METHOD STATEMENT FOR PRECAST AND PRESTRESSED

METHOD STATEMENT FOR PRECAST AND PRESTRESSED 

The under-discussion topic for today is the method statement for the precast and prestressed work uploaded by qhse documents in free and editable reedy to use format. to download more health and safety various documents such as risk assessments, method statements, safety inspection checklists, safety forms, procedures and safety guidelines, keep visiting my site at qhsedocuements:

1. Purpose

This method statement aims to describe the procedure that will be adopted for the erection of Precast and Pre-stressed Concrete Elements. The process includes detailed design, workshop drawings, Sequence of work, Quality Control System, Tolerances, Risk involved and risk controls, and Housekeeping, to be adopted during the erection of Precast and Pre-stressed Concrete Elements.

2. Pre-construction activities

Before commencing, the precast subcontractor shall obtain the necessary approval for the subcontractor/applicator and their proposed material. 

1. Make sure that the proper approvals for the detailed shop drawings for the sub-structure regarding the raft foundation/base with all related other required and provided drawings. 
2. Also, make sure that this work method is essentially approved by the Consultant accordingly 

3. Safety risk assessment in the precast/pre-stressed concrete industry

Large numbers of people work every day in the precast/prestressed industry. The products designed on the plant are very useful as they are used for low and mid-rise apartment buildings, hotels, beams, piles, railway sleepers, bridges, and so on. Due to the design and nature of the products, employees are occasionally exposed to hazards. The industry recognizes risks and tries to mitigate them by investing money and time into safety. The employer not only needs to design the training to help employees follow safety procedures, but the training methods should be equally cost-effective and effectively engaging. The risk and loss that occur with risk depend on the level of hazard and how it can be avoided. The goal of quality and safety management is to stop the occurrence of accidents, requiring them to take initiative to prevent accidents from occurring.

The initial methodology to make sure that safety practices are followed is to organize different pieces of training and workshops to help employees stay safe and avoid hazardous incidents. OSHA has provided strict guidelines to various employers to manage operational safety in the concrete manufacturing industry. While management is developing a plant safety management plan, the risk assessment is conducted using the following five steps: 

The first step includes setting up a multidisciplinary task force. This step helps to promote general understanding between all departments. 

The second step is to identify hazards. All task force members are given a tour of the plant during working hours, which helps them experience and understand hazardous communications. 

After this step, they are asked to identify hazards in the plant. This step is followed by the determination and likelihood of the risks. The severity of the risk is classified into three general categories: minor, moderate, major (ranging from 1 to 3 respectively)

The likelihood is classified as remote, occasional, and frequent (ranging from 1 to 3 respectively). The total risk is equal to the work/product of severity and likelihood. The risk factor ranges from 1 to 9, where 1 to 3 is low to moderate, 4 to 6 is moderate to severe, and 7 to 9 is severe to extreme. 

The fourth step plans for safety management. This step decides and modifies the control measures. 

And for the last step, the process will be implemented and imposed. However, this process is not a one-time effort as it needs to be done repetitively. Accordingly, workers are re-trained after a certain amount of time. This process also includes employee feedback, which benefits the training plan with continuous improvisation and that will lead to a decrease in the accident rate.

4. Construction activity

General

1. The Erection of the PPC elements shall be accomplished by a Mobile crane with recommended and sufficient lifting capacity. 
2. PPC elements shall be lifted appropriately and safely from the lifting anchor provided. 
3. The essential, equipment, tools and lifting sling and a safety device shall be used for lifting. 
4. Before proceeding to the erection of the PPC and other objects/materials, a survey of the working area to get Precast/prestressed concrete (PPC) parts shall be accomplished to observe and monitor carefully for any difference in dimensions or levels beyond the tolerances.  
5. Precast/prestressed concrete segments will inspect before the erection by the subcontractor Erection Engineer /Supervisor and Engineer.

Transportation and delivery to site.

1. Precast/prestressed concrete elements shall be transported and shifted to the worksite only after the Quality Control department/personal final inspection and Approval. 
2. Precast/prestressed concrete Elements shall be transported to the site on a flatbed trailer, Low bed trailers and “A” frame trailers are generally standard 12 -15-meter length. Elements will be supported over the trailer by a special belt or steel chain fixed to the trailer. The wooden wedges/polystyrene bottom and side support will be provided to eradicate breakages if needed.
3. Various material shifting techniques and sources such as Loading, transportation & offloading work shall be accomplished with great care to avoid and minimize any major destruction and or deterioration to the precast structure and objects
4. Offloading and loading of panels should be done using a suitable mobile crane and elements shall be stacked in steel racks as per standards.       
5. Suitable lifting devices/sling/equipment will be used for loading and off-loading the elements. Crane will be used for loading and off-loading the Precast/prestressed concrete Segments. The capacity of the crane shall be decided depending on the weight of the elements and boom length required. 
6. Barricades are to be provided and signboards are to be placed in lifting to avoid unauthorized personnel entering the lifting area.
7. While the Precast/prestressed concrete elements are being lifted for loading or off-loading, a proper signboard will be kept if the operation time is more, or a competent person will be advising, educating and inducting the visitor or public away from the crane boom. 
8. If Precast/prestressed concrete Elements are stored at the site, they should be as close as possible to the crane to avoid double handling. 
9. The access road should be prepared by the main contractor to receive trailers transporting the Precast/prestressed concrete units. 
10. All the precast Precast/prestressed concrete Elements will be delivered to the site as per the sequence required to ensure continuous erection.  

Field survey

1. A field survey and stakeout of the existing cast in situ dimensions will be performed to permit accurate placement of Precast/prestressed concrete elements. 
2. Make sure that before the erection of Precast & prestressed concrete (PPC) elements is started, the project surveyor will observe and verify by correct field measurements as per the drawing, location of bearing pads, M&E-related service accessories etc.  
3. The exact position of all works will be established by the main contractor from control points, which are shown on the panels and in conjunction and as agreed with the Engineers surveyors
4. All grid lines should be given to the primary contractor for each zone and benchmark level.  
5. A proper careful and authentic survey also should be conducted for the dowel bars connecting the panels to the slabs appropriately. 
6. The level of slabs or rafts should be within the tolerance (zero gaps to the max of 30 mm between panels & slab and rafts), if exceeds special materials shall be used. 
7. All calculations and drawings mandatory to develop the correct positions of the work will be tidily made and will be readily available to the project or site Engineer for review and approval. 

Scaffolding and temporary work

1. Precast elements before and upon placing in their final position, will be securely supported and anchored. If necessary, suitable, and safe working platforms will be provided in all locations required to allow a clear and easy approach for the workers to produce quality connection details. 
2. The scaffolding erecting will be carefully inspected, observed, and coordinated with the primary contractor to make sure accessibility to other areas of work. 
3. Scaffolding will be used mainly for the temporary support or alignment of the panels or in case of grouting finishing or elements fixing. 
4. Ladders may be used in some conditions (ex-Grouting, etc.) to assure easy access, especially inside small rooms.  

5. Erection

Erection of precast column of foundation

1. Typical sketch for lifting &erection of precast column in attached Lifting and Erection drawings.
2. Cast-in-situ piles/foundation shall be accomplished as per the approved layout & drawing. Starter bar diameter and location shall be as approved drawing.
3. The precast column will be placed on the Cast-in-situ piles/foundation, (T20 dowel from CIS foundation will be inserted into 50 mm corrugated hole pipe of precast concrete element)
4. While the precast column is erected it shall be supported by push-pull prop jacks as per the attached propping design.
5. PPC Column alignment shall be done, and line, level, verticality, and straightness shall be kept as per the approved erection design and or layout.
6. Grout the 50mm corrugated hole pipe with approved non-shrink grout.  
7. All exposed areas should be completely stable and stronger in an accepted and approved way.  

Erection of precast beam

1. Typical sketch for lifting & erection of Precast column& beam in attached Lifting and Erection drawings.
2. The precast beam will be placed on the precast column as per the attached propping details &design.
3. Alignment of the beam shall be done to maintain the line, level, straightness, and verticality.
4. Cast in-situ steel reinforcement shall be provided as per the approved steel reinforcement drawing.
5. Apply the concrete to balance the portion of the beam. 
6. The grade of concrete strength shall be as per the project specification for the superstructure.
7. Curing shall be continued as per the project specification/standards.  
8. Erection of slab (hollow core/ form slab).
9. Typical sketch for lifting &erection of slab in attached Lifting and Erection drawings.  
10. Hollow core Slabs will be placed on beam CIS retaining wall corbel as per the attached details & design.  
11. Precast form slab will be placed on precast beam as per attached propping details &design. 
12. Maintain the minimum bearing as per drawings & design.
13. Alignment of the slab shall be done to maintain the line, level, straightness, and verticality.  
14. Cast in situ Steel reinforcement shall be provided as per the approved steel reinforcement drawing and below connection details.  

Apply the concrete to the topping of the Slab

Make sure that the grade of concrete strength shall be as per the project particularizations, recommendations, and requirements for the concrete superstructure. 

Curing shall be continued as per the project specification/standards.  

6. Repairing

Repairing works for any well-known defects in precast /prestressed concrete elements shall be accomplished using authorized restoration materials or any system-authorized fabric. Repairs could be completed in line with the manufacturer's guidelines.

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