The Fields Of Construction And Engineering Construction Essay

In the fields of civil engineering, construction is a process that consists of the building  or assembling of infrastructure. Normally, the job is managed by a project manager, and supervised by a construction manager, design engineer and construction engineer.

For the successful execution of a project, effective planning is essential. Those involved with the design and execution of the infrastructure in question must consider the environmental impacts of the job, the successful scheduling, budgeting, construction site safety, availability of building materials and inconvenience to the public caused by construction delays.

TYPES OF CONSTRUCTION PROJECTS UNDERGOING

Two types of projects are activated inside campus:-

1. Building construction,

2. Maintenance of roads.

BUILDING CONSTRUCTION

Several buildings are under construction inside campus to be used as central library, staff residences, educational buildings for B.D.S. and M.B.B.S., shopping mall, boys hostel no.5,hospital, extrusion of built buildings, passage between hostels, footpath repairing , repairing and maintenance, administration building. The contracts are undertaken by different companies in order to have the work done in the shortest possible time. Some of these companies are mentioned below.

Building construction of two types:-

1. Framed structure construction,

2. Unframed structure construction.

1. Framed structure is an assembly of slabs, beams, columns and foundation connected to one another so that it behaves as one unit. It is a methodology, which enables the construction of tall buildings and building with stilts. Majority of urban structures and multistoried buildings are built as RCC framed structures. In an RCC framed structure, the load is transferred from a slab to the beams then to the columns and further to lower columns and finally to the foundation which in turn transfers it to the soil. The walls in such structures are constructed after the frame is ready and are not meant to carry any load.  As against this, in a load bearing structure, the loads are directly transferred to the soil through the walls, which are capable of carrying them. A well describing picture of a framed building inside lovely university is displayed on next page.

FRAMED STRUCTURE

2.Unframed structures are those in which masonry is done with the help of mortar along with pillars and columns are also extruded..

VARIOUS OPERATIONS CONTINUING

The foundation. It is the inferior or bottom part of a building that penetrates the terrain it is on, this carries the weight of the building and supports it. Type of foundations provided that I saw inside the university campus were:-

#Spread footing foundations consists of strips or pads of concrete which transfer the loads from walls and columns to the soil or bedrock. Embedment of spread footings is controlled by several factors, including development of lateral capacity, penetration of soft near-surface layers, and penetration through near-surface layers likely to change volume due to frost heave or swell. These foundations are common in residential construction that includes a basement, and in many commercial structures.

This type of foundation is provided below the buildings to be used as boys hostel no.5.

#Mat-slab foundation are used to distribute heavy column and wall loads across the entire building area, to lower the contact pressure compared to conventional spread footings. Mat-slab foundations can be constructed near the ground surface, or at the bottom of basements. In high-rise buildings, mat-slab foundations can be several meters thick, with extensive reinforcing to ensure relatively uniform load transfer.

This type of foundation is provided below the building to be used as central library and staff residence.

The walls. The walls of a building  receive the weight of the different ceilings and floors and pass this weight over to the foundation. Masonry has done to construct walls in all buildings inside campus.

Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone such as marble, granite, travertine, limestone; concrete block, glass block, stucco, and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can significantly affect the durability of the overall masonry construction

Brick masonry is undertaken inside campus. Solid brickwork is made of two or more layers of bricks with the units running horizontally called stretcher bricks bound together with bricks running transverse to the wall called header bricks. Each row of bricks is known as a course. The pattern of headers and stretchers employed gives rise to different bonds such as the common bond, the English bond, and the Flemish bond .Bonds can differ in strength and in insulating ability. Vertically staggered bonds tend to be somewhat stronger and less prone to major cracking than a non-staggered bond.

A picture of brick masonry is given below.

Concrete blocks masonry is also under process in some parts of LPU. Blocks of cinder concrete, ordinary concrete, or hollow tile are generically known as Concrete Masonry Units (CMU)s. They usually are much larger than ordinary bricks and so are much faster to lay for a wall of a given size. Furthermore, cinder and concrete blocks typically have much lower water absorption rates than brick. They often are used as the structural core for veneered brick masonry, or are used alone for the walls of factories, garages and other industrial style buildings where such appearance is acceptable or desirable. Such blocks often receive a stucco surface for decoration. Surface-bonding cement, which contains synthetic fibers for reinforcement, is sometimes used in this application and can impart extra strength to a block wall. Surface-bonding cement is often pre-colored and can be stained or painted thus resulting in a finished stucco-like surface.

The primary structural advantage of concrete blocks in comparison to smaller clay-based bricks is that a CMU wall can be reinforced by filling the block voids with concrete with or without steel rebar. Generally, certain voids are designated for filling and reinforcement, particularly at corners, wall-ends, and openings while other voids are left empty. This increases wall strength and stability more economically than filling and reinforcing all voids. Typically, structures made of CMUs will have the top course of blocks in the walls filled with concrete and tied together with steel reinforcement to form a bond beam. Bond beams are often a requirement of modern building codes and controls. Another type of steel reinforcement, referred to as ladder-reinforcement, can also be embedded in horizontal mortar joints of concrete block walls. The introduction of steel reinforcement generally results in a CMU wall having much greater lateral and tensile strength than unreinforced walls.

cmus can be manufactured to provide a variety of surface appearances. They can be colored during manufacturing or stained or painted after installation. They can be split as part of the manufacturing process, giving the blocks a rough face replicating the appearance of natural stone, such as brownstone. CMUs may also be scored, ribbed, sandblasted, polished, striated (raked or brushed), include decorative aggregates, be allowed to slump in a controlled fashion during curing, or include several of these techniques in their manufacture to provide a decorative appearance

A COLUMN in structural engineering is a vertical structural member that transmits through compression, the weight of the structure above to other structural element below. Other compression members are often termed as columns due to similar stress conditions. These are designed to and frequently used to support beams and arches on which upper part of walls or ceiling rests. A column might also a decorative member and but need not to support any load.

Early columns were constructed of stone, some out of a single piece of stone, usually by turning on a lathe-like apparatus. Single-piece columns are among the heaviest stones used in architecture. Other stone columns are created out of multiple sections of stone, mortared or dry-fit together. In many classical sites, sectioned columns were carved with a center hole or depression so that they could be pegged together, using stone or metal pins. The design of most classical columns incorporates enchases (the inclusion of a slight outward curve in the sides) plus a reduction in diameter along the height of the column, so that the top is as little as 83% of the bottom diameter. This reduction mimics the parallax effects which the eye expects to see, and tends to make columns look taller and straighter than they are while enchases ads to that effect.

Modern columns are constructed out of steel, poured or precast concrete, or brick. They may then be clad in an architectural covering or left bare.

There are many types of columns such as steel, concrete, wooden etc. but inside lovely professional university, columns preferred are made up of concrete.

The high compressive strength of high-strength concrete is especially advantageous in compressed members such as columns, which can be made more slender and, consequently, make economic benefits possible. However, the behavior of high-strength concrete columns is not yet fully understood. This thesis deals with the behavior of reinforced normal and high-strength concrete columns under compressive loading. Numerical results from non-linear finite element analyses were compared with results from columns tested.<p /> In the present study, thirty reinforced short stub concrete columns and sixteen reinforced long slender concrete columns have been tested under axial compressive short-term loading to failure. In addition, two long slender columns were subjected to sustained compressive loading. The parameters varied in the study were the concrete strength, stirrup spacing, reinforcement strength, slenderness of the columns, and eccentricity of the axial load applied.<p /> The test results for the short stub columns show that the load capacity increased in proportion to the increased compressive cylinder strength. The short stub columns of high-strength concrete exhibited a sudden, explosive type of failure. When the concrete strength of the long slender columns was increased, the maximum load capacity became greater. Although closer stirrup spacing did not provide an increase in load bearing capacity, it did give the columns a more ductile behavior in the post-peak region. The most important parameters for obtaining a ductile behavior were the spacing of the stirrups and the reinforcement configuration. Furthermore, it was observed that the stirrups in the high-strength concrete columns did not necessarily yield at maximum load. Therefore, to estimate the strength correctly it is necessary to use the actual stirrup strain or to design the reinforcement configuration so that yielding is reached at maximum load. Tests showed that the structural behavior of a reinforced high-strength concrete columns is favorable for sustained loading, i.e., the column exhibited less tendency to creep and could sustain the axial load without much increase of deformation for a longer period of time.<p /> The nonlinear finite element analyses show good agreement with the test results. The analyses have been performed with two types of elements, beam elements and three-dimensional solid elements; each type has its advantages. This study has shown that the non-linear finite element method, together with non-linear fracture mechanics, provides a useful tool for the detailed analysis of reinforced concrete structures and contributes to a better understanding of the structural behavior of reinforced concrete columns subjected to axial loading.

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4.The beams. These consist of the horizontal elements that rest over the floor. The beams lean their weight over the pillars and are often times made out of concrete mix with reinforcement. A beam is a structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads, own weight, span and external reactions to these loads is called a bending moment.

Beams generally carry vertical gravitational forces but can also be used to carry horizontal loads (i.e., loads due to an earthquake or wind). The loads carried by a beam are transferred to columns, walls, or girders, which then transfer the force to adjacent structural compression members. In light frame construction the joists rest on the beam.

Beams are characterized by their profile (the shape of their cross-section), their length, and their material. In contemporary construction, beams are typically made of steel, reinforced concrete, or wood. One of the most common types of steel beam is the I-beam or wide-flange beam (also known as a “universal beam” or, for stouter sections, a “universal column”). This is commonly used in steel-frame buildings and bridges. Other common beam profiles are the C-channel, the hollow structural section beam, the pipe, and the angle.

Most beams in reinforced concrete buildings have rectangular cross sections, but the most efficient cross section for a simply supported beam is an I or H section. Because of the parallel axis theorem and the fact that most of the material is away from the neutral axis, the second moment of area of the beam increases, which in turn increases the stiffness.

An I-beam is only the most efficient shape in one direction of bending: up and down looking at the profile as an I. If the beam is bent side to side, it functions as an H where it is less efficient. The most efficient shape for both directions in 2D is a box (a square shell) however the most efficient shape for bending in any direction is a cylindrical shell or tube. But, for unidirectional bending, the I or wide flange beam is superior.

Efficiency means that for the same cross sectional area (volume of beam per length) subjected to the same loading conditions, the beam deflects less.

Other shapes, like L (angles), C (channels) or tubes, are also used in construction when there are special requirements

5.Shuttering and scarf folding. It can be seen in most of the buildings. Shuttering is filling the concrete mix to construct pillars, beams, roof slabs etc. Scaffolding is done to provide a platform for workers.

READY MIX CONCRETE .Ready-mix concrete is a type of concrete that is manufactured in a factory or batching plant, according to a set recipe, and then delivered to a work site, by truck mounted transit mixers . This results in a precise mixture, allowing specialty concrete mixtures to be developed and implemented on construction sites. Ready-mix concrete is sometimes preferred over on-site concrete mixing because of the precision of the mixture and reduced work site confusion. However, using a pre-determined concrete mixture reduces flexibility, both in the supply chained in the actual components of the concrete. Ready Mixed Concrete, or RMC as it is popularly called, refers to concrete that is specifically manufactured for delivery to the customer’s construction site in a freshly mixed and plastic or unhardened state. Concrete itself is a mixture of Portland cement, water and aggregates comprising sand and gravel or crushed stone. In traditional work sites, each of these materials is procured separately and mixed in specified proportions at site to make concrete. Ready Mixed Concrete is bought and sold by volume – usually expressed in cubic meters.

Ready Mixed Concrete is manufactured under computer-controlled operations and transported and placed at site using sophisticated equipment and methods. RMC assures its customers numerous benefits.

CONCRETE MIX PLANT AT L.P.U

Advantages of Ready mix Concrete over Site mix Concrete

A centralized concrete batching plant can serve a wide area.

The plants are located in areas zoned for industrial use, and yet the delivery trucks can service residential districts or inner cities.

Better quality concrete is produced.

Elimination of storage space for basic materials at site.

Elimination of procurement / hiring of plant and machinery

Wastage of basic materials is avoided.

Labor associated with production of concrete is eliminated.

Time required is greatly reduced.

Noise and dust pollution at site is reduced.

Reduce cost.

Disadvantages of Ready-Mix Concrete

The materials are batched at a central plant, and the mixing begins at that plant, so the traveling time from the plant to the site is critical over longer distances. Some sites are just too far away, though this is usually a commercial rather than technical issue.

Generation of additional road traffic; furthermore, access roads, and site access have to be able to carry the weight of the truck and load. Concrete is approx. 2.5tonne per m³. This problem can be overcome by utilizing so-called ‘minimix’ companies, using smaller 4m³ capacity mixers able to access more restricted sites.

Concrete’s limited time span between mixing and going-off means that ready-mix should be placed within 90 minutes of batching at the plant.

I am looking forward for your satisfaction towards this submission.

WITH THANKS

REFFERENCE:

=Wikipedia

=Er. Deepak kumar,J.E., G.S. TRADERS

=Self visits on sites

=Photography source – self captured photos from different sites inside LPU