DAR GROUP

Project

The Pearl

Job Ref.

Q09079

Section

PA

Sheet no./rev.

1

Calc. by

Eng.MS

Date

09-July-06

Chk'd by

Eng.AE

Date App'd by Date

RC SINGLE CORBEL DESIGN TO ACI 318-05

Vu

Nuca

d h

Framingbars

Maintensionbars

Horizontalbars

Steel angle

min

d /

2

Shd23

Sh

Sh

Corbel geometry

W idth of corbel; b = mm

Total thickness of corbel; h = mm

Depth to main reinforcement; d = mm

Material properties

Yield strength of reinforcement; fy = MPa

Compressive strength of concrete; f’c = MPa

Type of concrete;

Unit weight of concrete; =

Corbel construction;

Coefficient of friction; = 1.4 = 1.40

Design load data

Factored vertical load; Vu = kN

Distance of vertical load from face of column; a = mm

Horizontal force acting on corbel; Nuc = kN

Strength reduction factor; =

Vertical load capacity check

Nominal vertical load; Vn = Vu / = kN

Nominal vertical load capacity; Vn_cap = min(0.2 f’c b d, 5.5 MPa b d) = kN

Find shear friction reinforcement

Minimum horizontal force acting on corbel; Nuc_min = 0.2 Vu = kN

Horizontal force acting on corbel; Nuc_act = max(Nuc, Nuc_min) = kN

For balanced condition; j =

Area for shear friction reinforcement; Avf = Vn / (fy ) = mm2

A f = [(Vu a) + (Nuc_act (h –d))] / ( fy j d) = mm2

Nominal area required; An = Nuc_act / ( fy) = mm2

DAR GROUP

Project

The Pearl

Job Ref.

Q09079

Section

PA

Sheet no./rev.

2

Calc. by

Eng.MS

Date

09-July-06

Chk'd by

Eng.AE

Date App'd by Date

Main tension reinforcement check

Minimum area of tension reinforcement; Asc_min = 0.04 f’c b d / fy = mm2

Area of tension reinforcement required; Asc = max([(2 Avf) / 3] + An, A f + An) = mm2

Asc_req = max(Asc, Asc_min) = mm2

Main tension reinforcement;

Diameter of tension bars; D tension = mm

Number of tension bars; N tension =

Area of tension reinforcement provided; Asc_prov = N tension D tension2 / 4 = mm2

Horizontal reinforcement check

Minimum area of horizontal reinforcement; Ah_min = 0.5 (Asc_req - An) = mm2

Area of horizontal reinforcement required; Ah = max(Avf / 3, A f / 2) = mm2

Ah_req = max(Ah, Ah_min) = mm2

Horizontal reinforcement;

Diameter of horizontal bars; Dhorizontal = mm

Number of horizontal bars; Nhorizontal =

Area of horizontal reinforcement provided; Ah_prov = 2 Nhorizontal Dhorizontal2 / 4 = mm2

Maximum spacing of horizontal bars; Sh_max = 2 d / (3 Nhorizontal) = mm

Actual spacing of horizontal bars; Sh = mm

Design Summary

Single corbel 300 mm wide by 500 mm deep with 35 MPa concrete and 415 MPa steel

Provide main tension reinforcement as 3 No. 6 bars

Provide horizontal reinforcement as 3 No. 3 link bars at maximum 100 mm centres