ARCH 331 - Quiz 1

shell

A this surface forming element which resists forces in the plane of the shell. It must be curved to minimize the bending, which is why it is able to be thin

space force system

Forces cannot be categorized into a planar system. The force have no common characteristics.

live load

In the general sense, any load that comes and goes with time. As a specific category of live load, it generally refers to occupancy (people)

grids and patterns

Regular, square, and triangular, cellular, vertical and horizontal, irregular. Useful to give order.

light loads and structure type

Surface forming elements appropriate. Joints or trusses at regular intervals.

horizontal span to depth relationship

The depth squared is related to the length. Increasing the span will require more than a proportional depth increase.

force polygon

The resulting multi-sided figure obtained by drawing force vectors tip to tail. The polygon will "close" if the resultant vector is zero (as in equillibrium)

special truss member configurations with three members

Three members (or forces) with two in line have will have equal forces of the ones in line. The other must have zero force.

special truss member configuration with two members

Two members (or forces) in line have equal forces. Two members out of line must have zero force in each.

number of levels in horizontal systems

a classification system to describe how many horizontal collectors are used, for example, joist with beams is a two-level system

Arch

a curved element that is an efficient shape to support gravity and compression loads and for large spans

beam

a horizontal element that carries transverse bad and resists bending and shear

slab or plate

a horizontal surface forming element which resists two-way bending stress and shear

cable

a linear or curvilinear element that has a small cross section and resists tensile loads

bearing wall

a load bearing wall that typically carries both vertically acting loads and laterally acting loads, such as wind load, along its depths

impact load

a load from an impact which is significantly higher than the same load applied gradually

seismic load

a load that is a result of the acceleration of the ground wave and a building mass, resulting in a lateral or shear force

zero-force member

a member carrying force, but required for geometric stability

shearwall

a rigid planar surface element that resists lateral forces or shear and resists lateral movement

column

a slender vertical element that carries axial load in compression

cable-stayed

a system in which the cables are linear or straight, typically involving masts to withstand the compression forces

equivalent force systems

a system that has the same resulting force and moment, but with a different arrangement of forces and moments

coplanar force system

all forces act in the same place

colinear force system

all forces act on the same time

concurrent force system

all forces act through a single point

parallel force system

all forces are parallel

tension

an action, force, or stress that elongates or pulls

compression

an action, or stress that shortens or pushes

moment couple

an arrangement of two equal and opposite parallel forces separated by a distance which have only rotational effects on a body

truss

an assembly of shorter members which is used to span horizontally, and commonly is used for large spans

graphical truss analysis (or Maxwell's diagram)

analysis using force polygons based on the joint loads and angles of the truss analysis

perpendicular

at 90 degrees

lateral resistance options

bracing of pin or rigid frames, rigid frames, shear walls, cores and diaphragms

cable force

cables are in tension with the force in the direction of the geometry of the cable (neglecting gravity)

two-way systems

characterized by elements that channel load in a complex manner involving load transfer in two directions

one-way systems

characterized by elements that channel load in one direction only

evaluation

comparing the analysis results to the limiting requirement specified by structural codes and determining if the criteria is met

pin connections

connections between two or more bodies that only resist translation, and do not resist rotation

wind load

equivalent load as a result of wind gust or wind pressure

actions

externally applied force or moment

external forces

forces that are applied or act on bodies

internal forces

forces that are within bodies, or at connections between bodies

special truss member configurations with four members

four members (or forces) with the two each in line will have equal forces of the ones in line

negative result for a variable from equilibrium equations

indicates that the assumed direction of unknown quantity was not verified and the direction is actually opposite of the assumption

snow load

load from the weight of snow

dead load

long term load on a structure due to material weights and gravity loads

opposite, adjacent, and hypotenuse

names given to the sides of a right triangle with respect to the angle defined

structural system organization schemes

one-way, two-way, tubes, braced and unbraced

law of transmissibility

principle that the external force acting at a point is replaced by a force of equal magnitude at another point on the same line of action

scalars

quantities that have magnitude

vectors

representation of quantities that have magnitude and direction, and are commonly represented by symbols with arrows above them

reactions

response to an externally applied force or moment to keep a body in equilibrium

force

result of acceleration on a mass

structural system performance requirements

strength of elements, stability of elements, stability of system, lateral resistance (no overturning, sliding or excessive distortions)

equillibrium

the condition when all forces and moments have no tendency to translate or rotate a body (i.e. at rest)

resultant of forces

the final magnitude and direction from the vector addition of more than one concurrent force

weight

the force due to the acceleration of gravity on mass

Newton's Third Law

the forces of action and reaction between bodies in contact have the same magnitude, same line of action and opposite sense

kinetic friction

the friction force which is a magnitude based on the coefficient of kinetic friction and the normal force for an object in contact with a material that will keep an object in motion

static and friction

the maximum friction force that is a magnitude based on the coefficient of static friction and the normal of an object in contact with a material that will maintain equllibrium

member configurations

the members must form triangles with no pins in the middle of members for stability

tip-to-tail method

the method applied to determine the resultant of any number of vectors by placing the tail of the next vector at the tip of the last

parallelogram law

the method applied to determine the resultant of two vectors by constructing parallel lines

method of joints

the method fro truss member analysis using free body diagram of the joints and two equations of equillibrium

Varignon's Theorem

the moment of a force about a point is equal to the algebraic sum of the moments of the components of the force with respect to the same points

free body diagram

the representation of a body or a system with only forces, and no attached or supporting elements

components of a force

the resolution of a force into vectors, commonly orthogonal, along an axis, which when added, are equivalent to the original force

assumptions for analysis

the truss members have force only running through the pins (axial forces) and any bending is negligible

two-force bodies and relationship to loads

the two forces must be equal and opposite and colinear for the body to be in equilibrium

moment of a force

the vector quantity represented by the product of a force with the perpendicular lever arm to some axis, or the tendency of a force to produce a rotation for a body

scale

to increase in amount or size according to a fixed scale or standard, commonly using a fraction or factor

sin, cos, and tan

trigonometric functions describing the relationships between sides of a right triangle

heave concreted loads and structure type

uniquely designed elements without multiple identical elements

analysis

using the methodology and structural tools to evaluate the loads, stresses, moments, and displacements in a system to compare with design limits

structural system materials

wood, steel, reinforced concrete, masonry and composite construction