Hardscape Structures Flashcards
What are the preferred gradients for walkways? Widths of walkways?
Shouldn’t exceed 5% (5 ft rise over 100 ft run), 3% is preferred. 5-8% are considered ramps and need a 5ft landing every 30 ft. Cross slops should be less than 3%.
Widths: 48” min for public with 72” preferred. 36” min for wheelchair use.
Steps: Exterior risers 4.5-6”, 12-18” treads. All should be the same.
What is meant by compression strength and tension strength of concrete?
Compression is two objects pushing against each other. Concrete is great at that. Tension is pulling apart and rebar is good at that. Together they can resist bending movement and concrete gets it’s strength from both working together.
Describe the differences between control joints , construction joints and expansion joints in concrete.
Construction joints are what’s made between two unique and separate pours. Control joints are joints within a pour that are purposely placed to provide a weak point in the concrete to break and expansion joinst are placed next to a fixed object such as a column or shaft so that the slab can move independently of the fixed object.
What is asphalt concrete? What are its advantages?
Made out of tar and gravel it’s more flexible and cheaper than concrete.
What is meant by curing of concrete?
Portland Cement and water interact to create a chemical reaction which gives concrete it’s strength. As this reaction occurs and the concrete sets it is called curing. Typically done to full strength at 28 days. Usually during this process the top surface should stay wet using moisture or a chemical compound sprayed on the surfacd.e
What are some types of precast pavers?
Brick, Concrete, Asphalt, Open Celled, Natural Stone
What is the most common type of wood used for exterior landscape construction in our area?
Southern Yellow Pine
In Deck Construction, what is meant by a platform system with grab beams?
The joists attach to the sides of the poist, essentially pinching or grabbing the post.
Why should deck planks always be installed bark side up?
So that the board don’t cup over time.
Define the following: Stringer, treads, ledgers, cleats.
Stringers support the treads of the stairs. Treads are the part that you step on. Ledgers would span the stringers or attach to the side of stringers which the treads then rest on and Cleats hold the steps out forward of the stringer.
Describe various ways retaining walls may fail.
Tipping, Crushing, sliding
What are three types of retaining walls?
Gravity, Cantilever, Timber
