Construction engineering

UNIT – I

Chapter - 1. (B)

CONSTRUCTION ENGINEERING

 

1. BUILDING CONSTRUCTION

Construction technology is a related field that deals more with the practical aspects of projects. Construction technologists or construction technicians learn some of the design aspects similar to civil engineers and some of the project site management aspects similar to construction managers. These technicians are unique such that they are a cross between civil engineers and construction managers. An overview of various aspects pertaining to building construction is presented in this section.

A building can be divided into substructure (foundation) and superstructure, the plinth being the dividing line between them. The superstructure of a building is the portion of the structure above the foundation. In building construction, attention is paid as to how the civil works are carried out in the field after they have been planned by an architect and structurally designed by an engineer.

All buildings have the same components such as foundation, walls, floors and roof. In addition, they are decorated with plastic, paint, etc. to make them aesthetically beautiful. These items of building works are called civil works. Water and electricity have also to be supplied to the buildings to make them habitable. These items are called building services.

When planning buildings in cities, towns and municipalities in India, rules and regulations • have to be met. For example, enough space is to be left around the building for ventilation.

 

1. SITE PREPARARTION

The first work to be undertaken before the actual construction of a building is checking the dimensions of its boundaries once the site is made available for construction. The vital boundary stones should be in their position and they should be checked with reference to the survey plan.

Site Layout: It consists of the layouts of the access roads, sheds, etc.

Site Clearing: Site clearing means any one or all of the following works:

(i) Surface cleaning of grass, trees, anthills, hillocks, etc.

(ii) Cleaning of obstructions which may be above or below the ground level. The obstructions may be old drainage works, old septic tanks, soak pits etc.

(iii) Cleaning of the obstructions belonging to other organisations such as drainage or water supply lines, underground electric or telephone cables

Enclosing the Site: The building site needs to be enclosed for public safety.

Water Supply for Construction: Water is an important building material. If groundwater is available, it should be tested suitably for various uses. The cost of water comes to about one or two percent of the cost of the civil works. If ground water is not available, water connection can be obtained from municipal authorities.

Electrical Supply: Electricity supply is necessary for building works. The following aspects need attention:

(i) Cables should be of good quality and suitable supported.

(ii) The switch board, etc., must be properly enclosed and capable of being locked.

(iii) The switch board should be about 1.5 m above the ground level.

 

2. EARTHWORK

Excavation: Excavation for the foundation is part of earthwork that comes after site preparation. For a building having a basement, the whole area in the plan of the building has to be excavated to the desired depth. For column footings, excavation is made only around the column. The earthworks are classified into the following categories:

(i) Soft/loose soil

(ii) Hard/dense soil

(iii) Ordinary rock not requiring blasting

(iv) Hard rock where blasting is allowed

(v) Hard rock where blasting is not allowed

Filling: Another major item of the earthwork is earth filling. After construction of the foundation and the walls to a height above the ground level, vacant spaces are to be refilled to the original surface of the ground with approved materials. The filling earth should be devoid of clods and should be watered and rammed.

The purpose of sand filling under floors is to break the upward movement of capillary water under the floors. It can lead to floor sweating of the ground floor during rainy season. Sand filling also reduces settlement of floors. Finally, earth filling around the building is required as part of earthwork.

 

3. COMPONENTS OF BUILDING

The major components of building are the following:

1. Foundation (Details explained in Chapter 5)

2. Superstructure Details explained in Chapter 6)

Bulldozers for site clearance and equipment such as concrete mixer, concrete pump, bar bending machine, hoists for lifting materials and pumps are used in civil engineering construction. A study on the selection of the type and quantity of appropriate equipment needed for a large project is also part of construction engineering.