179134494 Tower Crane Footing Structural Design for All Cranes PDF

CLIENT:

EQUINOX – NORTHGATE

CONSULTANT:

ASSOCIATED CONSULTING ENGINEERS

MAIN CONTRACTOR:

HABTOOR LEIGHTON GROUP

SUB CONTRACTOR:

UNITED EQUIPMENTS GROUP

SUBCONSULTANT TO UNITED:

MZ & PARTNERS

MZ Project No:

10109 Rev. 0

Project: Northgate Retail/Office Building Sheet: 1 of 13

DESIGN CALCULATIONS – TOWER CRANE FOOTING

0 27-12-2011 A.Z F.H F.M.I ISSUED FOR APPROVAL

Rev. Date By Chkd Appr. Status Revision reason for issue description

TOWER CRANE FOOTING STRUCTURAL DESIGN REPORT

MZ & PARTNERS ARCHITECTURAL & ENGINEERING CONSULTANCY

Tel: 44 79 845-Fax: 44 79 673-POBox: 5785Doha-Qatar

STRUCTURAL DEPARTMENT

PROJECT: NORTHGATE RETAIL/OFFICE BUILDINGS

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



TABLE OF CONTENTS

1.0 CHAPTER I: GENRALITES ........................................................................................................ 3

1.1 OBJECT OF THE PRESENT DOCUMENT ............................................................................ 3

1.2 REFERENCE DRAWINGS & DOCUMENTS .......................................................................... 3

1.3 REFERENCES AND CODES ................................................................................................. 3

1.4 MATERIALS PROPERTIES ................................................................................................... 3

2.0 CHAPTER II: DESIGN CALCULATIONS .................................................................................... 5

2.1 DESIGN CONCEPT ............................................................................................................... 5

2.2 DESIGN LOADS ..................................................................................................................... 5

2.3 LOADING COMBINATIONS ................................................................................................... 5

2.4 GEOMETRY OF CRANE LEGS ............................................................................................. 5

2.5 OVER TURNING STABILITY CALCULATIONS ..................................................................... 5

2.6 CHECK SLIDING AND SOIL CAPACITY................................................................................ 7

2.7 CHECK PUNCHING ............................................................................................................... 8

2.8 REINFORCEMENT ................................................................................................................ 8

APPENDIX A ………………………………………………………………………………………………………14

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



1.0 CHAPTER I: GENRALITES

1.1 OBJECT OF THE PRESENT DOCUMENT

The purpose of this document is to provide the final structural analysis and design for the footing related to the tower crane in the considered project (Northgate Retail/Office Buildings).

1.2 REFERENCE DRAWINGS & DOCUMENTS

The following drawings & documents have been used for establishing the final design of the present structure:

� Foundation reaction forces Data sheet - Page 2-39 - For 52.0m height crane The above data sheets are attached. refer to appendix A.

1.3 REFERENCES AND CODES

The references of codes and standards are:

- Qatar Construction Specification 2002

- BS 8110, 1997 Structural use of concrete - Code of practice For design and Construction

- BS 8004, 1986 Code of Practice for Foundations

- BS449, 2005 steel for the reinforcement of concrete

1.4 MATERIALS PROPERTIES

1.4.1 Concrete

Concrete compressive strength (Cube) at 28days :

- Blinding Concret C20/25 20MPa

- footings C32/40 40MPa

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



1.4.2 Reinforcement

Steel bars of yield strength not less than 420MPa to be used for longitudinal &

transversal bars.

This design is for an isolated tower crane foundation.

1.4.3 Soil

The allowable bearing capacity was taken 300KN/m2.

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



2.0 CHAPTER II: DESIGN CALCULATIONS

2.1 DESIGN CONCEPT

• The footing dimensions was estimated based on over turning moment calculations with factor of safty 1.5

• Checking for Sliding stability and soil capacity. • Checking for Punching shear • calculations for required reinforcement

2.2 DESIGN LOADS

As per manufacturer data sheet, the most critical design loads were considered

for the case of crane in operation as follows:

Moment (Over turning) M=4908 KN.m

Horizontal force (Sliding) H=91KN

gravity Load V=917 KN

2.3 LOADING COMBINATIONS

The given loads are mixed of dead loads, wind loads and live loads. However, a 1.5 ultimate factor can be considered as conservative load factor for concrete design.

2.4 GEOMETRY OF CRANE LEGS

The crane have a base dimensions with square shape of 1.98m side length. The fixing leg of 1.4m length should be embedded with 1.13m inside the footing. This means that the footing should has minimum thickness 1.40m.

2.5 OVER TURNING STABILITY CALCULATIONS

As per the figure below, the stability calculations were calculated as follows:

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



Figure 1: Stability against over turning

assume h=1.50m ==>

over turning moment MOT = 4908+91*1.5 = 5044.5 KN.m

footing weight = 25*1.5*L2 = 37.5L2

Stability moment = Mst = 917*L/2 + 37.5*L2*L/2 = 18.75 L3 + 458.5 L

Use Factor of safty = F.O.S = 1.5 ==>

1.5=Mst / MOT ==>

18.75 L3 + 458.5 L - 7566.75 = 0 ==> L=6.5 m satisfy the equation.

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



2.6 CHECK SLIDING AND SOIL CAPACITY

- Sliding:

Sliding coefficient is equal H=tan I where I=angle of internal friction ==> H=tan 30 = 0.57, Use 0.5

Sliding force = H = 91KN

resisting force = (V+W)*H = (917+1584.375)*0.50 = 1250.7 >>91, OK

- Soil capacity:

soil stress = f = (V+W)/A ± MOT/(L*L2/6)

A=footing area=L2

==>

f= 2501.375/42.25 ± 4908/(6.53/6) = 59.2 ± 107.23

Negative value is rejected ==> use another approach. refer to figure 2.

Figure 2: soil stress calculations

e=MOT/(V+W) = 4908/2501.375 = 1.96 m ==> r=1.29 m

0.5f*(3r)*L = (V+W) ==> 0.5f*3.87*6.5=2501.375 ==> f=198.88 KN/m2 < 300KN/m2, OK

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



2.7 CHECK PUNCHING

The fixing leg consists of several steel plates welded to the main shaft. Each plate of 350x350mm dimensions. The maximum force act for punching is considered for the case where the moments is diagonal on the footing.

Fpunching = MOT/√(2*2.32) +V/4 = 4908/3.25 + 917/4 = 1510.2+229.25=1739.45 KN

fs= punching stress directly at plate edge = 1.5*1739450/(4*350*d)

where d=footing depth = 1500-65=1435mm ==>

fs=1.3MPa << 0.8√fcu=5MPa (BS8110-1:1997, clause 3.7.7.2)

it is obvious that the punching effect is very negligible.

2.8 REINFORCEMENT

For hign accuracy, the bending moment calculations were performed through finit element analysis. Autodesk ROBOT structural analysis software was used for that purpose. Note that only the large footing was considered (most critical) and the reinforcement was applied to the small one.

The acting forces on the crane legs were calculated and applied to the model as follows:

Compression side = M/2.3 + V/4 = 4908/2*2.3 + 917/4 = 1067+229.25=1296.25 KN

Tension side = M/2.3 - V/4 = 4908/2*2.3 - 917/4 = 1067-229.25 =837.75 KN

The fixing leg

The following figures represent the footing geometry with acting loads, soil stress (As a verification on the manual calculations) and the service bending moments maps.

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



Figure 3: acting forces on footing

Figure 4: Soil reaction

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



Figure 5: Moment on footing

The ultimate bending moment = 347*1.5=520.5 KN.m/m

==> T25@200mm is sufficient as per following data sheet extracted from ROBOT expert software.

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



Section design for simple bending

1. Assumptions:

Concrete: fcu = 40.0 (MPa) Reinforcing steel: fy = 420.0 (MPa)

• Code: BS 8110

2. Section:

b = 1000.0 (mm)

h = 1500.0 (mm)

ds = 75.0 (mm)

d' = 75.0 (mm)

3. Applied loads:

Mmax (kN*m) Mmin(kN*m)

at Ultimate Limite State 520.50 0.00

4. Results:

Reinforcement:

Theoretical area: As = 2264.3 (mm2) A's = 0.0 (mm2)

Reinforcement ratio: ρ = 0.16 (%)

ρmin = 0.16 (%)

ρmax = 4.00 (%)

Case analysis:

Case No 1: ULS M = 520.50 (kN*m)

- not significant case

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



APPENDIX A

(Data sheets)

CLIENT:


CONSULTANT:


MAIN CONTRACTOR:


SUB CONTRACTOR:



MZ & PARTNERS

MZ Project No:

10109 Rev. 0



Documents

179134494 Tower Crane Footing Structural Design for All Cranes PDF