Methor statement for production of super - T Girder

Methor statement, for production of super, T Girder

1 General 3

2 Materials 3

3 Main Equipment and Tools 4

1) Fabrication Yard No.1.1 4

2) Fabrication Yard No.1.2 5

3) Fabrication Yard No.2 5

4 Site Organization Chart 6

5 Construction Flow Chart 7

6 Detail Construction Procedure 8

1) Detail Work Procedure 11

a) Preparation work 11

b) Pre-assemble rebar cage 12

c) Installation rebar cage 12

d) Installation PC strands 13

e) Installation inner formwork 18

f) Casting concrete 19

g) Curing and removal of inner formwork 20

h) Cutting tendons 21

i) Lifting girder to stock yard 24

j) Filling the non - shrinkage mortar 25

2) Cycle Time of Super-T Girders Fabrication 25

7 Schedule for Production of Super T Girder 25

8 Quality Control 25

9 Environmental Control 25

10 Safety Control 26

11 Emergency Call out Procedure 36

1) Initiation 36

2) Second Stage 36

3) Third Stage 36

4) Emergency response chart 37

12 Appendix 37 1) Appendix – 1: Plan of fabrication yard No.1.1; No.1.2 and No.2

2) Appendix – 2: Working drawing for production of super T girder

3) Appendix – 3: General drawing gantry crane 80 tons and 5 tons

4) Appendix – 4: General drawing of formwork system

5) Appendix – 5: Drawing of pre-installation of rebar cage frame for super T girder 6) Appendix – 6: Drawing lifting crane of rebar cage for super T girder

7) Appendix – 7: Drawing of frame system for hanging inner formwork

8) Appendix – 8: Drawing of detail for lifting hook

9) Appendix – 9: Drawing of protection frame during stressing

10) Appendix – 10: Calculation of formwork system

11) Appendix – 11: Calculation of camber of permanents

12) Appendix –12: Lifting device calculation of Super T girder

13) Appendix –13: Calculation for pre-stressing of Super T girder

14) Appendix –14: Inspections and test plan

15) Appendix –15: Inspection sheet form

1 General:

Project information:

 P r o j e c t n a m e : N o r t h – S o u t h E x p r e s s w a y C o n s t r u c t i o n P r o j e c t ( B e n L u c - L o n g T h a n h

Section) – Contract Package No.J2

for Superstructure of Approach Span Structures in accordance with General Specifications

length in consideration with the effect of horizontal curve and change in width of

carriage-way

 T h i s w o r k i t e m s h a l l b e d o n e i n a c c o r d a n c e w i t h t h e r e q u i r e m e n t s o f C l a u s e S 0 7 4 5 0

concrete structures of the Technical Specifications

There are 3 types of Pre-cast super-T girders as below table:

Precast Girder

Work Classify Unit Total Comment

Number strand

approved by the engineer shall be shown as the below table:

Name of material Specification Quantity Remarks

or others measures

 M a t e r i a l q u a l i t y c o n t r o l a t s i t e , e s p e c i a l l y r e b a r , s t r e s s e d c a b l e w h i c h a r e s e n s i t i v e

against corrosion shall be carefully stocked and controlled in dry condition

 D e t a i l e d q u a n t i t i e s s h a l l b e i n d i c a t e d a n d s h o w n o n t h e w o r k i n g d r a w i n g w h i c h i s

approved by the engineer

3 Main Equipment and Tools:

The quantity of equipment’s below may be changed with required actual conditions

1) Fabrication Yard No.1.1:

2) Fabrication Yard No.1.2:

No Item Capacity Unit Q’ty Remark

3) Fabrication Yard No.2:

type 34.3m set 01 Production SPT girder

 H y d r a u l i c J a c k i n g M a c h i n e ( H y d r a u l i c p u m p & G a u g e ) w i l l b e v e r i f i e d b y i n d e p e n d e n tlaboratory under supervision of Engineer

4 Site Organization Chart:

5 Construction Flow Chart:

Technical

Surveyor

Worker (25)

TechnicalSurveyorWorker (30)

TechnicalSurveyorWorker (45)

Yard no.2

TechnicalSurveyorWorker (30)

6 Detail Construction Procedure:

1) Detail Work Procedures:

 Inspection of shape and dimension of fabricated rebar

concrete cover…)

rebar cage

 Using trussing beams for lifting the whole rebar cage

 Inspection of rebar after installation (stability, verticality, position, concrete cover thickness…)

cage

cage

 Checking strands testing result, certification of anchorage

 Checking the calibration of jack and gauge

strands and

tensioning

cage

 Carefully install inner form after tensioning

 Checking the stability of inner form after fixing into bed

form work

cage

 Checking resource of concrete supply

 Checking slump and temperature of concrete

 Checking stability and deflection of form during casting process

process

cage

 Checking and recording the curing duration, temperature

 Shifting girder to storage by gantry crane and lifting

 Finishing and repairing (if any) shall be carried out

stock yard

cage

a) Preparation Works:

for material testing and calibration of stressing jack and pump shall be confirmed

attendance of the Engineer

production of super-T girder

a c c o r d i n g t o a l l o w a b l e e r r o r i n s p e c i f i c a t i o n a n d w o r k i n g d r a w i n g o f f a b r i c a t i o nyard

b) Pre-assemble Rebar Cage:

provided with suitable cover

in the approved working drawing, and shall be fabricated in a manner that will notinjure the material

b e n t b y h e a t i n g , t h e e n t i r e o p e r a t i o n s h a l l b e a p p r o v e d b y t h e e n g i n e e r Reinforcing bars that cannot be straightened by means of fabrication shall not be

 R e i n f o r c i n g b a r s b e f o r e b e p o s i t i o n e d s h a l l b e c l e a n e d a n d f r e e f o r m r u s t , d i r t ,

mud and loose scale and from paint, oil, or any other foreign substance destroys

or reduces the bond

for super T girder

 R e i n f o r c e m e n t f r a m e i s f a b r i c a t e d w i t h c o n f o r m i n g d i m e n s i o n s t o e a s i l y i n s t a l l

reinforcement for super T girder

 F a b r i c a t e d r e i n f o r c i n g b a r s s h a l l b e i n s t a l l e d o n t h e f r a m e b e f o r e s e t t i n g i n t o

casting bed

Rebar cagePre-installation frame

firmly held during placing concrete

or lager diameter or suitable clips

 C o n c r e t e c o v e r s s h a l l b e s e t t o m a i n t a i n t h e d i s t a n c e f r o m t h e f o r m w o r k s t o

reinforcing bars

nominal diameter of bars In lapped splices the bars shall be lapped the required

lapped in any one cross section

working draw

bé nèi lo¹i 2 coupler type 2

1140

50 660 50 760

c) Installation Rebar Cage:

tons End form is hold by 4 support jack as below drawing :

SUPPORT JACK

TENSIONING BEAM B2

TENSIONING BEAM B2

SUPER T GIRDER

SUPPORT JACK END FORM

with approved working drawing

 Concrete blocks with steel wire or plastic spacer shall be installed at bottom and

side of rebar in order to keep the appropriate concrete covering

the bond

work shall be installed at proper location

Casting bed

Outer form

Lifting frameRebar cage

Plat form

d i s m a n t l e d a n d r e m o v e d t o o u t o f r e b a r c a g e b y g a n t r y c r a n e f o r i n s t a l l a t i o nremaining bar

 A f t e r s e t t i n g , r e i n f o r c e m e n t b a r s , c o n c r e t e c o v e r s h a l l b e a d j u s t e d t o e n s u r e

correctly position, spacing, and shall be inspected ,approved by the Engineer

 T h e r e i n f o r c e m e n t b a r s d u r i n g t h e p r e - a s s e m b l y p e r i o d a n d w a i t i n g t i m e a f t e r

to prevent rust and corrosion

setting of inner forms

locate PVC holes by ruler, installing PCV D170 pipes in the positions which hadbeen located by the steel wires to create waiting holes for PVC tubes

d) Installation PC strand:

to requirements of ASTM 416 Grade 1860

 A l l t h e s t r a n d s s h a l l b e c u t w i t h e n o u g h l e n g t h P V C p i p e s w i t h o u t e r d i a m e t e r

22mm and inner diameter 18mm and adhesive tapes shall be installed at end ofstrands for de-bonding

notice position of each tendon at ends girder must be same

twisted or stuck

 W h e n t e n s i o n i n g t h e s t r a n d s s h a l l b e l e n g t h e n e d , t h e r e f o r e t o m a k e s u r e d e

-bonding length of the strands complied with design, ends of PVC pipes shall be

l e n g t h e n e d t o i n n e r f a c e o f t e n s i o n i n g b e a m s s o t h a t P V C p i p e s s h a l l n o t b emoved when the strands are being tension

- Before carry out the tensioning work, having to check whether the forms andcasting bed have the defects or not, in case of defects have no repair.

or otherwise instructed by the Engineer

- S t r e s s i n g o n a l l s t r a n d s s h a l l b e m a i n t a i n e d b e t w e e n a n c h o r a g e s u n t i l t h e

c o n c r e t e h a s r e a c h e d t h e c o m p r e s s i v e s t r e n g t h r e q u i r e d a t t i m e t r a n s f e r o fstress to concrete, it is the minimum 85% of design concrete strength

- I n a n y c a s e t h e j a c k i n g s t r e s s s h a l l n o t e x c e e d 7 5 % o f s p e c i f i e d m i n i m u multimate tensile strength of the pre-stressing steel

determination should be done for every jack)

rust, dirt, oil, mud…

strands

- S t r e s s i n g s h a l l b e a c c o m p l i s h e d b y s i n g l e s t r a n d s t r e s s i n g T h e a m o u n t o fstress to be given each strand shall be as shown in the calculation which the

contractor proposed and the Engineer approved

girder with the following sequence

Order of pre- stressing of Super T girder type 38.3m (44 strands):

38 37

39 26

35 36 34

23 24 22

32 33 31

20 21 19

11 10

8 9 7

18 6

Order of pre- stressing of Super T girder type 34.3m (35 strand):

20 21 19

11 10

8 9 7

18 6

2322

20 2119

1110

8 97

186

Pk, marking on ends of strands to measure elongation

 Tensioning with each force level 0.2; 0.4; 0.6; 0.8; 1 Pk.

both of ends

e) Installing Inner Formwork:

oil which the contractor uses is Sika Separol and It was approved by consultant

lifted by gantry crane and shall be installed inside casting bed

girder web, using tie steel to hold PCV tube on positions which are marked

f) Casting Concrete:

 Preparation of Concrete Casting:

- B e f o r e c a s t i n g c o n c r e t e g i r d e r , u s i n g P V C D 1 7 0 t u b e s t o m a k e d r a i n a g e

w a i t i n g - h o l e o f b r i d g e s u r f a c e a t p o s i t i o n s w h i c h a r e m a r k e d o n t h e g i r d e rflange of exterior girder

prepared and checked carefully

openings of forms shall be sealed to prevent leakage concrete

 Casting Concrete:

- C h e c k i n g t h e t e m p e r a t u r e a n d s l u m p o f c o n c r e t e C o n c r e t e , w h e n t h i s i splaced, shall have a temperature is satisfied in according to the specification

reinforcing bars and from drying ahead of the final covering with concrete

meters

and make the good connection between layers Proposal layer heights mightbe: layer 1 to layer 5 with 30cm and layer 6 with 25cm

- E x t e r n a l v i b r a t o r s h a l l b e s e t u p o u t s i d e o u t f o r m T h e n u m b e r o f v i b r a t o r sused shall be sufficient to consolidate the concrete properly within 30 minutes

after it is deposited in the forms

down, no air, bubble, surface leveled and no mortar exposed

t h a t t i m e s h a l l b e l e s s t h a n i n i t i a l s e t t i n g t i m e o f l e s s t h a n t i m e f o r r e compaction of previously cast layer

concrete area shall covered in order to ensure the quality of concrete

immediat e adj ustment sh all be don e t o re posit ion t he forms b efore concret eplacing keep on

- A p p o i n t s o m e p e r s o n s c o n t r o l o p e r a t i o n o f v i b r a t o r s o u t s i d e a c c o r d i n g t oconcreting position, avoiding activation of vibrator at positions which concrete

was cure

- Vibrators system is operated following each compartments of outer formwork,

l ay e r by l a ye r w e ca rry ou t c om pa ct by R ee d l ey vi b ra t o r t h en u si n g vi b rat or

f r o m 1 0 - 1 5 s P r o c e s s i n g s e q u e n t i a l l y l a y e r b y l a y e r a n d f o l l o w i n g e a c hcompartments of outer formwork

increase temperature of concrete in waiting process

casting concrete

- O n c e c o m p l e t i o n o f c o n c r e t e p o u r i n g a n d c o n c r e t e i n i n i t i a l s e t t i n g t i m e i f

then leveling 2nd time for smoothly and make roughness

Q = 5 Ton

Mixtruck

ConcreteBucket No.1

Gantry crane

5 Tons

Gantry crane 5T

Concrete

Gantry crane 5T

Concrete bucket no.2 Moving

76

98

1110

1312

141

32

54

76

98

111013

g) Curing and Removal of Inner Formwork:

 Curing Concrete:

- A f t e r c a s t i n g c o n c r e t e , w e n e e d p r e v e n t a f f e c t s o f f o r c e s o u t s i d e o n g i r d e r

w h e n g i r d e r c o n c r e t e s t r e n g t h h a s n o t r e a c h e d 8 5 % o f d e s i g n s t r e n g t h ,especially positions on the girder flange

hours

- A f t e r c a s t i n g c o n c r e t e p r o c e s s m a k e r o u g h b y b l o w s i k a d u r a n d u s e s t e e lbesom to cleaning surface

All preparation of curing works must be checked carefully

- T e m p e r a t u r e o f c u r i n g s h a l l b e c a l c u l a t e d c a r e f u l l y f o r c o n c r e t e t o r e a c hrequired strength fast and don’t make bad impact to concrete

 Removal of Inner Formworks:

- U s i n g h y d r a u l i c j a c k f o r m o v a b l e o f i n n e r f o r m t o s e p a r a t e i n n e r f o r m a n d

g i r d e r , t h e n u s i n g g a n t r y c r a n e t o l i f t c o r e o f i n n e r f o r m o u t o f g i r d e r I n

o p e r a t i o n w e n e e d p r o c e s s i t v e r y c a r e f u l l y a n d l i g h t l y t o p r e v e n t i m p a c tbetween inner form and girder

Removal bolt for PC bar

Casting bed

Inner form

Lifting

Support frame

cast super-T girder

- E x p o s e d s u r f a c e o f g i r d e r ( t o p s u r f a c e o f g i r d e r ) s h a l l b e c o v e r e d b y w e tburlaps immediately after final finishing of concrete surface

1900 975

have a signal man by using horn

center of girders with the following sequence:

Order of cutting tendons of Super T girder type 38.3m (44 strands):

35 3634

23 2422

32 3331

20 2119

1110

8 97

186

20 2119

1110

8 97

186

2322

20 2119

1110

8 97

186

28

24

 Measuring p ore-cambert t s o g n a he l op urfacec l o f irder long ongitudinal entre ine f

g i r d e r a f t e r f i n i s h i n g o f c u t t i n g o f t h e s t r a n d s M a r k i n g a t c e n t r e o f b e a r i n g a n dcentre of to monitor the pre-camber Checking the pre-camber at these positions

before and after cutting the strands

shall be covered by Sikadur 731

i) Lifting Girder to Stock Yard:

28-days strength

gantry crane

with slowly speed

agreement of engineer

of casting by using templates

D19 rebar to support and connect girder as drawing:

SUPER - T

wood plate 1200X100X50mm

TUMBUCKLET

 C h e c k i n g s t a b i l i t y o f f o u n d a t i o n u n d e r t e m p o r a r y b e a r i n g o f s u p e r T g i r d e r

regularly

No Fabrication yard Quantity Remark

1 Fabrication yard no.1.1 38 1 layer

j) Filling the bonding mortar.

particles

ends of girder

2) Cycle Time of Super-T Girders Fabrication:

Installation of rebar and PC cable, tensioning(IR)

0.5 day

7 Schedule for Production of Super T Girder

8 Quality Control:

 Q C E n g i n e e r / S i t e e n g i n e e r s h a l l i n s p e c t a l l w o r k s t o e n s u r e c o m p l i a n c e t o t h erequirement of Construction Scheme

 A l l m a t e r i a l s h a l l c o m p l y w i t h a l l r e q u i r e m e n t s i n t h e S p e c i f i c a t i o n ; r e f e r t o a t t a c h e d

Inspection and Test Plan on Appendix 14 and Inspection sheet form on Appendix 15

 T h e t o l e r a n c e s l i s t e d i n T a b l e 1 a r e t h e a l l o w a b l e d e v i a t i o n s f o r p r e - s t r e s s e d c o n c r e t e

structures These tolerances will be included in assessments for the acceptance of work

Acceptance Tolerances of Pre-stressed Super T Girder (Refer to S07450)

Tolerance

by contractor in construction process

Cutting Tendon and shifting (S)

 Prior t s o otartings s wf ubt f tructurem s bork,i het a r ollowing atters hall e nformed o ll elatedstaffs working in the construction site to prevent any environmental pollution.

1) Site Organization Layout

m a i n t a i n a l l n e c e s s a r y b a r r i c a d e s , s u i t a b l e a n d s u f f i c i e n t l i g h t , d a n g e r s i g n a l a n d

o t h e r s i g n , p r o v i d e a s u f f i c i e n t n u m b e r o f w a t c h m e n a n d t a k e a l l n e c e s s a r y

precautions for the protection of the works and the safety of the public

keep the construction site dry and clean Do not let water stagnate on the pavement

or run into the foundation hole For construction sites which are adjacent to sea, river

or stream, there must be method to prevent flood and land slide

t h e e n d o f w i n d d i r e c t i o n t o e n s u r e t h e s a f e d i s t a n c e f r o m t h e s t a f f a n d w o r k e r

accommodation and residential area Otherwise, there must be method, according to

the current regulations of the Government, to prevent hazardous elements

 W e l l s , t u n n e l s a n d h o l e s o n t h e g r o u n d a s w e l l a s i n t e r s t i c e s o n w o r k i n g p l a t f o r m

m u s t b e c o v e r e d o r h e d g e d w i t h m i n i m u m h e i g h t o f 1 m F o r d i t c h e s o r f o u n d a t i o n

h o l e s w h i c h l o c a t e s a d j a c e n t t o t r a f f i c r o a d s , t h e r e m u s t b e f e n c e w i t h m i n i m u m

height of 1m and sufficient lighting system at night

ground, without fence, warning signposts or guards, is strictly prohibited

 I n t h e s t o r a g e a r e a f o r m a t e r i a l , f u e l , c o m p o n e n t a n d e q u i p m e n t , t h e r e m u s t b e

accesses The width of access must satisfy the size of handling and transporting

vehicles There must be aisles between material stacks with minimum width of 1m

the traffic roads, railways, crane ways

c l o s e d b a s k e t , s i l o o r b u n k e r … C o n c u r r e n t l y , t h e r e m u s t b e m e t h o d t o p r e v e n t

dust when handling material

 L i q u i d m a t e r i a l ( p e t r o l , o i l , l u b r i c a n t … ) m u s t b e p r e s e r v e d i n s t o r a g e h o u s e

according to special regulations on fire prevention

1m Brick must be laid on the ground with maximum number of row of 25

(including lining pads)

m a x i m u m h e i g h t o f 2 5 m S t e e l p i l e o r c a s t - i r o n p i p e , w h o s e d i a m e t e r i s o v e r

3 0 0 m m , m u s t b e p i l e d u p a s l a y e r s w i t h m a x i m u m h e i g h t o f 1 2 m a n d s u p p o r t

method

Small-sized ones shall be placed on shelves with the same maximum height The weight

of steel placed on shelves must not exceed the safe load of shelves

a) Daily Safety Housekeeping Cycle

and not allowed to accumulate on site and checking of safety facilities at the end

of the day on daily basis before leaving the site, shall be performed by all workersand checked by their Site Engineers

 T h e n i g h t s h i f t w o r k f o l l o w i n g t h e e a r l i e r d a y w o r k r e q u i r e s t h e c o n c l u d e d w o r k

done schedule with the daily safety duties carried out

b) Weekly Safety Housekeeping Cycle

p r e v i o u s w e e k c a r r i e d o u t a n d i t s a c t i v i t i e s w i t h t h e p l a n n e d s c h e d u l e f o r t h ecurrent week shall be informed to all staff and workers

 C l e a n i n g o f w o r k p l a c e s b y a l l w o r k e r s s h a l l b e c a r r i e d o u t a f t e r t h e g r o u p

discussion on Saturday morning before the start of that day’s work

c) Monthly Safety Housekeeping Patrol /Cycle

E n g i n e e r s h a l l b e c a r r i e d o u t w i t h r e p o r t s p r e p a r e d b y t h e S a f e t y O f f i c e r f r o mthese patrols These reports shall be issued to all attendees at the Safety Patrols

and also to discuss any issues at the Daily Meeting for follow-up actions

 T h e m o n t h l y p a t r o l s h a l l b e h e l d a t e n d o f e a c h m o n t h a s p a r t o f t h e m o n t h l y

s c h e d u l e m e e t i n g w h e r e b y d i s c u s s i o n o n s u g g e s t i o n s f o r a n y s i t e s a f e t y / w o r kschedule relating to the patrol can be taken into action for the following month

4) Working around Equipment / Machineries

accidentally knocked/hit workers working too close to them If such situation arises,

the followings must be observed:

within close vicinity of machineries Site Engineer should inform such requirements to

the workers and operators of machineries

safety or relief valves and pressure gauges

OF SERVICE”, “DO NOT USE” Use of such unsafe equipment is prohibited

 P r e s s u r i z e d e q u i p m e n t s h a l l b e o p e r a t e d a n d m a i n t a i n e d o n l y b y q u a l i f i e d a n d

authorized personnel