NATIONAL BUILDING CODE

A) The Draft Building Act: Its salient features include provision for the following:

• i) Set-up of a National Building Council or Committee with responsibility for the

determination and updating of a National Building Code, and to assistnNG in its

implementation. (This is conceived to be the apex body, and is entrusted with a wide range of

responsibilities for the successful implementation of a NBC)5 2146

• ii) Classification of buildings into four categories in line with draft NBC philosophy.

• iii) Implementation, supervision and monitoring of compliance.

• iv) Arrangement, classification and authorization of approved design certifiers at

different levels - in line with the four levels of the draft NBC.

• v) Arrangements for building permits and building construction.

• vi) Enquiries and response re compliance or otherwise with the NBC provisions by

builders, etc.

• Power to prepare and implement regulations/by-laws.

B) Draft Engineering Council Act: Its salient features include the following:

• i) Provision for the formation and management of the Council, with the President of the

Nepal Engineers Association as its ex-officio chairman.

• ii) Provision of a registrar with defined functions, duties and authority.

• iii) Provision for the registration of engineers and the issuing of certificates.

• iv) Provision for restrictions on employing a non-registered engineer by HMGN and

other agencies.

C) Model Local Authority By-laws for Enforcement of the NBC: Its major provisions include:

• i) Applicability and conditions of application of the Code (level and conditions of

building).

• ii) Requirement of the local authority to have a building section headed by a building

officer with defined powers, qualifications and functions.

• iii) Requirement for all persons and agencies to obtain building permits prior to

undertaking construction, and specification of the documents to be submitted to obtain the

same.

• iv) Responsibilities and duties of the owner/ builder.

• v) Inspection during construction by the local authority.

• vi) Connections of utility services to be authorized only to those buildings which have

complied with the Code. No transfer of ownership to be permitted for buildings not complying

with the provisions of the Code.

• vii) Registration by a local authority of technical personnel (engineers, architects,

overseers, etc.) who want to operate within its territory. Only registered technicians to be

allowed to prepare the building approval drawings, and to undertake periodic supervision for

certification purposes.

• viii) Definition of unsafe buildings and requirements for demolition.

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Composite structures

I. INTRODUCTION

Composite structures can be defined as the Structures in which composite sections made up of two different types of materials such as steel and concrete are used for beams, and columns. This paper include comparative

study of R.C.C. with Steel Concrete Composite (G+12, G+16, G+20, G+24) story buildings which situated in

Nagpur earthquake zone II and wind speed 44m/s. Equivalent Static Method of Analysis is used. For modeling of Composite & R.C.C. structures, STAAD-Pro software is used and the results are compared. Comparative study includes deflection, axial force and shear force, bending moment in column and beam, cost. It is found that composite structure is more economical and speedy than R.C.C structure.

II. COPOSITE MULTISTORIED BUILDINGS

The primary structural components use in composite construction consists of the following elements.

1. Composite deck slab

2. Composite beam

3. Composite column

4. Shear connector

2.1. COMPOSITE DECK SLAB

Composite floor system consists of steel beams, metal decking and concrete. They are combined in a very

efficient way so that the best properties of each material can be used to optimize construction techniques. The most common arrangement found in composite floor systems is a rolled or built-up steel beam connected to a formed steel deck and concrete slab. The metal deck typically spans unsupported between steel members, while also providing a working platform for concreting work. The composite floor system produces a rigid horizontal diaphragm, providing stability to the overall building system, while distributing wind and seismic shears to the lateral load-resisting systemsComposite action increases the load carrying capacity and stiffness by factors of around 2 and 3.5 respectively. The concrete forms the compression flange – the steel provides the tension component and shear connectors ensure that the section behaves compositely. Beam spans of 6 to 12 m can be created giving maximum flexibility and division of the internal space. Composite slabs use steel decking of 46 to 80 mm depth that can span 3 to 4.5 m without temporary propping. Slab thicknesses are normally in the range 100 mm to 250 mm for shallow decking, and in the range 280 mm to 320 mm for deep

decking. Composite slabs are usually designed as simply supported members in the normal condition,

with no account taken of the continuity offered by any reinforcement at the supports.

 COMPOSITE ACTION IN BEAMS :- Composite action increases the load carrying capacity and stiffness by factors of around 2 and 3.5 respectively. The concrete forms the compression flange – the steel provides the tension component and shear connectors ensure that the section behaves compositely. Beam spans of 6 to 12 m can be created giving maximum flexibility and division of the internal space. Composite slabs use steel decking of

46 to 80 mm depth that can span 3 to 4.5 m without temporary propping. Slab thicknesses are normally in

the range 100 mm to 250 mm for shallow decking, and in the range 280 mm to 320 mm for deep decking. Composite slabs are usually designed as simply supported members in the normal condition, with no account taken of the continuity offered by any reinforcement at the supports. zero at mid-span and maximum at the support of the simply supported beam subjected to uniformly distributed load. Hence, shear is less in connectors located near the centre and maximum in connectors located near the support.Composite beams are often designed under the assumption that the steel beam supports the weight of the structural steel or wet

concrete plus construction loads.This approach results in considerably less number of connectors than they are required to enable the maximum bending resistance of the composite beam to be reached. However the use ofsuch partial shear connection results in reduced resistance and stiffness.

2.2 ADVANTAGES OF COMPOSITE BEAMS

1. Keeping the span and loading unaltered, more economical steel section in terms of depth and weight) is adequate in composite construction compared with conventional non-composite construction.

2. Encased steel beam sections have improved fire resistance and corrosion.

3. It satisfied requirement of long span construction a modern trend in architectural design.

4. Composite construction is amenable to fast track construction because of use of rolled steel sections.

5. Composite sections have higher stiffness than the corresponding steel sections and thus the deflection is lesser.

6. Permits easy structural repairs/ modification.

7. Provides considerable flexibility in design and ease of fabrication.

8. Enables easy construction scheduling in congested sites.

9. Reduction in overall weight of the structure and there by reduction in foundation cost.

10. Suitable to resist repeated earthquake loading which requires high amount of resistance and

ductility.

THE ADVANTAGES OF COMPOSITE COLUMNS ARE

1) Increased strength for a given cross sectional dimension.

2) Increased stiffness, leading to reduced slenderness and increased bulking resistance.

3) Good fire resistance in the case of concrete encased columns.

4) Corrosion protection in encased columns.

5) Significant economic advantages over either pure structural steel or reinforced concrete alternatives.

6) Identical cross sections with different load and moment resistances can be produced by varying steel thickness, the concrete strength and reinforcement. This allows the outer dimensions of a column to be held constant over a number of floors in a building, thus simplifying the construction and architectural detailing.

7) Erection of high rise building in an extremely efficient manner.

8) Formwork is not required for concrete filled tubular sections.

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Study of Soil properties

Properties Of Soil

Soil is a complex material produced by the weathering of solid rock. Weathering is caused by the agent such as temperature change, impact, flowing water, ice, wind, plants and animal. Weathering (disintegration) may be of physical or chemical. Due to physical weathering of rocks, cohesion less soil (sand, gravel, boulder) is formed.

Chemical weathering may be caused due to oxidation , hydration, carbonation etc. Clay minerals (cohesive soil) are produced by chemical weathering.

    The various agencies are of transporting and redepositing soils are water, ice, wind, and gravity. In soil mechanics we study behavior of soil under different condition, which are made with the engineering practice.

Soil Mechanics is that branch of civil engineering where we study about the application of laws of mechanics and hydraulic to engineering problems dealing with sediments and chemical disintegration of rocks.

Scope, Purpose and uses of soil mechanics  

Soil mechanics is useful in the following problem in civil engineering

1. Foundation design and Construction :- Every structure like building, bridge, dam or canal is founded in or on the surface of the earth. It is therefore necessary to know the bearing capacity of the soil and stress distribution in the soil, settlement of the foundation, effect of ground water etc.  The stability of various types of foundation depends upon the types of soil  strata, the magnitude of loads and ground water condition.
2. Design Of Earth Dam :- Since soil is used as the only construction material in an earthen dam. Therefore the construction of an earthen dam requires a very through knowledge whole of the soil mechanics.
3. Design Of Retaining  wall :- A knowledge of earth pressure is essential to design properly a retaining wall. Earth pressure is dependent on following factors;

Angle of repose(θ)
Unit weight of soil (ϒ
Height of retaining wall (H)

The magnitude of earth pressure is found out with the help of rankine’s theory of earth pressure.

Design Of Embankment and Excavation :- To design the slop and height of the embankment  or depth of excavation, a thorough knowledge of shear strength and problems of soil is essential. Design of canal required through study of seepage through embankment which was suggested by Dr. Darcy.

Pavement Design: - The thickness of pavement depends upon characteristics of sub-soil on busy pavement (highway and runway) where the intensity of traffic is very high. The effected repetition of loading and the consequence fatigue  failure has to be taken into account. A knowledge of the technique for improvement of the soil properties such as strength and stability is very much helpful in constructing pavement on poor soil.

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