Civil Engineering

"The limitations of architecture in the past were created by a lack of _____. A. Knowledge regarding architectural design B. A need for larger structures C. Materials that were both light and strong D. The machine-power needed for heavy-lifting."

C. Materials that were both light and strong

"A beam where one of its ends is fixed so that it cannot rotate at that point `

Cantilever beam

Why are composite materials used?

Composite materials are chosen for components because of the weight it saves for its relative stiffness and strength.

"How is plasticity useful? A.) It helps keep buildings perfectly rigid so they don't moved when put under stress or pressure B.) It is never useful C.) It helps a structure return to its original form after being stressed D.) It can indicate when a structure is reaching its maximum capacity or in danger of falling"

D

"If an elevator cable originally 300 ft long (3,600 inches) becomes 4 inches longer under a load, what is its strain? a.) 4/300 b.) 4*3,6000 c.) 4*300 d.) 4/3,6000"

D

"In an office building, a live load that the building must support would be... a)The extremely heavy printer that is dropped on the floor accidentally b)The structure's own weight c)The large, heavy air conditioning vents d)The employees that go in and out of the building"

D

"What kind of load has the biggest risk to a structure? a) Static load b) Dynamic load c) Dead load d) Live load"

D

What are "dead loads" and why do they matter when constructing a building?

Dead loads are columns, beams, floors, domes, and essentially and member of a structure that holds up the shape of the building. Without dead loads structures could not stand because there would be nothing supporting them.

consists of two weaknesses which leaning one against the other make a strength. a structure that spans a space, and supports structure and weight above it. They are all compression

arch

A load of 200 pounds would cause how much deflection compared to a load of 100 pounds? a) the same amount b) two times more c) two times less d) four times more"

b

In comparison to ancient architecture, modern architecture is more a.)more expensive b.)lighter c.) made of the same materials as ancient architecture d.)up to 10x larger on average

b lighter

"""the load (in pounds force or Newtons or kilograms force) which will just break the structure"" (Gordon 55) ""load which causes fracture in a tensile, compression, flexure or torsion test""

breaking load

"""The bending of a straight element under compression"" (Salvadori 86). When a compressing force reaches its ""critical value,"" the straight element will suddenly bend. Think of the ruler on a table example when pressing down with your hand."

buckling

"How does wind pressure increase relative to wind speed? a.) they are the same b.) It it is the square root of wind speed c.) It is the square of wind speed d.) Wind pressure doesn't exist"

c

"The tendency of materials (concrete or rope for example) to permanently deform over time when under stresses. The creeping process is generally sped up when the members are subjected to higher temperatures and greater loads over longer periods of time.

creep

"The minimum value of a load sufficient in buckling a column.

critical load

A type of system that consists of a large glass panel and, because it usually does not have the strength to hold it's own weight, it is supported by ""a frame of steel or concrete"". It's main purpose is ""lighting and temperature-conditioning""(Salvadori 22). It also functions as a wind break for the rest of the structure by ""minimiz[ing] the degree of erosion"" and ""helping to provide some degree of insulation from cold winds during a storm""(wiseGEEK article).

curtain wall

"When constructing a high-rise building, which of the following must be taken into account? I The soil beneath the construction site. II The climate of the surrounding area. III The materials used to make the structure. A. I and III B. I only C. II and III D. I, II, and III"

d

"the weight of the components of a structure; includes ""heavy elements like columns, beams, arches, or domes which must...support their own weight""

dead load

The degree to which a structure is displaced when a load is present. For example, as in the reading, the deflection of a bookshelf when it is filled with books. Gordon discusses it in terms of how designers and architects do not take into account mathematical properties such as deflection when designing their structures.

deflection

"The maximum wind a building is designed to withstand without serious damage. ""a 30 or 50 year wind is often considered acceptable unless the strength of a 100 year wind is such as to endanger the entire building and the life of its occupants"" (Salvadori 50)"

design wind

"""loads change value rapidly and even abruptly,"" ""may be exceedingly dangerous because they often have a much greater effect than the same loads applied slowly"" (Gordon 45). ex. wind gust, an objected dropped on the floor "

dynamic load

"The measure of an object's ability to resist forces, stresses, and loads, and return to its original state once all of the forces are removed. The measure of this is different for all materials.

elasticity

"An error in structure that refers either to the complete breaking of a part of a structure, or in addition an unstableness or wobbliness in a structure's ""accuracy or rigidity""(23)

fault

a structure that you can stand on, that is attached to the outside wall of a building, above ground level with no mass directly beneath it. They are supported either by cantilevers or steel cables that are fixed to the ends of the balcony and attached to the main building.

Balcony

"True or False: The introduction of technological metal to the world made a large and immediate difference to most structures. If False, make True"

"False The introduction of technological metal to the world did not make a large or immediate difference to most structures, as most metals were scarce, expensive, and difficult to use."

T or F Resonant forces produce large effects immediately."

"False Resonant forces do not produce large effects immediately, but their effects steadily increase over time and can be disastrous if they last long enough. "

"True or False: A ""well-engineered"" building or structure does not move when a small force is applied to it. If false, make it true. "

"False. Buildings move ""minuscule distances due to their elasticity"". Corrected: A ""well-engineered"" building or structure does not move when a small force is applied to it except for ""minuscule distances due to their elasticity""."

True or False and if False explain why. If a 30 MPH wind does no damage to a building, a 30 MPH wind would never be able to damage the same building.

"False. Resonance can make the 30 MPH build up to more force. Must mention Resonance and Force."

According to the reading, what are some improvements humans have made to structures and what are some current limitations to further developments of structures?

"Improvements 1. Better understanding of laws of nature 2. Use of computers for calculations 3. Improvements of steel, concrete, and other materials Limitations 1. Materials can only be so strong (ex. steel has a limit to how strong it can be for structural purposes) 2. Laws of nature must be obeyed (ex. cantilever beams must always be narrower at the end and thicker at the base to be structurally sound)"

Describe the transition of commonly available/utilized structural materials from early humankind to present day.

"Initially, wood and stone were the most readily available materials available. Then the discovery of metal as a useful building material largely replaced wood and stone as the material of choice. In more modern times, composite materials as structural components have become more popular. 1. Wood and Stone 2. Metal 3. Fiberglass or Composite Materials"

According to Gordon, why is it important for Engineers to understand the structures in living organisms in addition to structures of our own creation? In other words, why does Gordon believe studying nature is beneficial to engineers?"

"Required points: 1. Natural structures have been evolved and refined by natural selection 2. Natural structures are made to withstand the same forces and natural elements that our own structures are created to resist"

Short answer: What is elasticity and how does it relate to structure?

"Sample answer: Elasticity is a way to describe how forces and deflections act on structures and materials, and how the structures and materials change shape as they react. Hooke showed that elasticity relates to a structures size, shape, and material, and the reactions are proportional to the loads acting upon it. Key terms to include: forces, deflections, materials change shape, Hooke"

A common beam type used in construction is the I-beam, named for the cross-section's likeness to an uppercase I. Explain why the I-beam takes the shape that it does.

-The shape moves material away from the center of the beam, where there is the least stress, and towards the top and bottom which experience tension and compression respectively

What is a key difference between the design process of ancient and modern day structures? A) Ancient structures were made using trial and error, modern structures are calculated. B) Ancient structures were drawn on parchment, modern structures are drawn on blueprint paper C) Ancient structures were modeled using wood, modern structures use steel models. D) Ancient structures required approval from many people, modern structures only require consent from the architect and structural engineer

A

Explain what a rigid substance and the uses of them. Give two examples of rigid substances.

A rigid substance is a material that does not bend. They are ideal for building, as most engineers would say they do not want the structures they make to move. By using substances that do not bend or change shape in any way, a building can be constructed and stand for many, many years and also not be affected by the weather conditions around it. Two examples of rigid substances are steel and concrete.

What are three ways in which structure influences architecture of a building?

Any three of the following: 1 - unavoidable and necessary for any architecture 2 - required follow the laws of nature 3 - cannot always accommodate the architect's intended design 4 - ""hidden and does not appear to contribute to the architecture it supports"" 5 - it is costly, and therefore influences the budget for other components of the architecture"

A Cantilever beam, when under load, will tend to rotate about a) the top edge b) the middle c) the bottom edge d) noone knows

B the middle

Earthquake loads are used for buildings in places with high chances of Earthquakes, especially those that are moderately high on the Richter Scale. Salvadori claims that these are "built with particularly strong 'wind-bracing' type structures, which tests and calculations prove capable of resisting the jerking forces of an earthquake" (Salvadori 53). He also claims that the horizontal jerking motion of an earthquake can be resisted using the same type of bracing used against wind.

Earthquake Loads

How are inanimate solids able to resist mechanical force and produce reactive forces? (short answer)

Every kind of solid changes its shape - by stretching or contracting itself - when a mechanical force is applied to it...It is this change of shape which enables the solid to do the pushing back"" (Gordon 37). So essentially, the answer is that a solid changes its shape to produce reaction forces. Bonus points if the student describes how strong chemical bonds strongly resist being deformed, even to a very small extent, and thus resist tension and compression forces."

True or false: The sole purpose of a curtain wall is for decoration. If the statement is false, correct it.

False - a curtain wall does much more than provide decoration: the glass structure is built for temperature-control, lighting, and providing a stable barrier between the outside weather conditions and the inside of the building.

Why does J.E Gordan say that "practically everything is a structure of one kind or another" ?"

In order for an object to carry a load it must have a durable and strong structure. Without this structure it would cause a building for example to fall during a storm. Engineers design these structures to prevent people from getting injured. Gordan is explaining that without these structures around us the ability for us to be succesful would minor. For structures are the key to any engineers success.

The first states that a body will stay at rest unless an outside, unbalanced force is applied to it. This is commonly called the ""law of inertia""(article). The second states that the force of an object is equal to its mass times its acceleration. The third and final states that for every action, there is an equal and opposite reaction.

Newton's laws of motion

Plastic is strong and can be shaped in any way you want. It also does well under tension and compression. If this is true, why is plastic not being used as a material for construction?

Plastic is just too expensive, to produce plastic at a level that is big enough to make buildings it is to expensive in comparison to steel. This is why plastic is good for small things, but at the level of builds, it isn't.

What is the difference between a static load and a dynamic load?

Static loads exert a constant force, while dynamic loads exert varying amounts of force on a structure.

A wind gust strikes the top of building, then reaches a maximum force and dissipates over a total of 3 seconds. Which of the following could be the oscillation period of the top of the building if the gust is considered to be a static load? A) 2.5 Seconds B) 3 Seconds C) 0.5 Seconds D) 5 Seconds"

The correct answer is C, because according to Salvadori a wind force is a static load only if "it grows and vanished in a time much longer than the period of the building." C is the only option where the duration of the wind gust is significantly longer than the period.

Where do cracks appear in a beam supported on either end, made out of a low tensile strength material?

They appear on the bottom because the fibers of the beam on the bottom are in tension when a load is put on the beam.

a load evenly spread over the surfaces of the floors""

Uniform Load

= Stress/Strain=E. It expresses how stiff or how flobby the material is. (Strength is not the same as stiffness)"" (Gordon 58)

Young's module

"A material that is made up of many strands and so is flexible. Modern engineering often has the tendency ""to sweep the whole business of flexible materials under the carpet"" (Gordon 23). Fibrous structures are often unappreciated due to peoples misconception that a sound structure must be rigid, however this is not the case.

fibrous

Constraints and purposes for which the structure is constructed. In the example of the bridge, the functional requirement is to span two points. Can be contrasted with a non-functional requirement, which describes the execution of the structure. For example, the bridge must be a suspension bridge and not an arch.

functional requirement

a main supporting beam, usually horizontal and often constructed with timber, steel or concrete. They are used to support concentrated loads at isolated points along at its length.

girder

the deformation of a structure is proportional to the loading, and deformations disappear upon unloading; i.e. if one man stands on a diving board and it bends one inch, then another man of the same weight does the same, it will bend two inches, but then come back to normal once the men get off the diving board

linear elasticity

An impermanent loads that structure must support that "may be shifted around and they may change in value". This changing value load accounts for things like "people, furniture, equipment, stored goods", and more (Salvadori 44).

live load

Consists of loads caused by "daily or seasonal change" by uneven settling of dirt under the building or in the temperature of the air. They can also be called hidden loads.

locked in load

thin "vertical metal struts" used in contemporary high rise buildings to hold in place or frame the large glass windows used for curtain walls(Salvadori 22).

mullion

"a disk or short cylinder fitting closely within a tube in which it moves up and down against a liquid or gas, used in an internal combustion engine to derive motion, or in a pump to impart motion.

piston

process of creating intentional and permanent stresses on an object with the intent of improving its overall performance. It is broken up into 3 categories: precompression (normally the structure itself acts as the compressor), pre-tension (the concrete is cast around tendons that are themselves under stress), and post tension (concrete is cast around tendons that are not put under stress until the concrete has hardened.

prestressing

" Combining the compressive strength of concrete and the tensile strength, it can be poured into forms and given any shape suitable to the channeling of loads."

reinforced concrete

force is applied to an object. The longer the ____ keeps up, the likelier it is for the object to collapse. "

resonance

"When an object is completely balances about a pivot (i.e. it does not rotate); the downwards torque force (= Force x perpendicular Radius) of either sides to be both opposite (clockwise vs. counterclockwise) and equal.

rotational equilibrium

A shear load is a force that tends to produce a sliding failure on a material along a plane that is parallel to the direction of the force.

shear stress

"A static load is a load that is unchanging or changes slowly. A static load could be either a dead or live load, but does not change as abruptly as a dynamic load. The static load is the important in determining "" the maximum force a structure can support before it will collapse"", and so engineers often have to follow a set of rules about the amount of force a building should be able to support in order to protect people's safety.

static load

The ability to withstand the force of physical forces"

strength

the physical pressure, pull or other force exerted on a system by another; the load, force, or system of forces producing stress""

stress system

Beam, columns, and structures are examples of what in buildings

structural components

A structure that separates the outside from the inside of a building. Serves the function of protecting the people and objects that are inside."

surface

"An object (or in this case a bridge) to be held up by two sturdy objects permitting something to travel underneath it.

suspension

having to ability to be stretched or compressed or put under tension

tensile

"""at a temperature of minus 30 degrees F, called its transition temperature, steel becomes brittle and breaks suddenly"" the temperature at which a material acquires or in this cases loses some distinctive property. For steel, it loses its malleability and strength at 30 degrees F."

transition temperature

round, domed, and stone-built structures which do not have separate functional components."(Salvadori 22)

trulli

"the number of pounds each square inch of material will carry before it breaks" . It is the maximum load that a material can withstand. It varies from material to material, and in some cases, it varies from different points within the material itself.

ultimate strength

"Structures commonly found in tall buildings which provide resistance to horizontal movement caused by the wind. They often take the form of horizontal beams across ceilings, which distribute the force of the wind along the structure.

wind bracing

"The scale of the sway of a building under wind pressure, or the displacement from its original position. Designed into tall buildings to prevent cosmetic damage and protect the contents and belongings within the building.

wind drift

forces exerted on a building by the wind. According to the text "the forces exerted by winds on buildings have dramatically increased in importance with the increase in building heights" (Salvadori 49). Wind speed and consequently wind pressure increases as you go up higher.

wind load

an exact amount of stress put on a material where the material changes from having elastic behavior to plastic behavior.

yield stress