IS 6461 (Part 9) — Structural Aspects · Concrete Glossary

Allowa ble Load Cl 3.1

The ultima te load divided by factor of safety.

Allowable Stress Cl 3.2

Maximum permissible stress used in design of members of a structure and based on a factor of safety against rupture or yielding of any type.

Average Bond Stress Cl 3.3

The force in a bar divided by the product of its perimeter and its embedded length.

Balanced Load Cl 3.4

Load capacity at simultaneous crushing of concrete and yielding of tension steel.

Balanced Moment Cl 3.5

Moment capacity at simultaneous crushing of concrete and yielding of tension steel.

Balanced Reinforcement Cl 3.6

An amount and distribution of reinforcement in a flexural member such that in working stress design the allowable tensile stress in the steel and the allowable compressive stress in the steel and the allowable compressive stress in the concrete are attained simultaneously.

Beam Cl 3.7

A structural member subjected primar ily to flexure; also the graduated horizontal bar of a weighing scale on which the balancing poises ride.

Beam and Slab Floor Cl 3.8

A reinforced concrete floor system in which the floor slab is supported by beams of reinforced concrete.

Beam Test Cl 3.9

A method of measuring the flexural strength (modulus of rupture) of concrete by testing a standard unreinforced beam.

Bearing Capacity Cl 3.10

The maximum unit pressure which a soil or other material will withstand without failure or without settlement to an amount detrimental to the integrity or the function of the structure.

Bond Cl 3.11

Adhesion and grip of concrete or mo rtar to reinforcement or to other surfaces against which it is placed, including friction due to shrinkage and longitudinal shear in the concrete engaged by the bar deformations; the adhesion of cement paste to aggregate; adherence between plaster coats or between plaster and a substrate produced by adhesive or cohesive properties of plaster or supplemental materials; also the arrangement of units in concrete block or stone masonry and brickwork so that vertical joints are discontinuous.

Bond Area Cl 3.12

The area of interface between two elements across which adhesion develops or may develop, as between concrete and reinforcing steel.

Bond Length Cl 3.13

The length of grip of a rein forcing bar.

Bond Strength Cl 3.14

Resistance to separation of mortar and concrete from reinforcing steel and other materials with which it is in contact; a collective expression for all forces, such as adhesion, friction due to shrinkage, and longitudinal 1 IS 6461 (Part 9) : 2024 To access Indian Standards click on the link below: https://www.services.bis.gov.in/php/BIS_2.0/bisconnect/knowyourstandards/Indian_standards/isdetails/ IS 1786 : 2008 High strength deformed steel bars and wires for concrete reinforcement — Specification (fourth revision) shear in the concrete engaged by the bar deformations that resist separation.

Bond Stress Cl 3.15

The force of adhesion per unit area of co ntact between two bonded surfaces, such as concrete and reinforcing steel or any other material such as foundation rock; shear stress at the surface of a reinforcing bar, preventing relative movement between the bar and the surrounding concrete.

Brace Cl 3.16

Any structural member used to support another; always designed for compression and sometimes for compression and tension under special load condition.

Bracket Cl 3.17

An overhanging member projecting f rom a wall or other body to support weight outside the wall, or similar piece to strengthen an angle.

Cellular Raft Cl 3.18

A raft in which the intersecting beams form a number of cells.

Column Capital Cl 3.20

An enlargement of the end of a column designed and built to act as an integral unit with the column and flat slab and increase the shearing resistance.

Column, Combination Cl 3.21

A column in which a structural steel member, designed to carry part of the load, is encased in concrete of such quality, and in such manner that the remaining load may be allowed thereon.

Column Strip Cl 3.25

The portion of a flat slab over the column and consisting of the two adjacent quarter panels on each side of the column centre line.

Combined Footing Cl 3.26

A structural unit or assembly of units supporting more than one column load.

Composite Pile Cl 3.27

A pile made up of different materials, usually concrete and wood, or steel fastened together end to end, to form a single pile.

Compression Flange Cl 3.28

The widened portion of an I, T, or similar cross-section beam which is show tend or compressed by bending under normal loads, such as the horizontal portion of the cross-section of a simple span T-beam.

Compression Reinforcement Cl 3.29

Reinforcement designed to carry compressive stresses.

Compressive Strength Cl 3.30

T he measured maximum r esistance of a concrete or, mortar specimen to axial loading expressed as force per unit cross-sectional area.

Concrete Casing Cl 3.31

Protective concrete covering to structural steel.

Concrete Pile Cl 3.32

A reinforced or prestressed concrete pile driven into the ground by a pile driver or otherwise placing. 2 IS 6461 (Part 9) : 2024

Concrete, Structural Cl 3.33

Concrete used to carry structural load or to form an integral part of a structure; concrete of a quality specified for structural use; concrete used solely for protective cover, fill, or insulation is not considered structural concrete.

Concrete, Structural Lightweight Cl 3.34

Structural concrete made with lightweight aggregate; the unit weight usually): is in the range of 1440 kg/m3 to 1850 kg/m3.

Confined Concrete Cl 3.35

Concrete containing closely spaced special transverse reinforcement which is provided to restrain the concrete in directions perpendicular to the applied stresses.

Construction Loads Cl 3.36

The loads to which a permanent or temporary structure is subjected. during construction.

Contact Pressure Cl 3.37

Pressure acting at and perpendicular to the contact area between footing and soil, produced by the weight of the footing and all forces acting on it.

Continuous Footing Cl 3.39

A combined footing of prismatic or truncated shape, supporting two or more columns in a row.

Continuous Slab or Beam Cl 3.40

A slab or beam which exten ds as a unit over three or more supports in a given direction.

Continuously Reinforced Pavement Cl 3.41

A pavement with out transverse joints, except tied construction joints placed between successive days concreting, with sufficient longitudinal reinforcement, adequately lapped to develop tensile continuity, so that transverse cracks will be held tightly closed.

Conventional Design Cl 3.42

Design procedure using moments or stresses determined by widely accepted methods.

Cracked Section Cl 3.45

A section designed or analysed on the assumption that concrete has no resistance to tensile stress.

Cracking Load Cl 3.46

The load which causes tensile stress in a member to exce ed the tensile strength of the concrete.

Dead Load Cl 3.47

The weight of a structure or p ortion thereof.

Deflection Cl 3.48

In general, an angular variation from an established direction or plane, usually measured as a linear deviation from an established plane rather than an angular variation.

Deformation Cl 3.49

A change in dimensions or shape due to stress.

Design Compressive Strength Cl 3.50

The load - bearing capacity of a member computed on the basis of the allowable stresses assumed in design; the assumed values for the strength of the concrete and the yield stress of the steel on whose basis the theoretical ultimate strength of a section is computed.

Diagonal Tension Cl 3.51

The principal tensile stress resulting from the combination of vertical and horizontal stresses in a beam.

Double T Cl 3.52

Beam — A member composed of two beams and a top slab projecting on both sides; also a flat slab panel with projecting stems.

Dowel Shear Cl 3.53

The force applied in the plane of the cross-section of the dowel.

Drop Cl 3.54

in-Beam — A simple beam, usually suppo rted by cantilever arms, with joints so arranged that it is installed by lowering into position.

Drop Panel Cl 3.55

The structural portion of a flat slab which is thickened throughout an area surrounding the column, column capital or bracket.

Dynamic Analysis Cl 3.56

Analysis of stresses in framing as functions of displacement under transient loading. 3 IS 6461 (Part 9) : 2024

Dynamic Load Cl 3.57

A load which is variable, that is, not static, such as a moving live load, earthquake, or wind.

Dynamic Loading Cl 3.58

Loading from units (particularly machinery) which, by virtue of their movement or vibration, impose stresses in excess of those imposed by their dead load.

Dynamic Modulus of Elasticity Cl 3.59

The modulus of elasticity computed from the size, weight, shape, and fundamental frequency of a concrete test specimen, or from pulse velocity.

Edge Beam Cl 3.60

A stiffening beam at the edge of a slab.

Effective Area of Concrete Cl 3.61

Area of a section assumed to be active in resisting the applied stresses; the area of a section which lies between the centroid of the tension reinforcement and the compression face of the flexural member; for a cracked flexural member, the effective area of concrete is the area between the neutral axis and the compression face.

Effective Area of Reinforcement Cl 3.62

The area obtained by multiplying the normal cross -sectional area of reinforcement by the cosine of the angle between the direction of the reinforcement and the direction in which the effectiveness is required.

Effective Area of Reinforcement in Diagonal Bends Cl 3.63

The area obtained by multiplying the normal cross-sectional area of the reinforcement by the cosine of the angle at which the bend is inclined to the direction for which its effectiveness is considered.

Effective Depth Cl 3.64

Depth of a beam or slab section measured from the compression face to the centroid of the tensile reinforcement.

Effective Flange Width Cl 3.65

Width of slab adjoining a beam stem assumed to function as the flange element of a T-beam section.

Effective Length of Column Cl 3.66

The distance between infection points in a column when it bends.

Effective Modulus of Elasticity Cl 3.67

Combination of elastic and plastic effects in an overall stress -strain relationship in the service structure; often expressed as: 𝐸eff = 1 1 + 0.4 (𝐸c/𝐸f) 𝐸c where Eeff = effective modulus of elasticity; Ec = modulus of elasticity of concrete; and Ef = modulus of elasticity of the foundation rock.

Effective Reinforcement Cl 3.68

Reinforcement of a section assumed to be active in resisting the applied stresses.

Effective Span Cl 3.69

The lesser of the two following distances: a) the distance between centres of supports ; and b) the clear distance between supports plus the effective depth of the beam or slab.

Effective Stress Cl 3.70

In prestressed concrete, the stress remaining in the tendons after all losses of the prestressing load have occurred.

Effective Width of Slab Cl 3.71

That part of the width of a slab taken into account when designing T-beam or L-beam.

Elastic Design Cl 3.72

A method of analysis in which the design of a member is based on a linear stress-strain relationship and corresponding limiting elastic properties of the material.

Elastic Limit Cl 3.73

The limit of stress beyond which the strain is not wholly recoverable.

Elastic Loss Cl 3.74

In pretension concrete, the reduction in prestressing load resulting from the elastic shortening of the member.

Elasticity Cl 3.75

That property of a material by virtue of which it tends to recover its original size and shape after deformation.

Equivalent Rectangular Stress Distribution Cl 3.76

An assumption of uniform stress on compression side of neutral axis in a reinforced concrete section used in Whitney method of ultimate strength design to approximate actual conditions at ultimate bending load.

Exterior Panel Cl 3.77

In a flat slab, a panel having at least one edge which is noncontinous.

Extreme Compression Fibre Cl 3.78

A fibre farthest removed from the neutral axis on the compression side of a member subjected to bending.

Factor of Safety Cl 3.79

The ratio of the ultimate strength (or yield point) of a material to the working stress assumed in design (stress factor of safety); or the ratio of the ultimate load, moment, or shear of a structural member to the working load, moment, or 4 IS 6461 (Part 9) : 2024 shear, respectively, assumed in design (load factor of safety).

Fatigue Cl 3.80

The weakening of a material caused by repea ted or alternating loads.

Fatigue Strength Cl 3.81

The greatest stress which can be sustained for a given number of stress cycles without failure.

Flexural Moment Cl 3.82

See 3.145.

Flexural Rigidity Cl 3.83

A measure of stiffness of a member, indicated by the product of modulus of elasticity and moment of inertia divided by the length of the member.

Flexural Strength Cl 3.84

A property of a solid that indicates its ability to withstand bending.

Foundation Cl 3.85

The material or materials through which the load of a structure is transmitted to the earth.

Four Cl 3.86

Way Reinforcement — A system of reinforcement in flat slab construction comprising bands of bars parallel to two adjacent edges and also to both diagonals of a rectangular slab.

Frame or Panel Cl 3.87

The principal prefabr icated, welded structural unit in a scaffolding tower; also beam and column skeleton of a building.

Girder Cl 3.88

Any heavy, strong, or principal, usually horizontal flexural member on which the weight of a floor, partition, or beam is carried.

Grade Beam Cl 3.89

A reinforced concrete beam, usually at ground level, to form a foundation for the walls of a super-structure.

Grid Foundation Cl 3.90

A combined footing formed by intersecting continuous footings, loaded at the intersection points and covering less than 75 percent of the total area within the outer limits of the assembly.

Hardy Cross Method Cl 3.91

A method of distributing moments named after its inventor, a sign convention.

Haunch Cl 3.92

The deepened portion of a beam that increases in depth toward the support.

H/D Ratio Cl 3.94

Ratio of height, H, to diameter, D.

Hinge Joint Cl 3.95

Any joint which permits hinge action with no appreciable separation of the adjacent members.

Imposed Load Cl 3.96

The load assumed to be produce d by the intended use or occupancy of a building including the weight of movable partitions, distributed and concentrated loads, loads due to impact and vibration, and dust loads but excluding wind, seismic, snow and other loads due to temperature changes, creep, shrinkage, differential settlements, etc.

Inelastic Behaviour Cl 3.97

Deformation that does not disappear on removal of the force that produced it.

I Cl 3.98

section — Beam cross-section consisting of a top an d bottom flanges connected by a vertical web.

Isotropy Cl 3.99

The behaviour of a medium having the same p roperties in all directions.

Kern Area Cl 3.100

The area located within the kern distance from the centroid of a footing as seen in plan.

L Cl 3.101

Column — The portion of a precast concrete frame, composed of the column, the haunch, and part of the girder.

Lever Arm Cl 3.102

In a structural member, the distance f rom the centre of the tensile reinforcement to the centre of action of the compression.

Lift Slab Cl 3.103

A method of concrete construction in which floor and roof slabs are cast on or at ground level and hastened into jacking; also a slab which is a component of such construction.

Limit Design Cl 3.104

A method of proportioning reinforced concrete members based on calculations of their ultimate strength.

Load Cl 3.105

Bearing Wall — A wall designed and built to carry superimposed vertical and shear loads as opposed to non-load-bearing walls.

Load Factor Cl 3.106

The ratio of the collapse load to the working load on a structure or section. 5 IS 6461 (Part 9) : 2024

Mat Foundation Cl 3.107

A continuous footing sup porting an array of columns in several rows in each direction, having a slab-like shape with or without depressions or openings, covering an area at least 75 percent of the total area within the outer limits of the assembly (see also 3.90 and 3.152).

Membrane Theory Cl 3.108

A theory of design for thin shells, based on the premise that a shell cannot resist bending because it deflects; the only stresses that exist, there therefore, in any section are shear stress and direct compression or tension.

Middle Strip Cl 3.109

In flat slab framing, the slab portion which occupies the middle half of the span between columns (see 3.25).

Modular Ratio Cl 3.110

The ratio of modulus of elasticity of steel ES to that of concrete EC usually denoted by the symbol m.

Modulus of Deformation Cl 3.111

A concept of modulus of elasticity expressed as a function of two time variables; strain in loaded concrete as a function of the age at which the load is initially applied and of the length of time the load is sustained.

Modulus of Elasticity (E) Cl 3.112

The ratio of normal stress to corresponding strain for tensile or compressive stresses below the proportional limit of the material. This is also referred as elastic modulus, Young’s modulus, chord modulus and initial tangent modulus.

Modulus of Rigidity Cl 3.113

The ratio of unit shearing stress to the corresponding unit shearing strain; referred to as ‘shear modulus’ and ‘modulus of elasticity in shear’.

Modulus of Rupture Cl 3.114

A measure of the ultimate load -carrying capacity of a beam and sometimes referred to as ‘rupture modulus’ or ‘rupture strength’. It is calculated for apparent tensile stress in the extreme fibre of a transverse test specimen under the load which produces rupture.

Note — The actual stress in the extreme fibre is less than the apparent stress since the flexure formula employed in the calculation is valid only for stresses within the proportional limit of the material; nevertheless, the nominal rupture strength so obtained is considered the rupture modulus.

Mud Slab Cl 3.115

A 5 cm to 15 cm layer of concrete below structural concrete floor or footing over soft, wet soil.

Negative Moment Cl 3.116

A condition of flexure in which top fibres of a horizontally placed member, or external fibres of a vertically placed exterior member, are subjected to tensile stresses.

Neutral Axis Cl 3.117

A line in the plane of a structural member subject to bending where the longitudinal stress is zero.

One Cl 3.118

Way System — The arrangement of steel reinforcement within a slab that presumably bends in only one direction.

Overdesign Cl 3.119

To require adherence to structur al design requirements higher than service demands, as a means of compensating for statistical variation or for anticipated deficiencies or both.

Overturning Cl 3.120

Result of any combination of forces tending to overcome stable equilibrium.

Panel Cl 3.121

A concrete member, usually precast, rectangular in shape, and relatively thin with respect to other dimensions.

Panel Strip Cl 3.122

A strip used for design purposes extending across the length of width of a flat slab.

Pedestal Cl 3.123

An upright compression member whose h eight does not exceed 3.46 times its average lateral dimension or whose effective length does not exceed twelve times its least radius of gyration: such as a short pier or plinth used as the base for a column.

Pedestal Pile Cl 3.124

A cast-in-place concrete pile constr ucted so that concrete is forced out into a widened bulb or pedestal shape at the foot of the pipe which forms the pile.

Pier Cl 3.125

Isolated foundation member of plain or reinforced concrete.

Pilaster Cl 3.126

Column built within a wall, usually projecting beyond the wall.

Pilaster Cl 3.127

Face —The form for the front surface of a pilaster parallel to the wall.

Pilaster Side Cl 3.128

The form for the side surface of a pilas ter perpendicular to the wall.

Pile Cl 3.129

A long slender timber, concrete, or steel stru ctural element, driven, jetted, or otherwise embedded on end in the ground for the purpose of supporting a load or of compacting the soil.

Pile Bent Cl 3.130

Two or more piles driven in a row transver se to the long dimension of the structure and fastened together by capping and (sometimes ) bracing,

Pile Column Cl 3.132

Column made of steel pipe; often filled with concrete.

Pipe Column, Concrete Filled Cl 3.133

A metal pipe column filled with concrete, with or without reinforcement, designed to carry a portion of the column load.

Pipe Pile Cl 3.134

A steel cylinder, usually between 250 mm and 600 mm in diameter, generally driven with open ends to firm bearing and then excavated and filled with concrete. This pile may consist of several sections from 1.5 m to 8 m long joined by cast-steel sleeves or otherwise. Sometimes it is used with its lower end closed by a conical steel shoe.

Plane of Weakness Cl 3.135

The plane along which a body under stress will tend to fracture; may exist by design, by accident, or because of the nature of the structure and its loading.

Plastic Centroid Cl 3.136

Centroid of the resistance to load co mputed for the assumptions that the concrete is stressed uniformly to 0.85 its design strength and the steel is stressed uniformly to its specified yield point.

Plastic Deformation Cl 3.137

Deformation that does not disappear when the force causing the deformation is removed.

Plastic Design Cl 3.138

See 3.216.

Plastic Flow Cl 3.139

See 3.141.

Plasticity Cl 3.140

A complex property of a material involving a combination of qualities of mobility and magnitude of yield value; that property of freshly mixed cement paste, concrete, or mortar which determines its resistance to deformation or ease of moulding.

Plastic Loss (Creep) Cl 3.141

Time dependent deformation due to sustained load.

Plate Cl 3.142

In structural design; a member, the depth of which is substantially smaller than its length and width.

Point of Inflection Cl 3.143

The point on the length of a structural member subjected to flexure at which the direction of curvature changes and at which the bending moment is zero; called also point of contra flexure; location of an abrupt bend in a plotted focus of points in a graph.

Poisson’s Ratio Cl 3.144

The ratio of transverse (lateral) strain to the corresponding axial (longitudinal) strain resulting from uniformly distributed axial stress below the proportional limit of the material; the value will average about 0.2 for concrete and 0.25 for most of the metals.

Positive Moment Cl 3.145

In simple structures, flexural m oment such as occurs in a simply supported beam under gravity loading; in complex and indeterminate structures, flexural moment of a sense determined by the particular sign convention (hardy cross or slope defection) being used.

Precast Pile Cl 3.146

A reinforced concrete pile manufactured in a casting plant or at the site but not in its final position.

Precompressed Zone Cl 3.147

The area of a flexural member which is compressed by the prestressing tendons.

Proof Stress Cl 3.148

The stress which is just sufficient to produce, under load, a non proportional elongation equal to a specified percentage of the original gauge length, conventionally the specified percentage is fixed at 0.1 percent or 0.2 percent . IS 1786 specifies this limit as 0.2 percent.

Proportional Li mit Cl 3.149

The greatest stress which a material is capable of developing without any deviation from proportionality of stress to strain (Hooke’s law).

Protected Corner Cl 3.150

Corner of a slab with ad equate provision for load transfer, such that at least 20 percent of the load from one slab corner to the corner of an adjacent slab is transferred by mechanical means or aggregate interlock.

Raft Foundation Cl 3.152

A continuous slab of concrete, u sually reinforced, laid over soft ground or 7 IS 6461 (Part 9) : 2024 where heavy loads should be supported to form a foundation.

Resilience Cl 3.153

The work done per unit volume of a material in producing strain.

Rib Cl 3.154

One of a number of parallel structural members backing sheathing; the portion of a T-beam which projects below the slab; in deformed reinforcing bars, the deformations or the longitudinal parting ridge.

Ribbed Panel Cl 3.155

A panel composed of a thin slab reinforced by a system of ribs in one or two directions, usually orthogonal.

Ribbed Slab Cl 3.156

See 3.155 .

Rider Cap Cl 3.157

See 3.131.

Rigid Frame Cl 3.158

A frame depending on moment in join for stability.

Rigid Pavement Cl 3.159

Pavement that will provide high bending resistance and distribute loads to foundation over a comparatively large area, for example, Portland cement concrete pavement, and bituminous brick, or stone -block pavement supported on Portland cement concrete base.

Secant Modulus Cl 3.160

See 3.112.

Secondary Moment Cl 3.161

In statically indeterminate structures, the additional moments caused by deformation of the structure due to the applied forces.

Semiflexible Joint Cl 3.162

A connection in which the reinforcement is arranged to permit some rotation of the joint.

Service Dead Load Cl 3.163

The calculated dead weight supported by a member.

Service Live Load Cl 3.164

The live load specified by the general building code, or the actual load applied in service.

Shear Cl 3.165

An internal force tangential to the plane on which it acts.

Sheet Pile Cl 3.166

A pile in the form of a plank driven in close contact with others to provide a tight wall to resist the lateral pressure of water, adjacent earth, or other materials; may be tongued and grooved if of timber or concrete and interlocking if made of metal.

Shrinkage Reinforcement Cl 3.167

Reinforcement designed to resist shrinkage stresses in concrete.

Simple Beam Cl 3.168

A beam without restraint or continuity at its supports.

Slab Cl 3.169

A flat, usually horizontal or nearly so, moulded layer of plain or reinforced concrete usually of uniform thickness, but sometimes of variable thickness, as the flat section of floor or roof either on the ground or supported by beams, columns, or other framework.

Slab Strip Cl 3.170

See 3.109 .

Slenderness Ratio Cl 3.171

The ratio of effective length or height of a wall or pier to effective thickness; or least radius of gyration used as a means of assessing the stability of a masonry wall or concrete panel or column.

Sloped Footing Cl 3.172

A footing having sloping top or side faces.

Span Cl 3.175

The distance between supports of a flexural member.

Spandrel Cl 3.176

A beam in the wall of a building.

Spirally Reinforced Column Cl 3.177

A column in which the vertical bars are enveloped by spiral reinforcement; that is, closely spaced continuous hooping.

Splice Cl 3.178

Connection of one reinforcing bar to another by overlapping, welding, mechanical end connectors, or other means.

Spread Footing Cl 3.179

A generally rectangular prism of concrete larger in lateral dimensions than the column or wall it ‘supports, to distribute the load of a column or wall to the subgrade.

Static Load Cl 3.180

The weight of a single stationary body or the combined weights of all of the stationary bodies in a structure, such as the load of a stationary vehicle on a roadway; or, during construction, the weight of forms, stringers, joists, reinforcing bars, and the actual concrete to be placed.

Static Young’s Modulus of Elasticity Cl 3.181

The value of Young’s modulus of elasticity obtained by arbitrary criteria from measured stress strain relationships derived from other than dynamic loading.

Stepped Footing Cl 3.182

A step -like support consisting of prisms of concrete of progressively 8 IS 6461 (Part 9) : 2024 diminishing lateral dimensions superimposed on each other to distribute the load of a column or wall to the subgrade.

Stiffness Factor Cl 3.183

A measure of stiffness, ind icated by the ratio of moment of inertia of the cross-section to the length of the member.

Straight Cl 3.184

Line Theory — An assumption in reinforced-concrete analysis according to which the strains and stresses in a member under flexure are assumed to vary in proportion to the distance from the neutral axis.

Strain Cl 3.185

Deformation of a material expressed as the ratio of linear unit deformation to the distance within which that deformation occurs.

Strength, Creep Cl 3.186

The stress that causes a given creep in a given time and at a specified temperature.

Strength, Shear Cl 3.188

The maximum shearing stress which a material is capable of developing, based on the original area of cross-section.

Stress Cl 3.189

The intensity of the force developed per unit area within a body in resisting the forces acting on it; considered at a point within a plane passing through the body, stress may be divided into two components; normal stress acting perpendicular to the plane and shearing stress tangent to the plane.

Stress Cl 3.190

Corrosion — Corrosion of a metal accelerated by stress.

Stringer Cl 3.191

A horizontal structural member supporting joists and resting on vertical supports.

Strip Footing Cl 3.192

A combined continuous footing of prismatic or truncated shape supporting two columns in a row.

Strip Foundation Cl 3.193

A continuous foundation of which the length considerably exceeds the breadth.

Strut Cl 3.194

A member supporting an axial com pressive load and having an effective length exceeding 12 times its least radius of gyration, or, if its cross-section is rectangular, 3.46 times its least lateral dimension (see also 3.19).

Sustained Modulus of Elasticity Cl 3.196

Term includin g elastic and inelastic. Effects in one expression to aid in visualizing net effects of stress strain up to any given time; computed by dividing the unit sustained stress by, the sum of the elastic and plastic deformations at that time.

Sway Brace Cl 3.197

A diagonal brace used to resist wind o r other lateral forces.

T Cl 3.198

Beam — A beam composed of a stem and a flange in the form of a ‘T’.

Temperature Stress Cl 3.199

Stress in a structure or a member due to changes or differentials in temperature in the structure or member.

Temporary Stress Cl 3.200

A stress which may be produced in a precast concrete member or component of a precast concrete member during fabrication or erection, or in cast- in-place concrete structures due to construction or test loadings.

Tensile Strength Cl 3.201

Maximum stress which a material is capable of resisting under axial tensile loading, based on the cross-sectional area of the specimen before loading.

Tensile Stress Cl 3.202

Stress resulting from tension .

Test Cl 3.203

A decisive trial, such as a controlled loading to failure of a specimen or a specified number of similar specimens.

T Cl 3.204

Head — In precast framing a segment of girder crossing the top of an interior column; also the top of a shore formed with a braced horizontal member projecting on two sides forming a T-shaped assembly.

Thin Cl 3.205

Shell Precast — Precast concrete characterized by thin slabs and web sections.

Tied Column Cl 3.206

A column laterally reinfo rced with ties.

Tower Cl 3.207

A composite structure of frames, braces, and accessories.

Transformed Section Cl 3.208

A hypothetical section of one, material arranged so as to have the same elastic properties as a section of two materials.

Transverse Strength Cl 3.209

See 3.81 and 3.114.

Two Cl 3.210

Way Reinforced Footing — A footing having reinforcement in two directions generally perpendicular to each other.

Two Cl 3.211

Way System — A system of reinfo rcement: bars, rods, or wires placed at right 9 IS 6461 (Part 9) : 2024 angles to each other in a slab and intended to resist stresses due to bending of the slab in two directions.

Ultimate Design Resisting Moment Cl 3.212

The moment at which a section reaches its ultimate usable strength, most commonly the moment at which the tensile reinforcement reaches its specified yield strength.

Ultimate Load Cl 3.213

The maximum load which may be placed on a structure before its failure due to buckling of column members or failure of some component; also the load at which a unit or structure fails.

Ultimate Shear Stress Cl 3.214

The stress at a section which is loaded to its maximum in shear.

Ultimate Strength Cl 3.215

The maximum resistance to load that a member or structure is capable of developing before failure occurs; or, with reference to cross -sections of members, the largest moment, axial force or shear a structural concrete cross-section will support.

Ultimate Strength Design Cl 3.216

A method of proportioning structures of members for failure at a specified multiple of working loads, and assuming non-linear distribution of flexural stresses.

Unbraced Length of Column Cl 3.217

Distance between adequate lateral supports.

Unprotected Corner Cl 3.218

Corner of a slab with no adequate provision for load transfer, so that the corner should carry over 80 percent of the load.

Waffle Cl 3.219

Square prefabricated pan form used in two-way concrete joist floor construction.

Wheel Load Cl 3.220

The portion of the gross weight of a loaded vehicle transferred to a supporting structure under a given wheel of the vehicle.

Wing Pile Cl 3.221

A bearing pile, usually of concrete, widened in the upper portion to form part of a sheet pile wall.

Working Stress Cl 3.222

Maximum permissible design stress using working stress design methods.

Working Stress Design Cl 3.223

A method of pr oportioning structures or members for prescribed working loads at stresses well below the ultimate, and assuming linear distribution of flexural stresses.

X Cl 3.224

Brace — A pair of tension sway braces.

Yield Point Cl 3.225

That point during increasing s tress when the proportion of stress to strain becomes substantially less than it has been at smaller values of stress.

Yield Strength Cl 3.226

The stress, less than the max imum attainable stress, at which the ratio of stress to strain has dropped well below it value at low s tress, or at which ‘a material exhibits a specified limiting deviation from the usually proportionality of stress to strain.

Yield Stress Cl 3.227

Stress (that is, load per unit cross-sectional area) at which elongation first occurs in the test piece without increasing the load during tensile test. In the case of steels with no such definite yield point, the yield stress is the stress under the prescribed testing conditions at which the observed increase in the gauge length is 1/200 of the gauge length when the rate at which the load is applied is not more than 0.5 kg/mm 2/s when approaching the yield stress.

Prestressed Concrete