Match the information given in Group – I with those in Group  II.

Group I 

Group II 
P 
Factor to decrease ultimate strength to design strength 
1 
Upper bound on ultimate load 
Q 
Factor to increase working load to ultimate load for design 
2 
Lower bound on ultimate load 
R 
Static method of ultimate load analysis 
3 
Material partial safety factor 
S 
Kinematical mechanism method of ultimate load analysis 
4 
Load factor 
Kinematical mechanism method of ultimate load analysis:
It states that collapse is formed by assuming a mechanism will always be greater than or equal to true collapse load. i.e. P ≥ P_{u}.
It satisfies the equilibrium and mechanism conditions.
It is called Upper bound theorem as it gives upper limit of the true collapse load.
Static method of ultimate load analysis:
It states that collapse load found on the basis of any collapse bending moment diagram will be less than or equal to true collapse load. i.e. P ≤ P_{u}.
It satisfies the Equilibrium and Yield conditions.
It is called Lower bound theorem as it gives lower limit of the true collapse load.
Load factor:
It is the factor used to increase the working load to account the effect of various uncertainties in working load calculation. It is given as
Design load = Load factor × Working load
Factor of safety:
It is the factor used to reduce the ultimate strength of material so that more safety may be ensured while designing a structure.
Design strength = Ultimate strength/FOS