Structural Engineering Terms PDF

STRENGTH OF MATERIALS TERMS Strain energy: refers to the energy stored in a material due to its deformation Modulus of toughness: indicates the maximum amount of strain-energy the material can absorb just before it fractures (ability to absorb energy in plastic range). Modulus of Resilience:...

STRENGTH OF MATERIALS TERMS Strain energy: refers to the energy stored in a material due to its deformation Modulus of toughness: indicates the maximum amount of strain-energy the material can absorb just before it fractures (ability to absorb energy in plastic range). Modulus of Resilience: represents the largest amount of internal strain energy per unit volume the material can absorb without causing any permanent damage to the material (ability to absorb energy in the elastic range) Elasticity: refers to the property of a material which makes it return to its original state when the load is removed. Ductility: refers to the ability of a material to deform in the plastic range without breaking. Stiffness: ability to resist a deformation within the linear range. This is equal to the amount of force required to produce unit deformation. Inverse of stiffness is flexibility. Toughness: refers to a material’s resistance to fracture. Hardness: refers to a material’s resistance to indentation. Ductile Material: is any material that can be subjected to large strains before it fractures. Brittle Materials: are materials that exhibit little or no yielding before failure are referred to as brittle materials. Homogeneous material: is a material that has the same physical and mechanical properties throughout its volume or material has the same composition at any point. Isotropic material: is a material that has same physical and mechanical properties in all directions. Orthotropic material: is a material that has properties at a particular point, which differ along three mutually-orthogonal axes. Prismatic: describes a member with the same cross sections throughout its length. Creep: When a material must support a load for a very long period, it may continue to deform until a sudden fracture occurs or its usefulness is impaired. This time dependent permanent deformation is known as creep. Fatigue: When a material is subjected to repeated cycles of stress or strain, it causes its structure to break down, ultimately leading to fracture. This behavior is called fatigue. Buckling: lateral deflection that occurs when long slender members are subjected to an axial compressive force. Yielding: A slight increase in stress above the elastic limit will result in a breakdown of the material and causes it to deform permanently. This behavior is called yielding and the deformation that occurs is called plastic deformation. Strain Hardening: When yielding has ended, an increase in load can be supported by the specimen, until it reaches a maximum stress referred to as the ultimate stress. Necking: Just after the ultimate stress, the cross-sectional area will begin to decrease in a localized region of the specimen, until the specimen breaks at the fracture stress. EARTHQUAKE ENGINEERING TERMS Story: It is the space between two adjacent floors Diaphragms: are rigid horizontal planes used to transfer lateral forces to vertical resisting elements. Shear wall: refers to a wall designed to resist lateral forces acting in its own plane, typically wind and seismic loads. - stiffened walls are capable of transferring lateral forces from floors and roofs to the foundation. Center of gravity: refers to the point where the object “suffers” no torque by the effect of the gravitational force acted upon it. Center of rigidity: refers to the center of resistance of a floor or diaphragm against lateral forces - It is the point through which the resultant of the resistance to the applied lateral force acts. Center of mass: refers to the point through which the resultant of the masses of a system acts. - It is the point through which the applied lateral force acts. Center of stiffness: refers to the point point through which the resultant of the restoring forces of a system acts. Eccentricity: refers to the distance between the center of rigidity and the center of mass. Design seismic base shear: refers to the total design lateral force at the base of a structure. Story drift: refers to the lateral displacement of one level relative to the level above or below. Story displacement: refers to the lateral displacement of the story relative to the base Out-of-plane offsets: refers to the discontinuities in a lateral force path Torsional shear stress: refers to the shear stress that occurs when the structure’s center of mass does not coincide with its center of rigidity Resonance: refers to the phenomenon that occurs when a building period coincides with the earthquake period. Natural period: refers to the time period of undamped free vibration of a structure. Damping: refers to the rate at which natural vibration is absorbed. - The effect of internal friction, imperfect elasticity of material, slipping, sliding, etc in reducing the amplitude of vibration Epicenter: refers to the geographical point on the surface of earth vertically above the focus of the earthquake. Focus: refers to the origin/source of the elastic waves inside the earth which cause shaking of ground due to earthquake. Ductility: refers to the capacity to undergo large inelastic deformations without significant loss of strength or stiffness. Liquefaction: refers to the state in saturated cohesionless soil wherein the effective shear strength is reduced to negligible value. - condition when soil tends to behave like a fluid mass. Intensity: refers to the measure of the strength of shaking during the earthquake Magnitude: refers to the measure of energy released in an earthquake. Seismograph: refers to the instrument used to record the motion of the ground during an earthquake. Soft Storey Irregularity: refers to the condition in which the lateral stiffness is less than 70 percent of that in the storey above or less than 80 percent of the average lateral stiffness of the three storeys above. Weak Storey Irregularity: refers to the condition is one in which the storey lateral strength is less than 80 percent of that in the storey above.