Mike has a worksheet that contains some times. If he subtracts 6:33 from 6:21 he noticed that he doesn't get a negative elapsed time, as in -:12. Instead he gets ############# in the cell. Mike is wondering how he can display the negative time difference properly?

The easiest way to solve this problem is to just change the date system used by the workbook. This may sound goofy, but if you use a 1900 date system (which is the default for Windows versions of Excel), then you get the ############# in the cell. If, instead, you change to the 1904 date system (which is the default for Mac versions of Excel) then you'll see the correct negative elapsed time in your formula.

Crack Width Calc - BS 8110 - Free download as Excel Spreadsheet (.xls), PDF File (.pdf), Text File (.txt) or read online for free. Crack Width Calculation. Crack width calculation for (BS 8110 BS 8007) by The Concrete Center Reinforced Concrete Retaining Wall Design to BS 8110 by The Concrete Center Continuous Beam Analysis and Design to EC2 by Reinforced Concrete Council.

• The Bolted Joint Analysis calculator allows for stress analysis of a bolted joint, accounting for preload, applied axial load, and applied shear load.
• The crack width for lower values of concrete cover or grade of steel while the Indian standard as well as the other expressions under estimates it as shown in figure 5.1, 5.2, 5.3. Figure 5.1.1: Estimation of crack width using different formulas compared with expt. Data for 20 mm cover.

To change the date system, follow these steps:

1. Display the Excel Options dialog box. (In Excel 2007 click the Office button and then click Excel Options. In Excel 2010 or a later version, display the File tab of the ribbon and then click Options.)
2. Click Advanced at the left side of the dialog box.
3. Scroll through the options until you see the section called When Calculating This Workbook. (See Figure 1.)

Figure 1. The Advanced options of the Excel Options dialog box.

4. The Use 1904 Date System check box controls which dating system is used, just as in earlier versions of Excel.

If you prefer to not change the dating system used in the workbook (perhaps it may mess up some other date formulas you have in the worksheet), then the only thing you can do is to create a text-based version of the time differential using a formula such as the following:

If the difference between the two time values (in A2 and B2) is negative, then the formula concatenates a text value consisting of the minus sign and the absolute value of the difference between the times.

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 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

Crack Width Calculation Spreadsheet

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:

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.

First, change the following option if necessary:

Output

Crack Width Calculation Xls

Crack Width Calculation Spreadsheet Excel