What is the difference between portal method and cantilever method?
The difference in both the methods is where there used for example the portal method is used for buildings where the shear Mode is responsible for any kind of deformation in the building. While the cantilever method is used In case of buildings where the Mode responsible for deformation would be lecture mode .
What are the different approximate methods for lateral load analysis?
Approximate methods of analysis of multi-bay frames (lateral loads)
- Portal method (version 1) This method was developed by Robin Fleming (Norris and Wilbur,1960).
- Portal method version II.
- Cantilever method – Robin Fleming (1913)
- The factor method.
What are the assumptions of portal method and cantilever method?
The cantilever method is very similar to the portal method. We still put hinges at the middles of the beams and columns. The only difference is that for the cantilever method, instead of finding the shears in the columns first using an assumption, we will find the axial force in the columns using an assumption.
What are the assumptions in cantilever method?
The assumptions used in this method are that the points of contraflexure (or points of inflection of the moment diagram) in both the vertical and horizontal members are located at the midpoint of the member, and that the direct stresses in the columns are proportional to their distances from the centroidal axis of the …
What is Portal method in structural analysis?
The portal method is one of the common approximate methods in the analysis of statically indeterminate structures. This method is used to analyze the frames which subjected to lateral loadings such as wind, earthquake, and blast loadings.
What is the concept of cantilever?
A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilever can be formed as a beam, plate, truss, or slab.
How does a cantilever work?
cantilever, beam supported at one end and carrying a load at the other end or distributed along the unsupported portion. The upper half of the thickness of such a beam is subjected to tensile stress, tending to elongate the fibres, the lower half to compressive stress, tending to crush them.
What are the different methods of approximate methods of analysis?
Depending upon how the remaining two assumptions are made, we have two different methods of analysis: Portal method and cantilever method. They will be discussed in the subsequent sections. In this method following assumptions are made. 1) An inflexion point occurs at the mid height of each column.
What are the methods of frame analysis?
Building frames can be analyzed by various methods such as force method, displacement method, and approximate method. The method of analysis to adopt depends upon the types of frame, its configuration (portal bay or multi-bay) in multi-storied frame and degree of indeterminacy.
What are the assumptions in cantilever method of analysis?
What is a cantilever and example?
A balcony protruding from a building would be an example of a cantilever. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel, or box girders built from prestressed concrete.
How is the cantilever method based on a transverse load?
The cantilever method is based on the same action as a long cantilevered beam subjected to a transverse load. It may be recalled from mechanics of materials that such a loading causes a bending stress in the beam that varies linearly from the beam’s neutral axis, Fig. 6 (a).
Which is the best method for lateral load analysis?
For preliminary analysis of tall buildings, the only method available for lateral load analysis is the cantilever method. The power of the concept employed in this method is such that some engineers prefer to use the results of the analysis for final design. However, the method has the following disadvantage.
How are lateral loads used in frame construction?
Frame Structures with Lateral Loads: Cantilever Method the entire frame acts similar to cantilever beam sticking out of the ground. For tall and slender building frames under lateral loads, created due to the lateral load around the base of the building.
How is displacement analysis based on cantilever bending?
The method is based on the strength formula M/I=f/y. (The notations indicate their usual meaning). Hence it is called as strength approach. In this paper, based on the cantilever bending and using stiffness influence coefficient, displacement analysis is put forward.