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Showing posts with label timber. Show all posts
Showing posts with label timber. Show all posts

Thursday, March 14, 2019

Some best formwork methods

Formwork means the temporary or permanent molds which are applied to retain wet concrete unless it gets cured. It is a vital component in concrete construction as without formwork the schedule, labor requirements, quality and total cost of a project are significantly impacted.

In due course of time, formwork molds have changed from conventional job-built timber to pre-engineered systems comprising of a combination of steel, aluminum, manufactured timber, plywood and plastics.

These improvements in formwork molds make the jobsite production & safety better, with fewer labor, whereas creating a superior finished product.

Walls—Now-a-days, steel-framed, wood-faced panels, which need consumable ties at 2-feet-on-center and one connection per square foot, are extensively used for handset wall forming. These are substituted with larger, two-person handset systems which need less labor and get rid of consumable purchases due to reusable taper ties.

In recent times, clamp connection forms having wood or plastic form faces that offer tremendous labor savings in assembly, are utilized. Assembly and reconfiguration of these standard systems to satisfy changeable structure dimension takes place instantly, and also offers a consistent concrete finish.

Slabs—The application of fixed or tailor-made wood posts, stringers and joists is still considered as the most common method of shoring of slabs. This method delivers from generation to generation and considerable labor is required for that. Since, the posts are arranged as close as 2-feet-on-center, construction sites turn out to be very congested.

A new construction method that highlights engineered lumber and metal posts raise the post spacing up to 5 feet by 10 feet and suggests components which are systematic and can be reprocessed. This increases spacing and facilitates less material on site to develop the same slab area. Less material leads to lowered handling requirements, less labor to arrange and strip the formwork, fewer transport costs, and an improve overall job site productivity.

The existing method for gang-forming slabs applied trusses or structural decks based on significant amount of time for assembly and disassembly. Besides, this method requires a huge amount of crane time, thus accelerating the time for resetting a suitable operating method. The customer should also purchase the plywood facing and often restore it several times on the same project.

Gang-forming slabs are commonly found on the structures with height in excess of 15 stories with the purpose of reducing cost. To provide a greater solution to these types of systems, smaller tables are arranged to the job site fully assembled with plywood especially for mid-rise buildings where gang-forming was not inexpensive earlier.

The formwork-lifting elevators affixed to the exterior of a building that facilitates all formwork to be cycled from floor to floor devoid of requiring a crane to decrease job site crane time & formwork labor requirements. These table-lifting systems are applied along with the smaller table method and also allow for other construction material like handset shoring, vertical formwork and reshores from below to cycle from floor to floor with a crane.

How to choose the exact formwork

Structural engineers should be aware that concrete contractors carry out a detailed analysis of available formwork solutions to arrange the best system for the construction project since conditions differ for each individual project, there is no simple formula for the selection of the proper formwork supplier or system.

Generally, formwork should include 40- to 60-percent of the total cost of a building’s structural concrete frame. For concrete walls, the cost remains 50- to 60-percent range. These percentages involve the cost of material and labor, with the largest cost being for labor. It is vital to analyze the labor costs comprehensively since it is the higher expenditure and is that amount is decreased, it offers superior effect on the bottom line.

To provide the most effective solution for a project, a contractor will calculate different forming systems. Since the scarcity of available and capable labor continues, it has become even more important to opt for proper forming system. So, there are two options for a contractor - a low-priced forming material that is labor-intensive or a forming system that is costly but offer high productivity.

To get more details, go through the following link csengineermag.com

Some best formwork methods

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Published By
Rajib Dey
www.constructioncost.co
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Saturday, May 2, 2015

IS IT TIMBER OR STEEL OR CONCRETE? WHAT WOULD BE THE BEST IN USE?

IS IT TIMBER OR STEEL OR CONCRETE? WHAT WOULD BE THE BEST IN USE?
The most popular and common construction structural material Timber, Steel and Concrete has their own pros and cons. But the industry experts have also their own opinion about it. Sourceable.net has come up with great article published by Justin McGar. We have brought you an excerpt.


Timber

The chief executive of the timber development association Andrew Dunn opines, Timber has no such disadvantages but sometime creation of specific design may lead to be a huge design challenge.

The qualities of timber are well recognize and predictable now. People are started to believe that fear of fire or durability is no longer existed.

The timber use determined by its structural type, location and service life – but generally it is very lightweight, flexible of offsite manufacturing and cost effective.

Its main market is in short residential buildings but there is a rising interest in the mid-rise sector for apartments, office buildings as well as school buildings.

The Pitch: The timber’s load per unit weight to strengthen concrete and steel structure shows the high structural efficiency. Many timbers are either physically hard-wearing or can be easily treated to make very hard-wearing.

Wood with energy from the sun and carbon engrossed from the air (from the COin the air). Half the dry mass of timber is carbon engrossed from the air.

Timber used inside provides a healthier environment for dweller as it helps maintain a better relative humidity. The enormous preponderance of structural timber is sourced from sustainably managed forests and plantations.

The Treet or ‘the tree' (in picture) shows how far timber has come. A 14-storey (49-metre) apartment building in Bergen designed to comply with the Passivhaus sustainability standard. When completed it will be the tallest modern timber apartment structure in the world.

Concrete

The Concrete has been used for structures since Ancient Greece and Rome. Marianne Fourie of the International Federation for Structural Concrete believes   technological development and modernism over the centuries have polished its use. The structural concrete today permits engineers and architects to design, plan and achieve outstanding buildings that are as huge as they can be artistic. The advancement has also led to the more extensive use of pre-cast concrete, which presents great benefits of speed and cost of construction.

In the bigger edifices, such as tall buildings and bridges, nothing can be comparable to concrete. There are immense chances to add other tough materials to the concrete. The structural concrete is not only used in combination with other resources but also fit in with them as with fibre-reinforced concrete. It has ecological benefit, durability and less waste. The Centro Ovale concrete shell (Chiasso, Switzerland), exemplifies the adaptability of the material, while the Bella Sky Hotel (Copenhagen, Denmark) is an example of the innovative use of pre-cast concrete.

Steel

Steelwork in main construction is on the increasing as contractors become more in tune to the benefits of using the material in easing onsite risks, quick development for previous returns and environmental benefits, believes Alan Marshall, communications manager at the Australian Steel Institute. The US-based Council on Tall Buildings and Urban Habitat recently reported in a study that the number of composite multi-level projects over 200 metres that characteristically includes a steel frame with metal-decking, increased 54 per cent across the globe in 2014.

Speed and efficiency: The benefits are many liker computer modeling on CNC equipment, structurally efficient, easily fabricated in controlled conditions driven by 3D modeling and CNC equipment, test certificate is always available here

Reducing onsite risks: Less number of the workers onsite where approximately 10-20 per cent is necessary for concrete connection reducing the accident liability.

Sustainability and waste reduction: The waste clearance is considerably less than for a concrete building here. More than 95 per cent of all structural steel is recoverable and reusable or recycled.

The most popular and common construction structural material Timber, Steel and Concrete has their own pros and cons. But the industry experts have also their own opinion about it.
Image Courtesy: sourceable.net

The Metropol Parasol in Seville, Spain

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Published By
Rajib Dey
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