Advanced Reinforced Concrete Design
Assignment 1 Answers
Semester 1 2024
0027 65 934 4052
,
,
, RIBBED SLAB DESIGN
SANS10100 Loading
Dead load , DL= 9.5 kN/m2
Live Load = 12 kN/m2
Shear and moments in the rib
Consider 0.5 m width of floor. The ultimate design load per span is
0.5 [(1.2 x 9.5) + (1.6 x 12)] = 15.30 kN/m
= 8 x 15.30 = 122.40 kN/span
Checking of the slab topping thickness
𝑤𝑢 𝑙 2 15.30 × 82
𝑀𝑢 = = = 81.60 𝑘𝑁𝑚
12 12
3𝑀𝑢 3 × 81.60 × 106
𝑡=√ =√ = 148.6 𝑚𝑚 𝑢𝑠𝑒 𝑡 = 150𝑚𝑚
𝐹𝑏𝑓𝑐𝑢 0.5 6.75 × 300 × 300.5
Table 13 The design shears and moments are as follows;
Shear at A and C = 0.6 x 122.40 =73.44 kN
Moment at B = +0.086 x 122.40 = 10.53 kNm
Moment at A and C = -0.086 x 122.40 = -10.53 kNm
Effective depth d = 300 – 25 – 8 = 267 mm
Design of Moment Reinforcement
Mid-span T – section. Flange breath bw is 500 mm and the equivalent
breath is given by
𝐿𝑧 0.85 × 8000
𝑏 = 𝑏𝑤 + = 300 + = 1360𝑚𝑚
5 5
Assignment 1 Answers
Semester 1 2024
0027 65 934 4052
,
,
, RIBBED SLAB DESIGN
SANS10100 Loading
Dead load , DL= 9.5 kN/m2
Live Load = 12 kN/m2
Shear and moments in the rib
Consider 0.5 m width of floor. The ultimate design load per span is
0.5 [(1.2 x 9.5) + (1.6 x 12)] = 15.30 kN/m
= 8 x 15.30 = 122.40 kN/span
Checking of the slab topping thickness
𝑤𝑢 𝑙 2 15.30 × 82
𝑀𝑢 = = = 81.60 𝑘𝑁𝑚
12 12
3𝑀𝑢 3 × 81.60 × 106
𝑡=√ =√ = 148.6 𝑚𝑚 𝑢𝑠𝑒 𝑡 = 150𝑚𝑚
𝐹𝑏𝑓𝑐𝑢 0.5 6.75 × 300 × 300.5
Table 13 The design shears and moments are as follows;
Shear at A and C = 0.6 x 122.40 =73.44 kN
Moment at B = +0.086 x 122.40 = 10.53 kNm
Moment at A and C = -0.086 x 122.40 = -10.53 kNm
Effective depth d = 300 – 25 – 8 = 267 mm
Design of Moment Reinforcement
Mid-span T – section. Flange breath bw is 500 mm and the equivalent
breath is given by
𝐿𝑧 0.85 × 8000
𝑏 = 𝑏𝑤 + = 300 + = 1360𝑚𝑚
5 5
