Raft foundation design and analysis with a practical approach gupta, s. A raft foundation is essentially a reinforced concrete slab on the ground foundation designed for the specific soil conditions on the stand. Civil engineering downloads foundation construction raft foundation. Mat or raft foundation is a large concrete slab supporting several columns in two or more rows. Manual design of beam and raft foundation to eurocode 2 pdf. This example is carried out to show the differences in the design results when the raft is analyzed by different soil models. The smaller values of and should be used for design and reduction factor on account of subsoil water n penetration resistance. The book is very helpful for foundation engineering. Download handbook of material testing book by shiv kumar pdf. Elpla can analyze foundation of arbitrary shape with a real subsoil model. Design of raft foundations methods and calculations. Cfa and drilled pier for a building practical design example. The bearing capacity increased by combining all individual footings in to one mat since bearing capacity is proportional to width and depth of foundations.
Download raft foundation design and analysis pdf for free. It was in the earlier 1920s that a concerted effort was made to study and understand the physical laws governing the behavior of sub surface materials, i. Determine the stress distribution beneath the foundation 5. Rather than reading a good book with a cup of tea in the.
The extensive foundation which is usually called raft foundation, is a unified foundation that extends throughout the entire area of the columns. It explores the assumptions that are made in the analysis of soil structure interaction, together with the associated calculation methods. Raft foundation design and analysis with a practical approach. Design of raft footings is detailed in the following steps. Concordia university, 20 piledraftfoundation is a new concept, which has received increasing recognition in recent years. Feb 11, 2018 analysis simple raft foundation using robot structural analysis 2010. Foundation design robot structural analysis products. Sachpazis date 230420 chkd by date appd by date raft foundation design bs8110. Footings are structural elements, which transfer loads to the soil from columns, walls or lateral loads from earth retaining structures.
A typical example of a beam and slab raft is given in fig1. Raft foundations e optimized design of piled raft foundations has been actively investigated in recent years 1920 21 22, focusing on the mechanisms of different pile arrangements and. This foundation design software substantially simplifies timeconsuming calculations for structural engineering design. Analysis simple raft foundation using robot structural. Analysis and design of a raft for a high rise building.
If the values of n is greater than 15 in saturated silts, the equivalent penetration resistance should be taken for the design. Reinforcement pattern dialog rc foundation the reinforcement pattern dialog allows you to define the parameters of reinforcing bars used during the rc foundation design. The piled raft foundation utilises the pile group for the control of settlement, with the piles providing most of the stiffness at the service loads while the raft elements provide. For foundations of such high rise building, normally raft foundation, pile foundation or piled raft foundation are used. This example was carried out to show the influence of flexure rigidity of the superstructure on the settlements, contact pressures for a raft of high rise building. Asdip foundation is a structural engineering software utilized by engineers for design of pile caps and concrete footings, such as spread footings, strap footings, combined footings, and wall footings, per the latest aci 318 provisions this foundation design software substantially simplifies timeconsuming calculations for structural engineering design. Each model gives internal forces for the raft different from that of the others. Reinforced concrete design examples geotec software. Design of raft foundation excel sheet raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor.
Raft foundation analysis and design example scribd. Simplified design method for piled raft foundations. Brief survey of existing methods of raft foundation design. The dimensions definition dialog allows you to define the basic information pertaining to the geometry of the designed foundation. The soil in this method is replaced by an infinite number of isolated springs. The software is specifically designed for civil and structural engineers. Optimization technique has been applied for a raft foundation. Raft foundation design and analysis with a practical. Analysis of the performance of a large ribbed mat foundation supporting building 333.
In this section, only the rigid method will be covered. When considering soilstructure interaction to obtain foundation actions for structural design for example, the bending moments in the raft of a. Another design method still concentrates on providing adequate axial capacity from the piles to carry the structural load and the bearing capacity of the raft is neglected. The raft foundations are designed in earthquake zones to transmit building gravity and earthquake loads to the supporting soil without failure or large settlement 1 4. The raft will be used for economical consideration. Raft is a powerful software that can be used for making analysis, design, estimation, costing of rcc raft foundation with adherence to is. Basics of foundation engineering with solved problems. Structural design of raft foundation pe civil exam. These reactions were used as point loads for the design of the raft foundations. Learn raft in 14 easy steps is included with the software. The isobars on the right are for a strip continuous footing. Download raft foundation design and analysis with a practical approach by sc gupta. The analysis of piled raft foundations has improved over the last few decades to. In this example it is assumed that ground surface is at the top of the footing, i.
It adopts the calculation method given in annex d of en 19971. Collection of design excel sheets online civilforum. Raft foundation can be design using several methods. Raft foundation analysis and design example free download as pdf file. Raft foundation design and analysis with a practical approach hardcover january 1, 1997 by s. Mar 07, 2014 28 raft foundations design and analysis note. Where and allowable soil pressure under raft foundation in use a factor of safety of three. The design was performed using the finite element software staadfoundation, as shown in figure 11. Download the full calculation sheet from the link below. Figure 6 shows a footing carrying characteristic vertical actions vgk permanent and v qk variable imposed on it by the superstructure. Aug 12, 2017 design of raft foundation excel sheet raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor.
Numerical analysis of unconnected piled raft with cushion. Download raft foundation design and analysis with a practical. Elpla can analyze foundation of arbitrary shape with real subsoil model. We are currently based in the east of pretoria, gauteng. Elpla elastic plate is a powerful tool for analyzing piledraft foundations. However, all models are considered save and correct. Previous article rc beam design and analysis spreadsheet. Pdf optimization of raft foundation design researchgate.
Concordia university, 20 piled raft foundation is a new concept, which has received increasing recognition in recent years. Also download structural analysis and design of swimming pools and. Pressure bulb beneath a strip footing geoslope international. In the first one, the group of footings has no connections while in the second one, the group of footings is connected together by stiff tie beams considering the interaction effect among footings, tie beams. Despite such design assumptions, it is common for a raft to be part of the foundation system e. The design of the raft foundation has to satisfy the requirements for one way shear, punching shear, bending moments, stresses, and settlements. Units calculator excel sheet for conversion of measurement. May 26, 2015 foundation engineering has been practiced as an art, without help of science, since time immemorial up to 1920 when it had achieved a considerable amount of refinement. Poulos 18 presented this example of a raft supported on 9 piles, one under each. Analysis of rates of building construction in excel. Now, the values of d 1 and d 2 can be calculated easily as will be seen later. Whats the difference between defining the stiffness of the soil kz in the thickness of the plate or as a support.
Sometimes area covered by raft may be greater than the contact area depending on the bearing capacity of the soil underneath. See all formats and editions hide other formats and editions. The following diagram is taken from the textbook, foundation analysis and design, by joseph e. Elpla has models for analyzing single pile, pile groups, piled raft foundation. Raft foundation analysis and design example free download as text file. Design of raft footings the structural design of raft foundations can be carried out by two methods. This report shows the structural design of the raft foundation. In this special project the method used in the design called the. In conjunction with professional consulting engineers we provide a complete design and construction service for raft foundations. Design the structural component of the mat foundation using the stress distribution obtain from 4.
Asdip foundation is a structural engineering software utilized by engineers for concrete footings design, such as spread footings, strap footings, and combined footings, per the latest aci 318 provisions. Civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads. Raft foundation design for a typical 2 storey house example bs8110. Practical structural analysis and design of residential buildings using staad pro v8i, csc orion, and manual calculations. Figure 1 shows the layout and steel detailing of a raft foundation for a highrise building. The piled raft foundation utilises the pile group for the control of settlement, with the piles providing most of the stiffness at the service loads while the raft elements provide the additional capacity at the ultimate load levels. Pdf on nov 15, 2019, s a pechorskaya and others published raft foundations. Hello there, i am designing a raft foundation usign autodesk robot 2014 and i am facing some problems first question. This is an alternative if you cant use a traditional strip or trench fill foundations. The summation is to be done over all the storeys, including the foundation beam of raft. An example is carried out to design a spread footing according to ec 2, din 1045, aci and ecp codes. Introduction need of raft foundation types of raft foundation survey of available literature design approach and consideration structural designers dilemma. This type of foundation, which is sometimes referred to as a raft foundation, is a combined footing that may cover the entire area under a structure supporting several columns and walls figure 5.
It is used where the supporting soil has low bearing capacity. Raft foundation design and analysis with a practical approach pdf book by sharat chandra gupta. Elpla elastic plate is a powerful tool for analyzing piled raft foundations. Raft foundations sometimes known as mat foundations are a large concrete slab which can support a number of columns and walls. Manual design of beam and raft foundation to eurocode 2 pdf references ubani o. A number of methods have been proposed based on primarily on two approaches of simplified and truly elastic foundations. Analysis simple raft foundation using robot structural analysis 2010.
Oct 22, 2017 download code design calculation of raft foundation. Next article pavement design worksheet according to. As a rule, raft foundation is used as a buildings foundation when the soil has a low bearing capacity. Dec 23, 20 this book covers complete design of raft foundations including piled rafts, starting from their need, type, all the approaches suggested so far in published literature, effect of assumptions made and values of variables selected, on the design values of stresses, and brings out the limitations of these approaches using actually constructed rafts. This book examines alternative design procedures for plain and piled raft foundations.
Design calculation of raft foundation civil engineering. This example shows the analysis and design of a group of footings resting on an elastic foundation by two different structural systems. Raft foundations are built is this following steps. Raft foundation design raft design software raft analysis. Manual design of beam and raft foundation to eurocode 2 free. This type of foundation spreads the load of the building over a larger area than other foundations, lowering the pressure on the ground.
The behaviour of the raft foundation resembles the behaviour of a strip foundation grid. A conventionally reinforced mat raft foundation is selected, proportioned and designed, such as to. The mathematical solution of the raft is based on the finite. Curve 3 represents the case in which piles are positioned in such a way to act as a settlement reducers. Pile foundations applications with buildings and bridges. A raft foundation is a reinforced concrete slab under the whole of a building or extension, floating on the ground as a raft floats on water.
The bearing capacity increased by combining all individual footings in to one mat since bearing capacity. There are two categories which can be used to design a raft foundation. Mat raft foundation design in robot structural analysis 2019part1 duration. Instructional materials complementing fema p751, design examples. It is required to analysis a raft for the building shown in figure 6. Structural behavior of tall building raft foundations in. Download raft foundation design and analysis with a. In order to transfer these loads properly to the soil, footings must be design to prevent excessive settlement minimize differential settlement, and. Current design practice is based on conventional group pile or block failure theory, that ignore the bearing contribution from the raft. This diagram shows the pressure isobars based on the boussinesq equation for a footing. Brick,concrete, plaster,tile,converter excel sheet. Civilax is the knowledge base covering all disciplines in civil engineering. Types of deep foundation advantages and disadvantages of each type part two. The mathematical solution of the raft is based on the finite element method.
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