Plant Tour Video

Summary

This video outlines the complete process of producing pre-stressed concrete double tees, primarily used in parking structures and various buildings. It details the steps from cleaning forms and setting up for casting to mixing concrete and tensioning strands. Quality control checks are emphasized to ensure high standards, including pre-pour inspections and post-pour evaluations. The video also highlights the advantages of using self-consolidating concrete and the importance of precise curing and assembly for structural integrity. Ultimately, it showcases the diverse applications of pre-stressed products and the commitment to quality in the precast concrete industry.

Takeaways

• 🏗️ Double tees are a type of pre-stressed concrete unit primarily used in parking structures and can span lengths of 60 to 120 feet.
• 🧹 Maintaining a clean prestressing plant is crucial for safety and efficiency, preventing tripping hazards and ensuring a positive image.
• 🔧 The setup for casting involves thorough cleaning and preparation of forms, which may include fixed forms or forms between bulkheads.
• 🔗 Steel strands are carefully placed and tensioned within the forms, ensuring proper spacing and alignment for optimal strength.
• 📏 Quality control checks are essential throughout the process, including measuring elongation of strands to ensure tension levels meet specifications.
• 🧪 Self-consolidating concrete is used for double tees, which simplifies placement and reduces labor strain, while minimizing air bubbles.
• 🌡️ Curing methods vary; in cold climates, tarps may be used, and accelerated curing methods like live steam can be employed.
• 🔪 After curing, the strands are detensioned in a specific sequence to avoid damage, allowing the double tees to be stripped from their forms.
• 🔍 Post-pour quality checks ensure that dimensions and visual appearances meet standards, allowing for necessary repairs before shipping.
• 🚛 Completed double tees are stored and transported to job sites, highlighting the importance of precise production to ensure structural integrity.

Q & A

What is the primary use of double tees in construction?

Double tees are primarily used in parking structures but can also be utilized in various building types, including office buildings, industrial buildings, and schools.

What lengths can double tees span?

Double tees can span lengths of over 60 feet and sometimes as much as 120 feet.

Why is maintaining a clean plant important in prestressing operations?

Maintaining a clean plant is crucial for safety and image; debris can create tripping hazards and other safety issues.

What is the significance of the pre-pour quality control check?

The pre-pour quality control check is critical to ensure the highest quality of the final product by verifying the condition of materials and the setup of forms.

How is concrete mixed and delivered to the forms?

Concrete is mixed in a batch plant under controlled conditions and delivered using specialized vehicles called Tucker's, ensuring timely placement in the forms.

What type of concrete is used for casting double tees, and what are its benefits?

Self-consolidating concrete (SCC) is used for casting double tees. Its benefits include reducing labor needs, minimizing the potential for air bubbles, and providing a better finish.

What measures are taken to prevent plastic shrinkage cracking during concrete curing?

An evaporation-reducing spray is applied to the surface of the concrete to minimize the potential for plastic shrinkage cracking.

What does the quality control department check during the concrete placement process?

The quality control department checks the temperature of the concrete, conducts a spread test to check flow consistency, and monitors for segregation and air content.

What steps are involved in the detensioning process of the strands?

Strands are detensioned in a specific sequence established by the QC department, with personnel positioned at each end of the bent and at some intermediate locations.

What happens to the double tees after they are stripped from the forms?

After being stripped, double tees are inspected for defects, undergo minor cosmetic touch-ups, and are then moved to a storage area until they are ready to be shipped to the job site.