Retrofitting old Foundations | Civil Engineering

Retrofitting the Foundations of Old Structures

The level of deterioration of the foundation determines whether the building can be improved or needs to be demolished. Repairing and retrofitting of the building elements should be done at the initial stages of the deterioration. This would save time as well as costs of construction.

In case the deterioration is not paid attention to, it can lead to excessive damage of building components which may result into excessive retrofitting costs.

Failure of Structure due to ignoring the need for retrofitting
Failure of Structure due to ignoring the need for retrofitting

Small cracks in Buildings

In case there are cracks having occurred on the building are small, the building can be declared to be in a sound condition. It involves nominal repairs and lower repair costs which would save your time as well.

Large scale damage

For older buildings where the foundations of the building have been severely affected, all large retrofit work is then subject to professional assistance. This would require the evaluation of geotechnical and structural conditions of the structure.

Surveys to be carries out:

Majorly two important surveys are to be carried out:

  1. Technical Survey
  2. Historical Survey

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Height of Instrument Method | Surveying and Levelling

Height of the Instrument Method

The following readings were observed with a levelling instrument, the instrument was shifted after 5th and 11th reading.

0.585, 1.010, 1.735, 3.295, 3.775(5th)

0.350, 1.300, 1.795, 2.575, 3.375

3.895 (11th), 1.735, 0.635, 1.605

Determine the RLs of various points if the reduced level (RL) of a point on which the first reading was taken is 136.440 gives the height of collimation method and applies the check.

Station BS IS FS HI RL Remarks
123

4

5

0.585 

 

0.350

1.0101.735

3.295

 

 

3.775

137.025 

 

133.600

136.440136.015135.290

133.730

133.250

RL of I point 

 

CPI

678

9

10

 

 

1.735

1.3001.7952.575

3.375

 

 

3.895

 

 

131.440

132.300

131.805

131.025

130.225

129.705

CP II
1112 0.635 1.605 130.805

129.835

Sum of BS=2.670 Sum of FS =9.275

HL = RL + BS

= 136.440 + 0.585

= 137.025

RL = HL – IS

Check

(Summation of BS)-(Summation of FS) = Last RL – First RL

2.670 – 9.275 = 129.835 – 136.440

-6.605 = -6.605

Development of Surface Active Structure system

Development of Shell Structures | Structural Systems

In this article, we will discuss “Surface Active Structure System” with examples for better understanding….

In my earlier articles, we discussed “Structural Systems in the Post Modernist Period” and “Development of Suspended Structures“. Reading about different types of Structural Systems and their basis and purpose of evolution will help you understand the varied concepts of Structural Systems.

In this type of structure system, a thin curved structure is so shaped to transmit applied forced by compressive, tensile and shear stresses that act in the plane of the surface. They are usually constructed of concrete reinforced with steel mesh.

 

Sydney Opera House | Example of Shell Structure
Sydney Opera House | Example of Shell Structure

Shell construction began in the 1920s; the shell emerged as a major long-span concrete structure in postmodernism. Thin parabolic shell vaults and even complex forms i.e. hyperbolic paraboloids stiffened with ribs have been built with spans up to about 300 feet (90m). Thickness of the shell with this system can be achieved even less than 0.5 inches (1.25cm) thick. One of the most famous example of this is Sydney Opera House.

The shape of this majestic structure has been achieve with the help of plastic behaviour of the material. In this, the shells were constructed out of 2400 precast ribs and 4000 roof panels in an on-site factory. By this solution, they were able to avoid the need for expensive formwork construction.

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Use of Porcelain and Ceramic tiles in Modern Architecture

Porcelain and Ceramic Tiles in Modern Architecture

In my earlier articles, I have discussed about some of the Modern materials and “Modern Bathroom Designs“. But the fact that what materials make those Bathrooms modern and gives them an elegant look cannot be ignored. In this article, we will discuss in brief about two important materials responsible for giving beauty and elegance to your bathrooms and also some important places and corners in your homes.

Porcelain and ceramic tiles have been used throughout history and it is almost impossible to conceive a modern day structure without the use of ceramic tiles.

Modern Bathrooms | Use of Porcelain and Ceramic Tiles
Modern Bathrooms | Use of Porcelain and Ceramic Tiles

What was initially considered a piece of art in ancient times has become a product of mass utility now due to its intrinsic qualities, which perfectly match the demands of modern architecture.

 

A ceramic is an inorganic, non-metallic solid produced by the application of heat and subsequent cooling. Ceramic materials may be crystalline, partly crystalline or amorphous in appearance.

The earliest ceramics were pottery objects made from clay, either singly or mixed with other materials, hardened by fire.

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Window Air conditioners and Split Air conditioners | Electrical Engineering

Window Air conditioners and Split Air conditioners | Working and their Application

In this article, we will discuss “Window Air conditioners” in general. We are quite familiar with room air conditioners. As the name itself suggests, these air conditioners are mounted in the windows and hence the name.

Window Air conditioners comprise of the following parts:

  1. The compressor
  2. The condenser fan
  3. Condenser and evaporator

These components are all enclosed in a single cabinet. This unit is then installed in a window frame or a hole that specially casted during the construction for the purpose of installing Window air conditioners.

While we design the location and installation of Window air conditioners, we need to keep in mind a few important things that would affect the functioning of the window air conditioner. The air being blown through the condenser must pass freely through without restriction. We must therefore make sure that the condenser is not obstructed (for example by a neighboring wall).

Capacities of air conditioners

They come in cooling capacities from 0.5 to 2 tons in various tonnages, adequate for a room between 5 and 20 square meters in size. Larger spaces may be handled by using multiple units of this type.

Window air conditioners are easy to install and convenient to use and economical in cost, they could be noisy for some applications.

Probably the single biggest reason for inefficiency in Window ACs is a dirty filter. Usually most of us don’t pay attention to the maintenance of Window ACs which are accompanied by cleaning the AC filters to keep up the performance of the Window Air conditioners. Even if covered by maintenance contracts, dust is such a severe problem in most areas that the filter needs cleaning even between preventive maintenance visits by your supplier.

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Types of Air conditioning Systems | Electrical Engineering

Study of types of air conditioning Systems in Engineering

Studying different types of air conditioning systems is a part of Engineering. It helps us understanding the working and functioning of HVAC systems. For designing HVAC systems in an Auditorium or a Mall, the engineer has to be aware of various types of air conditioning systems along with its advantages and disadvantages.

Today, various types of air conditioning systems are available in the market. They can be broadly classified as follows:

  1. Central air conditioning systems
  2. Non central air conditioning systems

Central AC Systems are further subdivided into two categories:

  1. Ductable Packaged Air-conditioners
  2. Central Plants

Non-Central AC products are further classified as:

  1. Window ACs
  2. Split ACs

In this article, we will discuss the basic terminology of what are Central AC systems and Non-central AC products.

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Alamillo Bridge by Calatrava | Suspended Structures

Alamillo Bridge, Seville, Spain | Suspended Structures

In my previous article, we discussed the development of Suspended Structures and the technical aspects involved in the construction of Suspended Structures.

Alamillo Bridge, Seville, Spain, 1987-1992, designed by Calatrava Santiago, total span of the bridge is 250m and height of the tower is 142m. Materials used are steel for tower with concrete infill where needed, steel bridge deck structure and concrete abutments. The extraordinary weight of the concrete filled steel mast, which angles away from the roadbed at 58 degrees is enough to support the deck without the need for counter-stay cables or support piers.

Alamillo Bridge, Seville, Spain | Suspended Structures
Alamillo Bridge, Seville, Spain | Suspended Structures

The mass and the bed of the tower exerts a backwards downward force while the cable stays and roadbed mass exert a forward downward force. The mass of the tower was so calculated so that its backward and downward force wouldn’t lift the bridge off the ground.

For this reason, an additional mass was needed to counter the reaction of vertical forces. In order to increase the mass, the steel box girder of the tower and the steel deck structure were filled with concrete. This added to the stability of the structure.

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Development of Suspended Structures | Structural Systems

Suspended Structures | Structural Systems

Suspended Structures are those with horizontal planes i.e. floors are supported by cables (hangers) hung from the parabolic sag of large, high-strength steel cables. The strength of a suspended structure is derived from the parabolic form of the sagging high strength cable.

To make this structure more efficient, the parabolic form is so designed that its shape closely follows the exact form of the moment diagrams.

The sagging cable is more stable under symmetrical loading conditions as the cable may deform as it attempts to adjust to an eccentric loading. As the cable adjusts to this load its shifts the rest of the structure.

 

Dulles International Airport
Dulles International Airport

 

This adjustment causes secondary stresses in the horizontal surface and additional deformation. The parabolic curve of the cable is also designed for various eccentric or lateral loads such as wind, seismic etc.

The large curving cable may consist of many smaller cables which are tightly spun together. As the cables are being spun together, they are also stretched over the span and attached to the supports.

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Prefabricated Construction and Lightweight building systems

Prefabricated Construction and Lightweight building systems

What is Prefabrication?

Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out.

During the development in the industrial revolution, the people have full awareness regarding the behaviour of the structure.

It was fully analyzed and understood that for the existence of an object and its form, it is necessary that the object can bear all forces which act on it.

 

Precast Concrete House Construction
Precast Concrete House Construction

The structure thus, functions in three subsequent operations:

  1. Load reception
  2. Load transfer
  3. Load discharge

The flow of forces does not pose problem as long as the object form follows the direction of acting forces. With these analytical theories of structure and at the same time new technological developments like prefabricated construction influence the designer.

In the works of Buckminster Fuller and Moshe Safdie, there is extensive use of fabricated components.

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Deconstructivism | Walt Disney Concert Hall

Deconstruction in Architecture

Deconstructivism in architecture is a development of postmodern architecture that began in the late 1980s.

Characteristics of Deconstructivism:

  • Fragmentation
  • Non linear processes of design
  • Apparent non-Euclidean geometry
Disney Concert Hall
Disney Concert Hall

The building designing is dependent upon the construction technology, majority of functions are streamlined and computers are playing the major role in it. It mainly covers the designing of multidirectional ambiguous spaces and forms creating optical illusion.

The basic concept project is to give the look of a ship with its sail at full mast and the designer wanted to create the feeling of square-foot Concert Hall having 2,265-seat auditorium with natural lighting in which the audience surrounds the orchestra.

The auditorium has a curved wooden ceiling which fulfils the acoustical requirements. The dramatically curved exterior of Walt Disney Concert Hall is clad in 22 million pounds of primary steel joined out of 12,500 individual pieces that range from 13 inches to 110 feet long.

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