1 · Input Data
All internal calculations run in SI (N, mm); values are converted only at the input / output boundary.
Unit system: SI — N, mm, kN, m. Switch it any time from the header; every label and value updates instantly.
Design compressive stressCl. 38.1(c)
11.15 N/mm²
0.446 · fck
Design yield stressCl. 36.4.2
435.00 N/mm²
0.87 · fy
EcCl. 6.2.3.1
25,000.00 N/mm²
5000 · √fck
Effective depth, d
174 mm
D − cover − ø/2 = 200 − 20 − 6.0
Effective depth other direction, d'
164 mm
D − cover − ø_main − ø_dist/2
ly / lx
1.500
classified as Two-Way
Max bar dia (D/8)Cl. 26.5.2.2
25 mm
provided bar OK
ly/lx = 1.50 ≤ 2 — a two-way design (Annex D) is normally more economical.
End condition — short span
End condition — long span
Two-way panel edges — click an edge to toggle continuity
Table 26Auto-detected panel caseTable 26
Case 1
Interior panel — all four edges continuous
Design case in use: Case 1 — Interior panel — all four edges continuous
Minimum nominal coverTable 16
20 mm
provided cover adequate
Self weight (auto)
5.00 kN/m²
γc · D = 25 × 0.200 m
Total dead load, DL
8.00 kN/m²
self wt + FF + partitions + services
ULS: 1.5(DL + LL)Cl. 36.4.1, Table 18
1.5 × (8.00 + 3.00)
16.50kN/m²
ULS: 1.5DL (+1.5WL)Table 18
1.5 × 8.00
12.00kN/m²
ULS: 1.2(DL + LL + WL)Table 18
1.2 × (8.00 + 3.00)
13.20kN/m²
SLS: 1.0(DL + LL)Table 18
1.0 × (8.00 + 3.00)
11.00kN/m²
Design ultimate load, wu
governing ULS combination
16.50kN/m²
Service load, ws
SLS 1.0(DL + LL)
11.00kN/m²
Effective span, leffCl. 22.2
min(clear + d, c/c) — governed by clear+d
4.174m
Basic l/d ratioCl. 23.2.1
Simply Supported
20
Assumed pt for Fig. 4
engineering assumption
0.40%
Service steel stress, fsFig. 4
0.58 · fy
290N/mm²
Modification factor, MFFig. 4
1 / (0.225 + 0.00322·fs − 0.625·log₁₀(1/pt))
1.0988
Allowable l/d
basic × MF
21.976
Provided l/d
leff / d
23.989FAIL
Provided l/d exceeds the allowable value. Increase D to about 220 mm, or increase the reinforcement percentage. The final deflection check on each design page uses the actual provided steel.