BEAM

e

Max. Moment = 𝑤 𝑙−2𝑒 2

8

e

e e

Max. Moment = 𝑤𝑙2

8

l

CASE 1

For 5.0 meter span simply

supported beam.

Considering full span of 5.0 meter.

Maximum Moment = 𝑊𝐿2

8

=𝑊(5)2

8

=25/8W

=3.125W

CASE 2

For 5.0 meter span beam supported by corbel/half joint with eccentricity, e of 250mm.

Considering full span of 5.0 meter.

Maximum Moment = 𝑊(𝐿−2𝑒)2

8

=𝑊(4.5)2

8

=20.5/8W

=2.53W

Percentage of difference = 1-𝐶𝐴𝑆𝐸2

𝐶𝐴𝑆𝐸1x100

= 1- 2.53

3.125x100

= 1- 0.89x100

= 19 %!!

254.494kN

Hollow Core +Brick wall

(UDL)+Beam Sw

Beam 2/C-D

Hollow Core Slabs

41.52kN/m

Secondary

beam

Brick wall

Live Load (UDL)

15.5 kN/m

Secondary beam

(Point Load)

62.88 kN

Simply Supported Beam

Shear force diagram

-238.77kN

254.494kN

-343.136kNm

KOS PROJEK :RM 18,135,000.00

TARIKH SIAP :09-09-2016

5000

5000

5000

5000

5000

25000

1500

1075

1425

1500

4001

150020

0015

0023

0020

00

A B EDC

1a

1

A1

2

1b

G

F

K

J

3c

4

3aH

I

4a

3

5

2a

1e

F1

C9C10

C11

C12

C18

C19

C25

C26

C27

C28

C29

C30

C31

300 RC Wall

300 RC Wall

HC

200

mm

+ 7

5T

B

B

C

W4

W3

W2

W1

C

D

D

HS 1215HS 1215

HS 1220

HS

122

0

A

300 RC Wall

5000500050005000

8000

1500

C4 C5 C6 C7 C8

C13 C14 C15 C16C17

HC

200

mm

+ 7

5T

200m

m T

hk. C

oncr

ete

Sla

b

150m

m T

hk.

Con

cret

e S

lab

1g

1500

2700

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

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HC 200mm +75T

HC 200mm +75T

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HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T

HC 200mm +75T HC 200mm +75T HC 200mm +75THC 200mm +75T

HC 200mm+75T

HC 200mm+75T

HC 200mm+75T

HC 200mm+75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

HC 200mm + 75T

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HC 200mm + 75T

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HC 200mm + 75T

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HC 200mm + 75T

HC 200mm + 75T

12000

2000 2000

800

8000

Precast Column

400

600

100

800

200 100

Precast Continuous Beam

325

Continuous Beam

400x800

Hogging Moment Check

CANTILEVER END DETAIL

1375

440

360

300

2T25

2T202T202T20

4T25 4T25

C

C

B

B

A

A

SECTION A-A SECTION B-BSECTION C-C

4T25

4T25

2T20

2T20

2T20

2T25

2T20

2T20

2T20

2T25

2T25

2T25

VOID TO BE FILLED

UP WITH GROUT

2x400mm LENGTH

T25 GALVANISED

DOWEL BAR

150

330

PRECAST COLUMN

800

2x400mm LENGTH

T25 GALVANISED

DOWEL BAR

360

440

100

100

600

100

100

600

PRECAST BEAMPRECAST BEAM

Column

The effective height, le, of a column in a given plane = b lo

End condition at top End condition at bottom

1 2 3

1 0.75 0.80 0.90

2 0.80 0.85 0.95

3 0.90 0.95 1.00

BS 8110:1995 Table 3.19 — Values of for braced columns

End condition at top End condition at bottom

1 2 3

1 1.2 1.3 1.6

2 1.3 1.5 1.8

3 1.6 1.8 -

4 2.2 - -

BS 8110:1995 Table 3.20 — Values of for unbraced columns

Frame Structure

(Unbraced)

Cantilever Column

(Unbraced)

Cantilever Wall

(Braced)

Rigid

Joints

Pinned

Joints

Column le=1.6lo Column le=2.2lo Column le=1.0lo

lo lo lo

Picture source: K.S. Elliott

lo

Under ACI 318-11, the Stability Index, Q is introduced.

The stability index can be used to determine if a particular story in a frame

structure should be called braced or unbraced. The stability index may be

calculated as

Q = (Pu)

0

Vuslu

Where,

Pu = the sum of factored vertical loads for the story in question

0 = the 1st order lateral deflection of the top of the story relative to

the bottom of the story

lu = story height

Vus = the total shear acting on the given story.

The story is considered braced if Q ≤ 0.05.

However, the story is considered unbraced if Q > 0.05.

0

500

1000

1500

2000

2500

3000

3500

0 50 100 150 200 250 300

Column Capacity Result from Analysis

Ultimate Moment vs. Ultimate Shear

Ultimate moment,Mu (kNm)

Ultimate shear,Nu (kN)

65mm dia.

holes

4T25 Starter

bar

Shear Wall

Distribution of Horizontal Load On Shear Wall

Symmetrical Case ( Shear Center Meets with Center of Pressure)

Wall 1 Wall 2 Wall 3 Wall 4

b

h

Pi =F xki

ki

where

ki hb3

F=Horizontal wind load or

Notional load 1.5% of DL

Deflection due to

translation L/2

L

Shear

Center

-Subjected to translation only

Distribution of Horizontal Load On Shear Wall

Unsymmetrical Case ( Shear Center Shifted from Center of Pressure)

Wall 1

Wall 2

Wall 3 Wall 4

x= (kx

. x)kx

ȳ= (ky

. y)kx

Pi =Pd+Pr=F xkx

kx

± 𝐹. 𝑒 x F xkiri

(kiri2)

where

e is the eccentricity distance of

Horizontal force F to the center of

rotation

ri is the perpendicular distance

between the axis of each wall to the

center of rotation

F=Horizontal wind load or

Notional load 1.5% of DL

L/2

L

Center of

rotation

Wall 5 ȳ

x

-Subjected to both translation and rotation

h

H

N

P P

Shear

wall

Pilecap

Axial load on a single pile Pn is defined

as

Pn= Nn

± Hx.hIxx

𝑦𝑛± Hy.hIyy

𝑥𝑛

Where

N Vertical Load

n Numbers of pile

Ixx & Iyy Second area of moment of the pile group at

xx and yy axes

xn & yn Distance of each individual pile from axes YY

and XX respectively

Construction of In-situ R.C. Wall

Lifting and installation of precast

elements

Constrction of Level 1 Structures

Some Lessons

Learned

TACOMA NARROW

Lessons Learned

“All men make mistakes, but only wise men learn from their mistakes. ”

“I have not failed. I've just found

10,000 ways that won't work.”

-Winston Churchill

-Thomas Alva Edison

o A 2.5 storey structure design was proposed without proper bracing

system provided.

o Only few precast R.C. panel was proposed to act as shearwall. The

system was proposed without proper & precise detailing for the

actual construction.

o JKR reviewed the design and decided to improve the existing

design by providing additional in-situ R.C. shear wall and pile

system.

1. In-situ R.C. Shear wall shall be introduced. Cater

for horizontal loads.

o Checking on notional loads and unbalance moment.

o Foundation design –vertical load + unbalance moment

checks

o Pile stress analysis

o Pile cap reinforce concrete design.

o Reinforced concrete shear wall design

o Production of related drawings

Proposed

Shear Wall

Locations

Prestressed Concrete Planks

o Proposed Prestressed Concrete Planks 110mm+160mm

topping

o The topping is thicker than the Prestressed Concrete Plank

itself !

o Inefficient capacity for Prestressed Concrete Planks to

support massive dead load from in-situ topping.

o To proceed with original design the following conditions shall

met:

• Propping system may be required under the Prestressed

Concrete Plank during pouring of topping

• Require increment of the thickness of Prestressed Concrete

Planks

JKR’s proposal :

Replacing the Prestressing conc. Plank with

restressed Hollow Core 200mm +75 mm topping

eqv. to consulatnts 110+160=270mm thick.

o Design load comparison between both systems

o Prestressed hollow core design checks for:

• SLS –stress checks for and prestress losses calculation at

transfer stage

• SLS –stress checks for and prestress losses calculation at in-

service stage

• ULS- Shear and moment capacity checks.

Insufficient

Shear Capacity

Missing Beam

Location of Missing Beam

Structure instabilities noticed

due to missing column support

Steel Beams for Services at Roof Layout

Connection Details

Proposed M20

Bolts

o Expected bolts

clashing at beam

with connections of

both sides

o May encounter

difficulties of bolts

installation for

uneven gaps

between precast

beam and steel

plate.

o No seating provided,

steel beams has to

be held/supported

during installation.

o Holes drilling

process may

damage existing

rebars in precast

beam.