prediction of axial shortening - alhosn … · prediction of axial shortening. april 09 the...

THE LANDMARK ABU DHABI ALHABTOOR CCC JVSHORTENING PREDICTION

PREDICTION OF AXIAL SHORTENING

April 09THE LANDMARK ABU DHABI – ALHABTOOR CCC JV

SHORTENING PREDICTION 2

Introduction

� This presentation is intended toshed the light on the nature of the Shortening criterion in concrete, the method of predictionand application of information.



TYPES OF SHORTENING

� Elastic shortening (instant)

� Shrinkage- Drying shrinkage (instant)- Autogenous shrinkage (time dependant).

� Creep (time dependant)



FACTORS AFFECTING SHORTENING

1 – ELASTIC SHORTENING

� Strength of concrete.

� Age of loading.

� Magnitude of loading




2 – SHRINKAGE

� Ambient humidity.

� Dimensions of element.

� Composition of concrete.

SHRINKAGE DOES NOT DEPEND ON LOADING




3 – CREEP

� Ambient humidity.� Dimensions of element.� Composition of concrete.� Strength of concrete.� Magnitude of sustained load.� Age of loading.

CREEP IS DEPENDANT ON SUSTAINED LOADING



MONITORED OBJECTS

Shortening is being predicted and monitored for all “Vertical

Structural Elements”,That is:

COLUMNS and

COREWALL ELEMENTS



LET’S LOOK AGAIN AT THAT LAST IMAGE….

Long term Shortening yet to take place AFTER PLACEMENT is the key figure to assess impact.



LONG TERM SHORTENING YET TO TAKE PLACE AFTER PLACEMENT

� Long term Cumulative shortening for a column at level 30, starts well before placement date.

� Long term cumulative shortening yet to take place at that point equals:

Long term cumulative shortening at that point LESS Interim Cumulative Shortening that has already taken place at time of pouring the slab.



WE NEED TO AGREE ON THE DEFINITION OF THE TERMS

JUST MENTIONED:

� Final floor Shortening: “FFS”Is the final (30+ years) shortening for a “VSE” at a given level.

� Final Cumulative Shortening “FCS”: Is the final (30 + years) and cumulative shortening for all the VSEsunderneath a point at a given level.

� Interim Cumulative Shortening “ICS”: Is the cumulative shortening for all the VSEs underneath a Target Point at a given time.



MORE DEFINITIONS

� LEVEL ADJUSTMENT:

Floor slab should be constructed to a higher level than that designed such that design level would be reached to upon completion of final shortening.

Adjustment at a given level should be equal to the “Cumulative Shortening” yet to take place for all columns underneath that level from the date of slab placement and for 30 years to come after loading completion.

Level Adjustment = Final (30 Y) Cumulative Shortening at the point less the “Interim Cumulative Shortening at time of placement = FCS – ICS.



WHY DO WE NEED TO PREDICT SHORTENING ?.

� To determine the level adjustment amount.

� To assess the impact on interfacing structures.

� To establish construction tolerance in interfacing installations (cladding, pipe risers, vertical railing ..etc) .

� To assess the impact of column / core wall differential shortening on the structure.



CALCULATION METHODOLOGY

The magnitude of long term elastic, shrinkage and creep strains has been calculated as per the provisions of BS EN 1992-1-1:2004.



PREDICTION METHODOLOGY 1 - ANALYSIS PARAMETERS

SHORTENING CALCULATIONS TO THE REQUIREMENTS OF "EUROCODE 2, BS EN 1992-1-1:2004

RH Relative Humidity % age

��H

A coefficient depending on the relative 1.5[1+(.012 RH)18] ho + 250 ��3 , <= 1500 ��3

humidity & member size - for fcm => 35

t0 Age of concrete at loading

��c Compressive stress applied at age to

ho Section notional size = 2 Area / Perimeter

t Age of concrete at the moment)

t-t0 Non-adjusted duration of loading

��cc(t)Cefficient for the calculation of

exp{s[1-(28/t)1/2]} = e{s[1-��(28/t)]}

compressive strength fcm(t) at age t

fcm(t) Compressive strength at age t ��cc(t). fcm

Ecm Concrete secant modulus of elasticity 22 (fcm/10)0.3

Ecm(t) Tangent Modulus of Elasticity at age "t" [fcm(t) / fcm]0.3 .Ecm



PREDICTION METHODOLOGY 2 - ELASTIC SHORTENING

��e��t�� Elastic strain at time "t" ��c / Ecm(t)



PREDICTION METHODOLOGY 3 - DRYING SHRINKAGE

��RHCoefficient related to relative humidity 1.55 [1 - (RH/RHO)3]

��ds1 Coefficient depends on cement type

��ds2 Coefficient depends on cement type

��cd.0 Basic drying shrinkage strain

0.85[(220+110.��ds1).

exp(-��ds2.fcm/fcmo)].��RH/106

��ds(t,ts)(t-ts)

(t-ts)+0.04��ho3

kh Coefficient depending on "ho" Equals 0.7 for ho =>500

��cd (t) Long term drying shrinkage ��ds(t,ts).kh.��cd.0��ca (��) 2.5(fck-10)106

��as(t) 1 - exp(-2t0.5)��ca (t) The autogenous shrinkage ��as(t) . ��ca (��)

��cs Total shrinkage strain ��cd + ��ca



PREDICTION METHODOLOGY 4 - CREEP

Ec Tangent Modulus of Elasticity. 1.05 Ecm

��1 ��1��2,��3 are coefficients to (35/fcm)0.7

��2 consider the influence of the (35/fcm)0.2

��3 concrete strength on the creep strain. (35/fcm)0.5

��(to) A factor allowing for age of loading effect. 1 / (0.1 + to0.2)

��(fcm)A factor to allow for the effect of concrete 16.8

strength on the notional creep coefficient ��fcm

��(t,to) A coefficient to count time effect [(t-t0) / (��H + t - t0)]0.3

��RH A factor to allow for the effect of humidity. [1+(1-RH/100).��1/(0.1 ho^0.333)].��2

��0 Notional creep coefficient ��RH . ��(fcm). (��(t0)

��t,to�� The creep coefficient. �� . ��c(t,to)

��cc��t,to�� Creep deformation (strain) at time "t" ��t,to��c��Ec��



THE MASTER SPREADSHEET

Data base for geometric, material and loading information for each column / corewall element, including the construction schedule, has been entered into a Master Spreadsheet.

Cells of the Master Spreadsheet encapsulate the formulae needed to calculate the strain in the column corresponding to following loadings imposed by floor slabs supported by the column:

� SWL : Self Weight Load.� SDL : Super-imposed Dead Load.� SLL : Super-imposed Live Load.



MASTER SPREAD SHEET - INSERTING CONSTRUCTION SCHEDULE



MASTER SPREAD SHEET - INSERTING COLUMN PROPERTIES



MASTER SPREAD SHEET – PART 1



MASTER SPREAD SHEET – PART 2DETAIL “A”



MASTER SPREAD SHEET – DETAIL “A”



MASTER SPREAD SHEET – GETTING A SHORTENING VALUE ON A GIVEN DATE



LEVEL ADJUSTMENT ACHIEVED




MASTER SPREAD SHEET – GETTING A COLUMN PROFILE AT A GIVEN LEVEL

PREDICTED PROFILE FOR C1- L 30 TOP

-60.00

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

28-J

an-0

8

28-F

eb-0

8

28-M

ar-0

8

28-A

pr-

08

28-M

ay-0

8

28-J

un

-08

28-J

ul-

08

28-A

ug

-08

28-S

ep-0

8

28-O

ct-0

8

28-N

ov-

08

28-D

ec-0

8

28-J

an-0

9

28-F

eb-0

9

28-M

ar-0

9

28-A

pr-

09

28-M

ay-0

9

28-J

un

-09

28-J

ul-

09

28-A

ug

-09

28-S

ep-0

9

28-O

ct-0

9

28-N

ov-

09

28-D

ec-0

9

28-J

an-1

0

28-F

eb-1

0

28-M

ar-1

0

28-A

pr-

10

28-M

ay-1

0

PREDICTED

FINAL

MEASURED

CHART NO. C3-L30-04009-01 COLUMN C3 POINT AT L 30 DATE 3-Jun-08

April 09

THE

LAN

DM

AR

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OR

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N29

MASTER SPREAD SHEET –

IMPACT OF SHORTENING

ON INTERFACING STRUCTURES (THE CANOPY)

-70.0

0

-60.0

0

-50.0

0

-40.0

0

-30.0

0

-20.0

0

-10.0

0

0.0

0

9-Feb-08

9-Mar-08

9-Apr-08

9-May-08

9-Jun-08

9-Jul-08

9-Aug-08

9-Sep-08

9-Oct-08

9-Nov-08

9-Dec-08

9-Jan-09

9-Feb-09

9-Mar-09

9-Apr-09

9-May-09

9-Jun-09

9-Jul-09

9-Aug-09

9-Sep-09

9-Oct-09

9-Nov-09

9-Dec-09

9-Jan-10

9-Feb-10

9-Mar-10

9-Apr-10

9-May-10

9-Jun-10

-140.0

0

-120.0

0

-100.0

0

-80.0

0

-60.0

0

-40.0

0

-20.0

0

0.0

0

26-Apr-08

26-May-08

26-Jun-08

26-Jul-08

26-Aug-08

26-Sep-08

26-Oct-08

26-Nov-08

26-Dec-08

26-Jan-09

26-Feb-09

26-Mar-09

26-Apr-09

26-May-09

26-Jun-09

26-Jul-09

26-Aug-09

26-Sep-09

26-Oct-09

26-Nov-09

26-Dec-09

26-Jan-10

26-Feb-10

26-Mar-10

26-Apr-10

26-May-10

26-Jun-10

26-Jul-10

26-Aug-10

A B

PROFILE AT L-7

PROFILE AT L-1

INT

ER

FAC

ING

STR

UC

TU

RE

LO

NG

TE

RM

DIM

EN

SION

AL

CH

AN

GE

�� H

= A –

B = 4.9 m

m

INT

ER

FAC

ING

STR

UC

TU

RE

INST

AL

LA

TIO

N C

OM

PLE

TIO

N

14 APR

IL 2010



IMPACT ON INTERFACING STRUCTURES ASSESSED.



April 09

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N31

MASTER SPREAD SHEET –

IMPACT OF SHORTENING

ON INTERFACING INSTALLATIONS (CURTAIN WALL)

-350.0

0

-300.0

0

-250.0

0

-200.0

0

-150.0

0

-100.0

0

-50.0

0

0.0

04-Dec-08

4-Jan-09

4-Feb-09

4-Mar-09

4-Apr-09

4-May-09

4-Jun-09

4-Jul-09

4-Aug-09

4-Sep-09

4-Oct-09

4-Nov-09

4-Dec-09

4-Jan-10

4-Feb-10

4-Mar-10

4-Apr-10

4-May-10

4-Jun-10

4-Jul-10

4-Aug-10

4-Sep-10

4-Oct-10

4-Nov-10

4-Dec-10

4-Jan-11

4-Feb-11

4-Mar-11

4-Apr-11

A

B

PROFILE AT L-36 PROFILE AT L-35

INT

ER

FAC

ING

STR

UC

TU

RE

LO

NG

TE

RM

DIM

EN

SION

AL

CH

AN

GE

�� H

= A –

B = 2.1 m

m

INT

ER

FAC

ING

INST

AL

LA

TIO

N C

OM

PLE

TIO

N

20 APR

IL 2010

-350.0

0

-300.0

0

-250.0

0

-200.0

0

-150.0

0

-100.0

0

-50

.00

0.0

0

24-Dec-08

24-Jan-09

24-Feb-09

24-Mar-09

24-Apr-09

24-May-09

24-Jun-09

24-Jul-09

24-Aug-09

24-Sep-09

24-Oct-09

24-Nov-09

24-Dec-09

24-Jan-10

24-Feb-10

24-Mar-10

24-Apr-10

24-May-10

24-Jun-10

24-Jul-10

24-Aug-10

24-Sep-10

24-Oct-10

24-Nov-10

24-Dec-10

24-Jan-11

24-Feb-11

24-Mar-11

24-Apr-11

A



CONSTRUCTION TOLERANCE IN INTERFACING INSTALLATION VERIFIED






THE EXECUTIVE SUMMARY

Information extracted from various Master Spreadsheets has

been classified sorted in 5 schedules A through E.

These schedules were listed in an “Implementation Duty

Matrix” along with a listing for their

functions and concerned parties.



SCHEDULE A

A summary for 30 years final

cumulative shortening



SCHEDULE B

Balance Final Cumulative

Shortening yet to take place

after placement of VSEs



SCHEDULE C

Change in inter-floor

height



SCHEDULE D

Floor level adjustment



SCHEDULE E

Differential shortening

between corewall & columns at

pivots.



COLUMN / COREWALL DIFFERENTIAL SHORTENING COMPUTED.




� To assess the impact of column / core wall differential shortening on the structure.



THIS IS THE END OF THE PRESENTATION

Thank you very much for listening..

I shall be ready for your question after viewing a Master Spreadsheet.

M.H.

prediction of axial shortening - alhosn … · prediction of axial shortening. april 09 the...

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