Raft foundations are used when buildings have heavy loads, compressible soil, or require minimal differential settlement. A raft foundation is a continuous concrete slab that supports all building columns. It can be designed using either a rigid or flexible approach. The rigid approach assumes the raft bridges soil variations, while the flexible approach models soil-structure interaction. Key considerations for raft design include bearing capacity, settlement, stress distribution, and structural component sizing.
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.
This document provides an overview of different types of retaining walls, including gravity, cantilever, counterfort, sheet pile, and diaphragm walls. It discusses the key components and design considerations for gravity and cantilever retaining walls. Gravity walls rely on their own weight for stability, while cantilever walls consist of a vertical stem with a heel and toe slab acting as a cantilever beam. The document also covers lateral earth pressures, drainage of retaining walls, uses of sheet pile walls, and construction methods for diaphragm walls.
Prestressed concrete is concrete that is placed under compression using tensioned steel strands, cables, or bars. This is done through either pre-tensioning or post-tensioning. In pre-tensioning, the steel components are tensioned before the concrete is poured, while in post-tensioning, the steel components are tensioned after the concrete has hardened. Prestressed concrete provides benefits over reinforced concrete like lower construction costs, thinner structural elements, and longer spans between supports.
Footings are structural members that support columns and walls and transmit their loads to the soil. Different types of footings include wall footings, isolated/single footings, combined footings, cantilever/strap footings, continuous footings, rafted/mat foundations, and pile caps. Footings must be designed to safely carry and transmit loads to the soil while meeting code requirements regarding bearing capacity, settlement, reinforcement, and shear strength. A proper footing design involves determining loads, allowable soil pressure, reinforcement requirements, and assessing settlement.
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.
This document provides information on doubly reinforced concrete beams. It introduces the concept of doubly reinforced beams, which have reinforcement in both the tension and compression zones. This allows for an increased moment of resistance compared to singly reinforced beams. The key advantages of doubly reinforced beams are that they can be used when the applied moment exceeds the capacity of a singly reinforced beam, when beam depth cannot be increased, or when reversal of stresses may occur. The document includes stress diagrams, design concepts, and differences between singly and doubly reinforced beams.
The pile foundation uses piles to support walls, piers, and other structures. Piles can be placed individually or in clusters. Piles are used when loose soil extends to great depths, and transfer structural loads to harder soils below through end bearing and side friction. Common pile materials include timber, steel, and concrete. Piles can be load bearing, transmitting loads through end bearing and side friction, or non-load bearing, used as retaining walls or sheeting. Pile capacity is assessed through field load tests or theoretical calculations based on soil properties.
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.
This document provides an overview of different types of retaining walls, including gravity, cantilever, counterfort, sheet pile, and diaphragm walls. It discusses the key components and design considerations for gravity and cantilever retaining walls. Gravity walls rely on their own weight for stability, while cantilever walls consist of a vertical stem with a heel and toe slab acting as a cantilever beam. The document also covers lateral earth pressures, drainage of retaining walls, uses of sheet pile walls, and construction methods for diaphragm walls.
Prestressed concrete is concrete that is placed under compression using tensioned steel strands, cables, or bars. This is done through either pre-tensioning or post-tensioning. In pre-tensioning, the steel components are tensioned before the concrete is poured, while in post-tensioning, the steel components are tensioned after the concrete has hardened. Prestressed concrete provides benefits over reinforced concrete like lower construction costs, thinner structural elements, and longer spans between supports.
Footings are structural members that support columns and walls and transmit their loads to the soil. Different types of footings include wall footings, isolated/single footings, combined footings, cantilever/strap footings, continuous footings, rafted/mat foundations, and pile caps. Footings must be designed to safely carry and transmit loads to the soil while meeting code requirements regarding bearing capacity, settlement, reinforcement, and shear strength. A proper footing design involves determining loads, allowable soil pressure, reinforcement requirements, and assessing settlement.
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.
This document provides information on doubly reinforced concrete beams. It introduces the concept of doubly reinforced beams, which have reinforcement in both the tension and compression zones. This allows for an increased moment of resistance compared to singly reinforced beams. The key advantages of doubly reinforced beams are that they can be used when the applied moment exceeds the capacity of a singly reinforced beam, when beam depth cannot be increased, or when reversal of stresses may occur. The document includes stress diagrams, design concepts, and differences between singly and doubly reinforced beams.
The pile foundation uses piles to support walls, piers, and other structures. Piles can be placed individually or in clusters. Piles are used when loose soil extends to great depths, and transfer structural loads to harder soils below through end bearing and side friction. Common pile materials include timber, steel, and concrete. Piles can be load bearing, transmitting loads through end bearing and side friction, or non-load bearing, used as retaining walls or sheeting. Pile capacity is assessed through field load tests or theoretical calculations based on soil properties.
This seminar report discusses caisson foundations. Caissons are watertight structures used for deep foundations under water, such as for bridges, piers, and docks. There are three main types - open, box, and pneumatic caissons. Caissons can take various shapes and are used when foundations need to extend below riverbeds or in deep water. Advantages include ability to reach large depths, but difficulties include tilting or sinking during construction. Caisson diseases can affect workers if decompressed too quickly from pressurized conditions.
This document discusses different methods of prestressing concrete, including pretensioning and post-tensioning. Pretensioning involves stressing steel tendons before placing concrete around them, while post-tensioning involves stressing tendons after the concrete has cured using hydraulic jacks. Post-tensioning allows for longer spans, thinner slabs, and more architectural freedom compared to conventional reinforced concrete or pretensioned concrete. Common applications of post-tensioning include parking structures, bridges, and building floors and roofs.
The document discusses various types of footings used in building foundations. It defines a footing as the lower part of a foundation constructed below ground level on solid ground. The main purposes of footings are to transfer structural loads to the soil over a large area to prevent soil and building movement, and to resist settlement and lateral loads. Common footing types include isolated, strap, strip/continuous, and combined footings. Key data needed for footing design includes soil bearing capacity, structural loads, and column dimensions. The document outlines general design procedures and considerations for spread, combined, strap, and brick footings.
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
Retaining walls are used at the Shraddha Vivanta Residency construction site in Mumbai for two main purposes. Cantilever retaining walls around 3.5 meters deep allow for a basement and four floors of stacked parking underneath the residential building. Additional retaining walls surround underground water tanks for suction and firefighting. The walls are located along the building perimeter and around the tank areas. Proper waterproofing of the retaining walls is important given their underground locations.
Framed structures are building skeleton frameworks formed by columns and beams. There are two main types: in-situ reinforced concrete frames and prefabricated frames. Rectangular framed structures use columns and beams arranged at right angles to support floors, walls, and roofs. They are commonly used for multi-story buildings like offices, schools, and hospitals. Framed structures provide large open floor plans and are adaptable to different shapes. Earthquake-resistant features in framed structures include shear walls, moment-resisting frames, and braced structures which resist lateral forces during seismic activity.
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 the design of column braces for structures. It defines braced and unbraced columns, with braced columns having zero sway and stability provided by walls or bracing, while unbraced columns are subjected to sway with stability only from other columns. It describes different types of internal and external bracing patterns and factors to consider in brace analysis, including displacement, base shear, wind loads, maximum shear and bending moments. The document provides guidelines for designing braces based on column moments and explains how bracing type affects seismic resistance parameters through a parametric study.
The document describes different types of shallow foundations, including spread footings, combined footings, and raft/mat foundations. Spread footings include wall footings, reinforced concrete footings, inverted arch footings, and column footings. Combined footings are used when columns are close together or near a property line. Raft foundations consist of a thick concrete slab covering the entire structure area and are used when soil capacity is low or loads are large. The document also discusses advantages, limitations, and construction procedures of shallow foundations.
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 the functions and types of foundations for building construction. It describes that foundations serve to distribute weight over a large area, prevent unequal settlement, provide a level surface, and stability against sliding and overturning. There are two main types - shallow foundations, which include isolated footings, combined footings, strap footings, grillage footings, and mat/raft footings. Deep foundations include piles, cofferdams, and caissons. Shallow foundations transfer loads directly to the soil or bedrock, while deep foundations transfer loads to deeper, stronger layers using structural elements like piles.
TYPES OF PILE FOUNDATION & APPLICATIONSMaharshi Dave
The PPT about pile foundation and types of pile foundation.It is very useful and make very properly.If you don't know about pile foundation then no problem only just refer this PPT and then you will become to know about pile foundation very well.I hope this will helpful to someone.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression and improve its tensile strength. There are two main methods - pre-tensioning and post-tensioning. Pre-tensioning tensions the strands before the concrete is poured, while post-tensioning tensions strands inside ducts after the concrete has cured. This compression counteracts tensile and flexural stresses from loads to reduce cracking and increase strength, allowing pre-stressed concrete to be lighter and more durable than reinforced concrete. It is commonly used in bridges, buildings, tanks, and other structures.
This document discusses column jacketing, which is a method of retrofitting and strengthening existing columns. It involves adding reinforced concrete, steel, or fiber-reinforced polymer around the column. The key steps are preparing the column surface, adding shear keys and reinforcement, applying a bonding agent, and casting the new concrete or installing the jacket. Column jacketing increases the strength and seismic capacity of the column. It improves confinement and increases axial, shear, and foundation load capacity without significant weight addition.
This document provides information about pile foundations. Pile foundations are used when the soil cannot support building loads and piles are driven deep into the ground until they reach a bearing stratum. Piles can be made of timber, concrete, or steel. They transfer loads from the building to the stronger subsurface layer. The document discusses different types of piles including end bearing and friction piles and explains how pile caps are reinforced to resist tensile and shear forces from heavy loads. Diagrams show how pile foundations are arranged and how piles transmit loads into the ground.
Diaphragm wall: Construction and DesignUmer Farooq
The document discusses diaphragm walls, which are concrete or reinforced concrete walls constructed below ground using a slurry-supported trench method. Diaphragm walls can reach depths of 150 meters and widths of 0.5-1.5 meters. They are constructed using tremie installation or pre-cast concrete panels. Diaphragm walls are suitable for urban construction due to their quiet installation and lack of vibration. The document discusses different types of diaphragm walls based on materials and functions, and provides details on their design, construction process, and material requirements.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression before application of service loads. This counters the tensile stresses induced by loads and prevents cracking. There are two main methods: pre-tensioning applies tension before pouring concrete, while post-tensioning tensions strands after concrete curing. Pre-stressed concrete allows for smaller and lighter structures that resist loads, deflection, and cracking better than reinforced concrete.
1) High rise buildings are becoming more common due to scarcity of land and demand for space. They are defined differently but generally refer to buildings over 15 meters tall.
2) Foundations for high rise buildings include shallow foundations like spread footings and mat foundations, and deep foundations like piles. Piles transfer load through end bearing or friction along their length.
3) Structural systems for high rise buildings must resist both gravity and lateral loads. Interior systems include rigid frames and shear walls. Exterior systems such as tube and diagrid systems resist loads along the building perimeter.
Pile foundation is important for construction of foundation where bearing capacity of soil is poor. Pile foundation is use for distribution of uneven load of superstructure.There are so many type of pile are use for construction. Here i present some of pile with suitable condition for construction and methods for construction.
Thank you.
This document discusses the need for raft foundations. Raft foundations are recommended when:
1) Building loads are heavy or soil capacity is low, so individual footings would cover too much area.
2) Soil contains weak lenses or cavities, making differential settlement hard to predict.
3) Structures are sensitive to differential settlement.
4) Structures like silos naturally suit raft foundations.
5) Floating foundations are needed over very weak soil.
6) Buildings require basements or underground pits.
7) Individual footings would experience large bending stresses.
Raft foundations increase capacity, decrease settlement, and equalize differential settlement compared to individual footings. However,
Shilpesh Sitakant Adbal is a civil and structural designer with over 9 years of experience in process plants including oil and gas. He has expertise in software such as SP3D, PDMS, Tekla, and AutoCAD. He holds a diploma in civil engineering and has worked on numerous projects for companies such as Linde Engineering India, WorleyParsons, United Phosphorus Limited, and BASF India. His experience includes 3D modeling, preparing civil and structural drawings, designing steel and concrete structures, and coordinating with other teams.
This seminar report discusses caisson foundations. Caissons are watertight structures used for deep foundations under water, such as for bridges, piers, and docks. There are three main types - open, box, and pneumatic caissons. Caissons can take various shapes and are used when foundations need to extend below riverbeds or in deep water. Advantages include ability to reach large depths, but difficulties include tilting or sinking during construction. Caisson diseases can affect workers if decompressed too quickly from pressurized conditions.
This document discusses different methods of prestressing concrete, including pretensioning and post-tensioning. Pretensioning involves stressing steel tendons before placing concrete around them, while post-tensioning involves stressing tendons after the concrete has cured using hydraulic jacks. Post-tensioning allows for longer spans, thinner slabs, and more architectural freedom compared to conventional reinforced concrete or pretensioned concrete. Common applications of post-tensioning include parking structures, bridges, and building floors and roofs.
The document discusses various types of footings used in building foundations. It defines a footing as the lower part of a foundation constructed below ground level on solid ground. The main purposes of footings are to transfer structural loads to the soil over a large area to prevent soil and building movement, and to resist settlement and lateral loads. Common footing types include isolated, strap, strip/continuous, and combined footings. Key data needed for footing design includes soil bearing capacity, structural loads, and column dimensions. The document outlines general design procedures and considerations for spread, combined, strap, and brick footings.
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
Retaining walls are used at the Shraddha Vivanta Residency construction site in Mumbai for two main purposes. Cantilever retaining walls around 3.5 meters deep allow for a basement and four floors of stacked parking underneath the residential building. Additional retaining walls surround underground water tanks for suction and firefighting. The walls are located along the building perimeter and around the tank areas. Proper waterproofing of the retaining walls is important given their underground locations.
Framed structures are building skeleton frameworks formed by columns and beams. There are two main types: in-situ reinforced concrete frames and prefabricated frames. Rectangular framed structures use columns and beams arranged at right angles to support floors, walls, and roofs. They are commonly used for multi-story buildings like offices, schools, and hospitals. Framed structures provide large open floor plans and are adaptable to different shapes. Earthquake-resistant features in framed structures include shear walls, moment-resisting frames, and braced structures which resist lateral forces during seismic activity.
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 the design of column braces for structures. It defines braced and unbraced columns, with braced columns having zero sway and stability provided by walls or bracing, while unbraced columns are subjected to sway with stability only from other columns. It describes different types of internal and external bracing patterns and factors to consider in brace analysis, including displacement, base shear, wind loads, maximum shear and bending moments. The document provides guidelines for designing braces based on column moments and explains how bracing type affects seismic resistance parameters through a parametric study.
The document describes different types of shallow foundations, including spread footings, combined footings, and raft/mat foundations. Spread footings include wall footings, reinforced concrete footings, inverted arch footings, and column footings. Combined footings are used when columns are close together or near a property line. Raft foundations consist of a thick concrete slab covering the entire structure area and are used when soil capacity is low or loads are large. The document also discusses advantages, limitations, and construction procedures of shallow foundations.
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 the functions and types of foundations for building construction. It describes that foundations serve to distribute weight over a large area, prevent unequal settlement, provide a level surface, and stability against sliding and overturning. There are two main types - shallow foundations, which include isolated footings, combined footings, strap footings, grillage footings, and mat/raft footings. Deep foundations include piles, cofferdams, and caissons. Shallow foundations transfer loads directly to the soil or bedrock, while deep foundations transfer loads to deeper, stronger layers using structural elements like piles.
TYPES OF PILE FOUNDATION & APPLICATIONSMaharshi Dave
The PPT about pile foundation and types of pile foundation.It is very useful and make very properly.If you don't know about pile foundation then no problem only just refer this PPT and then you will become to know about pile foundation very well.I hope this will helpful to someone.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression and improve its tensile strength. There are two main methods - pre-tensioning and post-tensioning. Pre-tensioning tensions the strands before the concrete is poured, while post-tensioning tensions strands inside ducts after the concrete has cured. This compression counteracts tensile and flexural stresses from loads to reduce cracking and increase strength, allowing pre-stressed concrete to be lighter and more durable than reinforced concrete. It is commonly used in bridges, buildings, tanks, and other structures.
This document discusses column jacketing, which is a method of retrofitting and strengthening existing columns. It involves adding reinforced concrete, steel, or fiber-reinforced polymer around the column. The key steps are preparing the column surface, adding shear keys and reinforcement, applying a bonding agent, and casting the new concrete or installing the jacket. Column jacketing increases the strength and seismic capacity of the column. It improves confinement and increases axial, shear, and foundation load capacity without significant weight addition.
This document provides information about pile foundations. Pile foundations are used when the soil cannot support building loads and piles are driven deep into the ground until they reach a bearing stratum. Piles can be made of timber, concrete, or steel. They transfer loads from the building to the stronger subsurface layer. The document discusses different types of piles including end bearing and friction piles and explains how pile caps are reinforced to resist tensile and shear forces from heavy loads. Diagrams show how pile foundations are arranged and how piles transmit loads into the ground.
Diaphragm wall: Construction and DesignUmer Farooq
The document discusses diaphragm walls, which are concrete or reinforced concrete walls constructed below ground using a slurry-supported trench method. Diaphragm walls can reach depths of 150 meters and widths of 0.5-1.5 meters. They are constructed using tremie installation or pre-cast concrete panels. Diaphragm walls are suitable for urban construction due to their quiet installation and lack of vibration. The document discusses different types of diaphragm walls based on materials and functions, and provides details on their design, construction process, and material requirements.
Pre-stressed concrete uses tensioned steel strands or bars to place concrete in compression before application of service loads. This counters the tensile stresses induced by loads and prevents cracking. There are two main methods: pre-tensioning applies tension before pouring concrete, while post-tensioning tensions strands after concrete curing. Pre-stressed concrete allows for smaller and lighter structures that resist loads, deflection, and cracking better than reinforced concrete.
1) High rise buildings are becoming more common due to scarcity of land and demand for space. They are defined differently but generally refer to buildings over 15 meters tall.
2) Foundations for high rise buildings include shallow foundations like spread footings and mat foundations, and deep foundations like piles. Piles transfer load through end bearing or friction along their length.
3) Structural systems for high rise buildings must resist both gravity and lateral loads. Interior systems include rigid frames and shear walls. Exterior systems such as tube and diagrid systems resist loads along the building perimeter.
Pile foundation is important for construction of foundation where bearing capacity of soil is poor. Pile foundation is use for distribution of uneven load of superstructure.There are so many type of pile are use for construction. Here i present some of pile with suitable condition for construction and methods for construction.
Thank you.
This document discusses the need for raft foundations. Raft foundations are recommended when:
1) Building loads are heavy or soil capacity is low, so individual footings would cover too much area.
2) Soil contains weak lenses or cavities, making differential settlement hard to predict.
3) Structures are sensitive to differential settlement.
4) Structures like silos naturally suit raft foundations.
5) Floating foundations are needed over very weak soil.
6) Buildings require basements or underground pits.
7) Individual footings would experience large bending stresses.
Raft foundations increase capacity, decrease settlement, and equalize differential settlement compared to individual footings. However,
Shilpesh Sitakant Adbal is a civil and structural designer with over 9 years of experience in process plants including oil and gas. He has expertise in software such as SP3D, PDMS, Tekla, and AutoCAD. He holds a diploma in civil engineering and has worked on numerous projects for companies such as Linde Engineering India, WorleyParsons, United Phosphorus Limited, and BASF India. His experience includes 3D modeling, preparing civil and structural drawings, designing steel and concrete structures, and coordinating with other teams.
Advanced Type Civil Engineering StructuresMalay Talaviya
This document discusses different types of advanced civil engineering structures including multi-storey buildings, chimneys, dams, bridges, industrial structures, retaining walls, and hydraulic and marine structures. It provides brief descriptions of each type of structure, highlighting things like their purpose, common materials used, and important design considerations.
Examples of work of Oleg Kilchevskiy, MSc qualified Structural Engineer with extensive experience in structural design, project management and construction management, including Arctic conditions; business-minded engineer, with interests in many areas of engineering, technology, natural and social sciences and a strong focus on systems engineering.
The document discusses software used in civil engineering. It begins by noting how technology has improved efficiency in the field. It then outlines several categories of software including architectural, structural, and project management. Specific software like AutoCAD, Revit, Lumion, SketchUp, Staad Pro, ETABS, SAP2000, TEKLA, ANSYS, Primavera, and Microsoft Project are described. The conclusion emphasizes how software has reduced construction time from 1-2 years to 6-9 months on projects.
This document provides an overview of common building types and components. It describes materials like brick, block and concrete that are often used in construction. It also outlines different types of buildings such as solid construction, steel frame, and reinforced concrete. Additionally, it details common doors, windows, staircases and roofs, including components like treads, risers, casement windows and pitched roofs. The learning objectives are to understand typical construction materials, door and window types, staircase elements, and roof designs.
This document discusses Lafarge's climate change and energy strategy. The strategy focuses on three areas: 1) contributing to reduced societal emissions through more energy efficient construction solutions, 2) reducing direct emissions from cement production through performance programs and developing lower-carbon solutions, and 3) promoting responsible energy policies. Lafarge aims to reduce CO2 emissions per ton of cement produced by 33% by 2020 through improving kiln energy efficiency, substituting fossil fuels, and producing blended cements.
Raffles Institute_Building construction framing systemsSandra Draskovic
This document outlines the aims, schedule, and content for a Building Technology and Construction module. The module aims to teach students about load-bearing systems, construction documentation, and choosing appropriate structural solutions. Over 11 weeks, topics will include foundations, roofs, walls, floors, stairs, and finishes. Students will learn about building elements, structural systems, loads on buildings, and achieving structural equilibrium. They will complete modeling, drawing, and documentation assignments related to residential construction.
Slope deflection method for structure analysis in civil engineeringNagma Modi
This document provides the steps to determine moments at points A, B, C, and D using the slope-deflection method for multiple structures. For each structure, the equations relating slope and moment are written for each member. The slopes and moments are then solved for using these equations along with the boundary conditions of zero rotation and moment at supports. The final moments calculated at each point are provided at the end.
Shallow foundations are foundations with small depths limited to the width of the footing. They spread loads from the superstructure over a larger area of soil to reduce stress intensity to a level the soil can safely support. Shallow foundations are classified as isolated or combined footings. Isolated footings support single walls or columns, while combined footings support two or more columns and come in shapes like rectangular, trapezoidal, or T-shaped. Mat foundations are used for soils with very low bearing capacity, forming a single, continuous raft to support the entire structure.
Oldest branch of engineering, next to Military engineering. All engineering works other than for military purposes were grouped in to Civil Engineering. Mechanical, Electrical, Electronics & present day Information technology followed it.
A professional engineering discipline that deals with the analysis, design, construction and maintenance of infrastructural facilities such as buildings, bridges, dams, roads etc.
Civil Engineering is everywhere. Civil Engineering is a composite of many specific disciplines that include structural engineering, water engineering, waste material management and engineering, foundation engineering etc. among many.
Shallow foundation(by indrajit mitra)01Indrajit Ind
Shallow foundations transmit structural loads to near-surface soils and are used when the upper soil layer is sufficiently strong. They include spread, combined, strap, and raft foundations. Design considers factors like bearing capacity, settlement, and water table effects. Plate load tests determine ultimate capacity and settlement by measuring pressure-displacement curves. Terzaghi's theory and IS codes provide design guidance.
1. Superstructure construction includes column, beam, floor, wall and roof located above ground level. Materials used are timber, steel and concrete.
2. Timber floor construction involves plank wood supported by timber joists and beams. Reinforced concrete uses column and beam construction with formwork, steel bar installation and concrete pouring.
3. Load bearing walls support loads and transfer to foundation, with minimum thickness of one brick. Non-load bearing walls only support own weight and are half brick thickness.
Shallow foundations are foundations where the depth is equal to or less than the width. There are four main types of shallow foundations: 1) Spread footings which spread loads over a larger area and are used for light loads or strong soils, 2) Combined footings which are preferred when columns are close together to make construction more economical, 3) Strap or cantilever footings which connect independent footings with a beam that does not transfer pressure to the soil, and 4) Mat or raft foundations which cover the entire area beneath a structure and are used for supporting loads on soft soils by spreading them over a large area.
"Introduction to Civil Engineering" is a PowerPoint that provides an overview of civil engineering, and areas of specialization within the field, for primary and secondary students. Designed by Dr. Larry Rillet - Director of the Nebraska Transportation Center at the University of Nebraska-Lincoln - and his educational outreach team members, the aim of this PowerPoint is to provide students with further exposure as to who civil engineers are and what they do. This lesson can be paired with a "Penny Boat" activity.
Civil engineering is one of the oldest and broadest fields of engineering. It includes designing, building, and managing infrastructure projects like roads, bridges, dams, and sanitation systems. Civil engineers work to improve quality of life through transportation networks, water systems, and addressing environmental issues. Some major areas of specialization include structural engineering, transportation engineering, geotechnical engineering, and water resources engineering. The document also lists seven iconic examples of civil engineering wonders: the World Trade Center, Eiffel Tower, Empire State Building, Statue of Liberty, Metropolitan Museum of Art, Golden Gate Bridge, and Burj Al Arab hotel.
types of Foundations with animated sketchesGiri Babu S V
This document discusses different types of foundations used to support structures. It begins by stating the objectives are to understand foundation construction, types of foundations, and which are suitable for different soil types. It then defines foundations as the lowest part of a structure below ground that transmits the weight to the subsoil. The main types discussed are shallow foundations, which include wall, column, combined, and mat foundations, and deep foundations, such as pile, under-reamed pile, and well foundations. Specific foundation types like isolated column, combined, mat, pile, under-reamed pile and well foundations are then described in more detail.
The document discusses factors to consider when choosing the type of foundation for a structure, including the nature of the structure, loads, soil characteristics, and cost. Shallow foundations such as footings and rafts are suitable if the soil can support the loads without excessive settlement. Deep foundations using piles or piers transmit loads to a deeper bearing layer if the top soil is weak. Floating foundations may be used if no bearing layer is found by removing and replacing soil under the structure. The document provides details on analyzing loads and designing shallow spread footings to resist shear, bond, and bending stresses.
lecturenote_1463116827CHAPTER-II-BEARING CAPACITY OF FOUNDATION SOIL.pdf2cd
The document discusses bearing capacity of soils and methods to calculate the ultimate and safe bearing capacities of different types of foundations. It defines key terms like ultimate, gross, net and safe bearing capacities. It describes Terzaghi's, Meyerhof's and Skempton's methods to calculate the bearing capacity based on the soil properties and foundation geometry. It provides examples to calculate the ultimate and safe bearing capacities of strip, square, circular and rectangular foundations in cohesive and cohesionless soils using these methods.
This document defines foundations and foundation engineering. It discusses shallow and deep foundations. Shallow foundations include spread, combined, wall/strip, and mat foundations. Deep foundations include piles and piers. It describes factors in foundation design such as ultimate bearing capacity, settlement, and differential settlement. Footing failures by shear, tension, or bearing capacity are addressed. Examples of isolated, combined, and wall footings are provided along with factors in selecting the appropriate foundation type.
This document defines foundations and foundation engineering. It discusses:
1. Foundations transmit structural loads to the soil and come in two types - shallow and deep. Shallow foundations are placed at a shallow depth, typically less than 6m, and include spread footings and strip footings. Deep foundations like piles are embedded much deeper.
2. Foundation engineering involves evaluating soil load capacity and designing foundations to safely transmit loads to the soil while considering economics. It must prevent shear failure, settlement, overturning and sliding.
3. Foundations can fail due to shear, tension or excessive settlement, which depends on factors like soil type and load. Design considers ultimate and allowable bearing capacity as well as allowable settlement.
This document provides information on bearing capacity of soil and foundations. It defines key foundation terms like contact pressure, foundation depth, shallow and deep foundations. It describes different types of shallow foundations like spread footing, continuous footing, combined footing, strap footing, and mat or raft footing. Factors for selecting a foundation type and comparing shallow vs deep foundations are also discussed. Design criteria of safety against bearing capacity failure and limiting settlement are covered.
Braced cut excavations design and problems pptRoshiyaFathima
This document discusses braced cuts and excavations for deep foundations. It describes various methods for temporarily shoring vertical walls during excavation, including movable earth shields and steel sheet piles with horizontal walers and struts. Methods for analyzing lateral earth pressures, strut loads, and wale bending moments are presented. Peck's design pressure envelopes are shown for estimating earth pressures on retaining walls in cohesive and cohesionless soils. An example problem demonstrates analyzing and designing a braced wall system for a stiff clay excavation using a given strut spacing.
1) Two approaches are used to determine the safe bearing pressure of soil: allowable bearing pressure based on shear failure criteria, and safe bearing pressure based on settlement criteria.
2) Plate load tests can be used to estimate the safe bearing pressure that results in a given permissible settlement. Tests are conducted with plates of different sizes and the load-settlement data is used to calculate settlement of prototype foundations using empirical equations.
3) Housel's method involves conducting two plate load tests and solving equations involving load, plate area and perimeter to determine constants, which are then used to calculate load and size of a prototype foundation that results in the permissible settlement.
Regarding Types of Foundation, Methods, Uses of different types of foundation at different soil properties. Methods of construction of different types of foundation, Codal Provisions etc.
This document provides information about bearing capacity of soil and different types of foundations. It discusses key topics like:
- Types of foundations including shallow foundations like spread footings, continuous footings, combined footings, strap footings, and mat/raft foundations. It also discusses deep foundations.
- Factors that determine the selection of a foundation type including the structure's function/loads, sub-surface soil conditions, and cost.
- Comparison of shallow and deep foundations in terms of depth, load distribution, construction, cost, structural design considerations, and settlement.
- Criteria for foundation design including safety against bearing capacity failure and limiting settlement, especially differential settlement.
1) The document discusses methods to determine the safe bearing capacity of soil, which is the maximum pressure the soil can resist without failing or excessive settling.
2) Two common field methods are described: the plate load test, where a steel plate is loaded incrementally on an excavated pit to measure ultimate capacity and settlement; and the drop weight method, where a weighted cube is dropped into a pit to calculate resistance.
3) Factors that influence safe bearing capacity are also outlined, such as soil type, density, water content, and voids. Tests are needed to select appropriate foundation designs at a site.
This document provides an introduction to foundation engineering and different types of foundations. It discusses shallow foundations, which have a depth to width ratio of less than 4, including spread, strip, continuous, combined and raft foundations. It also discusses deep foundations, which have a depth to width ratio greater than 4, such as piles and drilled shafts. The document further explains bearing capacity and settlement criteria for foundations. It provides details on Terzaghi's and Skempton's bearing capacity theories and includes examples of calculating ultimate and allowable bearing capacities.
This document discusses the bearing capacity of soils and foundations. It defines bearing capacity as the load per unit area that can be supported by a foundation without failing. Several methods for calculating ultimate bearing capacity are presented, including Terzaghi's method, which uses bearing capacity factors that depend on soil properties. The document also discusses factors that affect bearing capacity like the water table, foundation shape and depth, layered soils, sloped ground, and estimates from standard penetration or cone penetration tests. Failure modes like general, local, and punching shear are described along with calculations for eccentric and two-way loading.
This document discusses different types of foundations for structures. It describes shallow foundations like spread footings, combined footings, cantilever footings, continuous footings, and raft foundations. It also describes deep foundations like piles, piers, and caissons. The key factors in selecting a foundation type are the structure's loads, subsurface soil conditions, and cost. Foundation design considers load distribution, settlement, and preventing differential movement.
The document defines different types of structural footings used to support columns, walls, and transmit loads to the soil. It discusses isolated, combined, cantilever, continuous, raft, and pile cap footings. It also covers footing design considerations like allowable bearing capacity, shear strength, bending moment, and reinforcement requirements. The document provides formulas and steps for calculating footing size, reinforcement, and checking design requirements.
The document provides information on shallow foundations, including definitions, design criteria, methods for determining bearing capacity, and modes of failure. It discusses Prandtl's analysis, Rankine's analysis, and Terzaghi's bearing capacity theory. Terzaghi's theory assumes a shallow strip footing fails along a composite shear surface through five zones: an elastic zone under the footing, two radial shear zones, and two linear shear zones forming a triangular shape. The theory is used to derive an expression for ultimate bearing capacity considering the soil's shear strength properties.
PAPER;
Comparison between λ, α, Meyerhof, Vesic, Coyle Castello, SPT, Briaud, O´Neill and Reese 1999 methods in Cast In Situ and Drilled Piles for Clay and Sandy Soils;
Ingeniería Civil;
Civil engineering;
Ingeniería Ambiental;
Ambiental Engineering;
Ingeniería De Puentes;
Bridge Engineering;
Jaime Navía Téllez;
JNT;
J.N.T.;
RESUMEN
El cimiento es la parte más importante de cualquier estructura ya que permite transferir cargas del mismo al suelo, Si tienes una estructura de la mejor calidad y la construyes sobre un suelo malo, este va a fallar inevitablemente, es por eso la importancia del estudio de diferentes tipos de cimentación. Un pilote es un elemento estructural que forma parte de la infraestructura utilizado para cimentación en obras, que permite trasladar las cargas hasta un estrato resistente del suelo, cuando este se encuentra a una profundidad tal que hace inviable, técnica o económicamente, una cimentación más convencional mediante zapatas o losas.
Existen diferentes métodos para calcular la capacidad de carga de un pilote, pero cuál es el mejor?, en este manuscrito se hará una comparativa de todos los métodos existentes y se determinara cual es el más efectivo.
Palabras Clave: Pilotes, Capacidad de Carga, Métodos, Cimentación
ABSTRACT
The foundation is the most important part of any structure, since it transfer loads from the structure to the ground. If you have a structure of the best quality and you build it on a bad soil, it will inevitably fail, that is why the importance of the study of different types of foundations A pile is a structural element that is part of the infrastructure used for foundations in structures, which allows the loads to be transferred to a resistant layer of the soil, when it is at a depth that makes a more conventional foundation using footings or slabs unfeasible, technically or economically.
There are different methods to calculate the bearing capacity of a pile, but which one is the best? In this paper a comparison of all the existing methods will be done, and it will be determined which is the most effective.
Keywords: Piles, Bearing Capacity, Methods, Foundations
INTRODUCCION
¿Qué es realmente el ensayo SPT?
Puede definirse como un ensayo que contabiliza el número de golpes necesarios para introducir un toma muestras tubular de acero hueco o con puntaza ciega, mediante una maza de 63,5 kg que cae repetidamente desde una altura de 76,2 cm. Son importantes estas medidas ya que sirven para diferenciarlos de otros ensayos de penetración. Él toma muestras debe introducirse en el terreno 60 cm y se contabilizan los golpes cada 15 cm. Tanto él toma muestras tubular como la puntaza ciega y el varillaje necesario están estandarizados. Los mismo puedes consultarlos en la norma SPT UNE-EN ISO 22476-3:2006 o ASTM D1586.
Pile&Wellfoundation_ManualUpdated as on 20.5.16.pdfDharmPalJangra1
This document provides guidelines for the design and construction of well and pile foundations for railway bridges in India. It covers topics such as the depth of well foundations, shapes and cross-sections of wells, allowable bearing pressures, types of pile foundations, pile spacing, and load carrying capacity of piles. The guidelines are intended to help transfer heavy bridge loads to deep soil strata in a safe and stable manner. Standards are provided for various aspects of well and pile foundation design to suit local soil and construction conditions in India.
This document discusses bearing capacity and shallow foundations. It defines bearing capacity as the maximum average pressure a soil can support before failing. There are two failure criteria: shear failure and settlement. Terzaghi's bearing capacity theory is then explained, with soil divided into three zones. Factors influencing bearing capacity are also listed, such as soil type, foundation properties, water table level, and loading eccentricity. Finally, common bearing capacity determination methods are outlined, including analytical calculations, load tests, and laboratory tests.
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.
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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
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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.
Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
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established using either cable media or wireless media.
Impartiality as per ISO /IEC 17025:2017 StandardMuhammadJazib15
This document provides basic guidelines for imparitallity requirement of ISO 17025. It defines in detial how it is met and wiudhwdih jdhsjdhwudjwkdbjwkdddddddddddkkkkkkkkkkkkkkkkkkkkkkkwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwioiiiiiiiiiiiii uwwwwwwwwwwwwwwwwhe wiqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq gbbbbbbbbbbbbb owdjjjjjjjjjjjjjjjjjjjj widhi owqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq uwdhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhwqiiiiiiiiiiiiiiiiiiiiiiiiiiiiw0pooooojjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj whhhhhhhhhhh wheeeeeeee wihieiiiiii wihe
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Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
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Raft foundations
1. DESIGN OF RAFT FOUNDATIONS
AS OF (AMERICAN CONCRETE INSTITUTE COMMITTEE 336, 1988)
Prepared by : Eng.Hatim Mohammed Ahmed
2. TYPES OF FOUNDATIONS
R A F T F O U N D A T I O N S 2
Shallow Strip Edge beams for lightly loaded buildings
Pad To support internal columns of
buildings
Raft To keep movements to a tolerable
amount
Deep Driven piles Significant depth to competent
layer
Bored piles Large capacity required
3. RAFT FOUNDATION?
A foundation system in which essentially the entire building
is placed on a large continuous footing.
Usually large concrete slab supporting many columns.
Commonly used as foundation for silos, chimneys, large
machinery.
It is a flat concrete slab, heavily reinforced with steel, which
carries the downward loads of the individual columns or
walls.
R A F T F O U N D A T I O N S 3
5. Raft foundation is generally suggested in the
following situations:
R A F T F O U N D A T I O N S 5
(a) Whenever building loads are so heavy or the allowable
pressure on soil so small that individual footings would cover
more than floor area.
(b) Whenever soil contains compressible lenses or the soil is
sufficiently erratic and it is difficult to define and assess the
extent of each of the weak pockets or cavities and, thus, estimate
the overall and differential settlement.
(c) When structures and equipment to be supported are very
sensitive to differential settlement.
6. R A F T F O U N D A T I O N S 6
(d) Where structures naturally lend themselves for the use of raft
foundation such as silos, chimneys, water towers, etc.
(e) Floating foundation cases wherein soil is having very poor
bearing capacity and the weight of the super-structure is
proposed to be balanced by the weight of the soil removed.
(f) Buildings where basements are to be provided or pits located
below ground water table.
(g) Buildings where individual foundation, if provided, will be
subjected to large widely varying bending moments which may
result in differential rotation and differential settlement of
individual footings causing distress in the building.
7. GENERAL NOTES
R A F T F O U N D A T I O N S 7
Distribution of soil pressure by means of sub-grade reaction has been
suggested where sub-soils are of such character that the deformations are
localized in the general vicinity of the loads and when the maximum contact
pressure is smaller than about one and a half times the ultimate bearing
capacity.
In case of rigid footings, it is suggested that uniform or linear distribution of
soil pressure can be assumed and the design based on statics.
Flexible footing procedure is divided into 2 parts i.e. uniform condition and
general condition.
Uniform conditions are considered to be those where the variation in adjacent
column loads and spans is not greater than 20%. For cases where supporting
columns are at random location with varying intensities of loads detailed design
procedure based on plate theories has been recommended.
9. TYPES OF RAFT FOUNDATIONS
R A F T F O U N D A T I O N S 9
10. TO DESIGN RAFT FOUNDATIONS:
1. Determine the capacity of the foundation
2. Determine the settlement of foundation
3. Determine the differential settlement
4. Determine the stress distribution beneath the
foundation
5. Design the structural component of the mat
foundation using the stress distribution obtain
from 4.
R A F T F O U N D A T I O N S 10
11. DESIGN APPROACH AND
CONSIDERATIONS
R A F T F O U N D A T I O N S 11
Basically two approaches have been suggested for analyzing the
behavior of raft foundation:
A. Rigid foundation approach
B. Flexible foundation approach
12. R A F T F O U N D A T I O N S 12
DESIGN OF COMBINED FOOTINGS AND MATS ACI COMMITTEE 336
The following factors should be considered while examining any
problem:
(1) Soil type immediately below the footing
(2) Soil type at the greater depth
(3) Size of footing
(4) Shape of footing
(5) Eccentricity of loading
(6) Rigidity of footing
(7) Rigidity of the super-structure
(8) Modulus of sub-grade reaction
13. THE COMMITTEE SUGGESTS PROCEDURE TO BE FOLLOWED:
R A F T F O U N D A T I O N S 13
Linear soil pressure distribution is suggested for footings which can
be considered rigid to the extent that only very small relative
deformations result from the loading.
The rigidity may result from the spacing of the columns on the
footing ,from the rigidity of the footing itself or the rigidity of the
super-structure.
Limitations which must be fulfilled to make this assumption valid
have been discussed in the report.
Distribution of soil pressure by means of sub-grade reaction has
been suggested.
14. BEARING CAPACITY OF THE FOUNDATION
Bearing Capacity Analysis follows the same
approach as for spread footings
Factor of Safety :
Under normal Dead loads = 3.0(Min)
Under extreme loads = 1.75-2.0(Min)
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5.0
14
15. SETTLEMENT OF FOUNDATION
The settlement tends to be controlled via the following:
Use of a larger foundation to produce lower soil contact
pressures.
Displaced volume of soil (flotation effect); theoretically if
the weight of excavation equals the combined weight of
the structure and mat, the system "floats" in the soil
mass and no settlement occurs.
In general, the pressure causing settlement in a mat
analysis may be computed as:
Net pressure = {[Total (including mat) structure weight] -
Weight of excavated soil}/Mat area
15
16. RIGID APPROACH:
In rigid foundation approach, it is presumed that raft is rigid enough to
bridge over non-uniformities of soil structure. Pressure distribution is
considered to be either uniform or varying linearly.
Design of rigid raft follows conventional methods where again following two
approaches have been suggested:
(a) Inverted floor system
(b) Combined footing approach
In rigid rafts, differential settlements are comparatively low but bending
moment and shear forces to which raft is subjected are considerably
high.
R A F T F O U N D A T I O N S 16
17. Bridging effects attributable to
a . Raft rigidity.
b. Contribution of superstructure rigidity to the raft.
17
Foundation type Expected
maximum
settlement, mm
Expected
differential
settlement, mm
Spread 25 20
Mat 50 20
18. RIGIDITY OF SUPERSTRUCTURE AND
FOUNDATION (CONT ):
As of (American Concrete Institute Committee 336, 1988)
12
3
ah
IIEIE bFb
3
flexural rigidity of the Superstructure and Mat
flexural rigidity of the framed members at right angles to B
/12 flexural rigidity of shear walls
shear wall thickness
shear wall
b
b
E I
E I
E ah
a
h
height
flexural rigidity of the mat foundationFE I
18
d
d
d d
If 0.5, then mat can be treated as rigid i.e. ( / ) 0
If 0.5, then ( / ) 0.1
If 0, then ( / ) 0.35(square mats) and ( / ) 0.5(long mats)
r
r
r
K
K
K
19. RIGIDITY OF SUPERSTRUCTURE AND
FOUNDATION
As of (American Concrete Institute Committee 336, 1988):
19
3
BE
IE
K
s
b
r
Width of raft
Moment of inertia of
structure per unit length
at right angles to B
Modulus of Elasticity of Soil
Modulus of Elasticity of Material used in
Structure
Rigidity Factor,
20. Determination Of Critical Column Spacing
Evaluation of the characteristics γ is made as follows:
Where,
k = modulus of subgrade reaction in KN/m3
B = width of raft in cm
Ec = modulus of elasticity of concrete in MPa
Z = moment of inertia of the raft in m4
Depth of Foundation :
The depth of foundation shall generally be not less than 1 m.
R A F T F O U N D A T I O N S 20
4
4
kB
EcI
21. FLEXIBLE APPROACH
In flexible foundation approach, raft is considered to distribute load in the
area immediately surrounding the column depending upon the soil
characteristics. In this approach differential settlements are
comparatively larger but bending moments and shear forces to which
the raft is subjected are comparatively low.
Analysis is suggested basically on two theories
(a) Flexible plate supported on elastic foundation, i.e., Hetenyi's Theory
(b) Foundation supported on bed of uniformly distributed elastic springs
with a spring constant determined using coefficient of sub-grade
reaction. Each spring is presumed to behave independently, i.e.,
Winklers's foundation
R A F T F O U N D A T I O N S 21
22. FLEXIBLE METHOD:
1. Compute the plate rigidity D
2. Compute the radius of effective stiffness L
(Note: the approximate zone of any column
influence is ~ 4L).
3. Compute the radial and tangential moments,
the shear, and deflection.
R A F T F O U N D A T I O N S 22
24. CONSTRUCTION PRACTICES APPLICABLE TO THE
DESIGN OF MATS.
Thickness T is determined from two-way shear (punching shear);
Typical mat thickness T:
Stories B=45' B=90' B=120'
< 5 24" 31" 39"
5 - 10 35" 47" 59”
10 - 20 59" 78" 98"
R A F T F O U N D A T I O N S 24
25. Burt G. Look , Handbook of Geotechnical Investigation and Design Tables, 2007 Taylor &
Francis Group, London, UK
ACI Committee 336, Suggested analysis and design procedures for combined footings and
mats, ACI Struct J (1988), pp. 304–324.
S.N. Shukla, A simplified method for design of mats on elastic foundations, ACI J (1984),
pp. 469–475. View Record in Scopus | Cited By in Scopus (2)
SHARAT CHANDRA CUPTA ,Raft Foundations Design and Analysis with a Practical
Approach, 1997 New Age International (P) Limited, Publishers.
REFERENCES:
R A F T F O U N D A T I O N S 25
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