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MAGNITUDE the amount of force, N
DIRECTION refers to the orientation of its path or line of action. It is usually described
by the angle that the line of action makes with some reference.
by the angle that the line of action makes with some reference.
SENSE refers to the manner in which it acts along its line of action
FORCE SYSTEM
COPLANAR all acting in a single plane of a vertical wall
PARALLEL all having the same direction
CONCURRENT all having their lines of action intersect at a common point.
MOMENT force x distance
moment can be about any point called CENTER OF MOMENT
MOMENT ARM distance from center of moment to force
shortest or perpendicular distance from the center of moment to line of
action of force.
KINDS OF LOADS
CONCENTRATED LOADS example is a beam supporting a column
UNIFORM LOADS a series of uniform concentrated loads, but for 5 or
more uniformly spaced concentrated loads.
more uniformly spaced concentrated loads.
OTHER LOADS varying load, moment load
TYPES OF SUPPORT
HINGED
ROLLER
FIXED/ RESTRAINED
TYPES OF BEAMS
SIMPLY SUPPORTED BEAM
SIMPLY SUPPORTED W/ OVER HANG (OVERHANGING BEAM)
CANTILEVER BEAM
PROPPED CANTILEVER BEAM (indeterminate)
CONTINOUS BEAM
INTERNAL FORCES TYPES
TENSION pulls away from joint
COMPRESSION pushes towards joint
SHEAR for connections
ASTM
AMERICAN SOCIETY FOR TESTING AND MATERIALS
ACI
AMERICAN CONCRETE INSTITUTE
According to ACI code, I the strain in concrete reaches
0.003 (Єconc= 0.003), Є=3mm
1000
It begins to crack
AISC
AMERICAN INSTITUTE FOR STEEL CONSTRUCTION
If a grade 60 steel (fy= 60ksi= 414Mpa) reaches a strain 0.0021 it begins to yield of (2.1mm)
FEATURES OF A STRAIN STRESS DIAGRAM:
STRESS- STRAIN DIAGRAM
a graphic representation of the relationship between unit stress values and the
corresponding unit strains for a specific material
1. PROPORTIONAL LIMIT
maximum stress which the material springs back to the original length when
the load is released
2. ELASTIC LIMIT
maximum stress below which the material does not return to its original
length but has incurred a permanent deformation we call permanent set
3.YIELD POINT
the stress wherein the deformation increases without any increase in the load.
The material at some portion shows a decrease in its cross section
4. ULTIMATE STRENGTH
the maximum stress that can be attained immediately before actual failure or
rupture
RUPTURE STRENGTH
stress at which material specimen breaks
ALLOWABLE STRESS
the maximum unit stress permitted for a material in the design of a structural member,
usually a fraction of the material’s elastic limit, yield strength, or ultimate strength.
Also called ALLOWABLE UNIT STRESS, WORKING STRESS.
the range of unit stresses for which a material exhibits elastic deformation
ELASTIC DEFORMATION
a temporary change in the dimensions or shape of a body produced by a stress
less than the elastic limit of the material
BRITTLENESS
the property of material that causes it to rupture suddenly under stress with little evident
deformation. Since brittle materials lack the plastic behavior of ductile materials, they
can give no warning of impending material
DUCTILITY
the property of a material that enables it to undergo plastic deformation after being stressed
beyond the elastic limit and before rupturing. Ductility is a desirable property
of a structural material since plastic behavior is an indicator of reserve strength and
can serve as a visual warning of impending failure.
ELASTICITY
the property of a material that enables it to deform in response to an applied force and
to recover its original size and shape upon removal of the force
MALLEABILITY
the ability of a material to regain and rebound to original shape when the load is released
TOUGHNESS
the property of a material that enables it to absorb energy before rupturing, represented
by the area under the stress- strain curve derived from a tensile test of the material. Ductile materials are tougher than brittle materials.
MODULUS OF ELASTICITY
a coefficient of elasticity of a material expressing the ratio between a unit stress and the corresponding unit strain caused by the stress, as derived from Hooke’s law and represented by the slope of the straight line portion of the stress- strain line diagram.
Also called COEFFICIENT OF ELASTICITY, ELASTIC MODULUS
PERMANENT SET
the inelastic strain remaining in a material after complete release of the stress producing deformation
YIELD STRENGTH
the stress necessary to produce a specific limiting permanent set in a material,
usually 0.2% of its original length when tested in tension. Yield strength is used to determine the limit of usefulness of a material having a poorly defined yield point.
Also called POOR STRESS.
STRAIN- RATE EFFECT
the behavior an increased rate of load application can cause in normally ductile material
TEMPERATURE EFFECT
the brittle behavior low temperatures can cause in a normally ductile material
STRESS RELAXATION
the time- dependent decrease in stress in a constrained material under a constant load
CREEP
the gradual permanent deformation of a body produced by a continued application of
stress or prolonged exposure to heat. Creep deflection in a concrete structure continues over time and can be significantly greater than the initial elastic deflection
FATIGUE
the weakening or failure of a material at a stress below the elastic limit when subjected to a repeated series of stresses
STRUCTURAL PROPERTIES OF A36 STEEL:
Maximum allowable stress (Fv) in shear is 14.5 ksi
Maximum allowable stress (Fb) for bending is 24 ksi
Modulus of elasticity (E) is 29,000 ksi
WEIGHT:
water= 1000 kg/ m3
steel= 7850 kg/ m3
concrete= 2400 kg/ m3
weight= density x volume
volume of cylinder= pi (diameter)2 x length
4
PROPERTIES OF A MATERIAL
TENSION
the act of stretching or state of being pulled apart, resulting in the elongation of an elastic body
TENSILE FORCE
an applied force producing or tending to produce tension in an elastic body
AXIAL FORCE
a tensile or compressive force acting along the longitudinal axis of a structural member and at the centroid of the cross section, producing axial stress without bending, torsion or shear also called AXIAL LOAD
AXIAL STRESS
the tensile or compressive stress that develops to resist axial force, assumed to be normal to and uniformly distributed over the area of the cross section.
Also called DIRECT STRESS, NORMAL TRESS
COMPRESSION
the act of shortening or state of being pushed together, resulting in the reduction in size or volume of an elastic body
COMPRESSIVE FORCE
an applied force producing or tending to produce compression in an elastic body
ECCENTRIC FORCE
force applied parallel to the longitudinal axis of a structural member but not to the centroid of the cross section, producing bending and uneven distribution of stresses in the section.
Also called ECCENTRIC LOAD.
STRESS-
the internal resistance or reaction of an elastic body to external forces applied to it. Equal to the ratio of force to area and expressed in units of force per unit of cross- sectional area.
Also called UNIT STRESS.
TENSILE STRESS
the axial stress that develops at the cross section of an elastic body to resist the collinear tensile forces tending to elongate it.
TENSILE STRAIN
the elongation of a unit length of material produces by a tensile stress
ELONGATION
a measure of ductility of a material, expressed as the percentage increase in length of a test specimen after failure in tensile test
REDUCTION OF AREA
a measure of ductility of a material, expressed as the percentage decrease in cross- sectional area of a test specimen after rupturing in a tensile test
TENSILE STRENGTH
the resistance of a material to longitudinal stress, measured by the minimum amount of longitudinal stress required to rupture the material
STRAIN
the deformation of a body under the action of an applied force. Strain is a dimensionless quantity, equal to the ratio of the change in size and shape to the original size and shape of a stressed element.
STRAIN GAUGE
an instrument for measuring minute deformation in a test specimen caused by tension,
compression, bending or twisting.
Also called EXTENSOMETER
YOUNG’S MODULUS
a coefficient of elasticity of material expressing the ratio of longitudinal stress to the
corresponding longitudinal strain caused by the strain.
POISSON’S RATIO
the ratio of lateral strain to the corresponding longitudinal strain in an elastic body under
ongitudinal stress
COMPRESSIVE STRESS
the axial stress that develops at the cross section of an elastic body to resist the
collinear compressive forces tending to shorten it.
COMPRESSIVE STRAIN
the shortening of a unit length of material produced by a compressive stress
SHEAR
the lateral deformation produced in a body by an external force that causes one part of
the body to slide relative to an adjacent part in a direction parallel to their plane contact.
SHEAR FORCE
an applied force producing or tending to produce shear in the body
SHEARING FORCE
an internal force tangenial to the surface on which it acts, developed by a body in
response to shear, shearing in a vertical plane necessarily involves shearing in a horizontal plane and vise versa
SHEARING STRESS
the force per unit area developed along a section of an elastic body to resist a shear
force.
Also called SHEAR STRESS, TANGENIAL STRESS
SHEARING STRAIN
the lateral deformation developed in a body in response to shearing stresses, defined as
the tangent of the skew angle of the deformation.
SHEAR MODULUS OF ELASTICITY
a coefficient elasticity of a material, expressing the ratio between shearing stress and
the corresponding shearing strain produced by the strain.
Also called MODULUS OF RIGIDITY, MODULUS OF TORSION
BENDING
the bowing of an elastic body as an external force is applied transversely to its length.
Bending is the structural mechanism that enables a load to be mechanism that enables a load to be channeled in a direction perpendicular to its application.
TRANSVERSE FORCE
a force applied perpendicular to the length of a structural member,
producing bending and shear
TORQUE
the moment of a force system that causes or tends to cause rotation or torsion
TORSION
the twisting of an elastic body about its longitudinal axis caused by two equal and
opposite torques, producing shearing stresses in the body
REINFORCED CONCRETE
EFFECTIVE LENGTH
the depth of concrete section measured from the compression face to the centroid of the
tension reinforcement
COVER
the amount of concrete required to protect steel reinforcement from fire and corrosion,
measured from the surface of the reinforcement to outer surface of the concrete section
BOND STRESS
the adhesive for per unit area of contact between reinforcing bar and the surrounding
concrete developed at any section of a flexural member
HOOK
a bend or curve given to develop an equivalent embedment length, used where there is
insufficient room to develop in adequate embedment length
STANDARD HOOK
a 90º, 135º, 180º bend made at the end of a reinforcing bar according to standards
any of various means, as embedment length or hooked bars, for developing tension or
compression in a reinforcing bar on each side of critical section in order to prevent bond
failure or splitting
CRITICAL SECTION
the section of a flexural concrete member at a point of maximum stress, a point of
inflection, or appoint within the span where tension bars are no longer needed to resist stress
BALANCED SECTION
a concrete in which the tension reinforcement theoretically reaches its specified yield
strength as the concrete in compression reaches its assumed ultimate strain
OVERREINFORCED SECTION
a concrete section in which the concrete in compression reaches its assumed ultimate
strain before the tension reinforcement reaches its specified yield strength. This is a dangerous condition since failure of the section could occur instantaneously without warning
UNDERREINFORCED SECTION
a concrete section in which the tension reinforcement reaches its specified yield
strength before the concrete in compression reaches its assumed ultimate strain. This is desirable condition since failure of the section would be preceded by large deformations giving prior warning of impending collapse
strength before the concrete in compression reaches its assumed ultimate strain. This is desirable condition since failure of the section would be preceded by large deformations giving prior warning of impending collapse
BEAM
BEAM
a rigid structural member designed to carry and transfer transverse loads across spaces supporting elements
SPAN
the extent of space between two supports of a structure
CLEAR SPAN
the distance between inner faces of the support of a span
EFFECTIVE SPAN
the center to center distance between the supports of a span
BENDING MOMENT
an external moment tending to cause part a structure to rotate or bend, equal to the algebraic sum of the moments about the neutral axis of the section under consideration
RESISTING MOMENT
an internal moment equal and opposite to a bending moment, generated by a force couple to maintain equilibrium of the section being considered
DEFLECTION
the perpendicular distance a spanning member deviates from a true course under transverse loading, increasing with load and span, and decreasing with an increase in the moment of inertia of the section of the modulus of elasticity of the material
NEUTRAL AXIS
an imaginary line passing through the centroid of the cross section of a beam, other member subject to bending, along which no bending stresses occur
BENDING STRESS
a combination of compressive and tensile stresses developed at a cross section of structural member to resist transverse force, having a maximum value at the surface furthest from the neutral axis
CAMBER
a slight convex curvature intentionally built into beam, girder, or truss to compensate for an anticipated deflection
How is camber treated in a steel truss 25 meters and longer?
Camber shall be approximately equal to the dead load deflection
TRANSVERSE SHEAR
an external shear force at a cross section of a beam or other member subject to bending, equal to the algebraic sum of transverse forces on one side of the section
VERTICAL SHEARING
the shearing stress developed along cross section of a beam to resist transverse shear,
having a maximum value at the neutral axis and decreasing nonlinearly toward the outer faces
HORIZONTAL SHEARING
the shearing stress developed to prevent slippage along longitudinal planes of a beam
under transverse loading, equal to any point to the vertical shearing stress at that point.
Also called LONGITUDINAL SHEARING STRESS
FLEXURE FORMULA
a formula defining the relationship between bending moment, bending stress, and the
cross sectional properties of a beam. Bending stress is directly proportional to bending
moment and inversely proportional to the moment of inertia of a beam section.
MOMENT OF INERTIA
the sum of the products of each element of an area and the square of its distance from a
coplanar axis of rotation. Moment of inertia is a geometric property that indicates how
the cross sectional area of structural member is distributed and does not reflect the
intrinsic physical properties of a material
SECTION MODULUS
a geometric property of a cross section, defined as the moment of inertia of the section
divided by the distance from the neutral axis to the most remote surface.
LATERAL BUCKLING
the buckling of a structural member induced by compressive stresses acting on slender
portion insufficiently rigid in the lateral direction
STRESS TRAJECTORIES
lines depicting the direction but not the magnitude of the principal stresses in a beam
SHEAR DIAGRAM
a graphic representation of the variation in magnitude of the external shears present in a
structure for a given set of transverse loads and support conditions concentrated loads
produce external shears which are constant in magnitude between the loads uniformly
distributed loads produce linearly varying shears
MOMENT DIAGRAM
a graphic representation of the variation in magnitude of the bending moment present in
a structure for a given set of transverse load and support conditions. The overall deflected
shape of a structure subject to bending can often be inferred from the shape
of its moment diagram
CONCENTRATED LOADS
produce bending moments which vary linearly between loads
UNIFORMLY DISTRIBUTED LOADS
produce parabolically varying moments
POSITIVE SHEAR
a net resultant of shear forces that acts vertically upward on the left part of the structure
being considered
NEGATIVE SHEAR
a net resultant of shear forces that act vertically downward on the left part of the structure
being considered
POSITIVE MOMENT
a bending moment that produces moment that produces a concave curvature at a section of a structure
INFLECTION POINT
a point at which a structure changes curvature from convex to concave or vise versa as
it deflects under a transverse load: theoretically an internal hinge and therefore a point of zero moment
NEGATIVE MOMENT
a bending moment that produces a convex curvature at a section of a structure
SIMPLE BEAM
a beam resisting on simple supports at both ends which are free to rotate and have no
moment resistance. As with any statistically determinate structure, the values of all reactions, shears, and moments for a simple beam are independent of its cross sectional shape and material
CANTILEVER BEAM
a projecting beam supported at only one fixed end
CANTILEVER
a beam or other rigid structural member extending beyond a fulcrum and supported by a
balancing member or a downward force behind the fulcrum
OVERHANGING BEAM
a simple beam extending beyond one of its supports. The overhanging reduces the
positive moment at midspan while developing a negative moment at the base of the cantilever over the support
FIXED END BEAM
a beam having both ends restrained against translation and rotation. The fixed ends
transfer bending stresses, increase the rigidity of the beam and reduces its maximum deflection
CONTINUOUS BEAM
a beam extending over more than 2 supports in order to develop greater rigidity and
smaller moments than a series of simple beams having similar spans and loading. Both fixed end and continuous beams are indeterminate structures for which the values of all reactions, shears and moments are dependent not only on span and loading but also on cross sectional shape and material
smaller moments than a series of simple beams having similar spans and loading. Both fixed end and continuous beams are indeterminate structures for which the values of all reactions, shears and moments are dependent not only on span and loading but also on cross sectional shape and material
HAUNCH
the part of a beam that is thickened or deepened to develop greater moment resistance. The efficiency of a beam can be increased by shaping its length in response to the moment and shear values which typically vary along its longitudinal axis
SUSPENDED SPAN
a simple beam supported by the cantilevers of two adjoining spans with pinned construction joints at points of zero moment. Also called hung span
EFFECTIVE LENGTH
the distance between inflection points in the span of a fixed end or continuous beam, equivalent in nature to the actual length of simply supported beam
COLUMN
COLUMN
a relatively slender structural member designed primarily to support axial, compressive loads, applied at the member ends.
POST
a stiff vertical support especially a wooden column in timber framing
BUCKLING
the sudden lateral or torsional instability of a slender structural member induced by the action of a compressive load. Buckling can occur well before the yield stress of the material is reached
BUCKLING
the axial load at which a column begins to deflect laterally and becomes unsuitable.
CRITICAL BUCKLING LOAD
the maximum axial load that can theoretically be applied to a column without causing it to buckle. The critical buckling load for a column is inversely proportional to the square of its effective length and directly proportional to the modulus of elasticity of the material and to the moment of inertia of the cross section.
Also called EULER BUCKLING LOAD
BIFURCATION
the critical point at which a column carrying its critical buckling load, may either buckle or remain undeflected. The column is therefore in a state of neutral equilibrium
CRITICAL BUCKLING STRESS
the critical buckling load for a column divided by the area of its cross section
SLENDERNESS RATIO
the ratio of the effective length of a column to its least ratio of gyration
The higher the slenderness ratio, the lower is the critical stress that will cause buckling. A primary objective in the design of a column is to reduce its slenderness ratio by minimizing its effective length or maximizing its effective length or maximizing the radius of gyration of its cross section
RADIUS OF GYRATION
the radial distance from any axis to a point at which the mass of a body could be concentrated without altering the moment of inertia of the body about that axis. For a structural section, the radius of gyration is equal to the square root of the quotient of the moment of inertia and the area
The higher the radius of gyration of a structural section, the more resistant the section is to buckling. In determining the cross- sectional shape of a column, the objective is to providethe necessary radius of gyration about the different axes. For an asymmetrical cross section, buckling will tend to occur about the weaker axis or in the direction of the least dimension
LONG COLUMN
a slender column subject to failure by buckling rather than by crushing
SHORT COLUMN
a thick column subject to failure by crushing rather than by buckling. Failure occurs when the direct stress from an axial load exceeds the compressive strength of the material available in the cross section. An eccentric load, however, can produce bending and result in uneven stress distribution in the section
INTERMEDIATE COLUMN
a column having a mode of failure between that a short column and a long column, often party inelastic by crushing and partly elastic by buckling
ECCENTRICITY
The amount by which an axis deviates from another parallel axis.
P-DELTA EFFECT
An additional moment developed in a structural member as its longitudinal axis deviates from the line of action of a compressive force equal to the product of the load and the member deflection at any point.
MIDDLE THIRD RULE
The proposition that a compressive load should be located within the middle third of a horizontal section of a column or wall to prevent tensile stresses from developing in the section.
EFFECTIVE LENGTH
The distance between inflection points in a column subject to buckling load. When this portion of a column buckles the entire column falls.
COMBINED STRESSES
A set of tensile and compressive stresses resulting from the superposition of axial and bending stresses at a cross section of a structural member, acting in the same direction and equal at any point to their algebraic sum.
KERN
The central area of any horizontal section of a column or wall within which the resultant of all compressive loads must pass if only compressive stresses are to be applied beyond this area will cause tensile stresses to develop in the section. Also called kern area.
KERN POINT
A point on either side of the centroidal axis of a horizontal column or wall section defining the limits of the kern area.
LATERAL BRACING
the bracing of a column or other compression member to reduce its effective length. Lateral bracing is most effective when the bracing pattern occurs in more than one plane.
UNBRACED LENGTH
the distance between the points at which a structural member is braced against buckling in a direction normal to its length.
EFFECTIVE LENGTH FACTOR
a coefficient for modifying the actual length of a column according to its end conditions in order to determine its effective length. Fixing both ends of a long column reduces its effective length by half and increases its load-carrying capacity by a factor of 4.
TRUSS
METHOD OF SECTIONS
a method of determining member forces in a truss by considering the equilibrium of any portion of the truss assembly.
METHOD OF JOINTS
a method for determining member forces in a truss by considering the equilibrium of the various joints idealized as points in free body diagrams
DEFINITION OF TERMS
ACTIVE EARTH PRESSURE
a soil pressure acting on any structure that will tend to push the structure wherein the structure or a wall tends to move away from the soil
ACCELEROGRAPH
is an instrument which measures the velocity and acceleration of an earthquake in the ground
ANCHOR BOLTS
a round, steel bolt embedded in concrete or masonry used to hold down machinery, steel columns or beam casting, shock beam plates and engine heads
BALANCED DESIGN
is one which both the concrete and the steel are so proportioned as to work to their full working stresses when the member carries its full allowable load
BATTER PILES
are piles at an inclination to resist forces that are not critical. This is also known as brace pile or spur pile
BEARING WALL SYSTEM
a structural system without a complete vertical load carrying space frame
BENDING MOMENT
is the algebraic sum of the moments of the forces acting on either side of the section of a beam about an axis through the center of the gravity of the section
BORED PILE (bearing pile)
a concrete pile which concreted either with a casing or without a casing at its permanent location. This is a cast in place pile
CAISSON
a watertight, cylindrical or rectangular chamber used to in under water construction to protect workers from water pressure and soil collapse
CEMENT GUN
is an ejector operated by compressed air to force gunite into cavities or cracks in rocks or cement works
CHUTE
is an open-top through which bulk materials are conveyed and by gravity
COFFER DAM
a temporary dam- like structure constructed which excludes water from the site of the foundation during its excavation and construction
CONSTRUCTION JOINT
the vertical or horizontal face in a concrete structure where concreting has been stopped and continued later
COLD JOINT
formed when a concrete surface hardens before the next batch o f concrete is placed
CREEP
he tendency of most material to move or deform over time under a constant load The amount of movement varies enormously depending upon the material. The area that is highly stressed will move the most. The movement causes stresses to be redistributed.
COUNTER (inner in retaining wall)
a cantilever wall that is reinforced with a masonry structure extending upward from the foundation or from the inner face of the retaining wall to provide additional resistance to thrust and are placed at regular intervals. (Buttress if outer)
COFFER DAM
a temporary watertight enclosure around an area of water or water bearing soil, in which construction is to take place, bearing on a stable statum at or above the foundation level of new construction. The water is pumped from within to permit free access to the area
DIAPHRAGM
a horizontal or nearly horizontal system including horizontal bracing system, that act to transmit lateral forces to the vertical resisting elements
DIAPHRAGM STRUT
a structural member of a horizontal bracing system that takes axial tension or compression. It is parallel to the applied load that collects and transfers shear to the vertical resisting elements or distributive loads within the horizontal bracing system
DIVING BELL
a watertight bell- shaped steel chamber which can be lowered to or raised from a fresh or seawater bed crane. It is opened at the bottom and filled with compressed air so that men can prepare foundations and undertake similar construction work under water.
DOWEL
a short steel bar extending from one concrete element to another as for instance a concrete foundation to a concrete column. It may or may not transfer direct stress
DRIFT BOLT
is a long pin of steel or wood, made with or without the head, driven through the timber and into an adjacent timber to hold them together and to transmit stresses
EXPANSION OR CONTRACTION
a joint designed to take expansion and contraction
the designed break in a structure to allow for the drying and temperature shrinkage of concrete, brickwork of similar material, thereby preventing the formation of harmful cracks
FATIGUE
is a phenomenon of failure under repeated stresses. A fact, based experience and experiments, is well known that stresses which are applied to a body a few times without causing apparent structure injury may, if applied repeatedly or causing a great number of times, causes failure
GUNITE
is a rich cement mortar which is applied by spraying under high air pressure
GRADE BEAM
a concrete beam placed directly on the ground to provide foundation for the superstructure
GRANOLITHIC FINISH
a surface layer or granolithic concrete which maybe laid on a base of either fresh or hardened concrete
GRILLAGE
is a footing which consist of steel beams arranged to distribute a concentrated load to the supporting masonry or soil
DISTRIBUTION OF HORIZONTAL SHEAR
design analysis requirement, considered as the basis for the structural design of structures where the total lateral forces are distributed to the various vertical elements of the lateral force resisting system in proportion to their rigidities considering the rigidity of the horizontal bracing system or diaphragm
HYBRID STEEL GIRDER
is a fabricated metal beam composed of flanges with a material of a specified minimum yield strength different from that of the web plate
INTENSITY
the measure of the damage level of an earthquake (subjective to visual assessment)
INFLECTION POINT
a point in the moment diagram where it changes from positive to negative moment of vise versa and the value of the moment at this point is zero
JETTING
a method of driving piles or well points into the sand in the situations where a pile hammer might not be suitable owing to the risk of damage by vibration to the piles of adjacent buildings.
LINTEL BEAM
a beam especially provided over an opening for a door, window, to carry the wall over the opening
MAGNITUDE
the measure of the energy released by an earthquake (measured by instrument)
MODULUS OF ELASTICITY
is the constant which, within the proportional limit, express ratio between the unit stress to the unit strain. It is the measure of the relative abilities of the different materials of construction to resist deformation under stress within proportional limit
MODULUS OF RESILIENCE
is a measure of the capacity of the material to absorb energy without danger of being permanently deformed
MOMENT OF RESITANCE
is the internal resisting moment of a beam. It is opposite in sense to the bending moment but of the same magnitude
MORTAR
is a mixture, composed of one part of Portland cement and one part of clean sand, used as a filter
MULLION
is a vertical member between two portions of window sash usually designed to resist wind load and not vertical load. It is different from muntin, which is smaller member which separates the panels of glass within the whole sash.
NON- BEARING WALL
is wall that carries no load other than its own weight
ORTHOGONAL EFFECT
the effect on the structure due to extreme lateral (earthquake) motions acting in directions other than parallel to the direction to the direction of resistance under consideration
PARTY WALL
is a wall used or adopted for joint service between two buildings
PLASTER CEMENT FINISH
a mixture of Portland cement, with water and sand applied to surfaces such as walls ceilings in a plastic state, later it sets to form a hard surface
POINTING
in masonry, the final treatment of joints by the troweling of mortar or putty like filler into joints
PORTAL METHOD
method of analyzing indeterminate modular building frames by assuming hinges at the center of beam spans and column heights or the interior column carries twice as much shear as the exterior column
PORTLAND CEMENT
is the product obtained by finely pulverizing clinker produced by calcining to incipient fusion an intimate and properly proportioned mixture of argillaceous and calcareous materials with no additions subsequent to calcinations except water and calcined or uncalcined gypsum
PROPORTIONAL LIMIT
is the highest unit stress for which the deformation of a body is proportional to the stress. Beyond this point, permanent deformation occurs
REDUNDANT MEMBER
is any framed structure or truss, is one which maybe omitted in the structure without affect in the possibility of analyzing the frame or truss by ordinary static method of computations such as the counter diagonal truss
RIP-RAP
consist of rough stones of various placed compactly or irregularly to prevent scour by water and protect material which maybe washed out by the water
SAGROD
structural member in the steel truss framing that counteracts forces in compression because of high probability of the purlins to deflect and bend down during purlin installation.
SAND DRAIN
it is provided to help in the compaction of natural soil which provide channels through which water can escape much more rapidly then through the clay itself. The weight of the drain itself helps in the compaction.
SHEAR WALL
a wall designed to resist lateral forces parallel to the plane of a wall
SOFFIT is the concave surface of an arch
SPANDREL BEAM
is a beam from column to column, carrying an exterior wall in a skeleton building
STIFFNESS RATIO (K)
in moment distribution method- (as used in analysis of indeterminate structures) is the ratio of moment of inertia of the cross section of its length
STRESS
is the cohesive force in a body, which resists the tendency of an external force to change the shape of the body
STRAIN OR DEFORMATION
is the change in the shape of any material when subjected to the action force
TIE BAR
a deformed bar, embedded in a concrete construction at a joint and designed to hold a butting edges together, not designed for direct load transfer
TORSION OR MOMENT OF INERTIA
is a quality which measures the resistance of the mass to being revolved about a line
TRANSFORMED SECTION
is one in which the flexural steel is conceived to be replaced by large area of imaginary concrete which can take tension. This gives a homogeneous section of concrete to which ordinary beam analysis may be applied
TREMIE
is a watertight pipe 300 mm to 600 mm in diameter with a flared top used in depositing concrete under water
UNDERPINNING
is an art of placing new foundation under old foundation
VIBRATOR
is an oscillating power operated machine used to agitate fresh concrete so as to eliminate gross voids including entrapped air and to produce intimate contact with form surfaces and embedded materials
VOID- CEMENT RATIO
is the ratio of volume of air plus water to the volume cement
WALL FOOTING
a continuous type of spread footing the supports vertical load, the weight of the wall itself and the weight of the footing
WATER CEMENT RATIO
the ration of the amount of water, to the amount of cement in a concrete or mortar mixture
WEB CRIPPLING
local failure of a thin web plate of a steel beam or girder in the immediate vicinity of a concentrated load
ASD
ALLOWABLE STRESS DESIGN
LRFD
LOAD RESISTANCE FACTOR DESIGN
SEISMIC DESIGN PROVISION
ARTIFICIAL RIGIDITY
will cause torsion (twisting)
BASE
is the level at which the earthquake motions are considered to be imparted to the structure
BASE SHEAR
is the total designed lateral force or shear at the base of the structure
BEARING WALL SYSTEM (shear type)
is a structural system without a complete vertical load carrying space frame
BOUNDARY ELEMENT
is an element at edges of opening or at the perimeters of shear walls or diaphragm
BRACED FRAME
is an essentially vertical truss system of the concentric or eccentric type which is provided to resist lateral forces
BUILDING FRAME SYSTEM
is an essentially complete space frame which provides supports for gravity loads
CONCENTRIC BRACED FRAME
is a braced frame in which the members are subjected primarily to axial forces
COLLECTOR
is a member or an element provided to transfer lateral forces from a portion of a structure to the vertical elements of the lateral force resisting system
DIAPHRAGM
is a horizontal or nearly horizontal system (including horizontal bracing system) acting to transmit lateral forces to the vertical resisting elements
DIAPHRAGM STRUT
also known as tie or collector, is the element of a diaphragm parallel to the applied load which collects and transfer diaphragm shear to the vertical resisting elements or distribute loads within the diaphragm. Such members may also take axial tension or compression.
DIAPHRAGM CHORD
is the boundary element of a diaphragm or a shear wall which is assumed to take axial stresses analogous to the flanges of the beam
DUAL SYSTEM
is a combination of a Special or Intermediate Moment Resisting Space Frame and Shearwalls or Braced Frame
ESSENTIAL FACILITIES
are those structures which are necessary for emergency post- earthquake operations
FLEXIBLE ELEMENT
an element or system is one whose deformation under lateral load significantly larger than adjoining parts of the system
HARMONIC MOTION
the coincidence of the natural period of structural with the dominant frequency in the ground
MOMENT RESISTING FRAME
is a space frame in which the members and joints are capable of resisting forces primarily by flexure
ORTHOGONAL EFFECT
is the effect of the structure due to earthquake motions acting in directions other than parallel to the direction of resistance under consideration
P- DELTA EFFECT
is the secondary effect on shears and moments of frame members induced by the vertical loads acting on the laterally displaced building frame
PERT-CPM
PROGRAM EVALUATION REVIEW TECHNIQUE- CRITICAL PATH METHOD
it is a presentation of project plan by a schematic diagram or network that depicts the sequence and interrelation of all the component parts of the project, and the logically analysis and manipulation of this network in determining the best overall program of operation.
PLATFORM
is the lower rigid portion of a structure having vertical combination of structural system
PNEUMATIC MORTAR
mortar applied to a surface with a cement gun in the same manner as gunite, with such mortar has a cube crushing strength of 20.68 Mpa
at 28 days with water/ cement ratio of 0.45
SHEAR WALL
is a wall designed to resist lateral forces parallel to the plane of the wall (sometimes referred to or a structural wall)
SOFT STOREY
is a storey whose lateral stiffness is less than 70% of the stiffness of the storey above
SOIL- STRUCTURE RESONANCE
is the coincidence of the natural period of structure which dominant frequency in the ground motion
STRENGTH
is the usable capacity of a structure or its members to carry loads within the deformation limits prescribed in the code
SOIL STABILIZATION
is the process of improving the properties of a soil to make it more suitable for a particular purpose
SPACE FRAME
is a three dimensional structural system without bearing walls composed of members interconnected so as to function as a complete self contained unit with or without the aid of horizontal diaphragms or bracing systems
STOREY
is the space between levels. Storey x is the storey below level x
STOREY SHEAR
is the summation of design lateral forces above the storey under consideration
STOREY DRIFT
is the displacement of one level relative to the level above or below
STOREY DRIFT RATIO
is the storey drift divided by the storey height
STRUCTURE
is an assemblage of framing members designed to support gravity loads and resist lateral forces. They maybe categorized as building or non- building.
RAINWATER LEADER
it is another term of a downspout. It is a vertical pipe, often of sheet metal, used to conduct water from a roof drain or gutter to the ground.
TORSION RIGIDITY (is used in seismic design)
refers to the relative stiffness of the structure to resist torsional stress
TOWER
is the upper flexible portion of a structure having a vertical combination of structural system
VERTICAL LOAD CARRYING SPACE FRAME
is a space frame designed to carry all vertical (gravity) loads
WEAK STOREY
is a storey whose strength is less than 80% of the strength of the storey
SEISMIC REQUIREMENT FOR TRANSVERSE REINFORCEMENT
1. maximum spacing of hoops shall not exceed 24 times the diameter of the hoop bars
2. maximum spacing of hoops shall not be 8 times the diameter of the smallest longitudinal bars
3. maximum spacing of hoops shall not be more than d/4
4. the first hoop shall be located not more than 50 mm from the face of the supporting member
GRADING AND EARTHWORK
AS GRADED is the extent of surface conditions on completion of grading
BEDROCK is in-place solid rock
BENCH is a relatively level step excavated into earth material
on which fill is to be placed
BURROW is earth material acquired from an off site location
for use in grading on a site
COMPACTION s the densification of a fill by mechanical means
EARTH MATERIAL is any rock, natural soil or fill or any combination
EROSION is the wearing away of the ground surface as a result of the movement of the wind, water or ice
EXCAVATION s the mechanical removal of the earth material
FILL is a deposit of earth material placed by artificial means
GRADE is the vertical location of the ground surface
EXISTING GRADE is the grade prior to the grading
FINISH GRADE is the final grade of the site that conforms to the approved plan
GRADING is any excavating or filling or combination thereof
KEY is a designed compacted fill placed in a trench excavated material beneath the toe of a proposed fill slope
REINFORCED CONCRETE DESIGN
ADMIXTURE
a material used as ingredient of concrete and added to concrete before or during its mixing to modify its properties
AGGREGATE
granular material such as sand gravel stone and iron blast furnace slag used with a cementing medium to form a hydraulic cement concrete or mortar
AGGREGATE LIGHTWEIGHT
aggregate with a dry, loose weight of 100 kg/m or less
in post tensioning, a device used to anchor tendon to concrete member, in pre- tensioning, a device used to anchor a tendon during hardening of concrete
BONDED TENDON
pre-stressing tendon that is bonded to concrete either directly or through grouting
COLUMN
member with a ratio to least lateral dimension of 3 or greater used primarily to support axial compressive load
COMPOSITE CONCRETE FLEXURAL MEMBERS
concrete flexural members of pre-cast and/or cast in place concrete elements but so interconnected that all elements respond to loads as a unit
CONCRETE
mixture of Portland cement or any other hydraulic cement, fine aggregate, coarse aggregate, and water, with or without admixtures
SPECIFIED COMPRESSIVE STRENGTH OF CONCRETE (f’)
compressive strength of concrete used in design expressed in megapascals (Mpa). Whenever the quantity F”c is under a radical sign, square root of numerical value only is intended, and result has units of megapascals (Mpa).
CONCRETE, STRUCTURAL LIGHT WEIGHT
concrete containing lightweight aggregate and has an air-dry unit weight not
exceeding 1900 kg/m3. lightweight concrete without natural sand is termed all- light weight concrete and lightweight concrete in which of the fine aggregate consists of normal weight sand is termed sand- lightweight concrete.
CURVATURE FRICTION
friction resulting from bends or curves in the specified pre-stressing tendon profile
DEFORMED REINFORCEMENT
deformed reinforcing bars, bar mats, deformed wire fabric and welded deformed fabric.
DEVELOPMENT LENGTH
length of embedded reinforcement required to develop the design strength of reinforcement at a critical section
EFFECTIVE DEPTH OF SECTION (d)
distance measure from extreme compression fiber to centroid of tension reinforcement
EFFECTIVE PRESTRESS
stress remaining in prestressing tendons after all losses has occurred, excluding effects of dead load and super imposed load
EMBEDMENT LENGTH
length of embedded reinforcement provided beyond a critical section
JACKING FORCE
in prestressed concrete, temporary force exerted into prestressing tendons
DEAD LOAD (DL)
dead weight supported by a member.
Loads of constant magnitude that remains in one position.
LIVE LOAD (LL)
loads that may change in magnitude and position
FACTORED LOAD
load multiplied by appropriate load factors, used to proportion a members by the strength design method.
MODULUS OF ELASTICITY
ratio of normal stress to corresponding strain for tensile or compressive stresses below proportional limit of material
MODULUS, APARENT (concrete)
also known as long term modulus, is determined by using the stress and strain obtained after the load has been applied for a certain length of time
MODULUS, INITIAL (concrete)
the slope of the stress strain diagram at the origin of the curve
MODULUS, SECANT (concrete)
the slope of the line drawn from the origin to appoint on the curve somewhere between 25% and 50% of its ultimate compressive strength
MODULUS, TENGENT (concrete)
the slope of tangent to the curve to some point along the curve
PEDESTAL
an upright compression member with a ratio of unsupported height to average least lateral dimensions of less than 3
PLAIN CONCRETE
concrete that does not conform to the definition of reinforced concrete
PLAIN REINFORCEMENT
reinforcement that does not conform to the definition of deformed reinforcement
POST TENSIONING
method of prestressing in which the tendons are tensioned after concrete has hardened
PRECAST CONCRETE
plain or reinforced concrete element cast elsewhere than its final position in the structure
POSTENSIONING
method of prestressing concrete which the tendons are tensioned before concrete is placed
REINFORCED CONCRETE
designed on the assumption that two materials act together in resisting forces
SPIRAL REINFORCEMNT
continuously wound reinforcement in the form of a cylindrical helix
STIRRUP
reinforcement used to resist shear and torsion stresses in a structural member: typically bars, wires or welded wire fabric (smooth or deformed) either single leg or bent into L, U or rectangular shapes and located perpendicularly to or at angle to longitudinal reinforcement (The term stirrups is usually applied to lateral reinforcement in flexural members and the term ties to those in compression members.)
DEIGN STRENGTH
nominal strength reduction factor, Ø
NOMINAL STRENGTH
strength of a member or cross- section before application of any strength reduction factors
REQUIRED STRENGTH
strength of a member or cross section required to resist factored loads or related internal moments and forces in such combinations
TENDON
steel element such as wire, cable, bar, rods or strand, or a bundle of such elements used to impart prestress to concrete
TIE
loop or reinforcing bar or wire enclosing longitudinal reinforcement
TRANSFER
act of transferring stress in prestressing tendons from jacks
or pretensioning bed to concrete member
WALL
member, usually vertical, used to enclose or separate spaces
WOBBLE FRICTION
in pre-stressed concrete, friction caused by unintended deviation of prstressing sheath or duct from its specified profile
YIELD STRENGTH
specified minimum yield strength or yield point or reinforcing in Mpa
BALANCED DESIGN
a design so proportioned that the maximum stress in concrete (with strain of 0.003) and steel (with strain of Fy/Es) are reached simultaneously once the ultimate load is reached, causing them to fall simultaneously
UNDERREINFORCED DESIGN
a design in which the steel reinforcement is lesser than what is required for balanced conditioned. Failure under this condition is ductile and will give warning to the user of thee structure to decrease the load
OVERREINFORCED DESIGN
a design in which the steel reinforcement is more than what is required for balanced condition
AGGREGATES
Fine aggregates- sand
are those that passes through a No.4 sieve (about 6mm in size)
Coarse aggregate -gravel or crushed stone
Coarse aggregate shall not be less than:
· 1/5 the narrowest dimension between sides of forms
· 1/3 the depth of slabs
¾ minimum clear spacing between individual reinforcing bars or wires, bundle of bars or prestressing tendons or ducts
CONCRETE PROTECTION FOR REINFORCEMENT
75 mm -for concrete cast and permanently exposed to earth such as footings
40-50 mm for concrete members exposed to weather
40 mm concrete cover of pipes, conduits or fittings and exposed to weather
40 mm for beams and columns
20 mm for concrete not exposed to weather or in contact with ground, such as slabs, walls and joists
FOR BUNDLED BARS
a. groups of parallel reinforcing bars bundled in contact as a unit shall be limited to 4 in any one bundle
b. bundled bars shall be enclosed within stirrups or ties
c. bars larger than 32mm shall not be bundled in beams
d. individual bars within a bundle terminated within the span of flexural members should terminate at a different points at least 40db stagger
The minimum concrete cover for bundled bars shall be:
· Equal to the equivalent diameter of the bundle but not exceeding 50 mm
· 75 mm- for concrete cast against and permanently exposed to earth
STANDARD HOOKS
A. 180º bend plus 4db extension but not less than 65 mm at free end
B. 90º bend plus 12db extension, at free end of bar
C. for stirrups and tie hooks:
· 16 mm bar and smaller, 90º bend plus 6db extension at free end of bar or
· 20 mm and 25 mm bar, 90º bend plus 6db extension at free end of bar or
· 25 mm bar and smaller, 135º bend plus 6db extension at free end of bar
MINIMUM BEND
The diameter of bend measured on the inside of the bar shall not be less than the following:
(a.) 6db for 10 mm to 25 mm bar
(b.) 8db for 10 mm to 28 mm bar
(c.) 10db for 10 mm to 36 mm bar
4db minimum inside diameter of bend of stirrups and ties for 16 mm bar and smaller in diameter
ONE- WAY SLAB
A one-way slab is considered as wide shallow rectangular beam. The reinforcing steel is usually spaced uniformly over its width. The flexural reinforcement of a one-way slab extends in one direction only.
Maximum flexural reinforcement spacing:
3 times the slab thickness or 450 mm
Minimum thickness of one-way slab:
Solid one-way slab
L/20 - simply supported
L/24 - one end continuous
L/28 - both end continuous
L/10 - cantilever
* Span length L is in millimeter
Ribbed one-way slab
L/16 - simply supported
L/18.5 - one end continuous
L/21 - both end continuous
L/8 - cantilever
LOAD FACTORS
Dead load, DL……………………………………………….. 1.40
Live load, LL…………………………….…………………… 1.70
Wind load, WL………...…………………………………….. 1.70
Earthquake, E……………………………………….………. 1.87
Earth or water pressure, H……………………...……….… 1.70
STRENGTH REDUCTION FACTOR Ø
Flexure w/o axial load……………………………………………….. 0.90
Axial tension & axial tension w/ flexure……………………………. 0.90
Shear and torsion ……………………………………………………. 0.85
Axial compression & axial compression w/ flexure
a. spiral reinforcement ……………………………………… 0.75
b. tie reinforcement …………………………………………. 0.70
Bearing on concrete ………………………………………………….. 0.70
REQUIRED STRENGTH, U or Pu
Required strength U to resist dead load DL and live load LL is
U= 1.4DL + 1.7LL
Wind load W are included in design
U= 0.75 (1.4DL + 1.7LL + 1.7W)
Earthquake loads or forces are included in design
U= 0.75 (1.4DL + 1.7LL + 1.87E)
Where structural effect T of differential settlement, creep, shrinkage or temperature change are significant in design
U= 0.75 (1.4DL + 1.4T + 1.7LL)
but required strength U shall not be less than
U= 1.4 (DL + T)
SIZE AND SPACING OF MAIN BARS AND TIES
1. Clear distance between longitudinal bars shall be not less than
1.5 db nor 40 mm
2. Use 10 mm diameter ties for 32 mm bars or smaller and at least
12 mm in size for 36 mm and bundled longitudinal bars
3. Vertical spacing of ties shall be the smallest of the following:
a. 16 x db (db = longitudinal bar diameter)
b. 48 x tie diameter
c. least dimension of columns
4. Ties shall be arrange such that every corner and alternate longitudinal bar shall have lateral support provided by the corner of the tie with an included angle of not more than 135º and no bar shall be farther than 150 mm clear on each side along the tie from such a laterally supported bar. Where longitudinal bars are located around the perimeter of a circle tie is allowed.
MINIMUM REQUIREMENT FOR DEVELOPMENT OF REINFORCEMNT
1. not less than 12 db
2. not less than 1/16 clear span
3. not less than d
whichever is greater
CRITERION FOR CONDUITS AND PIPES EMBEDDED IN CONCRETE
a. Conduits and pipes embedded in slab, the wall or beam shall not be larger in outside dimension than 1/3 the overall thickness of slab, wall or beam
b. Reinforcement with an area not less than 0.002 times the area of cross- section shall be provided normal to piping
c. Conduits and pipes with their fittings, embedded within a column shall not displace more than 4% of the area of the cross section on which strength is calculated
d. Concrete cover for pipes, conduits and fittings shall not be less than 40 mm for concrete exposed to earth or weather
CHARACTERISTICS OF HIGH BOLTED CONNECTION
1. High-strength bolted parts shall fit solidly together when assembled and shall not be separated by gaskets or any other interposed compressive material.
2. Bolts tightened by means of a calibrated wrench shall be installed with a hardened washer under the nut or bolt head whichever is the element turned in tightening.
3. When assembled, all joint surfaces, including those adjacent to the washer, shall be free of scale, except tight mill scales, dirts and burns.
4. Surface in contact with the bolt head and nut head shall have slope of not more than 1:20 with respect to a plane normal to the bolt axis.
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