Structural Engineering Sum

CE7111 and CE7113

RETAKE COURSEWORK: Year 2020-2021

Submission deadline: 26th April 2021 : submitted via Canvas

ALL calculation steps must be shown, including sketches, Tables, assumptions (if any) so that the design work can be checked by someone else. Therefore DO NOT use a computer program (commercial or not) other than your own purpose-written spreadsheet for ease of calculations / iterations. Even then you MUST write out the full design calculations for the final design sizes. Do NOT just present a print-out of the spreadsheet. Either hand-written or typed work is acceptable.

The only soil data available are in the borehole log (two sheets) provided. Assume the unit weights of all soil layers to be 18 kN/m3 and that the water table is variable and can be up to the ground surface. Take unit weight of reinforced concrete = 25 kN/m3. Make use of the lecture notes to obtain any parameters and correlation formulae/ design Tables you need. The standard penetration test (SPT) blow counts (shown as N=....) for various soil layers are to be treated as N55 (corresponding to 55% energy ratio. Assume that incompressible bedrock exists below the bottom of the borehole.

You are required to carry out the following tasks, using Eurocode 7 Design Approach 1 procedures and safety factors for GEO limit state verification:

(i) Determine the size of an isolated square pad for column A1 founded at 3 m depth and of thickness 0.3m. You must take into account all the actions (column forces, moments).

(ii) Check that, under the design pressure, the pad foundation settlement does not exceed 50 mm. If it does, then repeat the whole design task in step (i) above.

(iii) Calculate and plot pile design charts showing variation of design pile head resistance (kN) versus pile length (m), for the following trial diameters of a straight-shafted bored cast in-situ pile: 0.6m, 0.75m, 0.9m, 1.2m. Use your chart to determine the required pile length for column A1. Consider only column axial forces and ignore moments and shear forces.

Primary beams: along gridlines 1,2,3 and 4; Secondary beams: along gridlines A, B, C. Columns at all beam intersections.

VGk = 1200 kN; VQk = 550 kN [both of these act simultaneously as Fig. shows]

MGk about axis 1-1 = 170 kNm ; MGk about axis A-A = 125 kNm [both of these act simultaneously as Fig. shows]

MQk about axis 1-1 = 105 kNm; MQk about axis A-A = 95 kNm [both of these act simultaneously as Fig. shows]

Assume bedrock below bottom of hole

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AA11

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Gk

and M

Qk

) about axis 1-1(M

Gk

and M

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)about axis A-A

AA22

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Gk

and M

Qk

) about axis 2-2(M

Gk

and M

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)about axis A-AColumn A1V

Gk

Eccentricity = 0 both waysV

Qk

Eccentricity = 0 both waysColumn A2V

Gk

Eccentricity = 0 both waysV

Qk

Eccentricity = 0 both ways