The raft foundation reinforcement construction technology of hongyun building b tower. Code of practice for design and construction of raft foundations, part 1. Datta the percentage of reinforcement in footings is between 0. Chapter 3, foundations and foundation walls 55 in sdcs d1 and d2, no. One hundred twenty major categories of fully editable and scalable drawings and. A raft or mat foundation is a sizable concrete slab or slabandbeam system which supports all the loads of superstructure through walls or columns in two or more rows and rests on soil layer or rock. Detail of raft foundation reinforcement the foundation slabs are reinforced with two wire meshes, one placed at the lower fibers and one at the upper fibers. Services included the excavation of ground beams, installing of side shuttering, 250 micron plastic sheeting, fixing of reinforcement and pouring of readymix concrete. Reinforcement detailing will be shown in the next page. Beam and slab raft foundation as a foundation to support the heavier loads of walls or columns, a solid slab raft would require considerable thickness. Reinforcement supported by formwork shall rest on bar supports made of plastic or other acceptable materials.
For example, if the mat foundation is 6 ft 2 m thick and no. Raft foundation reinforcement and construction in detail. Columns shall be erected at locations by mobile crane if there are more number of columns to be erected in an area and when working platform is not available. Please practice handwashing and social distancing, and check out our resources for adapting to these times. Design a raft foundation for the layout of columns shown in figure 12. The raft foundation is usually used with this kind of soil. There are different types of reinforcement in footings. Design manual to bs8110 bs8110 design preface please note that the linkstudpsr design and optimum pattern layout details can be calculated very simply, by using the free linkstudpsr design software available later in 2010 with the minimum of input. All splices will be provided as indicated in the approved for construction drawings. Drawing labels, details, and other text information extracted from the cad file. Jun 26, 2018 friends in this drawing reading lecture i am going to tell you the reading tips related to the foundation drawing planproper reading of the foundation dr. Pdf the foundation of hongyun building b tower is made of raft board foundation which is 3300mm in the. 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.
Types of reinforcement in footings or types of mesh in. The unified solid raft foundation is the simplest form of foundation and its formwork assembling as well as its reinforcement is usually very easy. Sachpazis date 230420 chkd by date appd by date raft foundation design bs8110. One hundred twenty major categories of fully editable and scalable drawings and details in autocad. After completion of main mesh for raft, column starter bars shall be provided as per setting out details. The drawing shows one of the piles with detail of reinforcement. I want to see design formulas and calculation in details, thanks. It took twenty six designers a feat in itself to create it. Raft foundations sometimes referred to as raft footings or mat foundations are formed by reinforced concrete slabs of uniform thickness typically 150 mm to 300 mm that cover a wide area, often the entire footprint of a building. Every technologic leap was analyzed to make sure anything proposed was possible by 2050. Design of raft footings is detailed in the following steps. Soil properties and parameters, and foundation systems frost depth frost line or freezing depth is the depth to which the groundwater in soil is expected to freeze due to temperature drop. The summation is to be done over all the storeys, including the foundation beam of raft. This often is referred to as a twopour foundation because the concrete for the footing and the.
Library item raft title hedge bedge aedge hslab hhcoreslab hhcorethick asedgetop asslabtop asslabbtm asedgebtm asedgelink. Raft foundation is a thick concrete slab reinforced with stee. Raft foundation design requirements and applicability. The raft has x side spacing of 7 meters and yside spacing of 6 meters. We employ up to twenty teams of the most experienced site personnel in the raft foundation business and you can be assured of the best quality work available. Sometimes area covered by raft may be greater than the contact area depending on the bearing capacity of the soil underneath. Raft foundation reinforcement and construction in detail youtube. The three main modes of failure due to stability are, overturning sliding bearing overtur. Openings in the top mat of reinforcement allow access to lower levels change. Any additional top andor bottom reinforcement can be in the same layer as the outer, main reinforcement or within the interior layers. O 1 2 3 4 details of columns considering column a1 as origin o moment about. Review of investigation on raft foundations for major. It is very important to learn bar bending schedule for finding out the quantities of steel reinforcement required for every component of the building. This video shows the most effective proceduremethod for drafting the raft foundation detail.
All reinforcement shall be supported and fastened before concrete is placed and shall be secured against displacement within permitted tolerances. Raft foundation mat foundation details, complete footing and column reinforcement checking at site duration. Raft foundation when to use, types, construction civil. A good detailing of reinforcement covers topics like cover to reinforcement based on environmental considerations for durability, minimum. The blinding concrete facilitates to arrange a solid and flat surface for the reinforcement of raft foundation. Structural design of raft foundation pe civil exam. Engineers inspections and completion certificates are also provided. Typical wall construction detail on raft foundation with. Structures and equipment sensitive to differential settlement.
A foundation in residential construction may consist of a footing, wall, slab, pier, pile, or a combination of these elements. The design criteria and loads are needed for the foundation design load tables appendix b. Mar 07, 2014 28 raft foundationsdesign and analysis note. To get a better idea about when to use raft foundation, it is important to understand how raft foundation works. However, due to the fact that the footing and the inverted tbeams web form a unified body along the entire length of the structure, the systems inertia is larger therefore, its behaviour is more satisfactory. The required anchorage values are used in appendix c, foundation capacities tables, to determine the materials, dimensions, and construction details of the foundation. If spread footings used, the area of the footing required will be big as will be shown in column load section 3. Many applications, such as raft foundation, road pavement, airport runway, etc. Footings distribute the weight of the structure over the ground. The curing polythene sheets should be arranged instantly after finishing and when the concrete is set, it should be substituted with hessian cloth and should be retained wet unless the. Bar bending schedule for footings estimation of steel reinforcement in footings. Concerning the calculation of plate on an elastic foundation, the certainty analysis method has been used, i. Constructibility, has developed forums dealing with constructibility.
The raft foundation is conducted for the multistory buildings or building having heavy loads. Raft or mat foundations understand building construction. The method statement includes a safe work procedure and control measures, which you can edit and add your project details. In this big spread footing condition, the raft foundation could be much practical and economical. Twoway spanning, steel reinforcing rods are placed on. Installation of reinforcement steel bars for footing. The bearing capacity increased by combining all individual footings in to one mat since bearing capacity is proportional to width and depth of foundations. The strip foundation inverted tbeam behaves in a way similar to that of spread footings tied together by a connecting beam. Structural design of raft foundation structural engineering forum. The concrete raft is supported on a compacted hardcore base which extends out past the edge of the raft. It is vital that the concrete slab is strengthened by the use of steel reinforcement. This often is referred to as a twopour foundation because the.
The future living house is a testament to the will of design. Raft foundation design for a typical 2 storey house example bs8110. This raft foundation method statement template has been prepared and precompleted for the excavation and construction of a reinforced concrete raft foundation. The bearing capacity increased by combining all individual footings in to one mat since bearing capacity. One hundred twenty major categories of fully editable and scalable drawings and details in autocad format.
Buildinghow products books volume a the reinforcement. There are two main checks to carry out and they are stability and structural. Jun 12, 2017 raft foundation mat foundation details, complete footing and column reinforcement checking at site duration. Reinforcement detailing of footing is as much important as site investigation for the structural design of footing. Since the most intense stresses appear along the columns axis, their surrounding areas are usually reinforced with stronger or double grates. It is very important to learn bar bending schedule for finding out the quantities of steel reinforcement required for every component of the building for suppose, consider the case of high rise buildings, it requires tons of. The concept of stress is very basic to civil engineering. To make the most economical use of reinforced concrete in a raft foundation supporting heavier loads, it is usual practice to form a beam and slab raft. Raft foundation reinforcement details raft foundation. A good detailing reflects the design requirement of the footing for structural stability. Friends in this drawing reading lecture i am going to tell you the reading tips related to the foundation drawing planproper reading of the foundation dr. Initially, the surveyor should begin exaction and as soon as the survey is completed then exaction is carried out to the desired level on the basis of the validated shop drawings.
Our services included the design of your raft foundation including raft layout plans, reinforcement details, nhbrc documents and council approvals. We know that we have to insert reinforcement in footings for tension requirements. There are certain requirements that need to be considered during the of raft foundation in order to produce adequate design such as minimum depth of 50cm, required excavation depth of approximately 2. Mat or raft foundation is a large concrete slab supporting several columns in two or more rows. It ranges in the united states from about zero to six feet. Typical configuration of reinforcement in a deep mat foundation fig. Moments and shears for reinforcement should be checked for the overturning case plastic soil stress gives upper bound on moments and shears in concrete horizontal equilibrium. Aug, 2017 bar bending schedule for footings estimation of steel reinforcement in footings. This type of foundation spreads the load of the building over a larger area than other foundations, lowering the pressure on the ground. A raft foundation is a continuous slab of concrete usually.
Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor. For columns, the steel cages shall be prefabricated. The edge of the raft is stepped, creating a toe, which allows the outer leaf of the wall to continue below ground level. Mar 07, 2016 lets start with designing a raft foundation. This is an alternative if you cant use a traditional strip or trench fill foundations. A raft foundation is often used when the soil is weak, as it distributes the weight of the building over the entire area of the building, and not over smaller zones like individual footings or at individual points like pile foundations. Raft foundation is generally used to support structures like residential or commercial buildings where soil condition is poor, storage tanks, silos, foundations for heavy industrial equipment etc. This is a large continuous footing supporting all the columns of the structure. Its a paradigm shift in home resource creation and location.
A footing is a concrete support under a foundation that rests in solid ground and is wider than the structure supported. Raft foundations are a type of foundation with high integrity in which four foundation piers are connected together using a large foundation slab to form a massive structure and the foundation piers are connected through beams. Chapter 3, foundations and foundation walls 51 figure 33 overturning action resisted by foundation. Soft pockets or cavities of in the soil to unknown. Full learn to read structural drawing course at the cheapest rate. A raft or mat foundation is a sizable concrete slab or slabandbeam system which supports all the loads of superstructure through walls or columns in two. Pdf the raft foundation reinforcement construction technology of. It is used where the supporting soil has low bearing capacity. The irc discusses foundations footings and stem walls and foundation walls separately and contains requirements for those elements based on the materials used for their construction. Method statement for formwork, reinforcement and concrete.
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