safety in construction

                                                                

SAFETY

IN

CONSTRUCTION

S.NO                                                   CONTENTS                                                      PAGE NO

UNIT-I

    1                          GENERAL SAFETY CONSIDERATION                                          3         

    2                          ANALYZING CONSTRUCTION JOBS FOR SAFETY                   4

    3                          CONTRACT DOCUMENT                                                                  5

    4                          EXCAVATION                                                                                     7

    5                          FOUNDATION                                                                                     9

    6                          DEMOLITION                                                                                      10

    7                          DISMANTLING                                                                                                14

    8                          TYPES OF FOUNDATIONS                                                               14

                                                                                    UNIT-II

    1                          SAFETY IN ERECTION                                                                      22

    2                          CONSTRUCTION MATERIALS                                                        22

    3                          SAFETY IN TYPICAL CIVIL STRUCTURES-DAMS                     23

                                                                                    UNIT-III

1                                                    LOCK OUT OF MECHANICAL AND ELECTRICAL                     25

MAINTENANCE

    2                          HAND TOOLS                                                                                      27

                                ABBREVIATIONS

                                                                                                UNIT-I

1.      GENERAL SAFETY CONSIDERATION

v  Common tools such as hammers, utility knives, staple guns, ladders, rakes and power tools must be handled with care.

v  More complicated equipment such as blowers, foamers and sprayers require special instruction and practice.

v  Have a first aid kit and a fire extinguisher handy and know how to use them.

v  Protect your back when lifting heavy objects, do not lift and reach at the same time.

v  Take special care when handling heavy (or) bulky objects, especially when going up and downstairs and ladders.

v  Smoking is especially hazardous. Do not take smoke breaks near insulation (or) fumes.

v  Keep your work site well organized, with tools out of the way of traffic, and give yourself plenty of clear space to manoeuvre.

v  Make sure that the work space is well lighted and ventilated.

v  Ensure proper electrical supply for power tools.

v  Wear appropriate protective clothing for the job at hand.

v  Do not work in an attic on a hot day. Heat stress can cause accidents and serious illness.

v  Maintain a clean work area and separating it from the place will minimize exposure to materials.

v  Keep fibrous materials and materials that generate vapours well sealed until they are needed, and close them in containers at the end of the work day.

v  Vaccum the work area daily to remove fibres and dust.

v  Take particular care when you work with insulation and other particulate materials, plastic insulation and caulking, and always follow the recommended safety procedures for working with specific materials.

v  Long sleeves, tight cuffs and loose, thick clothing will help minimize any skin irritations.

v  Special barrier creams that protect the skin of people working with fibrous materials are available from safety supply houses.

v  Wear goggles wherever there is any possibility that insulation dust will come in contact with the eyes.

v  Wear a mask for non-toxic particles if there is a possibility of breathing air borne particles of insulation material.

v  Wear a well designed snug-fitting face mask respirator with a particulate filter when handling glass fiber, mineral wool (or) cellulose fibre insulation.

v  Wear a hard hat to prevent head injuries and to protect hair from insulation particles.

v  To prevent falls, passage ways and work areas should be kept orderly, and dry and slip-resistant materials should be in place.

v  Spills should be cleaned up immediately.

v  Guard rails should be provided where walk ways are elevated.

2.      ANALYZING CONSTRUCTION JOBS FOR SAFETY

v  Construction involves many hazardous activities.

v  While earning great wages, construction workers risk injury when working due to their work with dangerous mechanical equipment, electrical equipment, hazardous chemicals and heights.

v  To ensure that effective safety procedures are implemented, construction job safety analysis specialists analyze the processes of the construction job and create methodologies to ensure that hazards are avoided.

Function:

v  Construction job safety analysis specialists study a construction site in order to make sure that the site is safe.

v  They must be aware of both the nature of the construction site such as the environmental conditions and of what will be constructed and how that will be constructed.

v  They must identify all the potential hazards and then develop a set of procedures in order to help the workers avoid these hazards.

v  The method of hazard control must be communicated effectively to the workers through both oral and written communication.

v  Construction job safety analysis specialists must also be aware of the ergonomics of work in the particular construction site.

Conditions:

v  These specialists spend time outdoors analyzing construction sites, including sites that have significant hazards.

v  They are not as exposed to construction hazard as the construction workers.

v  They also spend time in an office communicating with various safety departments.

Skills:

v  Construction job safety analysis specialists must be aware of state regulations regarding construction safety.

v  They must be flexible and able to work under pressure.

v  Construction workers are more at risk for on the job injuries and fatalities than workers in most other industries.

v  According to the U.S. department of labor, masonry demolition workers are at risk from hazards that arise as a result of deviations.

Job safety analysis checklist:

v  Job safety analysis is all about evaluating the work environment to determine what types of hazards exist.

Construction site safety checklist:

v  Construction workers face numerous dangers on the job site, such as collapsing scaffolds, head injuries, electrocution and falls.

v  To make sure that everyone is aware of what is going on, JSA’s and safe work method statements are used in building and construction as a way to assess what hazards may

v  come upon the job and deal with them safely.

v  Jobs that are more dangerous than usual like working at heights, near electricity (or) working equipment.

v  These jobs are classified as high risk work:

Ø  Many construction injuries result from operational errors.

Ø  JSA was developed at construction sites the physical environment is constantly changing workers move through the site in the course of their work, they are often endangered by activities performed by other teams.

Ø  To address this difficulty a structured method for hazard analysis and assessment for construction activities called construction job safety analysis (CJSA) was developed.

Ø  The method was developed within the framework of research toward a lean approach to safety management in construction, which required the ability to predict fluctuating safety risk levels in order to support safety conscious planning and pulling of safety management efforts to the places and times where they are most effective.

3.      CONTRACT DOCUMENT:

ü  The contract documents are one of the most important pieces that will guarantee of a successful project.

ü  This list contains the most common documents that must form part of every construction contract.

ü  In addition to this list, there are numerous contract support documents that can be used in combination with the standard documents. For example:

§  Instruction forms

§  Time extension claim

§  Request for information

§  Preliminary building agreement

§  Progress payment certificate

§  Practical completion notice

§  Defects document

§  Contract information statement

     Other documents:

1)      Agreement

The agreement to be used by the contracting officer (owner) and the contractor. The most essential part of the contract documents.

2)      General conditions

This contract document will define the obligations and rights on how to execute the project.

3)      Special conditions

This is usually an extension of the contract and to the general conditions. This part must specify specific conditions and clauses to each particular project (or) job.

4)      Bill of quantities

This is formed by the list of diverse trades, and materials included that form part of the construction. Sometimes this document is not required by the contracting officer.

5)      Drawings

All set of drawings that form part of the job to be performed. These drawings are usually the latest drawings and must be received by the contractor prior to the date of commencement. It must include all drawings from consultants and will constitute the entire project being contracted.

6)      Specifications

The technical requirement to complete, execute and/or perform every little task (or) material being incorporated in the construction projects. It will add intelligence to the construction drawings, specify common standards, deviations accepted, materials accepted and the required testing for all materials. Usually specifications are composed by referencing construction standards and codes.

7)      Schedules

The construction schedule is an important piece of the document. In this part, the contractions will require updated schedules throughout the construction progress, and might form part of the monthly, or agreed term, application for payments.

      8) Pricing schedules

Breakdown of all items being incorporated in the construction project. This is usually the base of the application for payment. It can be detailed per item (or) in a lump sum form, not specifying individual items.

9)      Insurances

This part will be essential part of the contracting officer, since it will provide the guarantee to the owner that the contractor has the means and the economic backup to perform the construction contract. It will include specific types of coverage’s required bending, and all insurance protections to the owner, the contractor and third parties.

Ø  The contract documentation relates to all pre-tender, tender and contractual documentation.

Ø  Contract documentation provides builders with sufficient information to be able to construct required works to meet the service delivery requirements.

4.      EXCAVATION

v  Establish the locations of underground and overhead utilities and services before beginning excavation.

v  Contact utility companies and advise them prior to the start of excavation.

v  Super imposed loads like mobile equipment working close to the excavation edges require extra sheet piling, brazing.

v  The use of mobile equipment near excavation also require substantial barricades (or) stop logs.

v  A competent person must take ongoing daily inspections of excavations, the adjacent areas and protective systems, including after every rainfall or other hazard producing occurrence.

v  Walkways are required to cross over excavations.

v  Walkways (or) bridges over excavations greater than 4 feet in depth require standard guardrails.

v  Backfill excavations upon completion.

v  Have a registered professional engineers design sloping(or)benching for excavations greater than 20m feet depth.

Reference:

Standard number                  title

OSHA 1926 SUBPART P        -Excavations cope application

29 CFR 1926.650                      and definition

1926.651                                    -Specific excavation requirements

What you need to do?

Ø  The law says you must prevent danger to workers in or near excavations.

Ø  To maintain the required precautions, a competent person must inspect excavation supports (or) battering at the start of the working shift and at other specified times.

Ø  No work should take place until the excavation is safe.

Ø  Commercial clients must provide certain information to contractors before work begins.

This should include relevant information on:

·  Ground conditions.

·  Underground structures (or) water courses.

·  The location of existing services.

·  This information should be used during the planning and preparation for excavation work.

Key issues are:

Ø  Collapse of excavations.

Ø  Falling or disloding material.

Ø  Falling into excavations.

Ø  Inspections.

What you need to know?

ü  Every year people are killed (or) seriously injured by collapses and falling materials while working in excavations. They are at risk from:

·  Excavations collapsing and burying or injuring people working in them.

·  Material falling from the sides into any excavation.

·  People (or) plant falling into excavations.

ü  Trenchless techniques should always be considered at the design stage as they replace there for major excavations.

Ø  Collapse of excavations:

v  Temporary support-Before digging any trench pit, tunnel, or other excavations, decide what temporary support will be required and plan the precautions to be taken.

v  Make sure the equipment and precautions needed are available onsite before the work starts.

v  Battering the excavation sides-Battering the excavation sides to a safe angle of repose may also make the excavation safer.

v  In granular soils, the angle of slope should be less than the natural angle of repose of the material being excavated. In wet ground a considerably flatter slope will be required.

Ø  Falling(or)dislodging material:

v  Loose materials-May fall from spoil heaps into the excavation. Edge protection should include boards (or) other means, such as projecting trench sheets (or) box sides to protect against falling materials. Head protection should be worn.

v  Undermining other structures-Check that excavations do not undermine scaffold footings, buried sources (or) the foundations of nearby buildings (or) walls. Decide if extra support for the structure is needed before you start. Surveys of the foundations and the advice of a structural engineer may be required.

v  Effects of plant and vehicles-Do not park plant and vehicles close to the sides of excavations. The extra lodgings can make the sides of excavations more likely to collapse.

Ø  Falling into excavations:

v  Prevent people from falling-Edges of excavations should be protected with substantial barriers where people are liable to fall into them.

v  To achieve this use

·  Guard rails and toe boards inserted into the ground immediately next to the excavation side, or

·  Fabricated guard rail assemblies that meet the sides of the trench bore.

·  The support system itself eg.using trench box extensions (or) trench sheets longer than the trench depth.

Ø  Inspection:

v  A competent person who fully understands the dangers and necessary precautions should inspect the excavation at the start of each shift.

v  Excavations should also be inspected after any event that may have affected their strength (or) stability, or often a fall of rock or earth.

v  A record of the inspections will be required and any faults that are found should be corrected immediately.

ü  Newyork court of appeals, Cornell university law school, legal information institute (1992, Oct 29).

ü  This newyork case determined that safety precautions during excavation operations are not limited to building sites.

5.      FOUNDATION

v  Foundation also called a groundsill is a structure that transfers loads to the earth.

v  Foundations are designed to have an adequate load capacity with limited settlement by a geotechnical engineer, and the foundation itself is designed structurally by a structural engineer.

v  If the foundation is strong then it can withstand severe shocks and other problems, but if the foundation is weak (or) loose then we may land up into serious trouble.

v  Foundations that have either concrete strip footings and pads (or) a concrete slab will form the foundation and floor of the new home.

v  The general class type of soils when foundations are considered is as follows:

Ø  Foundation is as important as any other element of your structure.

Ø  The foundation is the first piece of a home to be constructed and creates a base for the rest of a component.

Ø  To create the foundation wall, mortar is used between blocks to hold them together forming the wall.

Ø  Insulated concrete forms (ICFs) are common in regions in which the local building code requires the foundation to be insulated.

6.      DEMOLITION

v  Demolition work involves many of the hazards associated with construction.

v  However demolition incurs additional hazards due to unknown factors such as:

Ø  Deviations from the structure’s design introduced during construction, approved or unapproved modification that alerted the original design, materials hidden within structural members, and unknown strengths (or) weaknesses of construction materials.

Ø  To counter these unknowns, all personnel involved in a demolition project must be fully aware of these types of hazards and the safety precautions to take to control the hazards.

Ø  Demolition hazards are addressed in specific standards for the general and construction industries.

What you need to do?

v  The law says that all demolition work should be carefully planned and carried out by competent people (or) practioners to avoid unplanned structural collapse.

Arrangements for demolition:

v  Demolition arrangements should be written down before the work begins.

v  This safe system of work maybe in the form of a safety method statement identifying the sequence required to prevent accidential collapse of the structure.

v  Establishing exclusion zones when using explosives in demolition CIS 45.

Key issues are:

v  Falls from height.

v  Injury from falling materials.

v  Uncontrolled collapse.

v  Risks from connected services.

v  Noise and vibration.

What you need to know?

v  A systematic approach to demolition projects is a team effort between many people, who all have responsibilities:

Ø  Clients must appoint duty holders who are competent and adequately resourced

Ø  Structural engineers survey the site and assess the stability of nearby structures the risks of uncontrolled collapse, and the risks from hazardous materials. This should be done before work begins and not be left for the principal contractor to organize.

Ø  CDM coordinators plan effective site management that keeps people (site workers and the public) as far as possible from the risks. They should give principal contractors as much information as possible.

Ø  Principal contractors coordinate and manage health and safety issues during the demolition project.

Ø  Site managers supervise workers and ensure they are following safe working practice.

Ø  Subcontractors and site workers must understand and follow the precautions and ensure that their colleagues do too.

Falls from height:

v  During demolition workers can be injured falling from edges, through openings, fragile surfaces and partially demolished floors.

v  Duty holders have a responsibility to assess eliminate and control the risks of falls from height.

Injury from falling materials:

v  Workers and passers-by can be injured by the premature and uncontrolled collapse of structures, and by flying debris.

v  A safe system of work is one that keeps people as far as possible from the risks. This may include:

Ø  Establishing exclusion zones and hard hat areas clearly marked and with barriers if necessary.

Ø  Covered walkways.

Ø  Using high reach machines.

Ø  Reinforcing machine cabs so that drivers are not injured.

Ø  Training and supervising site workers.

Uncontrolled collapse:

v  The structural survey should consider

Ø  The age of the structure

Ø  Its previous use

Ø  The type of construction

Ø  Nearby buildings (or) structures

Ø  The weight of removed material(or)machinery on floors above ground level

v  The method statement for the demolition should identify the sequence required to prevent accidential collapse of the structure.

Risks from connected services:

v  Gas, electricity, water and telecommunications services need to be isolated (or) disconnected before demolition work begins.

v  If this is not possible, pipes and cables must be labeled clearly, to make sure they are not disturbed.

Vibration:

v  Vibration hand tools used in demolition can cause hand arm vibration syndrome(HAVS).

v  Workers exposure to vibrating needs to be assessed and managed.

Standards:

v  This section highlights OSHA standards, standard interpretations (official letters of interpretation of the standards), and national consensus standards related to demolition.

Ø  1926 Subpart T. Demolition

Ø  1926.850 Preparatory operations

Ø  1926.851 Stairs, passage ways and ladders

Ø  1926.852 Chutes

Ø  1926.853 Removal of materials through floor openings

Ø  1926.854 Removal of walls, masonry sections, and chimneys

Ø  1926.855 Manual removal of floors

Ø  1926.856 Removal of walls, floors, and material with equipment

Ø  1926.857 Storage

Ø  1926.858 Removal of steel construction

Ø  1926.859 Mechanical demolition

Ø  1926.860 Selective demolition by explosives

Standard interpretations:

v  Application of the asbestos standard to demolition of buildings with ACM in place (2002, August 26).

v  OSHA standards addressing reverse signal alarms on excavators (1995, May 10).

v  Demolition regulations do apply to the removal of ceilings and interior non-load bearing walls and partitioners (1994, January 27).

v  1926.850 demolition work and the use of clamshells (1974,September 17).

v  Classification of 29CFR 1926.855(b) and (f) (1979,July 5).

v  American national standards institute (ANSI) A10:6-1983 Safety requirements for demolition operations.

Hazards and solutions:

v  Before starting a demolition the person (or) persons incharge of the demolition should be adequately prepared for the task with regard to the health and safety of the workers.

v  These preparatory operations involve the overall planning of the demolition job, including the methods to be used to bring the structure down, the equipment necessary to do the job, and the measures to be kept to perform the work safely.

OSHA Technical Manual (OTM):

v  1999 January 20.

v  OSHA directive TED 01-00-015-[TED 1-0.15A].

v  Demolition-Include information on preparatory operations, special structures demolition, and safe blasting procedures.

Newyork court of appeals, Cornell university law school, legal information (1992, out 29).This newyork case determined that safety precautions during demolition operations are not limited to building sites.

Construction industry safety and health outreach program OSHA 1996 May:

v  Demolition-Describes safety regulations for demolition, such as preliminary operations, engineering survey, utility location, medical services, first aid, fire prevention and protection, special structures demolition and safe blasting procedures.

Demolition services provided include the following:

v  Explosive and structural demolition services for commercial, industrial and government projects.

v  Selective demolition (or) strip out work.

v  Industrial demolition and dismantling services.

v  Emergency demolition services.

Ø  Demolition is the tearing down of buildings and other structures. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for reuse.

Ø  The building is pulled down either manually (or) mechanically using large hydraulic equipment:

ü  Cranes

ü  Excavators(or)bulldozers

Ø  The tallest building demolished by non-terrorist methods.

Ø  Before any demolition activities, there are many steps that need to take place including but not limited to performing asbestos abatement, removing hazardous(or)regulated materials, obtaining necessary permits, submitting necessary notifications, disconnecting utilities and development of site-specific safety and work plans.

Ø  The demolition project manager/supervisor will determine where undermining is necessary so that a building is pulled in the desired manner and direction.

Ø  Safety and cleanup considerations are also taken into account in determining how the building is undermined and ultimately demolished.

Ø  Hoe rams are typically used for removing the concrete road deck and piers during bridge demolition, while hydraulic shears are used to remove the bridge’s structural steel.

Ø  In some cases a crane with a wrecking ball is used to demolish the structure down to a certain manageable height.

Ø  However crane mounted demolition balls are rarely used within demolition due to the uncontrollable nature of the swinging ball and the safety implications associated.

Ø  High reach demolition excavators are more often used for tall buildings where explosive demolition is not appropriate (or) possible.

Ø  To control dust, fire hosed is used to maintain a wet demolition.

Ø  Rotational hydraulic shears and standard reinforced bucket attachments are common demolition tools.

7.      DISMANTLING:

v  The law says that all dismantling work should be carefully planned and carried out by competent people to avoid unplanned structural collapse.

8.      TYPES OF FOUNDATIONS

There are three types of foundations that are commonly used in the US.

Full height basements:

v  It is an accessible space between the soil and the bottom of the first floor.

v  It usually has more headroom than a crawl space.

v  This construction is predominant in cold climates where the foundation needs to be situated below the frost level.

Crawl space:

v  A crawl space is an accessible space with limited headroom, typically between the soil and the bottom of the first floor.

v  This construction is predominant in areas where there is heavy clay content in the soil.

Slab on grade:

v  Slab on grade is a type of foundation consisting of a structural concrete slab poured directly on the grade.

v  No accessible space exists in slab-on-grade construction.

v  Slab on grade foundations are popular in areas where there is a high water table.

v  All three types of building foundation are usually constructed out of poured concrete, but can also use concrete masonry units (or) insulated concrete forms.

Types:

Natural foundations:

v  It is the name applied to such as are formed on the soil itself, and it is applicable when the soil is practically in compressible.

v  If the site be fairly level it is only necessary to make it thoroughly so all loose and decayed portions being cutaway and failed up with cement concrete.

v  Sometimes fissures occur which, if not too deep, must be filled up with concrete (or) spanned by an arch.

v  If the site is on a slope (or) in a hollow the loose and decayed portions are cut away and a series of blasts made where the walls are designed to come.

v  The holes formed thereby are filled with concrete, which is then benched up into level steps, upon which the walls are raised.

v  The object of the blasting is to roughen the surface and thus prevent the concrete from sliding.

v  If the soil is likely to be shaken by blasting, then the soil itself must be cut into steps.

v  A drain must always be cut from the lowest point in the benching to prevent the foundation from becoming water-logged.

v  When the foundation is benched the walls must be brought up level with large stones with fire bed joists as otherwise the settlement of the more numerous joists in the deeper trenches will cause unsightly cracks to appear in the super structure.

Artificial foundations:

v  It is the term applied to any artificially formed support for a building, and may be classified as:

Ø  Spread foundation

Ø  Pile foundation

Ø  Pier foundation

v  Spread foundations is the name given to foundations used for buildings upon compressible soil.

v  These consequently require to extend considerably on each side of the walls, so as to reduce the bad per square inch to that which will be safely bome by such soils.

v  Foundations of this class are formed of concrete (or) large stores and sometimes of wood.

Concrete foundations:

v  For small buildings (or) comparatively firm ground concrete foundations are almost invariably used for important work the depth (or) width is rarely calculated, the width being simply made wide enough on each side of the footing to give a man foot-room to work in and the depth is made at least equal to the thickness of the wall.

v  The footings are usually stepped out to the width of the wall on each side.

Ø  Types of concrete foundations:

ü  There are many variations of concrete slabs depending on the purpose of the slab.

ü  Below are some useful links for understanding concrete foundations, along with the three types of concrete foundations.

Ø  T-shaped:

ü  A traditional foundation method to support a structure in an area where the ground freezes.

ü  A footing is placed below the frost line and then the walls are added on top.

ü  The footing is wider than the wall, providing extra support at the base of the foundation.

ü  T-shaped foundations are used in areas where the ground freezes.

ü  First the footing is placed.

ü  Second the walls are constructed and poured.

ü  Lastly the slab is placed.

Ø  Slab on grade foundation:

ü  As the name suggests, a slab is a single layer of concrete, several inches thick.

ü  The slab is poured thicker at the edges, to form an integral footing, reinforcing rods strengthen the thickened edge.

ü  The slab normally rests on a bed of crushed gravel to improve drainage.

ü  Casting a wire mesh is the concrete reduces the chance of cracking.

ü  A slab on grade is suitable in areas where the ground doesnot freeze, but it can also be adapted with insulation to prevent it from being affected by the frost heaves.

·  Slab on grade used in areas where ground doesnot freeze.

·  The edges of the slab on grade are thicker than the interior of the slab.

·  The slab on grade is monolithic (poured all at one time).

Ø  Frost protected:

ü  This method only works with a heated structure.

ü  It relies on the use of two sheets of rigid, polystyrene insulation.

ü  One on the outside of the foundation wall and the other laid flat on a bed of gravel at the base of the wall to prevent freezing, which is a problem with slab on grade foundations in areas with frost the insulation holds from the structure in the ground under the footings and prevents heat loss from the edge of the slab.

ü  This heat keeps the ground temperature around the footings above freezing.

·  Only works with a heated structure.

·  Has the benefits of a slab on grade method(concrete poured monolithically) in areas subject to frost.

·  Concrete is poured in one operation, versus 3 pours required for T-shaped foundations.

Shallow foundations:

v  Shallow foundations (sometimes called spread footings) include pads(isolated footings), strip footing and rafts.

Ø  Pad foundations

Ø  Strip foundations

Ø  Raft foundations

v  Shallow foundations are those founded near to the finished ground surface: generally where the founding depth (Df) is less than the width of the footing and less than 3m.

v  These are not strict rules, but merely guidelines.

Ø  Basically, if surface loading (or) other surface conditions will affect the bearing capacity of a foundation it is ‘Shallow’.

Ø  Shallow foundations are used when surface soils are sufficiently strong and stiff to support the imposed loads; they are generally unsuitable in weak or highly compressible soils, such as poorly-compacted fill, recent lacustrine and alluvial deposits etc.

ü  Pad foundations:

v  Pad foundations are used to support an individual point load such as that due to a structural column.

v  They may be circular, square (or) rectangular.

v  They usually consist of a block (or) slab of uniform thickness, but they may be stepped (or) launched if they are required to spread the load from a heavy column

v  Pad foundations are usually shallow, deep foundations can also be used.

v  This is where isolated columns(pillars) are casted from the foundation to carry a slab at the top of the ground.

v  This is mostly used when you want to make use of the under of buildings as parking space (or) when the other space is not conducive to have foundation.

v  Build a house across a flowing stream and you want a situation where you can see your boat to pass under the building because the stream is under.

v  Then you may not need to dig foundation that will cut across the river but by applying columns (pillars) at the edge of the river like a bridge, this columns are thus isolated and there foundations are referred to as pad.

Ø  Strip foundations:

v  Strip foundations are used to support a line of loads either due to a load bearing wall, or if a line of columns need supporting where column positions are so close that individual pad foundations would be inappropriate.

v  This is the most common type, it is mainly used where you have strong soil base and non-water logged areas.

v  Most small buildings of just a floor are constructed with this type of foundation.

v  Depends on the structural engineers recommendation, the depth of your foundation could be from 600mm to 1200mm mostly for small scale buildings.

v  When the soil is excavated, a level at which the concrete is poured this may be from 150mm(6’’) thick to 450mm(18’’) thick depending also on building after that block is set round the trenches at the center of foundation, the foundation usually follows the block lines.

v  The blocks are then layed to d.p.c level before another concrete is poured on top, this is the german (or) oversite concrete.

v  This type seems to be the cheapest.

  Raft foundations:

v  Raft foundations are used to spread the load from a structure over a large area, normally the entire area of the structure.

v  They are used when column loads (or) other structural loads are close together and individual pad foundations would interact.

v  A raft foundation normally consists of a concrete slab which extends over the entire loaded area.

v  It may be stiffened by ribs (or) beams incorporated into the foundation.

v  Raft foundations have the advantage of reducing differential settlements as the concrete slab resists differential movements between loading positions.

v  They are often needed on soft (or) loose soils with low bearing capacity as they can spread the loads over a larger area.

v  This is where you have concrete spread around your building from the base of foundation all through to the german floor/oversite concrete/ground floor slab.

v  It is mainly used in areas where the soil are sandy and loose, you spend more on tall through to the german floor/oversite concrete/ground floor slab.

v  It is mainly used in areas where the soil are sandy and loose, you spend more on this than the other previous two most of the time.

v  It is also recommended in water logged areas but with buildings of less storage.

v  It has a ground beam which shuts out from the foundation base and is also attached to the attached to the ground floor slab to form a network of concrete embedded round the building space.

v  The ground beams are usually from 600mm to 1200mm for low buildings.

Deep foundations:

Ø  Piles:

v  Deep foundations include piles, pile walls, diaphragm walls and caissons.

v  Deep foundations are those founding too deeply below the finished ground surface for their base bearing capacity to be affected by surface conditions, this is usually at depths >3m below finished ground level.

v  They include piles, piers and caissons (or) compensated foundations using deep basements and also deep pad (or) strip foundations.

v  Deep foundations can be used to transfer the loading to a deeper, more competent strata at depth if unsuitable soils are present near the surface.

v  Piles are relatively long, slender members that transmit foundation loads through soil strates of low bearing capacity to deeper soil (or) rock strates having a high bearing capacity.

v  They are used when for economic, constructional (or) soil condition considerations it is desirable to transmit loads to strates beyond the practical reach of shallow foundations.

v  In addition to supporting structures, piles are also used to anchor structures against uplift forces and to assist structures in resisting lateral and overturning forces.

v  The most expensive and the strongest type of foundation, this requires specialist engineering to do.

v  The soil are based deep down the earth and filled with concrete to be foundation type, a water logged area of high building ma may also require this.

v  It is the costliest hence it is used for high rise building mostly.

ü  Piled foundations can be classified according to:

Ø  The type of file:

(different structures to be supported, and different ground conditions, require different types of resistance) and

Ø  The type of construction:

(different materials, structures and processes can be used).

Ø  Types of pile:

o   End bearing

o   Friction

o   Settlement reducing

o   Tension

o   Laterally loaded

o   Piles in fill

ü  Piles are often used because adequate bearing capacity cannot be found at shallow enough depths to support the structural loads.

ü  It is important to understand that piles get support from both end bearing and skin friction.

ü  The proportion of carrying capacity generated by either end bearing (or) skin friction depends on the soil conditions.

ü  Piles can be used to support various different types of structural load.

  End bearing piles:

v  End bearing piles are those which terminate in hand, relatively impenetrable material such as rock (or) very dense sand and gravel.

v  They derive most of their carrying capacity from the resistance of the stratum at the toe of the pile.

  Friction piles:

v  It obtain a greater part of their carrying capacity by skin friction (or) adhesion.

v  This tends to occur when piles donot reach an impenetrable stratum but are driven for some distance into a penetrable soil.

v  Their carrying capacity is derived partly from end bearing and partly from skin friction between the embedded surface of the soil and the surrounding soil.

  Settlement reducing piles:

v  These are usually incorporated beneath the central part of a raft foundation inorder to reduce differential settlement to an acceptable level.

v  Such piles act to reinforce the soil beneath the raft and help to prevent dishing of the raft in the centre.

  Tension piles:

v  Structures such as tall chimneys, transmission towers can be subject to large overturning moments and so piles are often used to resist the resulting uplift forces at the foundation.

v  In such cases the resulting forces are transmitted to the soil along the embedded length of the pile.

v  The resisting force can be increased in the case of based piles by under reaming.

v  In the design of tension piles the effect of radial contraction of the pile must be taken into account as this can cause about a 10-20% reduction.

  Laterally loaded piles:

v  Almost all piled foundations are subjected to atleast some degree of horizontal loading.

v  The magnitude of the loads in relation to the applied vertical axial loading will generally be small and no additional design calculations will normally be necessary.

v  Traditionally piles have been installed at an angle to the vertical in such cases providing sufficient horizontal resistance by virtue of the component of axial capacity of the pile which acts horizontally.

v  However the capacity of a vertical pile to resist loads applied normally to the axis, although significantly smaller than the axial capacity of that pile, may be sufficient to avoid the need for such ‘rating’ (or) ‘battered’ piles which are more expensive to install.

v  When designing piles to take lateral forces it in therefore important to take this into account.

  Piles in fill:

v  Piles that pass through layers of moderately to poorly compacted fill will be affected by negative skin friction, which produces a downward drag along the pile shaft and therefore an additional load on the pile.

v  This occurs as the fill consolidates under its own weight.

Ø  Piers:

v  Piers are foundation for carrying a heavy structural load which is constructed insitu in a deep excavation.

Ø  Caissons:

v  Caissons are a form of deep foundation which are constructed above ground level, then sunk to the required level by excavating (or) dredging material from within the caisson.

Ø  Compensated foundations:

v  Compensated foundations are deep foundations in which the relief of stress due to excavation is approximately balanced by the applied stress due to the foundation.

v  The net stress applied in therefore very small.

v  A compensated foundation normally comprised a deep basement.

                                                    

                                                

                                          UNIT-II

1.      SAFETY IN ERECTION:

v  Before erection begins a risk assessment should be carried out and a safe system of work developed.

v  The cause of many past failures was foreseeable and could have been prevented by proper consideration when erecting the falsework.

v  Failures often occur on fairly simply structures erected by smaller falsework contractors, who may not employ design staff.

v  Designing falsework that can be erected safely including how striking will be achieved.

v  To ensure safety, falsework should be stable at all stages of erection and be regularly checked.

v  Erectors should know

·  Where to start

·  Whether the equipment supplied is the same as that ordered

·  At what stage checks (or) permits are required

·  Whether checks and permits have already been carried out (or) issued

The erection of low rise buildings:

v  This highlights the principal safety objectives associated with erection of steel work, such as the stability of part erected structure, safe lifting and placing of steel components and safe access and working positions.

2.      CONSTRUCTION MATERIALS:

v  A concrete shell also commonly called thin shell concrete structure is a structure composed of a relatively thin shell of concrete, usually with no interior column (or) exterior buttresses.

v  The shells are most commonly flat plates and domes, but may also take the form of ellipsoids (or) cylindrical sections, or some combination there of.

v  Concrete is the most suitable material for construction, since it can withstand compression forces, moreover it is workable and durable material, can be formed to any shape you like, also it in some how cheap materials; as disadvantages.

v  It requires special care and precautions during casting otherwise it could cause cracks and failure.

Uses:

v  Most concrete shell structures are buildings, including storage facilities, commercial buildings and residential homes.

v  Concrete shell construction techniques are well suited for complex curves and are also used to build boat levels (called ferro concrete).

Advantages:

v  Like the arch, the curved shapes often used for concrete shells are naturally strong structures, allowing wide areas to be spanned without the use of internal supports, giving an open, unobstructed interior.

v  The use of concrete as a building material reduces both materials cost and construction costs, as concrete is relatively in expensive and easily cost into compound curves.

v  Before during and after construction the advantages of concrete reinforce the value of concrete construction.

v  Concrete saves money over the entire life of your structure before, during and after construction.

v  Concrete can reduce project startup time and start to finish time compared with steel.

v  Concrete provides structural economy in many other ways too, including material costs and improved cash flow.

v  It can also maximize marketable space and increase ROI.

v  Concrete can handle the compression stresses 10 times more than the tension and the most of loads in our life is compression.

v  Concrete is a brittle material which gives the advantage to make a rigid structure.

v  Easy to handle over specially now there is plants that give you ready mix concrete.

Disadvantages:

v  Since concrete is a porous material, concrete domes often have issues with scaling.

v  If not treated, rain water can seep through the roof and leak into the interior of the building.

v  To the other hand, the seamless construction of concrete domes presents air from escaping, and can lead to buildup of condensation on the inside of the shell.

v  Concrete is weak in handling tension.

v  Because concrete is a brittle material the strength upon shear(specially at 45 degrees) must be checked.

v  It need another material to reinforce it against excessive shear and tension.

3.      SAFETY IN TYPICAL CIVIL STRUCTURES-DAMS:

Dams safety committee (DSC’s):

v  The DSC’s prime goal is to ensure that all prescribed dams in NSW are designed, constructional and operated to a standard where risks to the community are tolerably low.

v  The level of risk is determined by the likelihood and consequences of failure.

v  Dam owners are required to carefully consider the DSC’s guidance sheet on acceptable flood capacity for dams.

v  Dam owners should ensure that the design of embankment dams (including CRFD) clearly states the basis for design strong, the stability methodology, assumptions on pore pressures and the factor of safety and includes calculated predictions of the settlement behavior and states the safety against piping.

v  The design of all extreme, high and significant consequence category concrete dams reliant on uplift relief should consider the effectiveness of the uplift relief system and make provision for its accessibility and maintenance.

Filters/Drains:

v  The DSC is of the opinion that the design of effective drains and filters is highly cost effective in terms of the total safety of embankment dams with all extreme, high and significant consequence category earth fill and earth core/rock fill dams to have fully intercepting filters.

v  In addition, seepage collection and monitoring is required in all extreme, high and significant consequence category dams.

Conduits:

v  Where possible conduits should be embedded in the natural foundation and not located in the embankment and no unencased metal conduits are to be used in any part of the dam.

v  All mechanical/electrical systems essential for dam safety shall have adequate backup provisions including backup power sources.

v  Dam design documentation requirements are outlined in the DSC’s guidance sheets on demonstration of safety for dams and documentation and information flow over dam life cycle.

v  Partial (or) total failure of your dam may cause extensive damage to downstream properties, for which you the owner are likely to be held liable.

Safety surveillance:

v  Safety surveillance of a dam is a program of regular visual inspection using simple equipment and techniques.

v  It is the most economical means of ensuring the long-term safety and survival of your dam.

v  By regularly monitoring the condition and performance of the dam and its surroundings, adequate warning of potentially unsafe trends will enable timely maintenance.

UNIT-III

1.      LOCK OUT OF MECHANICAL AND ELECTRICAL MAINTENANCE:

v  This procedure provides the fundamental components necessary for the deactivation of the mechanical/electrical energy sources through a lockout system.

v  A lockout survey has been conducted to locate and identify all energy sources to verify which switches (or) valves supply energy to machinery and equipment.

v  Lockout procedures are not required if equipment must be operating for proper adjustment.

v  Lockout devices will be affixed to energy isolating devices by authorized employees.

v  Lockout devices will be affixed in a manner that will hold the energy isolating devices from the “safe” or “off” position.

v  Lockout all energy devices by use of hasps, chains and valve covers with an assigned individual locks.

v  Before lockout devices are removed and the energy restored to the machine (or) equipment, the following actions will be taken.

·  The work area will be thoroughly inspected to ensure that non essential items have been removed and that machine (or) equipment components are operational.

·  The work are will be checked to ensure that all employees have been safely positioned (or) removed. Before the lockout device are removed, the affected employees will be notified that the lockout devices are being removed.

·  Each lockout device will be removed from each energy isolating device by the employee who applied the device.

Supervisor responsibilities in the unit/branch that perform lockout practices:

ü  Supervisors are responsible for ensuring that all affected employees are trained in the safety significance, purpose, and use of lockout practices.

ü  Supervisors are responsible for ensuring all authorized lockout employees receive the appropriate level of training and that these employees are provided with the proper equipment and personal protective equipment to perform the job safety.

Lockout coordinator responsibilities:

The assigned lockout coordinator is responsible for:

v  Ensuring equipment specific lockout practices are used.

v  Ensuring that only authorized lockout employees perform lockout operations on necessary equipment.

v  Maintaining an inventory of all equipment in their department that requires specific lockout practices.

v  Receiving appropriate training to become an authorized lockout employee and perform lockout practices on equipment.

v  Purchasing (or) installing equipment and machinery to ensure that this equipment (or) machinery  has the capability to accept a lockout device on all energy isolating devices.

v  This will include, but its not limited to, electric power disconnect devices that can be locked only in the open(off) position, fluid control components (eg.valves) that can be locked in the safe position, or fluid lines that have the capability to place a mechanical barrier between a hazardous fluid and the point where work must be performed.

v  Whenever major replacement, repair, renovation, or modification of machines (or) equipment is to be performed, energy isolating devices for such machinery (or) equipment shall be installed and be designed to accept a locking device so they are capable of being locked out.

Practice:

ü  The authorized lockout employees performs the work, as well as their supervisor, must create the work plan, written lockout practices, and physically locate and identify all isolating devices to be sure which switches, valves, or other energy isolating devices apply to the equipment to be locked out.

ü  Employees authorized to lockout equipment must be certain which switch (or) other energy isolating devices apply to the equipment to be locked out.

ü  Notify all affected and other employees as necessary that a lockout is to be performed.

ü  These persons must be informed that they are not to disturb the lockout device (or) attempt to restart the equipment until they are informed that about has been cleared and it is safe to resume normal operations.

ü  All energy isolating devices must be locked out. Lockout the circuit breaker, disconnect switch, or other isolating device in the open (“OFF”) position with an assigned individual lock, and attach an identifying tag to the lock. If it is impossible to use a lock, refer to the “practice when physical locking is impossible” section.

ü  The equipment is now locked out.Work may now begin.

Situations involving more than one person locking out:

ü  Employees and/or contractors must engage in a group lockout situation.

ü  If more than one employee works on the equipment, a lockout adapter suitable for the installation of several locks must be used, enabling all workers to lockout the machine with individual locks.

ü  The method of applying a mechanical lockout device and a tag on an energy isolating device by an authorized employee in acceptance with established written procedures, inorder to control hazardous energies.

ü  Lockout device-Pad locks, combination locks (or) other methods (such as disconnecting conductor (or) removing fuses) which will effectively prevent unexpected (or) inadherent emerging of a designated circuit (or) release of equipment (or) machinery.

ü  These devices shall not bound for the purposes-and shall include a means to indicate the identity of the employee apply the device.

2. HAND TOOLS:

v  Construction workers are considered experts in the selection and use of hand tools, get every year workers are injured on the job as a result of hand-tool accidents.

v  Hand tools are designed to make jobs easier and more efficient.

v  Common types of hand tools include striking tools, turning tools, metal-cutting tools, wood cutting tools, screw drivers, pliers, knives, saws, hammers, axes, spanners and crowbars.

v  The greatest hazards posed by these tools result from misuse and improper maintenance.

v  According to a survey, hand tool injury rates were second highest in construction, outranked only by agriculture.

v  Poorly maintained portable tools in construction(hand tools) prevent significant health and safety risks to the workers using them.

v  Mechanical failure (or) loss of control when using a tool with defective parts.

v  Examples of unsafe tools are hammers with loose (or) damaged heads, screw drivers with broken handles (or) blunt edges, chisels with mushroom head and blunt saws.

Some basic rules to prevent hazards associated with the use of hand and power tools are:

v  Examine each tool for damage before use.

v  Check that the guards are present and secure.

v  Check wheels and blades for cracks.

v  Check electrical cards, connections, earthing. It is essential that the earth core of the flexible cable and associated earth connections of portable electric tools are tested regularly by a competent person to ensure continuity and strength of the earthing.

Care and maintenance of hand tools:

v  Proper care and maintenance of hand tools will help prevent injuries to crew members and will assist them.

Ø  Hand tools-Planes, chisels, gouges and the like absolutely require an adequate sharpening system.

Ø  A good sharpening system for the delicate cutting edges of fine hand tools will allow you to do two things: grind the tool to the correct shape, and hone it to a near-perfect edge.

Ø  Here you have a few options.

Ø  Perfectly acceptable results can be achieved using grinder outfilled with a cool running white aluminium oxide grinding wheel and a fairly simple honing system, like the rockler’s plate glass sharpening system (or) the precision sharpening system.

Ø  If hand tools figure prominently in your wood working, consider investing as a more advanced sharpening system.

Ø  Sharpening hand tools is really an art form in itself, and it would be impossible to do it justice here.

General requirements:

v  A tool maintenance procedure is one of the most important factors in any hand-tool safety program.

v  Extensively used hand tools require careful and frequent inspection to maintain them for safe use.

v  When hand tools are not sharpened and dressed, in efficient cutting and glancing off material often cause injuries.

v  Remove hand tools with defective handles from service immediately.

v  Personal protective equipment must protect a person using hand tools who is exposed to hazards, such as falling, flying, abrasive and splashing objects, or exposed to harmful dust, fumes, mists, vapors (or) gases.

ABBREVIATIONS

UNIT-I

1) U.S- UNITED STATES

2) JSA- JOB SAFETY ANALYSIS

3) CJSA-CONSTRUCTION JOB SAFETY ANALYSIS

4) OSHA-OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION

5) CFR-CODE OF FEDERAL REGULATIONS

6) ICF-INSULATED CONCRETE FORMS

7) CIS-CONSTRUCTION INDUSTRY SCHEME

8) CDM-CLEAN DEVELOPMENT MECHANISM

9) HAVS-HAND ARM VIBRATION SYNDROME

10) ACM-ASBESTOS CONTAINING MATERIAL

11) ANSI-AMERICAN NATIONAL STANDARD INSTITUTE

12) OTM-OSHA TECHNICAL MANUAL

13) TED-TRUNK ENCRYPTION DEVICE

14) Df- FOUNDING DEPTH

15) d.p.c- DAMP PROOF COURSE                                         

                                                      UNIT-II

1)    ROI- RADIUS OF INFLUENCE

2)    DSC-DAM SAFETY COMMITTEE

3)    NSW-NEW SOUTH WALES