Posts Tagged Steel structures
Guide to designing a Rolled Steel Beam
Posted by BenzuJK in Building Construction on October 20, 2010
Six Step Guide to Designing a Rolled Steel Beam
Here are a few simple steps that are to be followed for the design of Rolled Steel Beam:
Step one
Calculate the maximum Bending Moment and Shear Force
Step two
Depending upon whether the beam is laterally restrained or unrestrained, calculate the permissible stress in bending compression (sigma bc) using the equation;
sigma bc = 0.66fy
Step three
Find the required Section Modulus (Zreq)
Zreq = M/sigma bc
Step four
From the structural tables, choose a suitable section such that the section modulus is slightly more than the required section modulus.
Step five
Check for shear.
Calculate the maximum Shear force in the beam. Calculate the average shear stress in the web and this should be less than 0.4fy.
Tv = (Shear Force)/HLw
where = H = height of the web
Lw = length of the web
Step six
Check for deflection
Ymax < 1/325 of span
Methods of Structural Design | Design of Steel Structures
Posted by BenzuJK in Building Construction on May 14, 2010
Structural design is the science of studying the Mechanics of a structure. Designing the skeleton of a building determines the real strength of the structure.
If the structure is externally beautiful and internally weak, it results into dramatic structural failure.
Structural Framework in a building
In this article, we are going to discuss in detail about the “Various Methods of Structural Design”.
All parts of a structural steel framework of a structure shall be capable of sustaining the most adverse combination of dead loads, the prescribed super imposed roof and floor loads, wind loads, seismic forces where applicable, and any other forces or loads to which the building maybe reasonably subjected without exceeding the permissible stresses.
The following methods may be employed for existing steel framework:
- Simple design
- Semi-rigid design
- Fully rigid design
- Plastic design
Column Bases | Design of Steel Structures
Posted by BenzuJK in Building Construction on February 5, 2010
Column bases are structural elements used in the design of steel structures to transfer the column load to the footings.
Types of Column bases
- Slab base
- Gusseted base
Slab Base
Slab bases are used where the columns have independent concrete pedestals. A thick steel base plate and two cleat angles connecting the flanges of the column to the base plate. In addition to these, web cleats are provided to connect the web of the column to the base plate. These web cleats guard against the possible dislocation of the column during erection. The ends of the column and also the base plate should be mechanized so that the column load is wholly transferred to the base plate.
Area of base plate= (load of column)/(permissible bearing stress in concrete)