rubble trench foundations use loose stone to minimize concrete and improve drainage in an environmentally friendly way.
There are several types of deep foundations that can be used depending on the soil conditions and load requirements. These include basement foundations, buoyancy raft or hollow box foundations, well/caisson foundations, pier foundations, drilled shaft foundations, and pile foundations. Each type has advantages and disadvantages related to cost, construction difficulty, and suitability for different soil and loading conditions. Common examples of deep foundations used include caissons for bridge piers, drilled shafts for structures with large axial and lateral loads, and piles beneath structures with high groundwater or compressible soils. The type of deep foundation selected depends on the project needs and subsurface environment.
Raft foundations are concrete slabs that spread the load of a building evenly over a large area. They are often used when soil conditions are unstable or over 50% of the ground would need strip footings. There are different types including solid slab rafts, slab beam rafts, cellular rafts, piled rafts, and balancing rafts. Raft foundations are cheaper and easier to install than traditional footings and help reduce differential settlement. The main disadvantage is risk of edge erosion if not properly constructed.
The document discusses different types of foundations used in construction. It describes shallow foundations, which include wall, column, combined, and mat/raft foundations. It also describes deep foundations, including pile, under-reamed pile, and well foundations. It provides details on different types of piles and factors to consider when choosing a foundation type, and outlines the basic process for constructing foundations, including site preparation, layout, excavation, and pouring concrete.
1) The document discusses types of foundations including shallow foundations like spread footings, combined footings, strap footings, mat foundations, and grillage foundations. It also discusses deep foundations like pile foundations, pier foundations, and caisson or well foundations.
2) Functions of foundations include reducing and distributing load intensity, providing an even and level surface, imparting stability, and protecting against soil movements.
3) Essential requirements for good foundations are withstanding loads without excessive settlement, having sufficient rigidity and depth, and being located to avoid future influences.
This is an overview of my current metallic design and engineering knowledge base built up over my professional career and two MSc degrees : - MSc in Advanced Manufacturing Technology University of Portsmouth graduated 1st May 1998, and MSc in Aircraft Engineering Cranfield University graduated 8th June 2007.
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfBalvir Singh
Sri Guru Hargobind Ji (19 June 1595 - 3 March 1644) is revered as the Sixth Nanak.
• On 25 May 1606 Guru Arjan nominated his son Sri Hargobind Ji as his successor. Shortly
afterwards, Guru Arjan was arrested, tortured and killed by order of the Mogul Emperor
Jahangir.
• Guru Hargobind's succession ceremony took place on 24 June 1606. He was barely
eleven years old when he became 6th Guru.
• As ordered by Guru Arjan Dev Ji, he put on two swords, one indicated his spiritual
authority (PIRI) and the other, his temporal authority (MIRI). He thus for the first time
initiated military tradition in the Sikh faith to resist religious persecution, protect
people’s freedom and independence to practice religion by choice. He transformed
Sikhs to be Saints and Soldier.
• He had a long tenure as Guru, lasting 37 years, 9 months and 3 days
Online train ticket booking system project.pdfKamal Acharya
Rail transport is one of the important modes of transport in India. Now a days we
see that there are railways that are present for the long as well as short distance
travelling which makes the life of the people easier. When compared to other
means of transport, a railway is the cheapest means of transport. The maintenance
of the railway database also plays a major role in the smooth running of this
system. The Online Train Ticket Management System will help in reserving the
tickets of the railways to travel from a particular source to the destination.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
We have designed & manufacture the Lubi Valves LBF series type of Butterfly Valves for General Utility Water applications as well as for HVAC applications.
Cricket management system ptoject report.pdfKamal Acharya
The aim of this project is to provide the complete information of the National and
International statistics. The information is available country wise and player wise. By
entering the data of eachmatch, we can get all type of reports instantly, which will be
useful to call back history of each player. Also the team performance in each match can
be obtained. We can get a report on number of matches, wins and lost.
2. 1. Job Layout
1.Site Clearance
1.Site Clearance is an important factor to
be considered in the job layout plans ,
before commencement of project work
2.There should not be any obstruction like
trees , plants , shrubs, bigger size stones,
etc.
3. 3. Approach road should be wide so as to
allow the truck for loading and unloading the
constructional material . If site ground is
uneven , then it should be made plane , for
this contouring is done in advance.
4.In short site should be cleared by all the
way, otherwise no activity can be launched in
construction processes.
4. 1. A plan in which the arrangements for
placing site office, store room , labour
quarter, medical aid center , godowns
for keeping construction materials and
other facilities are properly prepared is
called as Job layout or site layout .
2.The arrangements for processes should
be such that the work is done smoothly
and in orderly manner.
2. Preparing Job Layout
5. 3. Job layout depends upon three factors as
follows:-
a) Location , area and topography of the site .
b) Method of construction.
c) Nature and type of work.
4. There should be proper co-relation and co-
ordination among the different units.
8. Correct measurement of distances , preferably
by steel tape.
Use of level , either dumpy level or mason’s
level.
Correct marking of face -line or center – line.
Use of correct plumb –bob for transferring
points on ground
Checking of distances from at least two
independent measurements .
5. Precautions while Marking Layout on Ground
9. 6. Excavation for Foundation
• Excavation of foundation ,trenches can be done either
manually with the help of conventional implements or
with the help of special mechanical equipment.
• Excavate foundation along the line created by batter
boards.
• Excavate remainder of soil inside the perimeter.
• Don’t excavate inside soil if slab is on the grade.
• If foundation is deep , taper edges are used to prevent
the collapse.
• If soil is unstable or very deep , Use shoring method.
10. Timbering and strutting is a method of
giving the temporary supports to the sides
of trench , when the depth of trench is
large or when the sub-soil is loose.
Timbering is also called as Shoring . It
consists of timber boards and struts to give
temporary support to the side of the
trench.
7.Timbering and Strutting
11. Following are the methods of timbering
and strutting :-
1. Box sheeting
2. Stay bracing
3. Runner system
4. Vertical sheeting
5. Sheet piling
12. If depth of the excavation is upto 4m and soil
is loose , the box sheeting method is used.
It is just like box consisting of vertical sheets
held in position by horizontal row of wales
and made tighten by providing strut.
If soil is very loose, that time horizontal sheets
are provided and supported by vertical wales
and made tighten on both sides by horizontal
strutting
Braces are provided when the height is more.
1. Box Sheeting
13.
14. When the depth of excavation is upto 2m ,
then stay bracing method is adopted to
support the sides excavated in fairly firm soil.
It consists of a vertical sheets or polling
boards opposite to each other against the two
walls of the trench and held these vertical
sheets in position by strutting
2. Stay Bracing
15.
16. This is used in extremely loose and soft ground
which need immediate support as excavation
process.
This system is similar to vertical sheeting of box
system, except in place of vertical sheeting, runner,
made of long thick wooden sheet or plank s with iron
shoe at the end are provided.
Wales and Struts are provided as usual.
These runner are driven about 30 cm in advance of
progress of the work, by hammering.
3. Runner system
17. 1.It is similar to the box system , only
difference is that in this case excavation is
progressed in stages by providing an
offset at the end of each stage.
2. This method is best suited for deep
trenches in soft ground.
4. Vertical Sheeting
18. This method is adopted as follows :-
When soil to be excavated is soft or loose.
The Depth of excavation is large.
When the Width of the trench is large.
When there is sub soil water . Sheet piles are used to
resist the lateral earth pressure.
These are driven in ground by mechanical means .
They can also be used for excavating for very large
depth.
5. Sheet Piling
20. If the plinth depth do not exceed 450mm above the
ground level and if the exposed ground is back
cotton soil , then remove the black cotton soil so as to
avoid the uneven settlement of ground flooring.
In process of plinth filling watering and compaction
should be carried out till the required level is reached
so as to from a thoroughly compacted base.
The material for plinth filling consist of hard murum
and broken rubbles.
On the compacted surface or consolidated plinth
filling , a concrete bed of thickness of 80 mm is done
for laying the tile work further.
Material for Plinth Filling
21. Lead and lift are the terms related to excavation
of earth / soil.
LEAD : 1.The horizontal distance up to which a
contractor will haul the material excavated and
it is included in the rates of excavation is called
as Lead. 2.The lead is 30m and called as
Standard or normal lead.
Lift : 1. The vertical distance up to which a
contractor will haul the material excavated and
it is included in the rates of excavation is called
as Lift. 2. The lift is 1.5m and called as Normal lift.
Lead & Lift in Excavation
22. SUB-STRUCTURE OR FOUNDATION is
the lower most portion of the building,
usually located below the ground level,
which transmits the load of super
structure to the supporting soil. A
foundation is therefore that part of the
structure which is in direct contact with
the ground to which the load are
transmitted.
Foundation
23. Purpose of foundation
To distribute the total load coming on the structure on a
larger area.
To Reduce the load Intensity
To support the structures.
To give enough stability to the structures against
various disturbing forces, such as wind and rain.
To prepare a level surface for concreting and masonry
work.
For the Lateral Stability.
24. 1. Open Foundation.
2. Shallow Foundation :-
Types of shallow foundation :-
1] Stepped Foundation
a)Wall footing , b) Reinforced concrete footing
c)Column footing :- 1.Isolated , 2. Combined
,3.Raft foundation.
3.Deep foundation :-1. Pile foundation ,2.Well
foundation, 3.Coffer dams.
Types of foundation
25. This is simply a layer of foundation
concrete provided at the base of a
column, pedestal or wall.
This type of foundation is provided when
hard stratum is available at very shallow
depth or the work is unimportant e.g.
Compound wall , pillars for barbed wire
fencing etc.
1.Open Foundation
26. When the foundation is placed immediately below
the lowermost part of structure it is called as
SHALLOW foundation.
It can also be defined as, when the depth of
foundation is less than or less than equal to the
width;, the foundation is called as SHALLOW
FOUNDATION.
PURPOSE: The purpose of shallow foundation is to
distribute the structural load over considerable
horizontal area .
LIMITATION:-
1. The load carrying is considerably less as compared
with deep foundation.
2. Can not be used under marshy land, made up of
ground water or water logged area.
2.Shallow Foundation
27. Stepped foundations = In this case , the base of
the foundation is made wider to distribute the
load on wider area .
A) Wall footing : 1.It can be achieved by
constructing several courses of bricks widening
the base, the lowest course is usually twice the
breadth of the wall. 2. The sectional elevation of
brick wall footing and stone wall footing is
shown.
Stepped Foundations
28.
29. B)Reinforced Concrete Footing :- When the bearing capacity of the
soil on which the wall footing is to rest is very low and when the
walls are subjected to heavy loading , under such circumstances
the reinforced concrete footing is used
30. C) Column footing :-
1.Isolated : It is provided under a
column or other similar member for
the distribution of concentrated load
in the form of uniformly distributed
load on the soil below.The shape may
be square, rectangular or circular in
plan . It may be constructed either in
brick masonry , stone masonry or
R.C.C. steel grillage etc.
31. 2. Combined : Combined column footing is provided as a
common footing for two or more columns.
This type of column helps in reducing the depth of
foundation and unequal settlement can be avoided.
In this type of footing ,a common P.C.C bed is provided on
which two or more column rest.
Combined footing is also provided when column are very
near to each other and isolated column will over lap each
other.
Shear force calculation is important in combined footing
33. C) Raft Foundation :-
When bearing capacity of the
supporting soil is very low and heavy
concentrated structural loads are to be
supported in case of marshy land or
made of soft clay.
It proves to be economical under water
logged area.
Raft is acting as a floor consisting of
thick reinforcement concrete slab
covering the entire area of the bottom
of the structure.
35. When the depth of foundation is
more than its width the foundation is
called as DEEP foundation.
It can also be defined as , if the depth
of foundation is more than 2.00 m, it
called as deep foundation.
3.Deep foundation
36. 1) Piles
A).Depending upon the function :-
1. Bearing piles
2.Friction piles
3.Sheet piles
4.Anchor piles
5.Batter piles
6.Fender piles
7.Compaction piles
Types of Deep foundation
37. 1. BEARING PILES: These are driven into the ground until a
hard stratum, directly supported on hard base and pile act as
pillar to transmit the load.
2. Friction pile : When the soil is soft to a considerable
depth the pile which is required to be driven is called
FRICTION PILE.
The load carried by a pile is borne by the friction
developed between the side of the pile and the
surrounding is called as SKIN FRICTION.
3.Sheet Pile :They are used to retain soil which is liable to
escape laterally when subjected to pressure or to
enclose the area for some foundation and to protect
the area from the flowing water.
38. ANCHOR PILE: when piles are used to provide
anchorage against horizontal pull they are called as
ANCHOR PILE.
BATTER PILES: When the piles are driven at an
inclination to resist large horizontal or inclined forces
then the piles are called ac BATTER PILES.
FENDER PILES: when the water front structure or
concrete check is required to protect from impact or
abrasion caused by the ship then the fender pile is used
at the front.
COMPACTION PILE: when the piles are driven to
increase the bearing capacity of the granular soil they
are called as compaction pile
39.
40. B) Depending upon the material :-
1.Timber piles
2.Concrete piles
3.steel piles
41. Economical for supporting light structures
Timber from sal, deodar , babul , khair, is used .
the pile cap of iron ring of about 25 mm is provided to
prevent the pile head from brooming .
The lower end of the pile is provided with a cast iron
conical shoe.
The load transfer mechanism is by skin friction hence
there should a minimum distance of about 60 cm
center to center
1.Timber pile
42. ADVANTAGES:
1. Economical.
2. Can be driven rapidly hence saves time.
3. Due to its elasticity it is recommended in region
where the piles are likely to be subjected to lateral
forces
4. Heavy machinery and skill supervision is not required.
DISADVANTAGES:
1. Should be cut of above ground water table to
prevent decaying.
2. Timber cannot be driven in filled up ground.
3. Likely to decay by salt water or insect.
4. Restricted length .
43. Concrete piles are classified as :-
1. Pre-cast piles.
2.Cast in – situ pile.
3. Pre-stressed concrete pile
2. Concrete Pile
44. 1.PRE-CAST CONCRETE PILE:
Precast piles are those which are manufactured in the
factory or at a place away from the construction site and
then driven to the ground at the place required.
Pre cast pile may be square ,octagonal, or round in cross
section or may be tapering or parallel in longitudinally.
The size of these piles varies from 30cm to 50cm in cross
sectional dimension and up to 30m in length .
Precast pile are useful in carrying fairly heavy loads
through soft material to firm strata .
45. 2. Cast in – Situ pile :- The piles which are cast in
position on site inside the ground , it may be
reinforced when pile act as column and when
subjected to lateral force.
Normally the cast in situ piles are constructed with
an enlarged bulb and corrugated stem.
A steel tube having internal diameter equal to the
diameter of the pile and 20mm thickness is driven
into the ground
when the has been driven up to the desired depth
a charge of concrete is poured and the tube is
gradually withdrawn and thus alternate pouring and
withdrawing of tube , the pile is constructed to the
full length.
In case the pile is to be reinforced , the
reinforcement cage is lowered in the steel tube
before pouring the concrete.
46. 3. Pre – Stressed concrete piles :Pre stressed piles are
stronger than the normal reinforced pile . Therefore ,
because of the reduction in cross sectional, they are
lighter and more easily handled.
47. It has greater ability to withstand extremely hard driving.
It more durable in sea water because of the crack.
It has great column
It has lesser handling cost because of light weight.
It has much lager moment of inertia then the
conventional pile of the same dimension .
Advantages of concrete piles :-
48. These piles cannot be driven rapidly.
It requires skilled technical supervision heavy driving
machinery.
To withstand handling stresses, reinforcement is essential.
Disadvantages of Concrete piles
49. A steel pile may be a rolled section , a fabricated
shape or a piece of sheet piles
Metal piles have been used in from of cast iron pipes
or solid wrought iron shaft .
These piles are excepted to penetrate through hard
rock.
Types of steel pile.
H-PILES, PIPIE-PILE, SCREW PILE, DISC PILE.
The pipes is normally filled with concrete and the
diameter varies from 25cm to 125 cm and the depth is
30m or more.
3.Steel Pile
50. Caisson
The caisson is a structure used for the purpose of
placing foundation in correct position under water.
It is Permanent in nature.
Used to pump out water in under water concreting
work.
Types of caisson:
1. Box caisson
2. Open caisson
3. Pneumatic caisson
2. Well foundation
Caisson is a foundation which comes under the type of well foundation.
51. Open caisson is a box of timber, metal, reinforced
concrete or masonry
Open at both end (top and bottom)
Whenever consideration for scour or bearing
capacity required foundation being taken to depth
of more than 5 to 7m
Costly and uneconomical (heavy timbering
required)
Due to greater earthwork, the progress of work is
very slow
1. Open Caisson :-
52. A box caisson open at top and close at
bottom.
It is Made up of timber, concrete or
steel.
Built on land and floated to pier site
where it is sunk in position
Used where bearing stratum is available
and loads are not heavy
2.Box Caisson :-
53.
54. DEFINITION: It is a temporary structure constructed in a
river or lake or any other water bearing surface for
excluding water from a given site to enable the water
building operation to be performed under dry conditions.
walls are water tight
Temporary structure
Built within or in pairs across a body of water
Allows the enclosed space to be pumped out ,creating a
dry work environment.
3.Cofferdams
55. 1. Earth filled cofferdams .
2. Rock filled cofferdams .
3. Sheet pile cofferdams :-
a) Single wall cofferdams,
b) Double wall cofferdams.
Types of cofferdams
56. Earthen cofferdam consist of earthen
embankment built around the area to be
enclosed.
It can be constructed if the water depth is more
than 1.4 to1.8m and the velocity of the flowing
water is very low.
Top width of the dam should not be less than
1.00m and the side slope may vary from 1:1.5 to
1:1.2. the inner portion called as embankment
consist of clay and sand or clay or gravel
1. Earth filled Cofferdams
58. In case of a rock filled cofferdam , the
depth of water to be retained is of order
of 1.8 to 3.00m .stone or rubble is used
for embankment
2.Rock Filled cofferdams
60. 1.Single wall cofferdams
If the area to be enclosed is very small and the depth of
water is about 4.5 to 6.0m then timber piles known as
guide piles are first driven deep into the firm ground
below the river bed, the distance between the piles
may vary from 1.7 to 3.5m depending upon the velocity
of the flow.
Then Wales are bolted to guide piles at suitable
distance
Then sheet or wooden sheet piles are driven into the
river bed along the Wales and secured by bolts to the
Wales.
Thus , the area can be enclosed and the water is
pumped out to start the construction in dry condition.
3. Sheet pile cofferdam
61. 2. Double walled cofferdam
If the area to be enclosed is very large and if
the depth of water is large then double wall
cofferdam are used instead of single wall
cofferdam.
The construction is same , only in case of a
single wall a pair of wall with a gap between
is provided.
This is suitable up to a depth of 10 to 12.0m
To prevent leakage the sheet piles are firmly
driven into the ground.
63. For Water Logged Foundation It Is Essential To
Carry Out Dewatering Of Soil Before Carrying
Construction Activity.
Methods Of Dewatering
1. Sumps and Ditches
2. Well Point System
3. Deep well System
4. Vaccum Method
Dewatering of foundation by
Pumping Method
64. This is the simplest form of dewatering
used in shallow excavation in coarse
grained soils.
Sallow low pits ,calls as sumps are dug
along the periphery of the area drainage
ditches.
The water from the slope or sides flows
under gravity and is collected in sumps
from which it is pumped out.
1. Sumps and Ditches
66. A well point system is a perforated pipe
of 5 to 8 cm in diameter and one metre
long covered by cylindrical wire gauge
screen known as STRAINER.
These pipes are joined to a horizontal
pipes known as HEADER pipe.
2. Well point Systems
68. 3. Deep well system :-This system is suited
when the depth of excavation is more than
16m.
69. In this method a hole of 30cm diameter is
bored around the well point and the riser
pipe.
It then sealed using bentonite ,soil-
cement or clay. The header pipe is then
connected to vacuum pump for removal
of water.
4. Vacuum Method
70. These foundations are provided
when the bearing capacity of the soil
is low and hard strata is not available
on the given site.
The most commonly constructed
special foundation are 1. Mat or raft
foundations , 2.Under-reamed piles .
Special Foundation
71. When bearing capacity of the supporting soil is
very low and heavy concentrated structural
loads are to be supported in case of marshy
land or made of soft clay.
It proves to be economical under water logged
area.
Raft is acting as a floor consisting of thick
reinforcement concrete slab covering the
entire area of the bottom of the structure
1. Mat or Raft Foundations
73. The under reamed piles are the best solution for foundation
black cotton soil.
Bored cast in situ concrete piles having bulb shaped enlarge
base
Such structure is anchored to the ground at depth where
ground movement due to change in moisture content
negligible
Bearing capacity increased by increasing the number of bulbs
Hand auger or machine auger used for boring with extension
rod
After boring upto certain depth the base of hole is enlarged in
the form of bulb
2. Under- Reamed Piles
75. Bearing capacity of soil is the is the intensity of the load
per unit area of the foundation . If the bearing capacity
is not sufficient , then the use of special type of
foundation becomes imperative.
Bearing capacity of the sub soil or foundation soil is
measured by plate load type.
In this method, the bearing plate is square of minimum
size 30cm square, and maximum size 75 sq.cm .
The thickness of the plate should not be less 25mm.
BEARING CAPACITY OF THE
FOUNDATION.
76. 1. Break direct contact between soil and masonry.
2. Construction should be taken in dry season.
3. Masonry should be start at least 15 cm below the ground level.
4. Mostly raft foundation should be provided.
5. Under reamed pile foundation is ideal foundation.
6. To take the foundation at such depths where cracks cease to
extend.
7.To provide reinforced concrete ties or band all around the main
wall of the building.
8.Under –reamed piles are ideal for foundation in black cotton
soil.
Precaution to be taken while
constructing the foundation black
cotton soil: