Stability of Structures
What does it mean for something to be stable?
What is...
"the ability of a structure to remain in or return to a stable, balanced.
What is a Beam and how can it be strengthened?
What is...A beam is a horizontal structure that supports a load. A beam can be strengthened by: 1. Adding supports underneath (like columns or trusses) 2. Using stronger materials (like steel or reinforced concrete) 3. Changing the shape (e.g., using an I-beam to resist bending better)
What is an arch? Why are they used?
What is...An arch is a curved structure o# en used to support loads. It's curved design transfers compression force downward
The collapse of the Tacoma Narrows Bridge in 1940. Strong, steady wind created unusual vibrations that the bridge design couldn’t handle. The wind acted as a______________, causing the bridge to sway violently and eventually collapse.
What is...extraordinary load.
The Beam: What is a strut and a tie? What is the difference between the two? Provide an example of each.
What is...1. A strut is a part that resists compression (pushing forces). EX: A leg of a table or the angled support under a bridge.
2. A tie is a part that resists tension (pulling forces). Example: The bottom bar of a roof truss or a cable on a suspension bridge.
They work in opposite ways.
What do designers need to find to determine if a structure is stable?
What is...The centre of gravity?
What is an I-Beam? What is an example structure it is used in?
What is...a beam that is in the shape of the letter “I” when seen from the end. EX. Industrial Buildings
What is a Truss? How is it connected to the creation of a cantilever?
What is...A truss is a network of beams that form triangles. A truss can be used to support a bridge or a cantilever.
The Quebec Bridge in Canada partially collapsed during construction in 1907. The bridge was built on soft riverbed soil that couldn’t adequately support the massive weight of the bridge. Combined with design miscalculations, the foundation couldn’t hold the structure’s load. What structural failure is this?
What is...Foundation failure.
Domes and Arches: What is one way arches and domes are similar? What is one way they are different?
What is...Arches and domes directs compression force downward. Where as arches compress in one plane of application where as a dome has many planes at once.
What are the two characteristics needed for a structure to have an maintain most stability?
What is...Objects with a low centre of gravity and wide support base tend to be stable.
What is a cantilever? What is an example in your community? Draw it correctly on the board.
What is.... a beam that is supported, or fixed, at only one end. EX. Street sign.
What is a dome? Why is it considered a series of arches?
What is...A dome is a structure that looks like the top half of a sphere or an egg.
You could consider a dome to be a series of arches that have been connected at a centre point.
The Hyatt Regency walkway collapse in Kansas City in 1981. The design of the walkways suspended over the hotel lobby was changed during construction, without properly recalculating the load distribution. The new design placed too much weight on a single connection point, which wasn't strong enough to support it. During an event the walkways collapsed, tragically killing 114 people. What structure failure is this an example of?
What is...bad design.
Stability of Structures: Why must large structures be built with stronger materials?
What is.. They need to be more durable, able to support heavy loads and resist natural forces like wind and earthquakes at great heights. Strong materials provide the necessary strength and stability for tall, large structures that materials like wood cannot safely handle.
A race car is designed to travel at very high speeds around sharp turns. What design feature helps make the car more stable and less likely to tip over?
What is...A wide heavy bottom with a low centre of gravity.
What is Rebar? How is it used to strengthen concrete?
What is... Steel reinforcing bars that are placed in the concrete to help it resist the forces of tension. Concrete that contains rebar is known as “reinforced concrete” and is able to resist both compression and tension
What are 2 advantages of using a truss in a structure?
What is...1. In a truss, forces are distributed between the points of the triangles that make up the truss. The triangles help the structure support more weight. 2. Trusses can be bent or curved and still retain their strength
The Rana Plaza collapse in Bangladesh in 2013. The building was originally designed for fewer floors, but additional floors were added without proper engineering approval. Poor-quality concrete and steel were used, and cracks were noticed the day before the collapse. This disaster highlights how ignoring building codes, overloading structures, and using poor materials can cause catastrophic failure. What structural failure is this an example of?
What is...faulty construction.
Stability and Structures: A zookeeper is designing a large enclosure for giraffes that includes artificial trees. To ensure the tall structures do not tip over in the wind, what should the zookeeper do?
What is ...the artificial trees that are planted should have a larger and wider base and should be heavier so that they can withstand different types of weather conditions.