12.1 Structural Engineering | unit 12 structural engineering

ICE

Unit - 12

Structural Engineering

12.1 Structural Engineering:

Structural engineering is a sub-discipline of civil engineering of structural engineers who are skilled to design the 'bones and muscles' that create the form and shape of manmade structures.

Structural engineers calculate the stability, strength, and rigidity of built structures for buildings and non-building structures.

The structural designs with other designers such as architects and building services engineer and constantly supervise the construction of projects by contractors on site.

Structural engineering is painstaking a forte discipline within civil engineering, but it studied in its own right.

In the United States, most working structural engineers are currently licensed as civil engineers, but it varies from state to state.

Some states have a separate license for structural engineers which is required to design special structures such as schools, hospitals, or skyscrapers.

In the United Kingdom is recording the structural engineers in the building industry are members of the Institution of Structural Engineers or the Institution of Civil Engineers.

12.2 Types of buildings:

The government various types of buildings based on different criteria depending on their usage, design, and height, safety standards, and other features as follows.

1) Residential Buildings

2) Educational Buildings

3) Institutional Buildings

4) Assembly Buildings

5) Business Buildings

6) Mercantile Buildings

7) Industrial Buildings

8) Storage Buildings

9) Wholesale Establishments

10) Mixed Land Use Buildings

11) Hazardous Buildings

12) Detached Buildings

13) Semi-Detached Buildings

14) Multi-Storey or High-Rise Buildings

15) Slums

16) Unsafe Buildings

17) Special Buildings

1) Residential Buildings:

These are buildings that are used for normal residential purposes and should facilitate doings such as sleeping, living, and cooking.

The building must contain one or more family residences, apartments, flats, and private garages.

2) Educational Buildings:

These are buildings housing educational institutions such as schools or colleges which are allied and recognized by an appropriate board, university, or any similar affiliation authority.

The building should endorse the aggregation of instructional, educational, and recreational activities pertaining to educational purposes.'

Further, it is compulsory for the building to have proper residential facilities for essential staff who need to be present within the campus.

Apart from this, the institution has a hostel exclusive to the institute either within its premises or outside.

3) Institutional Buildings:

These types of buildings involve buildings that are constructed by the government, semi-government organizations, or registered trusts for specific purposes.

Those specific purposes contain medical treatment purposes such as treatment of physical or mental illness, children’s hospitals, old age homes, center for the care of orphans or abandoned women, auditoriums or complexes destined to be used for cultural or allied activities, religious accommodation facilities such as jails, correctional facilities, juvenile reformatories, etc.

4) Assembly Buildings:

These are clear as buildings or parts of them which houses public gatherings congregated with the intent of amusement, recreation, social, religious, patriotic, civil, travel, or other like purposes.

Buildings such as movie houses, drama theatres, drive-in theatres, assembly halls, clubhouses, town halls, museums, gymnasiums, sports complexes, restaurants, boarding houses, dance clubs, gymkhanas, places of worship, bus stops, taxi stands, railway stations, airports, piers, etc. are categorized as assembly buildings.

5) Business Buildings:

If a building or a part of it is mainly used for keeping records of business transactions, maintaining accounts, bookkeeping purposes, or managing other types of records then it can be confidential as a business building.

Buildings under this category contain offices, banks, courthouses, and other professional establishments serving the aforementioned purposes.

6) Mercantile Buildings:

In these types of buildings, moreover, the entire building or a part of it is used for housing shops, stores or showrooms where display and sale of wholesale goods, retail goods or merchandise is carried out.

Such buildings should also house office, storage, and service facilities essential for the business which should be located in the same building.

7) Industrial Buildings:

The building used to manufacture, assemble, or process products or materials are called as industrial buildings.

They take in manufacturing units, assembly plants, factories, mills, power plants, oil refineries, gas plants, dairy plants, laboratories, etc.

12.3 Tall structures:

The world's tallest artificial structure is the 829.8-meter-tall (2,722 ft) Burj Khalifa in Dubai (of the United Arab Emirates).

The building is amplified the official title of "tallest building in the world" and the biggest self-supported structure at its opening on January 9, 2010.

The second-tallest self-backup structure and the tallest tower in the world are the Tokyo Skytree.

The Council on Tall Buildings and Urban Habitat, an organization that confirms buildings is "World's Tallest", distinguishes a building only if at least 50% of its height is made up of floor plates casing habitable floor area.

Structures that do not encounter this criterion, like CN Tower, are defined as "towers".

Dozens of radios and television towers measure over 600 meters (about 2,000 ft) in height, and only the tallest are recorded is available information sources.

12.4 Various types of bridges:

 Types of Bridges based on Type of Super Structure:

1) Arch bridge

2) Girder bridge

3) Truss bridge

4) Suspension bridge

 Types of Bridges based on Materials:

1) Timber bridge

2) Masonry bridge

3) Steel bridge

4) R.C.C bridge

5) Prestressed concrete bridge

 Types of Bridges based on Span:

1) Culvert bridge

2) Minor bridge

3) Major bridge

4) Long span bridge

 Types of Bridges based on Function:

1) Footbridge

2) Highway bridge

3) Railway bridge

4) Aqueduct bridge

5) Road cum railway bridge

 Types of Bridges based on Inter Span Relation:

1) Simple bridge

2) Continuous bridge

3) Cantilever bridge

 Types of Bridges based on Position of Floor:

1) Deck bridge

2) Through bridge

3) Semi-through bridge

 Types of Bridges based on High Flood Level (HFL):

1) Low-level bridge

2) High-level bridge

12.5 Water retaining structures:

One of the purposes of retaining structures is to create large bodies of water, or reservoirs, a variety of functions, including land irrigation, power generation, water supply, and flood control.

The retaining structures used to build reservoirs are called dams and dikes.

A dam is built on the riverbed; it helps to hold back water and raise the water level of the resulting reservoir.

Dikes are repeatedly built to increase a dam's effectiveness by preventing water from leaving the reservoir over secondary valleys.

Other dam owners, including municipalities, outfitters, and companies like Alcan, are also intricate in dam and dike operation, in addition to water management of the related reservoirs.

Retaining walls are moderately rigid walls used for supporting soil laterally so that it can be reserved at different levels on the two sides.

Retaining walls are structures considered to restrain soil to a slope that it would not naturally keep to (typically a steep, near-vertical, or vertical slope).

They are used to bound soils between two different elevations often in areas of terrain possessing unwanted slopes or in areas where the landscape needs to be shaped severely.

12.6 Other structural systems:

The term structural system or structural frame in structural engineering the load-battling sub-system of a building or object.

The structural system transfers load over interconnected elements or members.

Commonly used structures classified into the five major categories, depending on the type of primary stress that may arise in the members of the structures under major design loads.

However, two or more of the basic structural types labeled in the following may be combined in a single structure, as a building or a bridge in order to encounter the structure's functional requirements.

Tensile structures: Members of tensile structures are subject to pure tension underneath the action of external loads.

Compression structures develop mainly compressive stresses beneath the action of axial loads.

Because compressive structures are vulnerable to buckling or instability, the possibility of these failures well-thought-out in their design.

If necessary, adequate stimulating must be provided to avoid such failures.

1) Trusses:

Trusses are collected from straight members related at their ends by hinged connections to form a stable configuration.

Since their lightweight and high strength, they are amid the most commonly used types of structure.

2) Shear structures:

These are structures like as the reinforced concrete or wooden shear walls, which are used in multi-story buildings to reduce lateral movements due to wind loads and earthquake excitations.

Shear structures develop in-plane shear with relatively small bending stresses underneath the action of external loads.

3) Bending structures:

Bending structures develop largely bending stresses under the action of external loads.

The shear stresses allied with the changes in bending moments may also be significant, and should be considered in their design.

12.7 Experimental Stress Analysis:

The accurate assessment of stresses, strains, and loads in components under working conditions is an indispensable requirement of successful engineering design.

The most extensively used experimental stress-analysis technique in the industry today, particularly underneath working conditions, is that of strain gauges.

Whilst a number of different types of strain gauge are commercially available, this section will deal almost solely with the electrical resistance type of gauge introduced in 1939 by Ruge and Simmons in the United States.

The electrical resistance strain gauge is simply a length of wire or foil formed into the shape of a continuous grid, cemented to a non-conductive backing.

The gauge is then bonded firmly to the surface of the component under investigation so that any strain in the surface will be experienced by the gauge itself.

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Since the fundamental equation for the electrical resistance R of a length of wire is

Where,

L is the length,

A is the cross-sectional area and

ρ is the specific resistance or resistivity

It tails that any change in length, and hence sectional area, will result in a change of resistance.

Thus, measurement of this fight change with suitably calibrated equipment enables direct reading of linear strain to be obtained.

12.8 Wind tunnel studies:

Wind tunnels are large tubes with air blowing finished them.

The tunnels are used to replicate the actions of an object flying done the air or moving along the ground.

Researchers use wind tunnels to learn more near how an aircraft will fly. NASA uses wind tunnels to give test scale models of aircraft and spacecraft.

Some wind tunnels are large to contain full-size versions of vehicles.

The wind tunnel moves air every place an object, making it seem as if the object is flying.

The object tested is held firmly inside the tunnel so that it remains stationary and does not move.

The object can be a small prototypical of a vehicle, or it can be just any part of a vehicle. It a full-size aircraft or spacecraft. It can even be a common object like a tennis ball.

In that way, a stationary observer is the flying object in action and could measure the existence of the aerodynamic force forced on it.

The development of wind tunnels is present the development of the airplane.

Wind tunnel gives the testing of sporting equipment has prevalent over the years, including golf clubs, golf balls, Olympic bobsleds, Olympic cyclists, and race car helmets.

Helmet aerodynamics is important in open-cockpit race cars (IndyCar, Formula One).

Excessive lift forces on the helmet cause significant neck strain on the driver.

References:

1. Patil, B.S. (1974), Legal Aspects of Building and Engineering Contract

2. The National Building Code, BIS, (2017)

3. RERA Act, (2017)

4. Meena Rao (2006), Fundamental concepts in Law of Contract, 3rd Edn. Professional Offset

5. Chandiramani, Neelima (2000), The Law of Contract: An Outline, 2nd Edn. Avinash Publications Mumbai

6. Avtarsingh (2002), Law of Contract, Eastern Book Co.

7. Dutt (1994), Indian Contract Act, Eastern Law House

8. Anson W.R. (1979), Law of Contract, Oxford University Press

9. Kwatra G.K. (2005), The Arbitration & Conciliation of Law in India with case law on UNCITRAL Model Law on Arbitration, Indian Council of Arbitration

10. Avtarsingh (2005), Law of Arbitration and Conciliation, Eastern Book Co.

11. Wadhera (2004), Intellectual Property Rights, Universal Law Publishing Co.

12. P. S. Narayan (2000), Intellectual Property Rights, Gogia Law Agency

13. T. Ramappa (2010), Intellectual Property Rights Law in India, Asia Law House

14. Bare text (2005), Right to Information Act

15. O.P. Malhotra, Law of Industrial Disputes, N.M. Tripathi Publishers

16. K.M. Desai(1946), The Industrial Employment (Standing Orders) Act

17. Rustamji R.F., Introduction to the Law of Industrial Disputes, Asia Publishing House 18. Vee, Charles & Skitmore, Martin (2003) Professional Ethics in the Construction Industry, Engineering Construction and Architectural Management, Vol.10, Iss. 2, pp 117-127, MCB UP Ltd

18. American Society of Civil Engineers (2011) ASCE Code of Ethics – Principles Study and Application

19. Ethics in Engineering- M.W.Martin& R.Schinzinger, McGraw-Hill

20. Engineering Ethics, National Institute for Engineering Ethics, USA

21. www.ieindia.org

22. Engineering ethics: concepts and cases – C. E. Harris, M.S. Pritchard, M.J.Rabins

23. Resisting Bureaucratic Corruption: Alacrity Housing Chennai (Teaching Case Study) -S. Ramakrishna Velamuri -CEIBS

24. CONSTRUCTION CONTRACTS, http://www.jnormanstark.com/contract.htm

25. Internet and Business Handbook, Chap 4, CONTRACTS LAW, http://www.laderapress.com/laderapress/contractslaw1.html

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