It is important to understand that each project is unique and with this, requirements for architectural concrete solutions need to be customised and matched to each concrete element and to the requirements of each structure. Helping support in the selection process, the greatest results arise from close collaboration amongst all stakeholders involved in the construction process – from contractors to architects and also the formwork supplier.There are various types of concrete surface finishes achievable and which can be considered for those working with in-situ solutions specified by the building stakeholders. There are various types of concrete surface finishes achievable and which can be considered for those working with in-situ solutions specified by the building stakeholders.
Formwork is a temporary structure that supports part or the whole of a permanent structure until it is self-supporting. Individual components of formwork, for example frames, are plant. Once assembled the components form the temporary structure. Some formwork systems are designed to remain with the permanent structure. Generally work carried out to design, construct, erect, alter, maintain, dismantle or remove formwork will be defined as construction work. Formwork means the surface used to contain and shape wet concrete until it is self-supporting. This includes the forms on or within which the concrete is poured and the frames and bracing which provide stability. Although commonly referred to as part of the formwork assembly, the joists, bearers, bracing, foundations and footings are technically referred to as falsework.
A safe practice for formwork during construction at site is important for safety of workmen. Improper erection of formwork can cause damage to structural elements as well as pose a threat to the safety of workmen. Given below are good practises that need to be maintained for safer formwork construction.
Abide by the formwork Code of Practice
The Formwork Code of Practice is to give hands-on guidance about ways to manage the formwork in terms selection of materials, design, assembly, and dismantling procedures and mitigating / informing the risk associated with that and also to minimize failures. Because failures or unsafe formwork practice will cause financial losses, accidents some time which involves fatal, time loss etc. Certainly the losses in time and money that go along with construction mishaps are strong motivators for safe activity.
A code of practice applies to anyone who has a duty of care in the circumstances described in the code. In most cases, following an approved code of practice would achieve compliance with health and safety duties, in relation to the subject matter of the code. Like regulations, codes of practice deal with particular issues and do not cover all hazards or risks which may arise.
In accordance with the Factories Act 1948, an occupier of an establishment has to ensure the health, safety and welfare of all workers while they are at work in the factory.
It is obligatory for an employer/occupier to ensure the provision and maintenance of plant and systems of work that are safe and without health risks. Arrangements should be made to rectify risks involved in use, handling, storage and transport of articles and substances.
The establishment should be monitored to check the quality of the premises; cleanliness; disposal of wastes and effluents; ventilation and temperature; dust and fume; artificial humidification; overcrowding; lighting; clean drinking water; latrines and urinals; and spittoons.
Safety of the worker must be ensured by installing and maintaining the machinery, mechanisms, transmission apparatus, tools, equipment and machines in the best possible safety conditions. Tools, equipment, machines, or products used must be organized properly guaranteeing the safety of workers. The employer is obliged to take care to protect the worker’s health and safety by providing the means of rescue, first aid, and the cleanup; and arrangements and organization of the workplace health and safety duties require duty holders to consider all risks associated with work, not only those for which regulations and codes of practice exist.
Construction work inclusion for the formwork Code of Practice
Formwork design whether it is Simple or complex requires certain information prior to commencing of design. It is also the responsibility of the formwork designer to ensure that he has all relevant input to complete the schemes and the design. In case of any missing details, the same has to be sought from the relevant person. Most of the branded system formwork companies before submitting quotes or before preparation of schemes & design will have a format to be filled by the contractor / client containing project details etc.which are required as Input.
A good practise in formwork should adhere to the following-
- installation or testing carried out in connection with an activity referred to in the definition the removal from the workplace of any product or waste resulting from demolition
- the prefabrication or testing of elements at a place specifically established for the construction work, for use in construction work
- the assembly of prefabricated elements to form a structure, or disassembly of prefabricated elements forming part of a structure
- the installation, testing or maintenance of an essential service for a structure
- work connected with an excavation
- work connected with any preparatory work or site preparation including landscaping as part of site preparation carried out in connection with
- an activity referred to in the definition above, and an activity referred to in the definition carried out on, under or near water including work on buoys and obstructions to navigation.
Safety provision for the formwork Code of Practice
A person conducting a business or undertaking has the primary duty to ensure, so far as is reasonably practicable, workers and other people are not exposed to health and safety risks arising from the business or undertaking. This duty requires the person to manage risks by eliminating health and safety risks so far as is reasonably practicable, and if it is not reasonably practicable to eliminate the risks, by minimising those risks so far as is reasonably practicable.
It also includes ensuring-
- so far as is reasonably practicable design, provision and maintenance of safe formwork plant and structures
- safe erection, alteration, dismantling and use of formwork, and
- safe use, handling, storage and transport of formwork plants.
Designers, manufacturers, suppliers and importers of plant or structures, including temporary structures, must ensure, so far as is reasonably practicable, the plant or structure is without risks to health and safety. This duty includes providing information to manufacturers so that plants can be manufactured and erected to the design specifications. Designers must give the person who commissioned the design of the temporary structure a written safety report.
People installing, constructing or commissioning plants or structures must ensure, so far as is reasonably practicable, all workplace activity relating to the plant or structure including its installation, use, decommissioning or dismantling is without risks to health or safety.
Officers, such as company directors, have a duty to exercise due diligence to ensure the business or undertaking complies with the WHS Act and WHS Regulation. This includes taking reasonable steps to ensure the business or undertaking has and uses appropriate resources and processes to eliminate or minimise risks from the formwork activity.
Managing risks in formwork activities
Control measures to manage the risk of falls must be implemented in an order of priority and implemented before work commences. In many developed countries, risk management is considered important for all hazardous industries like construction. It is mandatory for all workplaces, and is enforced strictly for high-risk activities such as work at height. Accident investigations by the Ministry of Manpower (MOM) often highlight the absence of or inadequate risk assessment as a cause.
- To properly manage risks, a person must:
- identify hazards – find out what caused the harm
- assess risks that may result because of the hazards – understand the nature of the harm that could be caused by the hazard, how serious the harm could be and the likelihood of it happening
- decide on control measures to prevent, or minimise the level of, the risks and implement control measures, and
- monitor and review the effectiveness of the measures.
The risk assessment should look into the following areas, but not limited to: – Formwork structure erection, alteration and dismantling procedures, – Base support capacity; – Formwork structure stability – Placement of rebar; – Concrete casting; – Working at height; – Monitoring of formwork; – Formwork leakage; – Formwork structural failure; – Settlement of formwork structure; – Repair of formwork structure; – Emergency escape route; and – Emergency response plan.
All reasonably practicable steps shall be taken to eliminate any foreseeable risk arising from the work to be done. Where it is not possible to eliminate the risk, control measures and safe work procedures shall be implemented to minimise and control the risk.
Consultation involves sharing of information, giving workers a reasonable opportunity to express views and taking those views into account before making decisions on health and safety matters. Consultation with workers and their health and safety representatives is required at each step of the risk management process. In many cases decisions about construction work and projects are made before engaging workers so it may not always be possible to consult with workers in these early stages. However it is important to consult with workers as formwork activities progress. By drawing on the experience, knowledge and ideas of your workers you are more likely to identify hazards and choose effective control measures. You should encourage your workers to report hazards and health and safety problems immediately so the risks can be managed before an incident occurs and you must consult your workers when proposing any changes to the work that may affect their health and safety.
Design of formwork structure
All formwork structures (including but not limited to beam, slab, wall, column, cantilevered, curved and sloped formwork) shall be capable of withstanding the total dead load, live load and impact load imposed on it with a minimum safety factor of 2.
A Professional Engineer shall be engaged to design a formwork structure that is: – supporting a slab or beam to be cast that is greater than 300 mm thick; – greater than 9 m in height; or – constructed in 2 or more tiers.
The Professional Engineer who designs the formwork structure shall take, so far as is reasonably practicable, such measures to ensure that his design can be executed safely by any person who constructs or uses the formwork structure according to his design. The Professional Engineer’s design should include the following considerations, but not limited to: – Vertical and horizontal formwork components; – Bracing members; – Connections; and – Support on which the formwork rests. The formwork design should encompass all sides, corners and bends supporting the concrete to be cast. Bracing and coupling details should be provided in the design to ensure clarity.
The Professional Engineer who designs the formwork shall also provide to any person constructing the formwork structure all design documentation, including all relevant calculations, drawings and construction (erecting, dismantling and reshoring) procedures to facilitate the proper construction and dismantling of the formwork structure according to his design.
The drawings of the formwork structure should also include the safe means of access7 and escape routes for workers involved with the formwork structure. These should be clearly shown on the drawing plan.
Every responsible person undertaking any work including erecting/dismantling the formwork structure, installing steel reinforcement or concreting works is reminded to conduct a thorough risk assessment on his work processes and implement the necessary preventive measures to ensure that his undertaking can be and is carried out safely. Formwork structures are to have suitable edge protection to prevent formwork and concreting workers from falling from height. Measures to prevent falling from height as highlighted in the Fall Prevention Plan are to be implemented. Where a formwork structure is designed by a Professional Engineer, placement of concrete shall not commence unless the formwork structure, including any alteration thereto, has been inspected and certified safe for its intended use by a Professional Engineer.
During concreting, the formwork system should be regularly monitored by the formwork supervisor for movement, stability and soundness. The formwork supervisor and any other workers should not work under or in close vicinity of the formwork structure while the pouring of concrete is in progress. Proper risk assessment shall be conducted to ensure that the formwork supervisor watching the formwork is not exposed to the risk from formwork structure collapse.
If, during concreting, any weakness develops and the formwork shows any undue settlement or distortion, all work shall be stopped immediately. Prior to the commencement of any adjustment, strengthening or repair works, a thorough assessment of risk shall be conducted and all necessary measures to be taken to ensure that workers will not be exposed to risks from formwork structure collapse
Information, training, instruction and supervision
All persons who may be exposed to work health and safety risks resulting from formwork construction must be provided with information and training that is specific to the formwork system that is being used. Such training and information should include details of: the formwork system, tasks, activities and components the way the manufacturer or designer of the formwork system intended the system to be erected, installed, used, moved, altered or dismantled specific training and information required to undertake or participate in specific tasks or activities control measures to minimise exposure to the risks, correct use of controls, and how to ensure they are kept in full working order safe working procedures, including the use of mechanical aids and devices, where appropriate how to use and maintain equipment, including any specific conditions and prohibitions on the use of equipment. Reference must be made to operator’s manuals any special safety information needed such as safety precautions for working under certain conditions personal protective equipment required, including instruction in fitting, use, cleaning, maintaining and storing this equipment details of how accidents have occurred in the past involving the same work process.
Persons involved in formwork activities must also be provided with more general work health and safety information and training including: the effects of noise on their hearing and health Queensland’s work health and safety legislation, including relevant parts of this code of practice the workplace’s health and safety policies, and relevant procedures and safe work method statements the risk management process inspection and maintenance programs in place at the workplace how to access information such as manufacturer’s instructions about hazards emergency procedures, including persons with specific emergency roles and responsibilities.
Erection of Formwork Structure
The Occupier shall ensure that every formwork structure shall – be of sound material, good construction and adequate strength; – be free from patent defect; – be suitable and safe for the purpose for which it is intended; and – be properly braced or tied together so as to maintain position and shape.
Formwork components used to erect the formwork structure shall be of good condition and free from corrosion. As the structural capacity of the formwork structure is expected to be reduced over time, for example due to corrosion, Occupiers may consider, as an additional safety precautionary measure, conduct a load test (in the testing laboratory) to verify the design assumptions of the strength of the formwork structure and their supporting bases, especially for casting of significant structures. Couplers used for bracing and tying the formwork structure together shall be fit-for purpose, ie. right-angled couplers used for perpendicular members and swivel couplers used for bracing. Using the wrong components could reduce the structural capacity of the formwork structure.Responsible persons shall establish and implement a Fall Prevention Plan to ensure that their workers who are erecting and dismantling formwork structures are prevented from falling from height. Measures may include provisions of safe work platforms with proper guard-rails and personal fall arrest system, complete with safe and secure anchorages. Where it is a requirement for a Professional Engineer to design a formwork structure, the formwork structure shall be constructed in accordance with the design and drawings of the Professional Engineer.
No alteration shall be made or allowed to be made to a formwork structure designed by the Professional Engineer unless its design and drawings have been reviewed and endorsed by a Professional Engineer. After erection, the Professional Engineer appointed by the Occupier to oversee the construction of the formwork structure, shall take so far as is reasonably practicable, such measures as are necessary to ensure that the formwork structure – is constructed in accordance with the design of the Professional Engineer who designed it and is safe for its intended use when completely constructed and if so, issue a certificate stating that the formwork structure is safe for its intended use.
Dismantling of formwork structure
A formwork structure should only be dismantled after the concrete has sufficiently set and after a period of time as determined by the Qualified Person. The manner of dismantling a formwork structure should be in accordance with the Professional Engineer’s dismantling procedures, taking into account that the formwork structure could be unstable during dismantling.
The Construction Industry is a multifaceted industry, characterized by a broad range of high risk activities and complex work arrangements. The inherent risks in the building and construction industry makes it one of the priority areas for providing a safe environment for Contractors, subcontractors and their workers to face risks from hazards that must be managed to prevent deaths, injuries and illnesses.
As already stated earlier, Formwork is an important activity which needs to be given major attention when it comes to Safety during Construction. Even though the safety and construction is the responsibility of the builder or contractor, it is necessary that formwork designs and drawings are reviewed and approved. In these cases, the contract document shall clearly specify that the designs and drawing of formwork will be reviewed and approved by the Engineer – In-Charge. In order to bring the standard of constructions in India to International levels, the consultants should specify, systemise and implement the right formwork system for the projects and also the standardization body of India also to look to bring in more detailed Code of Formwork practice in India to suit the available materials / system and formwork practices in India.
Source – scribbd, wshc.sg, worksafe.qld.gov, thenbs.com, acchelp.in, ihsti.com,iijrte.com
Image Source – wshc.sg, worksafe.qld.gov, thenbs.com, acchelp.in, iijrte.com, ihsti.com, metsawood.com, formworkscaffoldingsystems.com, mevaformwork.com, concrete.org.uk, paschalindia.com, cassaform.com.au, directindustry.com.