SCAFFOLDING

 SCAFFOLDING

 

INTRODUCTION

                    Scaffolding is a temporary structure used to support people and material in the construction or repair of buildings and other large structures. Or It is temporary frame works of timber bamboo, steel element having platforms at different levels to enable the masons to work at different heights of building mason standing on ground, can work up to the height 1.5m. When work gains height more than this, mesons and labours need temporary platform to work at height.   

          It is usually a modular system of metal pipes or tubes, although it can be made out of other materials. Bamboo is frequently used in Terai region or the place where the bamboo found easily. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. This document sets out performance requirements for working scaffolds. These are substantially independent of the materials of which the scaffold is made. The standard is intended to be used as the basis for enquiry and design.

                    Scaffolding consists of 3 main parts, Tubes, Couplers for joining the tubes and Boards, to create a supporting area for human access. Scaffoldings are seldom alone, they are always attached to the building with ties. Independent scaffoldings are seldom seen and are usually not as stable as the ones attached to a structure.

Rules are regulations vary in every part of the world when it comes to construction. In certain parts of the world there exists rules for building scaffolding and norms and standards are practiced strictly. Britain has a strict code of conduct too and all scaffoldings are expected to meet certain standards based on Provision and Use of Work Equipment Regulations. Scaffolds in the UK have to meet the standards according to the BS 5973 Regulations and strictly meet its requirements.

Tubes are made of Steel or Aluminum. Steel is usually galvanized. The aluminum Tubes render more durable as its light and Flexible. Boards are made of seasoned wood and should be 50 mm-63 mm to meet the standards.

History

          The Berlin Foundry Cup depicts scaffolding in ancient Greece (early 5th century BC). The ancient Egyptians, Nubians and Chinese are also recorded as having used scaffolding-like structures to build tall buildings. The ancient Africans have also used wooden scaffoldings to support mosques.

Materials

          The basic materials are tubes, couplers and boards.Tubes are either steel or aluminium, although composite scaffolding uses filament wound tubes of glass fibre in a nylon or polyester matrix. If steel they are either 'black' or galvanized. The tubes come in a variety of lengths and a standard diameter of 48.3 mm. (1.5 NPS pipe). The chief difference between the two types of tubes is the lower weight of aluminium tubes (1.7 kg/m as opposed to 4.4 kg/m) and also a greater flexibility and so less resistance to force. Tubes are generally bought in 6.3 m lengths and can then be cut down to certain typical sizes. Boards provide a working surface for users of the scaffold. They are seasoned wood and come in three thicknesses (38 mm (usual), 50 mm and 63 mm) are a standard width (225 mm) and are a maximum of 3.9 m long. The board ends are protected by metal plates called hoop irons or sometimes nail plates.

Parts of scaffolding

·       Standards: Vertical bullies erected at a distance of 1m to2m from the structure are known as standards. All the loads are borne by standards; they should be strong & rigid enough to bear them.

·       Ledgers: These are the members laid horizontally, parallel the walls. They are rigidly connected to the standards by connectors at height where the temporary working platform has to be built.

·       Putlogs: These are lateral pieces, one end of which remains supported on ledgers and other end on the wall.

·       Braces: these are diagonal fixed on the standards to provide stiffness to the scaffolding.

·       Guard rail: It is an additional horizontal rail, like ledger, provided at                       working level as a safeguard for the worker & masons.

·       Toe Board: It is a wooden plank placed parallel to the ledgers and supported between the putlogs. It is provided to work as a Protective        measure on the working platform.

·       Raker:It is an inclined support given to the scaffolding or structures     etc.

Different parts

TYPES

 

1.    Putlog/Single/Dependent Scaffolding:

It consists of single row of upright or standards set away from wall at distance which accommodates required width of working platform.

ü Standards are joined together with horizontal members called ledgers.

ü Standards tied to building with cross members called putlogs.

ü Scaffolding is erected as building  rises & is mostly used for buildings of traditional brick     construction

          The distance between adjacent standards is about 2to 2.5m the standards are connected to each other with the help of ledgers at a vertical interval of 1.2mto1.8m.Ledgers are connected to the standard on side of the wall. Transverse pieces i.e. putlogs, with one end on the ledger and the other end on the wall are then put at a horizontal interval of about 1.2m to 1.8m putlogs are connected to ledgers with the help of lashings at one end and are supported in holes left in the wall at other end.

2.    Mason’s/Double/independent Scaffolding:

It consists of two rows of standards which are tied by cross member called  tansoms .This form of scaffolding does not rely upon building for support .Every scaffolding should be securely tied to building at intervals of approximately 3.6m vertically & 6m horizontal. This can be achieved by using horizontal tube called bridle bearing on inside of wall & across window opening with across members connected to it.

 

 

How to Build Scaffolding

Wood pole scaffolds were used before metal scaffolding was invented, and they are still used today when it is more convenient and economical to do so. When building scaffolding, there are several things to keep in mind.

How much weight will be on the scaffolding? How high will the scaffolding be? Is there a solid object or building to cleat the scaffolding to? After you answer those questions, you cab begin to build.

Instructions

ü Place the inside sills or pads on the ground next to the face of the building; use pads in the case of uneven ground. Set inside uprights at each end of the building and toenail them to the sill. Use a carpenter's level and plumb the uprights. Next, tie the uprights to the building using wood cleats.

ü Nail a one-by-six ribbon board to the uprights at three and one half inches below the plank height. Layout and nail intermediate uprights in place along face of wall. Uprights should not be spread out more than 10 feet.

ü Lay the outside sill or pads on the ground. Set up two outside uprights and nail in place. Level and nail ledger boards connecting the inside and outside uprights; all ledger boards will be resting on top of the ribbon boards. The ledgers should be at the height of where the walking planks will be placed. Place ribbon board below outside ledger and nail.

ü Place outside uprights opposite of the inside uprights and nail them into place. Next, connect each outside upright with the inside upright using ledger boards. Use a level to make sure ledgers are level before nailing.

ü Place walking planks for a platform on top of ledgers; the planks should run over the ledgers at least 12 inches on both sides. Nail second-level ribbons and ledgers in place at height of next work area. Next, nail diagonal braces to outside uprights to provide lateral support. Place the next work level planks on the ledgers.

ü Nail the guardrail into place; the guardrail should be installed around 42 inches height-wise. The mid-rail will be placed around 28 inches. In some cases, there may be a need for a toe board; this type of board protects people from falling objects that get kicked off of the scaffolding. The toe board will be nailed against the planks of the scaffold walk way.

Uses

Scaffolding is most often used for creating a working platform for either building or maintaining structures, but because it is so adaptable; it can be used for a variety of purposes, including:

• Maintaining the exterior of an existing structure eg. Painting.
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• Providing working platforms for workers building a structure.
• Stair towers for access to other raised platforms such as flat roofs.
• Suspended platforms, cradles or hanging platforms eg. for bridge maintenance.
• Platforms on uneven ground for stages or marquees.
• Stabilizing or shoring a structure or tall object to keep it vertical.
• Temporary roofs.
• Temporary walkways.
• Temporary bridges.
• Temporary buildings eg. Storage sheds.
• River bank or lake-side reinforcement.
• Ramps.
• Sign-boards frames and advertising hoardings.
• Bracing structural props.
• Racking and storage bays.
• Hand-rails and edge protection.
• Masts for aeriels.
• Stage sets for television, film and theatre.

Tips & Warnings

·        Scaffolding definitions, the bottom plate, usually 2x8s, 2x10s, or 2x12s; planks that run parallel to the building that the uprights rest on. Pads: Similar to sills, but are not full planks; they are good for using on uneven ground. Uprights: Vertical wood pools that support scaffolding; 2x4 for under 20 feet and 4x4 poles for above 20 feet. Ribbons: These are installed horizontally to provide horizontal stability for uprights; they are usually 1x6s or 2x4s. Ledgers: These are 2x4s nailed from the outside upright to the inside upright to provide support for the planks and tie together the uprights. Diagonal bracing: This is bracing which is attached to the outside face of the scaffold to provide lateral stability. Usually 2x4s or 1x6s. Tie-ins or guylines: These provide support for scaffolding and prevent tipping. Usually 2x4s or 1x6s nailed to the inside support then nailed to a building. Planks: These are OSHA-approved 2x10s or 2x12s used to provide a walking surface.

·        There are many strict rules when building scaffolding at any job site. You can find these rules in a OSHA handbook or go online. Rules are set in place to protect the people working on the scaffolding as well as the people on the ground. If you are not sure of rules, laws, and basic principles of scaffolding, you should hire someone to build the scaffolding who is licensed to build scaffolding.