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The entire process of structural planning and design requires not just imagination and conceptual thinking but also sound noesis of practical aspects, such every bit recent blueprint codes and bye-laws, backed up by ample experience, establishment and judgment. It is emphasized that whatsoever structure to be constructed must satisfy the demand efficiency for which it is intended and shall be durable for its desired life span. Thus, the pattern of any structure is categorizes into post-obit two principal types:-

  1. Functional design
  2. Structural blueprint

Contents:

  • Functional Pattern of Structures
  • Structural Design
  • Stages in Structural Pattern
    • 1. Structural Planning
    • 1. two Positioning of Beams
    • 1.three Spanning of Slabs
  • Structural Pattern of Foundations
  • Assumptions in Earthquake Resistant Design

Functional Design of Structures

The structure to exist constructed should primarily serve the basic purpose for which it is to be used and must accept a pleasing look. The building should provide happy environment inside too equally outside. Therefore, the functional planning of a edifice must take into business relationship the proper arrangements of room/halls to satisfy the need of the client, good ventilation, lighting, acoustics, unobstructed view in the case of community halls, cinema theatres, etc.

Structural Design

Once the form of the construction is selected, the structural pattern procedure starts. Structural blueprint is an art and science of understanding the behavior of structural members subjected to loads and designing them with economy and elegance to give a rubber, serviceable and durable construction. Structural design process

Stages in Structural Design

The process of structural pattern involves the following stages.

  1. Structural planning
  2. Action of forces and computation of loads
  3. Methods of assay
  4. Fellow member design
  5. Detailing, Drawing and Training of schedules

1. Structural Planning

After getting an architectural plan of the buildings, the structural planning of the building frame is done. This involves determination of the following.

  • Position and orientation of columns
  • Positioning of beams
  • Spanning of slabs
  • Layouts of stairs
  • Selecting proper type of basis.

i.one Positioning and orientation of columns Post-obit are some of the building principles, which help in deciding the columns positions.

  1. Columns should preferably be located at (or) near the corners of a building, and at the intersection of beams/walls.
  2. Select the position of columns and then as to reduce bending moments in beams.
  3. Avoid larger spans of beams.
  4. Avoid larger centre-to-centre distance betwixt columns.
  5. Columns on belongings line.

Orientation of columns i. Avoid project of columns: The projection of columns exterior the wall in the room should be avoided as they not just give bad appearance but also obstruct the use of floor infinite, creating issues in placing article of furniture flush with the wall. The width of the column is required to exist kept non less than 200mm to prevent the column from being slender. The spacing of the cavalcade should be considerably reduced and then that the load on cavalcade on each floor is less and the necessity of big sections for columns does non arise. two. Orient the column so that the depth of the column is contained in the major plane of bending or is perpendicular to the major axis of bending. This is provided to increase moment of inertia and hence greater moment resisting capacity. It will as well reduce Leff/d ratio resulting in increase in the load conveying chapters of the cavalcade.

one. 2 Positioning of Beams

i. Beams shall normally be provided nether the walls or beneath a heavy full-bodied load to avert these loads directly coming on slabs. 2. Avert larger spacing of beams from deflection and cracking criteria. (The deflection varies directly with the cube of the span and inversely with the cube of the depth i.e. L3/D3. Consequently, increase in bridge L which results in greater deflection for larger span).

1.3 Spanning of Slabs

This is decided past supporting arrangements. When the supports are just on reverse edges or only in one direction, and then the slab acts every bit a 1 style supported slab. When the rectangular slab is supported forth its four edges information technology acts every bit a i way slab when Fiftyy/Lten < two. The two way activeness of slab non only depends on the aspect ratio simply besides on the ratio of reinforcement on the directions. In 1 style slab, main steel is provided forth with short span just and the load is transferred to ii opposite supports. The steel along the long span but acts as the distribution steel and is not designed for transferring the load but to distribute the load and to resist shrinkage and temperature stresses. A slab is made to deed as a one way slab spanning beyond the brusque span past providing main steel along the short span and only distribution steel along the long span. The provision of more than steel in one management increases the stiffness of the slab in that direction. According to rubberband theory, the distribution of load being proportional to stiffness in two orthogonal directions, major load is transferred along the stiffer brusque span and the slab behaves as 1 mode. Since, the slab is also supported over the brusque border in that location is a tendency of the load on the slab by the side of support to become transferred to the nearer back up causing tension at top across this short supporting edge. Since, there does not be any steel at top beyond this short edge in a one manner slab interconnecting the slab and the side beam, cracks develop at the elevation forth that edge. The cracks may run through the depth of the slab due to differential deflection between the slab and the supporting brusque edge beam/wall. Therefore, care should be taken to provide minimum steel at top across the short edge back up to avoid this cracking. A two way slab is generally economical compare to one style slab because steel forth both the spans acts as main steel and transfers the load to all its four supports. The two way action is advantageous substantially for big spans (>3m) and for live loads (>3kN/mii). For short spans and low-cal loads, steel required for ii way slabs does non differ appreciably as compared to steel for ii way slab because of the requirements of minimum steel.

Structural Design of Foundations

The type of ground depends upon the load carried by the column and the bearing capacity of the supporting soil. The soil under the foundation is more susceptible to large variations. Even under i small edifice the soil may vary from soft clay to a hard murum. The nature and properties of soil may change with flavor and weather, like swelling in wet weather. Increment in moisture content results in substantial loss of bearing capacity in case of sure soils which may lead to differential settlements. It is necessary to conduct the survey in the areas for soil properties. For framed structure, isolated column footings are normally preferred except in case of exists for great depths, pile foundations can exist an appropriate pick. If columns are very closely spaced and bearing capacity of the soil is low, raft foundation tin can be an alternative solution. For a column on the purlieus line, a combined footing or a raft basis may exist provided.

Assumptions in Earthquake Resistant Blueprint

The following are the assumptions fabricated in the convulsion resistant design of structures:

  • Convulsion causes impulsive ground motions, which are complex and irregular in grapheme, changing in menstruation and amplitude each lasting for modest duration. Therefore resonance of the type as visualized under steady-land sinusoidal excitations, will not occur as information technology would need time to build up such amplitudes.
  • Convulsion is not probable to occur simultaneously with wind or max. Flood or max. sea waves.
  • The value of elastic modulus of materials, wherever required, maybe taken every bit per static analysis.