Analysis grid line grid similar

Consider grid line 1 as being 9.6 / 2 + 0.4 / 2 = 5.0 m wide with continuous spans of

6.0 m. Column strip is 6.0 / 4 + 0.4 / 2 = 1.7 m wide. Consider perimeter load is carried by column strip only. <5.1.1(4)>

Figure 3.21

Edge panel on grid 1 (grid 3 similar)

Figure 3.21

Edge panel on grid 1 (grid 3 similar)

Actions

Permanent from slab gk = 5 x 8.5 kN / m2 = 42.5 kN / m Variable from slab q k = 5 x 4.0 kN / m2 = 20.0 kN / m

Permanent perimeter load gk = 10.0 kN/m

Load combination and arrangement

As before, choose to use all-spans-loaded case and coefficients Ultimate load, n

By inspection, Exp. (6.10b) is critical. n = 1.25 x (42.5 +10) + 1.5 x 20 = 95.6 kN / m

0.666

Effective span, leff

Effective span = 6000 - 2 x 400 / 2 + 2 x 300 / 2 = 5900

Design moments in bay, MEd:

In spans (worst case, end span assuming pinned support)

MEd = 0.086 x 83.0 x 5.92 = 248.5 kNm At supports (worst case 1st support)

MEd = 0.086 x 83.0 x 5.92 = 248.5 kNm Additional moment in column strip only due to perimeter load, spans (and supports, worst case)

<Concise EC2 Table 15.2>

<Concise EC2 Table 15.2>

Apportionment to column strips and middle strips:

Apportionment to column strips and middle strips:

Percentages

Column strip, 1.7 m wide

Middle strip

<Table I.1, CS Flat slab guide [29]>

-ve (hogging)

Short span = 75%

Short span = 25%

+ve (sagging)

50%

50%

Short span moments:

MEd

Column strip, 1.7 m wide

Middle strip, 3.3 m wide

-ve (hogging)

(0.75 x 248.5 + 37.4) / 1.70 = 131.6 kNm / m

= 18.8 kNm / m

+ve (sagging)

(0.50 x 248.5 + 37.4) / 1.70 = 95.1 kNm / m

= 37.6 kNm / m

Punching shear force, VEd

For internal supports, as before = 516.5 kN For penultimate support, 516.5 x 1.18 = 609.5 kN

<Concise EC2 Table 15.3>

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