Filed under Design, Practical Guide by Gopal Mishra on 05/03/2010 at 01:23
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Assumptions
Concrete has no tensile resistance
The reinforcing resists all the tensile forces.
Maximum tensile stress in the steel:
The characteristic cube stress of the concrete = fcu and the compressive stress in the concrete = 0,4 fcu
The maximum neutral axis depth (dn) is limited to 0.5 d.
The internal moments are in equilibrium with the external moments.
Resistance moment [...]
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Filed under Design, Structural by Gopal Mishra on 19/02/2010 at 10:08
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The development length may be defined as the length of the bar required on either side of the section to develop the required stress in steel at that section.
DEVELOPMENT LENGTH OF BARS
The development length Ld, is given by
In the formula for development length, the appropriate values for u s and 7M are to be [...]
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Filed under Design, Structural by Gopal Mishra on 15/02/2010 at 20:28
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Reliability?
“BEST bus services are very reliable”
“BMC water supply is not very reliable”
“In Mumbai, Western Railway’s service is more reliable than that of the Central Railway”
What is reliability, in technical terms?
How do we measure it?
Why is not a system fully reliable?
Civil Engineering Systems
Structural (Buildings, Bridges, Dams, Fly-overs)
Transportation (Road systems, Railways, Air traffic)
Water (Water supply networks, [...]
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Filed under Design, Earthquake by Gopal Mishra on 06/02/2010 at 23:58
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A tuned mass damper, also known as an active mass damper (AMD) or harmonic absorber, is a device mounted in structures to prevent discomfort, damage, or outright structural failure caused by vibration. They are frequently used in power transmission, automobiles, and buildings.
How Tuned Mass Dampers Work
A tuned mass damper (TMD) consists [...]
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Filed under Design, Steel Design by Gopal Mishra on 05/02/2010 at 22:50
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Design of Steel Tanks
The steel tanks are defined as vessels made of steel plates. The steel tanks are either placed on ground or placed on towers. When the steel tanks are placed on ground, then, these are supported on cement concrete foundation or on steel grillage foundation. [...]
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Filed under Buildings, Design by Gopal Mishra on 04/02/2010 at 14:25
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MULTISTOREY REINFORCED CONCRETE BUILDINGS
A large number of reinforced concrete multistoreyed frame buildings were heavily damaged and many of them collapsed completely in Bhuj earthquake of 2001 in the towns of Kachchh District (viz., Bhuj, Bhachao, Anjar, Gandhidham and Rapar) and other district towns including Surat and Ahmedabad. In Ahmedabad alone situated at more than 250 [...]
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Filed under Design, Steel Design by Gopal Mishra on 12/01/2010 at 02:38
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The steel chimneys are of two types:
Self-supporting steel chimneys
Guyed steel chimneys.
Self-supporting steel chimneys: When the lateral forces (wind or seismic forces) are transmitted to the foundation by the cantilever action of the chimney, then the chimney is known as self-supporting chimney. The self-supporting chimney together with the foundation remains stable under all working conditions without [...]
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Filed under Beam Design, Design by Gopal Mishra on 08/12/2009 at 20:44
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Portal Frame Design with Example
Design Steps:
1. Design of slabs
2. Preliminary design of beams and columns
3. Analysis
4. Design of beams
5. Design of Columns
6. Design of footings
Problem:
A portal frame hinged at base has following data:
Spacing of portal frames = 4m
Height of columns = 4m
Distance between column centers = 10m
Live load on roof [...]
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Filed under Building Technology, Design by Gopal Mishra on 07/12/2009 at 09:52
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Pre-Engineered Steel Buildings use a combination of built-up sections, hot rolled sections and cold formed elements which provide the basic steel frame work with a choice of single skin sheeting with added insulation or insulated sandwich panels for roofing and wall cladding. The concept is designed to provide a complete building envelope system which [...]
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Filed under Beam Design, Design by Gopal Mishra on 03/12/2009 at 15:55
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Uncracked Elastic Beam Behavior
Look at the shear and bending moment diagrams. The acting shear stress distribution on the beam:
The acting stresses distributed across the cross-section.
The shear stress acting on the rectangular beam.
The equation of the shear stress for a rectangular beam is given as:
Note: The maximum 1st moment occurs [...]
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Filed under Architecture, Concrete by Gopal Mishra on 26/11/2009 at 19:00
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The main characteristics of arches common to all is the presence at the support of Horizontal thrust induced there, because of unyielding supports prevent the curved beams from straightening under vertical loads. The horizontal thrust acts towards the arch. It produces compression stresses at all sections of the arch.
DIFFERENT ARCH SHAPES:
STRUCTURAL BRICK ARCHES [...]
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Filed under Design, Structural by Gopal Mishra on 15/11/2009 at 18:30
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Reinforced concrete can provide substantial protection from even extreme blast loading. The relatively large mass of concrete elements provides an inherent resistance to impulsive loads. Structural design considerations include sizing members to provide an expected degree of deformation and associated damage and optimizing the structure to resist and transfer blast loads in a reliable manner. [...]
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Filed under Design, Earthquake by Gopal Mishra on 14/11/2009 at 13:13
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Base Isolation Method
Conventional Construction Practice assumes Fixed Base Structures
The Dynamic Characteristics of Fixed Base Structures are determined by the general characteristics of the structural system
The Designer can only slightly adjust those Dynamic Characteristics
As a matter of fact, most common Building Structures have unfavorable Dynamic Characteristics that result in increased [...]
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Filed under Design, Slabs by Gopal Mishra on 13/11/2009 at 14:43
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SLABS
The floor construction of a dwelling must fulfill several criteria and the following design functions must be taken into consideration.
n The provision of a uniform, level surface
n Sufficient strength and stability
n Exclusion of dampness from inside of building
n Thermal insulation (max.0.45 W/square metre K)
n Resistance to fire
DEFINITION OF SLABS
n Is [...]
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Filed under Design, Structural by Gopal Mishra on 09/11/2009 at 09:28
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Buildings are designed by architects and engineers. In reality, in most cases, buildings principally for human occupancy are designed conceptually by architects. That is to say that architects are the ones principally responsible for the configuration of buildings for human occupancy.
Configuration has to do with the shape and size of the building. Inevitably shape and [...]
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Filed under Design, Structural by Gopal Mishra on 08/11/2009 at 21:19
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With the occurrence of every major earthquake, there has been in the past, almost a world-wide tendency to increase the capacity demand of the structure to counteract such events. It is only in the last decade that new strategies have been successfully developed to handle this problem economically. The current international practice has shifted towards [...]
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