Wti Scaffold Blog

Today security is closely concerned with everyone.Especially in western countries ,they pay a lot of attention to the security .And relative dapartment or person should be responsible for the insecurity they caused.

As the caption mentioned,a firm has been fined £4,000 two years after scaffolding collapsed on a Teesside street injuring a man.

A number of cars were also damaged when a gust of wind blew the scaffolding down in Jedburgh Street, Middlesbrough, on 18 January, 2008.

William Bedford, of B & J Scaffolding, in Redcar, admitted a health and safety breach at Teesside Magistrates’ Court.

The firm was also ordered to pay £2,500 costs. The scaffolding had been erected as part of house restoration work.

The injured man was taken to hospital but his injuries were not serious.

Significant risk
 
The hearing heard how a Health and Safety Executive (HSE) investigation showed that the scaffolding was not adequately secured to the properties.

After the case, HSE Insp Natalie Wright, said: “The scaffold had been used as a working platform for at least five days before the incident, by workers on site carrying out work to the house fronts.

“It could have collapsed at any time, creating a significant risk to workers and members of the public.

“This incident demonstrates how important it is for contractors to follow the requirements for the construction of scaffolds.

“Contractors need to ensure that they meet the relevant standards in their work to erect safe and stable scaffolds, so that they do not expose workers and members of the public to risk.”

As we know our life now is more precious than everything;it’s invaluable.Some immigrant workers are very poor .They exchange their power for money in order to support their family,and here there happened a work accident happened.

TWO workers were injured after falling from a scaffold yesterday afternoon .Witnesses said the two were climbing on the 3-meter scaffold when a gust casusing the scaffolding to break down.Iis details are as follows.

Yesterday 5 p.m. an accident happened on the construction in the Nanjingxilu and huashan Road .Because of a sudden gust,the moble scffold on the spot suddenly collapse.As a consequence,TWO workers were injured.

Yesterday dusk, workers were installing the scaffolding before a garage of one building  on the Nanjingxilu Road.Unpredicately,sudden gust blowed .With the bang sound,4-meter scaffold collapsed all of a sudden.At that time ,two workers were worikng high up.Then they fell down with the scaffold.The other workers called 120 immediately and the two injured workers were sent to the hospital for first aid.Now the cause is still unclear and being invesigated.Fortunately, two injured workers were not injured badly.

We should learn something from the accident that we should take the safety point in the first place.Please love your life for your be loved.

Wood Scaffolding:

Lumber – All lumber used in constructing ramps, platforms, staging, scaffolding, etc., must be of good quality, seasoned and straight grained, free of large loose or dead knots and knots in groups, checks, splits and other defects which tend to decrease the structural strength.

Nails – No nail should be subjected to direct pull.  A minimum of four nails per joint is recommended.  The size of the nail used will depend upon the load that must be carried by the joint and the thickness of the material being joined, one inch stock requiring 8d nails, two inch stock requiring 16d nails, etc.

Tubular steel scaffolding:

Steel scaffolding should be erected and used in accordance with manufacturer’s recommendations.  Proper seating and locking of all connections, using the corrective devices, is of extreme importance.

A light duty tube and coupler scaffold shall have all posts, bearers, runners, and bracing of nominal 2 inch O.D. steel tubing.  The posts shall be spaced no more than 6 feet apart by 10 feet along the length of the scaffold.  Other structural metals when used must be designed to carry an equivalent load.  No dissimilar metals shall be used together on any tube coupler scaffold.

A medium duty tube and coupler scaffold shall have all posts, runners, and bracing of nominal 2 inch O.D. steel tubing.  Posts spaced not more than 6 feet apart by 8 feet along the length of the scaffold must be bearers of nominal 2 1/2 O.D. steel tubing.

A heavy duty tube and coupler scaffold shall have all posts, runners, and bracing of nominal 2 inch O.D.  Steel tubing, with the posts spaced not more than 6 feet by 6 feet 6 inches.

Drawings and specifications of all tube and coupler scaffolds above the limitations must be  designed by a qualified engineer competent in this field.

Posts must be accurately spaced, erected on suitable bases, and maintained plumb.

Runners shall be erected along the length of the scaffold, located on both the inside and the outside posts at even heights.  Runners shall be interlocked to the inside and the outside posts at even heights.  Runners shall be interlocked to form continuous lengths and coupled to each post.  The bottom runners must be located as close to the base as possible.  Runners must be placed not more than 6 feet-6 inches on centers.

Bearers must be at least 4 inches but not more than 12 inches longer than the post spacing or running spacing.

Manually propelled mobile scaffolding:

Cross bracing must be installed across the width of the scaffold at least every third set of posts horizontally and every fourth runner vertically.  Such bracing must extend diagonally from the inner and outer runners upward to the next outer and inner runners.

Longitudinal diagonal bracing on the inner and outer rows of poles shall be installed at approximately a 45 degree angle from near the base of the first outer post upward to the extreme top of the scaffold.  Where the longitudinal length of the scaffold permits, such bracing shall be duplicated beginning at every fifth post.  In a similar manner, longitudinal diagonal bracing shall also be installed from the last post extending back and upward toward the first post.  Where conditions preclude the attachment of the bracing to the posts, it may be attached to the runners.

The entire scaffold shall be tied to and securely braced against the building at intervals not to exceed 30 feet horizontally and 26 feet vertically.

Guardrails made of lumber not less than 2 x 4 inches (or other material providing equivalent protection), approximately 42 inches high, with a midrail of 1 x 6 inch lumber (or other material providing equivalent protection), and toe boards shall be installed at all open sides and ends on all scaffolds more than 10 feet above the ground or floor.  Toe boards shall be a minimum of 4 inches in height.  Wire mesh shall be installed when needed.

We may see saffolding around us used for buliding  or metro and things like that.But do you know the requirements of the scaffolding?

Scaffolds shall be furnished and erected in accordance with this standard for persons engaged in work that cannot be done safely from the ground or from solid construction, except that ladders used for such work shall conform to 1910.25 and 1910.26.

PURPOSE:Due to the large number of serious accidents associated with scaffolded work surfaces it is the intent of the University to provide maximum protection to all employees by the issuance of these requirements.

SCOPE:These requirements are to apply to all employees that work on scaffold work surfaces.  All scaffolds erected on University property shall be erected in accordance with the requirements of this section.

GENERAL:The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the maximum intended load without settling or displacement.  Unstable objects such as barrels, boxes, loose brick, or concrete blocks, shall not be used to support scaffolds or planks.

No scaffold shall be erected, moved, dismantled, or altered except under the supervision of competent persons or as requested for corrective reasons by the health and safety officer.

Guardrails and toe boards shall be installed on all open sides and ends of platforms more than 10 feet above the ground or floor, except needle beam scaffolds and floats.  Scaffolds 4 feet to 10 feet in height having a minimum horizontal dimension in either direction of less than 45 inches, shall have standard guardrails installed on all open sides and ends of the platform.

Guardrails must be 2 X 4 inches, or the equivalent, approximately 42 inches high, with a midrail, when required.  Supports must be at intervals not to exceed 8 feet.  Toe board and the guardrail, extending along the entire opening, consisting of No. 18 gauge U.S. standard wire 1/2 inch mesh, or the equivalent.

Scaffolds and their components must be capable of supporting without failure at least 4 times the maximum intended load.

Any scaffold damaged or weakened from any cause shall be immediately repaired and shall not be used until repairs have been completed.

All load-carrying timber members of scaffold framing shall be a minimum of 1,500 fiber (Stress Grade) construction grade lumber.

All planking must be Scaffold Grades, or equivalent, as recognized by approved grading rules for the species of wood used.  The maximum permissible span for 2 X 10 inch or wider planks is shown in the following:

   Full thickness Nominal
   undressed thickness     lumber  lumber

Working load (p.s.f.) 25   50   75         25    50
Permissible span (ft.) 10     8   6   8      6

The maximum permissible span for 1-1/4 X 9 inch or wider plank of full thickness shall be 4 feet with medium duty loading of 50 p.s.f.

All planking or platforms must be overlapped (minimum 12 inches), or secured from movement.

An access ladder or equivalent safe access must be provided.

Scaffold planks must extend over their end supports not less than 6 inches nor more than 18 inches.

The poles, legs, or uprights of scaffolds must be plumb, and securely and rigidly braced to prevent swaying and displacement.

Overhead protection must be provided for men on a scaffold exposed to  overhead hazards.

Slippery conditions on scaffolds shall be eliminated immediately after they occur.

No welding, burning, riveting or open flame work shall be performed on any staging suspended by means of fiber or synthetic rope.  Only treated or protected fiber or synthetic ropes shall be used for or near any work involving the use of corrosive substances or chemicals.

Wire synthetic, or fiber rope used for scaffold suspension shall be capable of supporting at least 6 times the rated load.

Bamboo is a grass and is one of the fastest growing plants on earth. The illustration above is but one of the over 1500 species that are known to exist on the plant today. This impressive number is rapidly decreasing as pressures from the second Industrial Age are destroying the once vast bamboo forests of Asia and Central America. A destruction that parallels is irresonsponsible and reprehensible. Yet, it is continuing at an ever increasing pace as Western “consumer values” are introduced to these regions.

Bamboo has long been used as an assembly material in china, particularly hong kong, because of its versatility.One of the most interesting applications of the wood is its structural function for scaffolding. Extremely eco-friendly and cost-effective resource, it continues to be
used for this purpose because it is durable enough to support the weight of builders, their equipment and materials, but is lightweight itself. Unlike typical metal scaffolding, bamboo can also be cut and tailor-made to suit any contour of construction – it can be configured
into a variety of shapes and follow irregular architectural features of a building, and takes very little time to build-up. It is light and easily transportable to other sites and no machinery is required to assemble the scaffold and put it in place. When one job draws to a close, bamboo can easily be recycled and used for another project.

Double-layered scaffolding consists of a single outer layered scaffold and an inner layer of posts and ledgers (horizontal limber which is fastened to the vertical uprights of a scaffold) which are erected inside. Between the two layers, short poles or transoms (crossbar pieces)
are used to support timber planks that form working platforms.

The main types of bamboo which are used for the purpose of scaffolding are mao jue and kao jue.When using the wood it needs to be completely dried out and free of any cracks or rot.The mao jue variety is the primary component of a scaffolding structure. It is used for vertical and diagonal members and maintains at least a 70 mm nominal external diameter.Kao jue is used for vertical and horizontal members and are at least 45 mm in their external diameter.

The frequency in which these structures should be inspected should not exceed more than 14 days.They would need to be monitored more closely in the event or arrival of any tropical cyclones or strong winds. In hong kong and other parts of southern china, bamboo scaffolds are one of the few traditional building systems which have survived through the practical experiences of scaffolding practitioners over generations. Thus, the safety and effectiveness of the bamboo scaffolds depends primarily on the individual skilled workers. Trade knowledge is passed down to younger workers through an apprenticeship system and on-the-job learning.

Ties to scaffold is what water to humanbeings.

Scaffolds are only rarely independent structures. To provide stability for a scaffolding (at left) framework ties are generally fixed to the adjacent building / fabric / steelwork.

General practice is to attach a tie every 4m on alternate lifts (traditional scaffolding). Prefabricated System scaffolds, however, require structural connections at all frames – ie. 2-3m centres.  The ties are coupled to the scaffold as close to the junction of standard and ledger (node point) as possible. Due to recent regulation changes, scaffolding ties must support +/- loads (tie/butt loads) and lateral (shear) loads.

Due to the different nature of structures there are a variety of different ties to cover all potential eventualities.

Through ties are put through structure openings such as windows. A vertical inside tube crossing the opening is attached to the scaffold by a transom and a crossing horizontal tube on the outside called a bridle tube. The gaps between the tubes and the structure surfaces are packed or wedged with timber sections to ensure a solid fit.

Box ties are used to attach the scaffold to suitable pillars or comparable features. Two additional transoms are put across from the lift on each side of the feature and are joined on both sides with shorter tubes called tie tubes. When a complete box tie is impossible a l-shaped lip tie can be used to hook the scaffold to the structure, to limit inward movement an additional transom, a butt transom, is place hard against the outside face of the structure.

Sometimes it is possible to use anchor ties (also called bolt ties), these are ties fitted into holes drilled in the structure. A common type is a ring bolt with an expanding wedge which is then tied to a node point.

The least ‘invasive’ tie is a reveal tie. These use an opening in the structure but use a tube wedged horizontally in the opening. The reveal tube is usually held in place by a reveal screw pin (an adjustable threaded bar) and protective packing at either end. A transom tie tube links the reveal tube to the scaffold. Reveal ties are not well regarded, they rely solely on friction and need regular checking so it is not recommended that more than half of all ties be reveal ties.

If it is not possible to use a safe number of ties rakers can be used. These are single tubes attached to a ledger extending out from the scaffold at an angle of less than 75° and securely founded. A transom at the base then completes a triangle back to the base of the main scaffold.

Elasticated ties for attaching scaffold sheeting to scaffold structure.These ties exceed the minimum requirements of British Standard BS 7955.It is recommended that 150 ties are used for each roll of 2m×45m sheeting.

Ⅰ.quality standards
Scaffolding speculations, scaffold construction program,Gate Scaffolding speculations, Gate Scaffolding construction program,mobile scaffolding speculations
 
1, ensure the project
⑴ All the components of gate scaffolding should have factory certificates,quality of which should meet the design requirements.
⑵ The distance between connection rod should be consistent with scaffold design requirements.
Ⅱ.Notes
1, the measure of ensuring the quality and safety
⑴ Gate frame and accessories should be checked carefully before erection;no deformed broken and rusty ones should not be applied into the construction.
⑵ Workers when building the scaffolding must strictly comply with the blueprint.If erection height is more than 45 meters,it needs checking and relative measures should be carried out to strengthen the construction.
⑶ Lines should be drawn on the outer surface so as to keep the scaffolding parellel to the building surface.
⑷ Attention should be paid to the infrastructer quality of scaffolding to avoid uneven settlement. The bottom of the base should be firmly fixed to prevent the base from gliding.
⑸ Gate frame and accessories should be tied tightly to avoid scatter when been lifted. And you should aviod misuse of these tools.
⑹ All connection pieces(fastening, locking pieces, etc.) must be in a fixed position. Fastener maybe loosen during use,so it should be regularly checked.
⑺ Only when  the construction is influenced can the inside cross bar of gate scaffolding be removed.
⑻ No compulsory removement should be inserted during the project.
⑼ The steps allowed in the simutaneous  gantry scaffolding allows simultaneous manipulations are as follows:
Within 40 ~ 50 meters 2 steps are allowed in simultaneous operation ;
within 19 ~ 40 meters 3 steps are allowed  in simultaneous operation ;
below 18 meters 4 steps are allowed  in simultaneous operation .
2, product protection
⑴ When fixind and removing the structure you should avoid the plate ,stake and the piller from falling on the scaffolding.
⑵ All parts of the scaffolding should be coated with the anti-rust lacquer before insallment.
⑶ The stand point of the plate can’t be on the scaffloding.
⑷ The removed gate frame and accessories are to be maintained and repaired,after which the same catagory of them should be stored together flatly.It should have well drainage system and the flashing.
⑸ Butter should be coated on the connection in order to avoid the connectioins being rusted.

ⅰ.Frame Scaffold
Such kind of scaffold have door-shaped , H-shaped, triangular, square, and some other forms .The door-shaped scaffolding was invented in the earliest time and most widely used in Europe , the United States, Japan and other countries, the use of which accounted  for about 50% of that of various types of scaffold.

 ●The door-shaped scaffold is mainly made of the main frame , cross-frame, cross brace, scaffold boards, adjustable base and other components. The door-shaped Scaffold was initially successfully developed by U.S. First,it is simple to be assembled and disassembled,could bear strength and is safe for use.Ii’s also characterized of quick development.By 1970s, we have import gate scaffold from Europe,Japan and some other countries sequentially which were used in the building of high-rise building. By the early 80s, the domestic manufacturers began to trial-manufacture a number of gate scaffold which were widely employed in some parts of the construction of application projects resulting in good effect.

●Square tower scaffold is made of the standard framework, cross braces, connecting rods, and adjustable base. The development and application of scaffolding first happened in  Germany called ID15.Nnow it has been widely used in Western Europe.In the early 90s, China employed scaffold in the Daya Bay Nuclear Power Station and the Ertan Hydropower Station, which achieved good results. The scaffold has been applied into more than 10 projects of bridges and viaduct engineering, which has fully demonstrated its superiority. Owing to its reasonable structure, safety, wide range of applications, good carrying capacity, and good quality, compared with the coupler scaffold, it can save 60% of the material used in scaffold—steel.It has high flexibility allows the workers to shorten the working time.

● Triangular frame scaffold is made of triangular frame,bar, diagonal bar, adjustable base and other components. The scaffold was first developed in the United Kingdom and France, Now it has been widely used in Western European countries .In 70s  in Japan it has been produced in large number.It has the similar characteristics as the above mentioned types.

ⅱ.Mobile Frame Scaffolding
This scaffold is made into the tower-liked frame on the basis of the door-type, trapezoidal-typed  and triangular-typed components of scaffold.At the bottom of the main pillar wheels are fixed which could be regarded as the movable construction .On the wheels fixes the finite-bit device and the wheel brake. It’s mainly used in the up-work, which is independent scaffold or it’s the work platform,and it can also be used as a stand of die plate.

ⅲ.Bridge Scaffold
This scaffold is made of the bridge and the supporting frames .

ⅳ. Hanging Scaffold
Hanging scaffold is designed through bearing point of strut.It’s made of three main parts: the hanger ,the strut system and the take-up system.

You may have noticed these placed beside a building that’s under construction. These are commonly used by a variety of contractors. This style is commonly available at local tool rental suppliers in your area. Each section is called a “buck”. The main consideration is a nice hard level surface for rolling around. Even if you don’t require wheels, you will want to place the legs onto a hard level surface. The first section will be composed of 2 frames, 2 cross braces, 4 casters, and 4 connector pins. Each succeeding section can have one cross brace omitted as long as you alternate sides.

Upon completion of the first section you will want to install the wheels and then lock them to avoid movement while assembling the scaffold. After the first section is complete you will want to place two walkboards on top for you to stand. Have an assistant pass you the verticle frames up and place the hollow legs of the frames onto the pins of the previous frame. Next connect the frames with the x shaped cross brace or braces. This style of scaffold will require someone to help you and even then it can be tricky. Working at heights can make you nervous and these components are made of steel which is not light. Please do not attempt this alone. Remember when each frame is set in place you will want to match the ladder rungs to create a complete ladder to the top. Please do not attempt to have someone roll you around while you are on top of this scaffold.

If at all possible you will need to secure this scaffold to whatever structure available. I have seen wheels fall out of the legs due to uneven surfaces. I have seen scaffold legs sink into the ground after a light rain. Also, depending on the application and height, you might consider using a safety belt to secure yourself to the building once in position.

On new construction, tubular scaffolding is efficient up to 60′ high or five stories. Above this it is usually better to use a hung scaffolding if construction permits. Swing scaffolding operations may interfere with tenants. In this case, the tubular is more practical at all heights.

In repairing or cleaning the front of an existing building, the cost of tubular scaffolding per SF of building front increases as the height increases above the first tier. The first tier cost is relatively high due to leveling and alignment.

The minimum efficient crew for erecting and dismantling is three workers. They can set up and remove 18 frame sections per day up to five stories high. For six to twelve stories high, a crew of four is more efficient. Use two or more on top and two on the bottom for handing up or hoisting. They can also set up and remove 18 frame sections per day. At 7′ horizontal spacing, this will run about 800 SF per day of erecting and dismantling. Time for placing and removing planks must be added to the above. A crew of three can place and remove 72 planks per day up to five stories. For over five stories, a crew of four can place and remove 80 planks per day.

For jobs under 25 frames, add 50% to rental cost. Rental rates will be lower for jobs over three months’ duration. Large quantities for long periods can reduce rental rates by 20%.

Scaffolding is often used as falsework over 15′ high during construction of cast-in-place concrete beams and slabs. Two foot wide scaffolding is generally used for heavy beam construction. The span between frames depends on the load to be carried with a maximum span of 5′. Heavy duty shoring frames can be spaced up to 10′ OC depending on form support design and loading.

Scaffolding used as horizontal shoring requires less than half the material required with conventional shoring. On new construction, erection is done by carpenters.

Rolling towers supporting horizontal shores can reduce labor and speed the job. For maintenance work, catwalks with spans up to 70′ can be supported by the rolling towers.