Problem 1 (10 points)
Draw a concrete pressure diagram for a column form 20 feet tall that will be placed at a rate of 7 ft/hr. The mix design indicates the concrete having a density of 145 lb/ft3, a slump of 4 inches, temperature of 60°F, and is made with a cement blend containing 30% slag. Indicate the dimension of the hydrostatic load zone (fluid pressure height) on your diagram. If we changed the concrete pour rate to 25 ft/hr, what would be the new concrete lateral pressure?
Problem 2 (15 points)
Review the report published by the FHWA Links to an external site.that describes in detail the Maryland Route 198 Bridge Collapse incident that occurred in 1989. In your own words, describe the formwork/falsework components that failed and resulted in the catastrophic failure of the bridge. What were two major initiatives that occurred as a result of this bridge collapse incident?
Link:
Problem 3 (25 points)
Design a concrete formwork system for a 12-ft tall wall with a length of 40 ft and thickness of 6 inches. Follow the same design method covered in Lecture 6. Your submitted design should focus on the safety and quality aspects over the form costs. Your solution should summarize the type and size of materials chosen for the form components and should state their on center spacings.
Use the following conditions:
General Conditions
- You will be using new construction materials to assemble this formwork.
- You have Douglas Fir-Larch No. 2 Grade dimensional lumber of all sizes available for use for the stud and wale material.
- You are limited to using only 3/4″ thick B-B Plyform Class 1 plywood for the sheathing material.
- You have flexibility on using any type of ties available. You can search for concrete form ties from any vendors online. Here are some suggestions:
Load Properties:
- Concrete unit weight: 153 lb/ft3
- Pour rate of 4 ft/hr and temperature of 60 degrees F
- Does not contain any supplementary cementitious material or admixtures
