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Instructions are provided below to manually accomplish the installation without running the executable file. Frequently Asked Questions. Create a folder named: " StructuresManual", include only the text and underbars between the " " quote marks. Open each PDF file from the links above and select "save as", to save the file in the folder created in step 1.
DO NOT change the file or folder names, as this will cause the links to malfunction. If desired, a shortcut may be created to link to the Structures Manual Introduction PDF, which will then operate much like the downloaded. The linear loading of beams, columns, walls, parapets, etc. Step3 a : Preliminary Sizes of structural members. Beam : The width the beam generally taken as the width of wall i. Column:- Size of column depends upon the moments from the both the direction and the axial load.
Step ii : Over this load, the weight of wall if any , self weight of beam etc. Step iv :Then the loads from the beams are transferred to the columns. Step v :Step i to Step v is repeated for each floor.
Step vi :These loads at various floors on each column are then added to get the total loads on each column, footing and the whole building. The loads calculated in Para-II above at various floor levels are modified as per the requirement of Para 7. Fundamental National Period Seconds Clause 7.
As per the clause 7. It is presumed that the reinforcements are always so arranged that all joints of the frame are monolithic. If the normal moment distribution is applied to all joints, the work involved is enormous. However with certain assumptio ns, it is possible to anal yze the frames and get results which will be adequate for design purposes.
To simplify anal ysis the three dimensional multistoried R. It is assumed that each of these planer frames act independentl y of the frames. Step iv :Step i to Step iii is repeated for each floor Step v :Then these load s are used as u. Therefore, it become necessa r y to evolve simpler methods. Some of these are: - a. Hardy cross method of moment distribution. The frame is analyzed by this method either: i.
Floor-wise assuming the columns to be fixed for ends. Taking the frame as a whole. The whole frame anal ysis can be carried out for several alternative loading arrangements for obtaining maximum positive and negative bending moment.
Generall y frames are anal yzed floor-wise for the worst conditions of loading. The method is described in the following steps. Step1: Calculate the stiffness of all members. Enter them in the calculation scheme. Step2: Calculated the distribution factor at all joints from the stiffness.
Step3: Look the joints and calculate the fixed -end moments. Distribute the imaginary external moment among all members Meeting at the joint in proportion to their relative stiffness and enter these value in the scheme.
This operation is called balancing. Step5: Enter the carry-over moments at the far in the scheme. Step7: Balance the unbalanced moment obtained from the last carry-over operation. A sample of moment distribution method is shown on next two pages.
L III 6. Approximate methods are used for preliminary designs only. For final design we may use exact method i. Design of columns : - With the knowledge of i Vertical load ii Moments due to horizontal loads on either axis; iii Moments due to vertical loads on either axis, acting on each column, at all floor levels of the building , columns are designed by charts of SP Design Aids with a load factor of 1.
The step confirms the size of columns assumed in the architectural drawings. The design of each column is carried out from the top of foundation to the roof, varying t he amount of steel reinforcement for suitable groups for ease in design. Further, slenderness effects in each storey are considered for each column group.
Important Considerations in design of Columns: - i Effective height of column :- The effective height of a column is defined as the height between the points of contra flexure of the buckled column. For effective column height refer table 28 Annexure E of IS: Refer Annexure E of IS: Column design required: - I.
Determination of the cross sectional dimension. Transverse steel. The transverse reinforcement is provided to impart effective lateral support against buckling to every longitudinal bar. It is either in the form of circular rings of pol ygonal links late ral ties. Design of foundations: - With the knowledge of the column loads and moments at base and the soil data, foundations for columns are designed The following is a list of different t ypes of foundations in order to preference with a view to ec onom y: i Individual footings ii Combination of individual and combined footings iii Strip footings with retaining wall acting as strip beam wherever applicable; iv Raft foundations of the t ypes a Slab b beam -slab.
The brick wall footings are also designed at this stage. Often, plinth beams are provided to support brick walls and also to act as earthquake ties in each principal direction. Plinth beams, retaining wall if any, are also designed at this stage, being considered as part of foundati ons. Important Considerations in design of Foundations: - a Introduction : - Foundations are structural elements that transfer loads from the building or individual column to the earth. If these loads are to be properl y transmitted, foundations must be designed to prevent excessive settlement or rotation, to minimize differential settlement and to provide adequate safet y against sliding and over turning.
Punching shear shall be around the perimeter 0. For two way shear action, the nominal shear stress is calculated in accordance with lause Reference Clause The total reinforcement shall be laid down uniformly in case of square footings.
For rectangular footings, there shall be a central band, equal to the width of the footings. The reinforcement in the central band shall be provided in accordance with the following equation.
The reinforcement may be provided either by extending the longitudinal bars into the footing or by providing dowels in accordance with the code as give in the following:- 1 Minimum area of extended longitudinal bars or dowels must be 0.
A short summary of this paper. First the architectural drawings of the building are studied, structural sys tem is finalized sizes of structural members are decided and brought to the knowledge of the concerned architect. The procedure for structural design will involve some steps which will depend on the t ype of building and also its complexity and the time ava ilable for structural design.
Often, the work is required to start soon, so the steps in design are to be arranged in such a way the foundation drawings can be taken up in hand within a reasonable period of time. Further, before starting the structural design, the following information of data are required: i A set of architectural drawings; ii Soil Investigation report SIR of soil data in lieu thereof; iii Location of the place or cit y in order to decide on wind and seismic loadings; iv Data for lifts, water tank capacities on top, special roof features or loadings, etc.
Choice of an appropriate structural system for a given building is vital for its economy and safet y. There are two t ype of building systems:- a Load Bearing Masonry Buildings.
This system is suitable for building up to four or less stories. These beams are to rest on mm thick brick walls or reinforced concrete columns if required. Load bearing brick wall Structural system b Framed Buildings:- In these t ypes of buildings reinforced concrete frames are provided in both principal directions to resist vertical loads and the vertical loads are transmitted to vertical framing system i.
The brick walls are to be regarded as non load bearing filler walls onl y. This system is suitable for multi -storied building which is also effective in resisting horizontal loads due to earthquake. In this system the floor slabs, generall y 10 mm thick with spans ranging from 3. In certain earthquake prone areas, even single or double storey buildings are made framed structures for safet y reasons.
Also the single storey buildings of large storey heights 5. Framed Structural system 2. The design should be carried so as to conform to the following Indian code for reinforced concrete design, published by the Bureau of Indian Standards, New Delhi: Purpose of Codes National building codes have been formulated in different countries to lay down guidelines for the design and construction of structure.
The codes have evolved from the collective wisdom of expert structural engineers, gained over the years.
These codes are periodicall y revised to bring them in line with current rese arch, and often, current trends. The codes serve at least four distinct functions. Secondl y, they render the task of the designer relativel y simple; often, the result of sophisticate anal yses is made available in the form of a simple formula or chart.
Thirdl y, the codes ensure a measure of consistency among different designers. IS : — Ductile detailing of reinforced concrete structure subject to seismic forces. Design Handbooks The Bureau of Indian standards has also published the following handbooks, which serve as useful supplement to the version of the codes. Although the handbooks need to be updated to bring them in line with the recently revised version of the Code, many of the provisions continue to be valid especiall y with regard to structural design provisions.
General Design Consideration of IS: It is the dimension used in design and indicated in the drawings. It shall be not less than the diameter of the bar. For main reinforcement up to 12 mm diameter bar for mild exposure the nominal cover may be reduced by 5 mm. In the case of columns of minimum dimension of mm or under, whose reinforcing bars do not exceed 12 mm, a nominal cover of 25 mm may be used.
It is possible to reduce the load combinations to 13 instead of 25 by not using negative torsion considering the symmetry of the building. Note: For beams continuous over support For unsymmetrical or very tall structures, more rigorous methods should be used. For moments at supports where two unequal spans meet or in case where the spans are not equally loaded, the average of the two values for the negative moment at the support may be taken for design.
Where coefficients given in Table below are used for calculation of bending moments, redistribution referred to in For such a condition shear coefficient given in Table below at the end support may be increased by 0. For non-monolithic construction the design of the member shall be done keeping in view However, where simplified analysis using coefficients is adopted, redistribution of moments shall not be done. This will not apply to deep beams. For slabs spanning in two directions, the shorter of the two spans should be used for calculating the span to effective depth rations.
For two-way slabs of shorter spans up to 3. Simply supported slab 35 Continuous slabs 40 For high strength deformed bars of grade Fe ,the values given above should be multiplied by 0. Simply supported slab 28 Continuous slabs 32 If such supports are formed due to beams which justify fixity at the support of slabs, then the effects on the supporting beam, such as, the bending of the web in the transverse direction of the beam, wherever applicable, shall also be considered in the design of the beams.
Comparison reinforcement in beams shall be enclosed by stirrups for effective lateral restraint. The total area of such reinforcement shall be not less than 0. In T-beams and I-beams, such reinforcement shall pass around longitudinal bars located close to the outer face of the flange. In no case shall be spacing exceed mm. However, this value can be reduced to 0. Torsion reinforcement - Slab Torsion reinforcement is to be provided at any corner where the slab is simply supported on both edges meeting at that corner.
It shall consist of top and bottom reinforcement, each with layers of bars placed parallel to the sides of the slab and extending from the edges a minimum distance of one-fifth of the shorter span. The area of reinforcement in each of these four layers shall be three-quarters of the area required for the maximum mid-span moment in the slab. Longitudinal Reinforcement a. The cross sectioned area of longitudinal reinforcement shall be not less than 0. The bar should not be less than 12 mm in diameter so that it is sufficiently rigid to stand up straight in the column forms during fixing and concerting.
A reinforced concrete column having helical reinforcement must have at least six bars of longitudinal reinforcement with the helical reinforcement. Spacing of longitudinal should not exceed mm along periphery of a column. In case of pedestals, in which the longitudinal reinforcement is not taken into account in strength calculations, nominal reinforcement should be not be less than 0.
Transverse Reinforcement a. Spacing of lateral ties should not exceed least of the following:- Least lateral dimension of the column. SHEAR The definition of seismic zone and importance factor are given in IS
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