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)

А2= 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 u reinforcement

М= 810,7 kNm

Bending moment

Concrete class
Class of reinforcement

С20/25
A400С

 

Initial data in ARBAT:
Importance factor γn = 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 %