Consider a n = 3-storey building, Bx = 36 m and By =14 m on plan, divided into Nx = 6 bays in the building`s long direction and Ny = 2 bays in its short direction (shown below).

2025-04-24 15:20:58

                           TC60034E – Geotechnical Design Academic Year 2024–2025

Level: 6

Assessment 1 (30% weight)

Submission: 16 January 2024 

Instructions:

Students must work in a group of a maximum of 3 students.

A contribution statement signed by the students should be included. 

Associate Professor in Civil Engineering

School of Computing and Engineering University of West London

Marking criteria: 

%

Descriptor

86 - 100

The standard achieved is exceptional, and the work provides clear evidence that the knowledge, understanding, and skills required are appropriate for the study level. There is evidence showing that all the learning outcomes

appropriate to that level are achieved, with many at an exceptional standard.

76 - 85

The standard achieved is outstanding and the work provides clear evidence that the knowledge, understanding and skills are appropriate to the study level. There is evidence showing that all the learning outcomes appropriate to

that level are achieved, with many meeting an outstanding standard.

70 - 75

The standard achieved is excellent and the work provides clear evidence that the knowledge, understanding and skills are at a level appropriate to the level of study. There is evidence showing that all the learning outcomes

appropriate to that level are achieved with many at an excellent standard.

65 - 69

The standard achieved is very good, and the work provides clear evidence that the knowledge, understanding, and skills are appropriate for the level of study. There is evidence showing that all the learning outcomes appropriate

to that level are achieved with many at a very good standard

60 - 64

The standard achieved is good and the work provides evidence that the knowledge, understanding, and skills are appropriate to the study level. There is evidence showing that all the learning outcomes appropriateto that

level are achieved with many at a good standard

50 - 59

The standard achieved is acceptable and the work provides evidence that the knowledge, understanding and skills are appropriate to the study level. There is evidence showing that all the learning outcomes appropriate to that level

are achieved with many at an acceptable standard

40 - 49

pass

The standard achieved is acceptable and the work provides evidence that the knowledge, understanding and skills are appropriate to the study level. There is evidence showing that all the learning outcomes appropriate to that level

are achieved through a few at only a very basic level

30 - 39

The standard achieved is very weak and the work provides evidence of insufficient knowledge, understanding and/or skills appropriate to the level of study. The evidence shows that some of the learning outcomes appropriate to level are achieved OR that none is achieved but there is evidence that many of the learning outcomes may be almost achieved.

15 - 29

The standard achieved is unacceptable and the work provides very little evidence of the knowledge, understanding and/or skills appropriate to the level of study. The evidence shows that very few, if any, of the learning

outcomes appropriate to that level are achieved.

0 - 14

The standard achieved is unacceptable and the work provides negligible or no evidence of the knowledge, understanding and/or skills appropriate to the level of study. The evidence fails to show that any of the learning outcomes appropriate to that level are achieved.

Question 1: (50 marks)

Consider a n = 3-storey building, Bx = 36 m and By =14 m on plan, divided into Nx = 6 bays in the building`s long direction and Ny = 2 bays in its short direction (shown below). The height of each storey is h = 3.2 m. The roof and floors of the building are 275 mm thick. Shear walls, intended to resist overturning are located at both ends of the building and are t = 300 mm thick by bw=4 m wide on plan. 

The following characteristic imposed/wind actions act on the building:

Roof loading = 0.6 kPa Office floor loading = 2.5 kPa Partition loading = 0.8 kPa

Wind (horizontal) loading =1.15 kPa

The characteristic unit weight of reinforced concrete is γc =25 kN/m3.

  1. Take a column size of 0.3 × 0.3 m and a beam size of 0.3 m wide and 0.5 m deep. Calculate the design value of actions according to EN 1990, in a way that is suitable for the geotechnical design of foundations. (10 Marks)

Select a suitable type of foundation out of the isolated shallow foundation, strip foundation, or mat foundation and carry out the geotechnical design according to EN 1997 in the soil profile shown on the next page.

  1. Verify the Ultimate Limit State (ULS) by calculating the resistance in the short term based on EC7 DA1. (10 Marks)
  2. Verify the Ultimate Limit State (ULS) by calculating the resistance in the long term based on EC7 DA1. (20 Marks)
  3. Verify the Serviceability Limit State (SLS) by calculating the total settlement of the foundation. (10 Marks)

Geotechnical site investigations were carried out, and a soil profile was established.

NSL

Loose alluvium; γ = 16.3 kN/m3, c′ = 0 kN/m2, ϕʹ = 24o

1 m

London clay                                                                                GWT = 5m

γ = 19.3 kN/m3, γsat = 20 kN/m3, cu = 150 kPa, cʹ = 0 kPa, ϕʹ = 22o

Cc = 0.32, mv = 0.0104 m2/kN, E = 25 MPa

20 m

Structured chalk

γ = 20 kN/m3, γsat = 21 kN/m3, quc = 10.5 MPa, RQD = 80%

Question 2: (25 Marks)

A site where the ground conditions consist of 5.5 m of soft organic silty clay overlying 35 m of stiff to very stiff over-consolidated clay followed by rock is reclaimed by placing and compacting 4 m of sand fill covering the entire site area. Six months after completing the reclamation, a 15-storey building imposing an overall dead load of 120 kN/m2 and a sustained imposed load of 75 kN/m2 on a ground floor area of 48 m by 27 m is to be constructed on the site. The soil properties are given below. The water table lies at a depth of 8 m.

Sand fill: γ = 21 kN/m3, ϕ` = 38օ

Organic silty clay: γ = 15.6 kN/m3, γs = 17.0 kN/m3, cu = 33 kPa, ϕ` = 18օ Over-consolidated clay:

Top, γ = 17.6 kN/m3, γs = 19.0 kN/m3, cu = 90 kPa, ϕ` = 22օ, E = 20 MN/m2, mv = 0.08 m2/MN Bottom, γ = 19.6 kN/m3, γs = 21.0 kN/m3, cu = 290 kPa, ϕ` = 25օ, E = 120 MN/m2, mv = 0.04 m2/MN

The RQD value of the sandstone was 85%, and the average unconfined compressive strength was 14 MN/m2.

Design a suitable piled foundation.

  1. Design a single pile according to Eurocode 7 DA1. (15 Marks)
  2. Design a pile group. (10 Marks)

Question 3: (25 Marks)

The figure below represents a cross-section of an excavation supported by a reinforced concrete cantilever-embedded wall. Take the wall thickness equal to 0.6 m and γconc = 25 kN/m3.

Calculate the embedded wall length by considering safety factors according to Eurocode 7 –

Design Approach 1. The water table lies at the excavation level.

 END

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