• Crack Width Calculation Spreadsheet Download
• Crack Width Calculation Spreadsheet
• Crack Width Calculation Spreadsheet 2019

The short review of three crack width calculation methods (RILEM, supplemented EC2 and corrected EC2) of steel fibre and ordinary reinforced concrete flexural members is presented in this paper. Bridge Design and Assessment Spreadsheets. These Design and Assessment Spreadsheets were written using Microsoft Excel 2000 and 2010 and they contain macros. Excel will need to be set to 'Enable Macros'. Warning: The layout of the spreadsheet should not be changed. The macros carry out calculations using values from specific cells in the.

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Indian or British Codes

IS 456 - 2000 Annex F and BS 8110 Part II, Clause 3.8 include the same method for determining the nominal crack width for design. This procedure is based on work by Andrew Beeby. The crack width determined by this method represents a best-fit for experimental data where the stress in the tension steel is limited to 0.8x F_y.

The following assumptions are made for this method:

• S_m = 1.5 a_cr
• W_mean is a funciton of S_m and ε_m
• W_max = 2x W_mean

The following procedure is then used by the program to evaluate the crack width for design:

1. Calculate the modular ration, m as:

   m = E_c/E_s

   Where:

   Es = 20,000 N/mm² (IS 456 - 2000, Annex F)

   Ec = 5,000·√(f_c) (Cl. 6.2.3.1 of IS 456 - 2000)

2. Calculate the depth of the neutral axis, x, per the limit state method (IS 456 - 2000 Annex G and BS 8110 Part I Cl. 3.4.4.4)

3. Calculate the moment of inertia of the equivalent section, I_eff.

4. Calculate the effective modulus of elasticity of concrete, E_eff.

   Where:

   c = safety factor taken as 1.0.

5. Calculate the average steel strain at the depth considered (e.g., the centerline of rebar), ε₁, based on the absolute value of the critical bending moment.

6. Calculate the average strain, ε_m, at the point of interest as:

7. Calculate Crack Width W_cr from IS 456 -20000 BS 8110 Part II

   Where:

   a_cr = distance from the point of interest to the surface of the nearest longitudinal bar

   h = total depth of the section

   C_min = clear cover to longitudinal steel

8. Check whether the crack width value is safe or not depending upon the maximum allowed range defined by codes (IS 456 2000 & BS 8110 Part II)

Eurocode 2 part 1-1: Design of concrete structures 7.3 Crack control

The crack width, w_k, may be calculated as follows:

wk = sr,max⋅(εsm - εcm)

(7.8)

where:

s_r,max

is the maximum crack spacing

ε_sm

is the mean strain in the reinforcement under the relevant combination of loads, including the effect of imposed deformations and taking into account the effects of tension stiffening

ε_cm

is the mean strain in the concrete between cracks.

(7.9)

where:

σ_s

is the stress in the tension reinforcement assuming a cracked section,
see application for a rectangular section or application for a T-section

E_s

is the design value of the modulus of elasticity of the reinforcing steel, see § 3.2.7 (4)

α_e

is the ratio

Crack Width Calculation Spreadsheet Download

E_s/E_cm

with

E_cm

the secant modulus of elasticity of concrete

f_ct,eff

is the mean value of the tensile strength of the concrete effective at the time when the cracks may first be expected to occur:
f_ct,eff = f_ctm or lower, (f_ctm(t)), if cracking is expected earlier than 28 days

ρ_p,eff

= (As + ξ1⋅A'p)/Ac,eff

(7.10)

with

A_s

the cross sectional area of reinforcement

A'_p

the area of pre or post-tensioned tendons within A_c,eff

A_c,eff

the effective area of concrete in tension surrounding the reinforcement or prestressing tendons of depth, h_c,ef, where h_c,ef is the lesser of 2,5(h - d), (h - x)/3 or h/2 (see Figure 7.1)

ξ₁

the adjusted ratio of bond strength taking into account the different diameters of prestressing and reinforcing steel:

ξ1 =

(7.5)

with

ξ

the ratio of bond strength of prestressing and reinforcing steel, according to Table 6.2

Φ_S

the largest bar diameter of the reinforcing steel

Φ_P

the diameter or equivalent diameter of prestressing steel:
Φ_p = 1,6⋅√A_P for bundles, where A_P is the area of a prestressing steel,
Φ_p = 1,75⋅Φ_wire for single 7 wire strands,
Φ_p = 1,20⋅Φ_wire for single 3 wire strands, where Φ_wire is the wire diameter.

k_t

is a factor dependent on the duration of the load:
k_t = 0,6 for short term loading,
k_t = 0,4 for long term loading.

• Where the bonded reinforcenlent is fixed at reasonably close centres within the tension zone (spacing ≤ 5(c + Φ/2), cf. Figure 7.2), the maximum crack spacing s_r,max may be calculated as follows:

sr,max = k3c + k1k2k4Φ / ρp,eff

(7.11)

where:

Φ

is the bar diameter. Where a mixture of bar diameters is used in a section, an equivalent diameter, Φ_eq, should be used.

c

is the cover to the longitudinal reinforcement

ρ_p,eff

see the difference of the mean strains above

k₁

is a coefficient which takes account of the bond properties of the bonded reinforcement:
k₁ = 0,8 for high bond bars,
k₁ = 1,6 for bars with an effectively plain surface (e.g. prestressing tendons).

k₂

is a coefficient which takes account of the distribution of strain:
k₂ = 0,5 for bending,
k₂ = 1,0 for pure tension.
Intermediate values of k₂ should be used for cases of eccentric tension or for local areas:

k2 = (ε1 + ε2)/(2ε1)

(7.13)

where ε₁ is the greater and ε₂ is the lesser tensile strain at the boundaries of the section considered, assessed on the basis of a cracked section.

k₃

is a Nationally Determined Parameter, see § 7.3.4 (3)

k₄

is a Nationally Determined Parameter, see § 7.3.4 (3).

• Where the spacing of the bonded reinforcement exceeds 5(c + Φ/2) (cf. Figure 7.2), or where there is no bonded reinforcement within the tension zone, the maximum crack spacing s_r,max may be calculated as follows:

sr,max = 1,3(h - x)

(7.14)

where:

Crack Width Calculation Spreadsheet

h

is the overall depth of the section (see Figure 7.1)

x

is the neutral axis depth of the section (see Figure 7.1).

This application calculates the crack width w_k from your inputs. Intermediate results will also be given.

Crack Width Calculation Spreadsheet 2019

First, change the following option if necessary:

Output