- •Requirements for building structures and general principles of their designing
- •Basis of calculation of structures and foundations for limit states
- •The concept of calculation based on the first group of limit states
- •The concept of the calculation on the second group of limit states
- •3. Regulatory and calculated values of materials resistance and loads
- •Account settlement and normative properties of materials load coefficients in calculating structures for first and second groups of limit states
- •4. Load and impact
- •4.1. Classification of loads by the time of operation.
- •5. Characteristic values of loads and safety factors for the load
- •5.1. Constant loads
- •1. Field of application. Advantages and disadvantages of mc.
- •2. Construction Steel
- •3. Physical and mechanical properties of steel
- •Sample for tension trial; b) Diagram of tension of steels
- •4. Aluminum alloys
- •5. Assortment of rolled profiles
- •1) Plate; 2) equal-shelf angle; 3) unequal-shelf angle; 4) channel
- •1. Calculation of metal construction elements for limit states
- •1.1. The structure of rated formulas
- •Inner effort r γс
- •3. Calculation of elements on the central compression
- •4. Calculation of elements on a bend
- •1. Welds. Understanding
- •1.1. Typesofwelds
- •3. Calculation of the fillet weld tension and compression
- •1. General. Range of application.
- •3. Design rules centrally compressed steel columns
- •1. Understanding. Scope beams
- •Stress in the steel I-beam: a) the notation for the calculation of composite welded beams, b) diagram ах, in the diagram j хх
- •2. Calculation of rolled beams
- •3. Girder cells
- •3.4 Components and parts of steel beams
- •4. Modern beams
- •1. Understanding. Types of trusses and general dimensions
- •2. Calculation and design of trusses
- •1. Concrete structure
- •2 . Classification concrete. Concrete Stamps
- •3. Mechanical properties of concrete
- •3.1. Cube strength
- •3.2. Prism strength
- •3.3. Axial tensile strength
- •3.5 Strength of concrete under long-term load
- •3.6. Strength of concrete at multiple repeated loads
- •4. Concrete classes
- •2. Loss of prestressing
- •2. Conclusion of the settlement equations for elements of any profile
Theme 1. Principles of designing and calculation of building constructions
Requirements for building structures and general principles of design
Principles of construction calculation and grounds for limit States
Based on the concept of the first group of limit states
The concept of the calculation of the second group of limit states
Regulatory and calculated values of resistance of materials and loads
Loadandimpact
Requirements for building structures and general principles of their designing
Requirementsforbuildingstructures:
strength
stability
rigidity
durability
the required degree of thermal insulation of external barriers
frost-resistance
economy of manufacture and exploitation
industry of manufacture and installation
Durability can be determined as construction indestructibility during exploitation. Stability refers to shape conservation of construction. Rigidity is the resistance of constructions to deformations.
The purpose of calculation of building structures:
Verification of durability, stability and structural rigidity in certain sizes;
Size refinement and ensuring of construction reliability with minimal expenses of materials.
The procedure of building structures calculation:
Drawing up a design scheme
Definition of internal efforts by the methods of strength of materials
Assortment of section dimensions or verification of bearing capacity of specified sections
Constructionrestraints.
Basis of calculation of structures and foundations for limit states
Building constructions are calculated in order to ensure the safety, reliability and durability of their exploitation under the load at the most economical section sizes.
Existing building codes are prescribed to conduct calculation of building structures on power impacts according to the method of limiting states.
Limit state is a condition of building structure at which it ceases to satisfy operational requirements, as well as the requirements adjusted in the construction.
The purpose of the calculation of the building structure is to prevent the occurrence of the limit state in the process of its construction and operation.
In accordance with the standards two groups of limit states are taken into account at calculation.
The first group includes limit states according to the loss of bearing capability (strength or stability), i.e. unfitness for exploitation.
The second groupincludes limit states according to unsuitability for normal exploitation. This group includes states that impede normal operation of the construction or reducing its durability due to the occurrence of unacceptable movements (deflections, sediments and rotation angles), vibrations and cracks.
The concept of calculation based on the first group of limit states
The calculation on limit states of the first group is called the calculation on bearing capacity (strength and stability).
The purpose of this calculation is to prevent the onset of any of the limiting states of the first group, i.e. to ensure the bearing capacity as a separate structure, and entirely the whole building.
The bearing capacity of the structure is considered to be secured if the inequality of the type
N <Ф{R,A}, where N is the calculated internal strain from external rated loads. Rated strain depends on the type of loading (it is the longitudinal force for compressed and stretched elements, and bending moment for bending elements and etc.). Settlement efforts are determined by the rules of structural mechanics, depending on the design scheme, ways of connecting assemblies, etc.
F is the smallest possible section bearing capacity of the structural element subjected to compression, tension, bending and etc., it depends on the strength properties of the construction material (R is the calculated resistance of the material) and the geometric characteristics of the section (A is cross sectional area on the tensile or compressive modulus of section at a bend, etc.).