Account settlement and normative properties of materials load coefficients in calculating structures for first and second groups of limit states
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Group limit states
Loads
Resistance
Normative
Settlement
Normative
Settlement
First
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N=Nn*y1
N*yn
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R=Rn/ym
R*yc
Second
Nser=Nn
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Rser=Rn
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4. Load and impact
4.1. Classification of loads by the time of operation.
S |
pecialLoads and impacts |
P |
ermanent
T |
emporary
L |
ong
M |
omentary
Weight constructions: weight and pressure of soil; impact of presstressing etc. |
Seismic and blast effects; load in case of accidents, irregular planting soil soaking, etc. |
Weight people load of cranes hoists, belt equipment, bliss, wind, etc. |
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L
oad
combinations
Special |
Main
|
G |
|
G |
roup
I
roup
IIPermanent |
Permanent |
Permanent |
Long CΨ1=0,95
|
Long |
Long CΨ1=0,95 |
Two one more short CΨ2=0,8 |
One short |
Short CΨ2=0,8 |
One special |
5. Characteristic values of loads and safety factors for the load
5.1. Constant loads
Normative values for the constant loads are determined by the geometric design and structural dimensions and medium values of the density of materials based on the data of the manufacturer of the actual weight of structures.
5.2. Temporary loads
Useful loadfor overlapping depends on the purpose of the premises and is determined by the table 3.
The value of the reliability coefficient of the load is appointed by γf in the accordance with the instructions.
Snow load depends on the area of construction.
Normative value of snow load is determined by multiplying the calculated value to the factor of 0, 7.
Quiz: What is the composition of the project with the use of MC?
How did the theory of limit states emerge?
What calculations of structural elements should be performed?
Theme 2. General information about metal constructions.Materials for metal constructions.
1. Field of application. Advantages and disadvantages of MC.
2. Construction steels.
3. Physical and mechanical properties of steel.
4. Aluminum alloys.
5. Assortment of rolled profiles.