Reinforced Concrete Beam Design
Essay by Joy Camille Malacaste • February 24, 2019 • Study Guide • 6,257 Words (26 Pages) • 700 Views
- Related Definition
Aggregate
A granular material, such as sand, gravel, crushed stone and iron-blast furnace slag, and when used with a cementing medium forms a hydraulic cement concrete or mortar.
Balanced Design
A design so proportioned that the maximum stresses 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 fail simultaneously.
Cementitious materials
Materials with cementing value when used in concrete either by themselves, such as Portland cement, blended hydraulic cement, or such materials in combination with fly ash, raw or other calcined natural pozzolans, silica fume, or ground granulated blast-furnace slag.
Concrete
Mixture of water, cement, sand, gravel, crushed rock, or other aggregates.
Dead Load
Loads of constant magnitude that remains in one position.
Design
The determination of general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout its useful life.
Design Load Combinations
Combination of factored loads and forces.
Design Strength
The nominal strength multiplied by a strength-reduction factor, ø.
Effective Depth of Section, d
The distance measured from extreme compression fiber to centroid of tension reinforcement.
Extreme Tension Steel
The reinforcement (prestressed or nonprestressed) that is the farthest from the extreme compression fiber.
Live Load
Loads that may change in magnitude and position.
Modulus of Elasticity
The ratio of normal stress to corresponding strain for tensile or compressive stresses below proportional limit of material.
Nominal Strength
The strength of a member or cross section calculated in accordance with provisions and assumptions of the strength design method before application of any strength-reduction factors.
Over Reinforced Design
A design in which the steel reinforcement is more than what is required for balanced design.
Plain concrete
Structural concrete with no reinforcement or with less reinforcement than the minimum amount specified for reinforced concrete.
Reinforced concrete
Concrete in which reinforcing bars or other types of reinforcement have been integrated to improve one or more properties of concrete.
Required Strength
The strength of a member or cross section required to resist factored loads or related internal moments and forces.
Stress
The intensity of force per unit area.
Specified Compressive Strength of Concrete, f’c
The compressive strength of concrete used in design of reinforced concrete members in MPa.
Under Reinforced Design
A design in which the steel reinforcement is lesser than what is required for balanced design.
Water
Used in mixing concrete that should be clean and free from injurious amounts of oils, acids, alkalis, salts, organic materials, or other substances that may be deleterious to concrete or reinforcement.
Concrete Proportion (NSCP Section 405.3)
Proportions of materials for concrete shall be established by:
- Workability and consistency to permit concrete to be worked readily into form and around reinforcement under conditions of placement to be employed without segregation or excessive bleeding.
- Resistance to special exposures.
- Conformance with strength test requirement.
Basic Components of Concrete
The basic components of concrete are cement, water and aggregates (sand and gravel). Cement and water form a paste that fills the space between the aggregates and binds them together. Chapter 3 of the ACI Code and Section 403 of Nationals Structural Code of the Philippines (2010) contains the minimum requirements for these components and other materials that are commonly used in concrete.
Cementitious Materials
Cement shall conform to one of the following specifications:
- Specifications for Portland Cement (ASTM C150-05)
- Specifications for Blended Hydraulic Cements (ASTM C595-07)
- Specifications for Expansive Hydraulic Cements (ASTM C845-04)
- Specifications for Hydraulic Cements (ASTM C1157-03)
- Fly ash and natural pozzolans (ASTM C618-05)
- Ground–granulated blast-furnace slag (ASTM C989-06)
- Silica fume (ASTM C1240-05)
The eight different types of Portland cement referenced in ASTM C150 and their typical applications are summarized below.
Cement Type | Application |
Type I – normal | General purpose cement commonly used in all types of structures |
Type IA – normal, air-entraining | Used in the same structures as Type I where air entrainment is desired |
Type II – moderate sulfate resistance | General purpose cement used in structures where protection against moderate sulfate attack is important or where moderate heat of hydration is desired. |
Type IIA – moderate sulfate resistance, air-entraining | Used in the same structures as Type II where air entrainment is desired |
Type III – high early strength | Used in structures where high early strength of the concrete is desired or where structures must be put into service quickly |
Type IIIA – high early strength, air-entraining | Used in the same structures as Type III where air entrainment is desired |
Type IV – low heat of hydration | Used in structures where a low heat of hydration is required, such as massive concrete structures like dams |
Type V – high sulfate resistance | Used in structures where high sulfate resistance is required, such as elements in direct contact with soils or ground waters that have high sulfate content |
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