Concrete Construction Flashcards
Before placing concrete, you should inspect all supporting members because wet concrete will always exert what type of pressure on them?
Hydrostatic
Nailing requirements must comply with directives?
Plans and specifications
Supervisors should inspect all forms before and after each pour.
True
When working with concrete, personnel should wear gloves and protective goggles and have their shirt sleeves rolled down to prevent what hazardous results?
Cement poisoning (lime)
When working with concrete, personnel should stand with their backs to the wind to prevent cement and sand from being blown into their eyes.
True
What term is used to refer to a temporary structure that can support its own weight and that of freshly place concrete, as well as the weight of materials, workmen, and equipment imposed upon it?
Formwork
As a supervisor of a form building crew, you should consider what factors as your principal objectives?
Economy, quality, and safety
Formwork may represent as much as what percentage of the cost of a concrete structure?
33%
Concerning formwork, in what areas will good judgment and ingenuity on the part of the supervisor help reduce costs?
- Selection of materials and equipment
- Planning fabrication and erection procedures
- Scheduling reuse of forms
Forms must be designed to meet what weight factor?
Total weight to which they may be subjected
Earth, metal, lumber, plywood, and fiber are the most commonly used types of form material.
True
The majority of all formwork involves concrete. Concrete ways a total of how many pounds per cubic foot?
150
For each inch of slab thickness, concrete slabs place a total load of how many pounds per cubic foot on the formwork?
12.5 pounds per square foot
In pounds per square foot of horizontal projection, what is the minimum recommended construction live load provision for the weight of crewmembers and equipment?
50
When powered concrete buggies are used in concrete operations, what is the minimum construction live load recommended for use in PSF?
75
What bracing technique is most often used to brace forms against lateral pressure?
Nailing a diagonal member and a horizontal number to a stud or wale with the diagonal member at a 45° angle to the horizontal number
Which of the following factors does not have an affect on lateral pressure?
Sulfate content
You have been given the assignment of determining the maximum concrete pressure for a form. The rate of placement is 5 ft./h and the temperature is 70°. What is the maximum concrete pressure for the form in PSF?
800
To determine the uniform load on a stud, you multiply the maximum concrete pressure by the maximum stud spacing. Then, by dividing the result by 12, you convert the answer into what unit of measurement?
Pounds per linear foot
To determine the time required to place concrete, you divide the height of the form by the rate of placement.
True
Braces are used against wall forms to protect from mishaps due to external forces. The value of the external force is estimated to be how many times the wall height in feet?
12.5
Designing wall forms and the bracing for them should be the responsibility of what person?
Project engineer
What is the first step in designing wooden forms for a concrete column?
Determine the materials available for sheathing, yolks, and battens.
In which of the following forms may reinforcing steel be used?
Bars or rods
To calculate manpower estimates, you must first estimate what factor?
Square footage of contact surface (SFCS)