Section bearing capacity

Objective: Section bearing capacity

Task: Calculate ultimate moment strength of the section

References: Bliharsky Z.Y. Calculation and construction of bending reinforced concrete elements: Educational Guide / Z.Y. Bliharsky, I.I. Karhut. – Lviv: Lviv Polytechnic Publisher, 2017. – 188 p. (Example 5.10, pp. 73-75)

Initial data file:

ARBAT program section – Check, mode – Strength of RC Sections

Example-5.10-DBN.SAV
report – Arbat 5.10-DBN.doc.

Compliance with the codes: DBN V 2.6-98:2009, DSTU B.V 2.6-156:2010

Initial data:

b×h = 300×900 mm	Beam section sizes
а1= 27,5 mm	Distance from the edge of the lower reinforcement to the lower edge of the cross-section (protective layer)
a2= 20 mm	Distance from the edge of the upper reinforcement to the upper edge of the section (protective layer)
As1 = 2945 mm2 (6Ø25)	Area of the lower reinforcement Cross-sectional area of reinforcement
As2 = 942 mm2 (3Ø20)	Area of the upper reinforcement
М= 810,7 kNm	Bending moment
Concrete class Class of reinforcement	С20/25 A400С

 

Initial data in ARBAT:
Importance factor γ_n = 1

Effective length factor in the XoY plane 1

Effective length factor in the XoZ plane 1

Random eccentricity along Z according to DBN B.2.6-98:2009 with modification No.1

Random eccentricity along Y according to DBN B.2.6-98:2009 with modification No.1

The structure is statically determinate

 

 

Section

b = 300 mm h = 900 ммmm a1 = 27,5 mm a2 = 20 mm	S1 - 3Ø25, second line 3Ø25 (Clear distance between rows 35 mm) S2 - 3Ø20

 

Reinforcement	Class	Additional service factor
Longitudinal	A400C	1
Transverse	A240C	1

 

Concrete

Concrete type: Heavy-weight

Concrete class: C20/25

Aggregate: Quartzite

 

Additional parameters
Additional service factor	1
Age of concrete (days)	28
Cement strength class	Class R
Creep development time	36500	days
Temperature T(Δt)	20	°C
Number of days when the temperature T prevails Δt	28	days
Relative humidity	40	%

 

Results of analysis by load case combinations

 

	N	My	Qz	Mz	Qy	T	Factor for sustained load	Short-term	Seismicity	Special
	kN	kN*m	kN	kN*m	kN	kN*m
1	0	810,7	0	0	0	0	1

 

Checked according to DBN	Check	Utilization Factor
	Ultimate moment strength of the section	0,991

 

Comparison of solutions

Check	Ultimate moment strength of the section
Guide	810,7 kNm
ARBAT	810,7/0,991 = 818,1 kNm
Deviation, %	0,9 %