DK Ching VD - Load

load

forces to which a structure is subjected

static load

a load applied slowly to a structure until it reaches its peak value without fluctuating rapidly in magnitude or position

concentrated load

a load acting on a very small area or particular point

distributed load

a load extending over the length or area

uniformly distributed load

a distributed load of uniform magnitude

occupancy load

live load on a structure resulting from the weight of people, furniture, stored material, and other similar items in a building

water load

live load of water that may accumulate on a roof because of its form, deflection, or the clogging of its drainage system

live load

moving or movable load

dead load

static load acting vertically downward; comprising the self-weight of the structure and the weight of building elements, fixtures, and equipment permanently attached to it

water pressure

the uplifting force a water table exerts on a foundation system

earth pressure

the horizontal force a soil mass exerts on a vertical retaining structure

settlement load

a load applied suddenly to a structure

moving load

a kinetic load of short duration due to moving vehicles, equipment, and machinery; also called "impact load"

impact factor

factor by which the effect of a static load is multiplied to approximate the effect of applying the same load dynamically

equivalent load

a load substituted by a building code for an actual load

load combination

the dead load and two or more live loads assumed to occur simultaneously on a structure

erection stress

the stress induced on a building unit or component by loads applied during the erection process

erection bracing

the temporary brazing required to secure the units or components of a building until permanently fastened in place

construction load

a temporary load on a structure occurring during its erection, as from wind or the weight of construction equipment and stored materials

lateral load

a load acting horizontally on a structure, such as wind or earthquake

earthquake load

the forces exerted on a structure by an earthquake

seismic force

any of the forces caused by the vibratory ground motions of an earthquake

drift

the lateral deflection or movement of a structure due to wind, earthquake, or asymmetrical vertical loading

oscillation

a single swing of an oscillating body from one extreme limit to another

site class

the classification of a site according to the types of soils present within the upper 100 ft (30.48 m) of the site profile and their engineering properties of shear wave velocity, shear strength, and penetration resistance

site coefficient

any of the coefficients for modifying the mapped acceleration parameters according to the effects of site class

liquefaction

the sudden loss of shearing resistance in a cohesionless soil, causing the soil to behave as a liquid

seismic design category

the classification of a structure according to its occupancy category, site soil conditions, and the probability of significant seismic ground motion at the site

occupancy category

the classification of a building according to the nature of its occupancy or contents

seismic weight

the total dead load of a structure, including applicable portions of storage live loads, partition loads, permanent equipment loads, and design roof loads

seismic base shear

the shearing force (V) developed at the base of a structure by the tendency of its upper mass to remain at rest while the base is translated by ground motions during an earthquake

horizontal torsion

the torsion resulting from a lateral load acting on a structure having noncoincidental centers of mass and resistance

overturning moment

an external moment generated at the base of a structure by a lateral load applied at a distance above grade

restoring moment

a resisting moment provided by the dead load of a structure acting about the same point of rotation as the overturning movement

seismic-force-resisting system

the part of a building's structural system that provides the required resistance to the prescribed seismic force

story shear

the total shear in any horizontal plane of a structure subject to lateral loads, distributed according to the various lateral force-resisting elements in proportion to their rigidities

P-delta effect

the second-order effects on shear, axial forces, and moments introduced during displacement of a structure

story drift

the horizontal movement of one level of a structure relative to the level above or below

drift index

the maximum ratio of story drift to story height allowed by a building code in order to minimize damage to building components or adjacent structures; also called "drift limitation"

building separation

the distance required to avoid contact between separated structures under deflection from seismic action or wind forces

wind load

any of the forces exerted by the kinetic energy of a moving mass of air

sliding

the horizontal movement of a structure in response to a lateral load

uplift

the raising of a structure or portion of structure in response to an overturning moment or wind suction

flutter

the rapid oscillations of a flexible cable or membrane structure caused by the aerodynamic effects of wind; also called "aerodynamic oscillation"

height factor

a coefficient increasing design wind pressure to account for the increase in wind velocity with height above the ground

gust factor

a coefficient increasing design wind pressure to account for the dynamic effects of wind gusts

surface roughness category

a method for classifying the degree of roughness of the ground surface within each 45d sector for a specified distance upwind of a site for the purpose of assigning an exposure category

Surface Roughness B

urban and suburban areas, wooded areas, or other terrain with numerous, closely spaced obstructions having heights of 30 ft (9144 mm) or more

Surface Roughness C

open terrain with scattered obstructions having heights generally less than 30 ft (9144 mm), including flat open country, grasslands, and water surfaces in hurricane-prone regions

Surface Roughness D

flat, unobstructed areas and water surfaces outside hurricane-prone regions

wind suction

the negative pressure exerted by wind on the sides and leeward vertical surfaces of a building and normal to windward roof surfaces having a slope less than 30d

leeward

pertaining to, being in, or facing the direction toward which the wind is blowing

windward

pertaining to, being in, or facing the direction from which the wind blows

wind pressure

the pressure exerted by wind horizontally on the windward vertical surfaces of a building

normal force method

a design method in which wind pressures are assumed to act simultaneously normal to all exterior surfaces

projected area method

a design method in which the total wind effect is considered to be a combination of a single inward or positive horizontal pressure acting on the full vertical projected area of the building and an outward or negative pressure acting on the full horizontal projected area of the building