桥梁施工计划英文版BridgeFoundationandsubStructureConstructionProgr.doc

Bridge Foundation and Substructure Construction Programme (k5+000 3×25m=75m Mamboleo Bridge)

1. Basis
(1) The Standard Specification for Kenya Road and Bridge Construction.
(2) Contract of the Rehabilitation of Kisumu-Kakamega Road, Special Specification.
(3) Drawings.
(4) The General Requirement of Construction Period.
(5)Actual condition in-site.

2. General Status of the Bridge
we plan to commence construction of Km5+000 bridge recently. The superstructure is 3×2.5m cast-in-situ continuous “T” girder(30/20 concrete). The bridge pier and abutment of substructure is extended open cut foundation(30/20 concrete). Pier body adopts thin-walled pier (30/20 concrete) and bridge cap beam (30/20 concrete). The type of abutment body uses wing-wall abutment(30/20 concrete) and 30/20 reinforced concrete structure. Attached please find Km5+000 Manboleo bridge substructure programme.

3. Foundation (Extended Open Cut Foundation) Construction Technology Scheme
(1) Preparation
The preparation of construction mechanical equipment, staffs, location set-out, original material test and standard ratio test have been completed, and the side road around construction location could meet bridge construction requirement.
(2) Foundation Pit Excavation
Mechanical equipment shall apply to foundation pit excavation,and labor forces clear the bottom of pit. Based on the actual condition of excavated culvert, foundation pit slope sets out is 1:0.33 or1:0.25. 10cm20cm width shall be reserved for labor force cleaning. If the underground water in high level, a ring drain will be excavated around foundation pit. The top width of drain is 0.5m, and underpart is 0.3m; One water collection pit(0.5＊0.5＊0.8m3) shall be excavated if necessary.
(3) Set Out and Blinding Concrete
After finishing foundation pit cleaning, the surface of pit shall be compacted. Then, commencing set out base location, dimensions and elevation,the results of which shall be reported to Engineer for inspection and approval. After that,casting100mm blinding concrete(15/40) in-situ. The top elevation of blinding concrete is the same with the bottom elevation of pile cap, which is under the requirement of specification. The width of blinding concrete is 0.05m larger than pier cap outline,which need strictly control during construction.
(4) Reinforcing Bar Engineering
The bearing platform foundation reinforcement is centralized blanking and processing. Concrete cushion block is applied between steel reinforcement and formwork to insure protective layer thickness under the design requirement.
A, Steel Reinforcement Processing
a, The test result of reinforcement steel shall be approved by the Engineer. All the steel bars shall have quality certificate.
b, The steel surface shall be cleaned for oil spot , paint and rust pitting; the steel shall be straight without local bending. When cold drawing method adopted, Grade I steel cold drawn rate ≦2% ,and Grade II steel ≦1 .
c, Based on reasonable, economic and practical principle, steel blanking shall obey the requirement of drawings, and avoid processing large quantities of short steels. Reinforcement steel is processed in strip slab which is cast-in-place concrete(15/20concrete) slab with width 1.2m and length 20m. Steel will be marked by steel ruler or flexible ruler on strip slab, and processed by machine with settled bending angle.
d, Connection of Steel Bar:to meet the requirement of lap length , lapped bar will be applied to main reinforcement.
B, Others matters shall strictly adhere to the requirement of construction specification.
(5) Formwork
A,the formwork for bridge bearing platform(foundation) is bulk assemble split formwork. To ensure the joints smooth without joint trace, the steel plate for formwork is δ≮5mm (or fabricated formwork whose back arris is made by 1.22*2.44m wood glue board and lumps of wood).
B, the stiffness,strength and stability of fromwork shall meet requirement. No formwork shall be applied to construction without inspection and approval.
C,fromwork shall be shuttered by skilled labor at one time. In order to avoid leakage and insure concrete quality, the joint seam shall less than1.5mm, faulting of slab less than 1.5mm. Releasing agent shall be applied to reinforcement before installation.

D, Formwork installation shall be tight. The joint shall be sealed in good condition to avoid spillage and ensure structure surface looks good, lines and shape smooth.
E, the planimetric position, top elevation, joint and longitudinal stability shall be checked after formwork installation. Meanwhile, the length and planimetric position of embedded bar shall be checked. The concrete shall not be cast without the approval of Engineer. Formwork shall be inspected during casting in case out of shape.
F, Formwork Dismantlement: concrete work shall not be damaged during dismantlement. Dismantlement shall follow the procedure of “support first dismantle afterward”, “dismantle first support afterward”, and formwork shall not be threw during removal. The dismantlement minimum period is according to the requirement of general specification clause 17-4.
(6) Construction of Concrete Work
Concrete shall be mixed in mixing plant, measured by E-metrics and transport by truck, truck crane or concrete pump, and vibrated mechanically to avoid honeycombs and holes. Once forming continuous concrete casting shall be applied to concrete work without construction joint and seam. Test sample no less than 2groups.
(7) Foundation Pit Backfill
Concrete curing shall be at least 7 days after foundation concrete complete, then back-filling in layers when concrete strength meet requirement. Back-filling and compaction shall adhere to the standard specification.
4, Thin-walled Pier, Bridge Beam and Wing-Walled Abutment Construction Technology Scheme
(1)Reinforcing Bar Engineering
The reinforcement of pier and abutment is centralized blanking and processing, and concrete cushion block will applied between reinforcement and formwork to insure the thickness of the protective layer and design requirement.
A, Reinforcement Processing
a,The test result of reinforcement steel shall be approved by the Engineer. All the steel bars shall have quality certificate.
b, The steel surface shall be cleaned for oil spot , paint and rust pitting; the steel shall be straight without local bending. When cold drawing method adopted, Grade I steel cold drawn rate≦2% ,and Grade II steel ≦1% .
c, Based on reasonable, economic and practical principle, steel blanking shall obey the requirement of drawings, and avoid processing large quantities of short steels. Reinforcement steel shall be processed in strip slab which is cast-in-place concrete(15/20concrete) slab with width 1.2m and length 20m. Steel shall be marked by steel ruler or flexible ruler on strip slab and processed by machine with settled bending angle.
d, Connection of Steel Bar
To meet the requirement of lap length, lapped bar will be applied to main reinforcement.
B, Other matters need attention shall under the requirement of construction specification.
(2) Formwork

A,the formwork for pier is bulk assemble sheet steel form, and form for abutment is fabricated formwork whose back arris is made by wood glue board and lumps of wood. To ensure the joints smooth without joint trace, split billot turnover form method shall applied to construction, and casting length is 3-4m every time. Special-shaped form shall be prepared according to different pier and bridge mast, and the steel plate for formwork is δ≮5mm. Formwork shall be reinforced by steel framework.
B, the stiffness,strength and stability of fromwork shall meet requirement. No formwork shall be applied to construction without inspection and approval.
C,fromwork shall be shuttered by skilled labor at one time. In order to avoid leakage and insure concrete quality ,the joint seam no more than 1mm, faulting of slab shall follow the regulation of specification. Releasing agent should be applied to reinforcement before installation.
D, To avoid form skew,outside of formwork shall be reinforced. The method of reinforcing form as follows: a, steel scaffold; b, mooring rope; c, split bolt and drawbar. Total station instruments or drop ball shall be used to check up foresaid form. Total station instrument shall applied to examine high pier concrete construction.
Pier formwork reinforced as follows:

E, the installation of the formwork shall be tight. The joint shall be sealed in good condition to avoid leakage and ensure surface looks good, line and shape smooth.
F, the planimetric position, top elevation, joint and longitudinal stability shall be examined after formwork installation. Meanwhile, the length and planimetric position of embedded bar shall be checked. The concrete shall not be cast without the approval of Engineer. Formwork shall be inspected during casting in case out of shape.
G, Formwork Dismantlement: concrete work shall not be damaged during dismantlement. Dismantlement shall follow the procedure of “support first dismantle afterward”, “dismantle first support afterward”, and formwork shall not be threw during removal. The dismantlement minimum time is according to the requirement of general specification clause 17-4.
(4) Construction of Concrete Work
Concrete shall be centralized mixed and hardened in mixing plant, and stored according to different materials, and separated by brick wall. Mixed concrete shall be measured by E-metrics and transport by truck, truck crane or concrete pump, and vibrated mechanically to avoid honeycombs and holes. Pier body shall cast 2-4m every time, and construction joint and seam shall be remained. Test sample no less than 2groups.
Staffs and equipment arrangement for each pier, abutment as follows:
Staffs
No
Item

Qty
Remark
1
Bar placer/concrete worker
5

2
woodworker
6

3
Electrician
1

4
Unskilled staff
4

5
Test controller
2

6
Quality inspector
1

7
试
Foreman
1

8
Loader driver
2

9
Crane operator
2

10
Lifting worker
2

11

Truck driver
2

12
Excavator operator
1

13
Roller operator
1
Pit backfill

Equipment

No
Item
Qty
Remark
1
vibration rob
5

2
crane
1

3
loader
1

4
roller
1

5
excavator
1

6
200kw generator
1 or2

7
water tank
1

8
Electric welding machine
1

9
Reinforcement processing equipment
1 set

10
Woodworking equipment
1set

11
Concrete mixer
3

12
Water pump
1

13
gradienter
1

5, Attention of Bridge Substructure Concrete Construction
(1) Concrete Transport
Concrete transportation capability shall meet the requirement of concrete condensation rate and casting speed to ensure dispersion uniformity and regulated slump of concrete and continues casting. The loss of slump from mixing plant to casting shall less than 25%.
(2) Concrete Casting
A, No concrete shall be cast before support, formwork, reinforcement and embedded part are checked and recorded and meet design requirement. Sundries and water of formwork and dirt of reinforcement shall be removed. Form crack shall be sealed, and releasing agent shall be applied to formwork. Concrete uniformity and slump shall be examined before casting.
B, Concrete shall be cast layer by layer according to certain thickness, sequence and direction. The upper layer shall be cast at the beginning of lower layer solidification. Should both layers commenced casting at the same time, the distance of which remains more than 1.5m. If concrete casting on inclined plane, it shall started form low to upper section gradually and keeping horizontal slicing.Concrete casting thickness no more than 500mm, and no less than quadruple size of the biggest aggregate.
(3) Cast-in-place concrete shall be vibrated by vibration rob, except few plasticity concrete which could vibrate to dense by labor force,
The following regulations shall be followed while vibration rob applied to use.
A, Plug-in vibration rob working space shall no more than 1.5time of its action radius, and shall keep 50-100mm from side form. The depth of rob plug in is 50-100mm. Rob shall be moved out slowly after finishing vibration to avoid impacting form, reinforcement and other embedded parts.
B, The moving space of surface vibrator shall ensure vibration plate covering 100mm vibrated concrete.
C, Concrete shall be vibrated to density for every part. The symbol of well vibrated concrete are no sinking and bubble, and surface of which is smooth and bleeding.
(4) Concrete shall be cast continuously.If casting was interrupt for some reason, the period shall less than concrete initial curdle time or concrete retempering time of the front layer. The time of transporting, casting and break shall follow the requirement of the following form. Construction joint shall be reserved if time out of regulation.
(5) In process or after casting, water shall be drained away without stirring cast concrete if its bleeding in the surface of concrete. Measures shall be taken to avoid bleeding during continuous casting.
Time for concrete transport, casting and break(Min)
Strength grade of concrete
Temperature≦25℃
Temperature>25℃
≦C30
210
180
>C30
180
150
(6) the exposed surface of concrete shall be trimmed, troweled after finishing casting. Concrete shall be troweled again, and pressed polish or galled after concrete grout stabilized. Protection measures shall be taken if large surface exposed or bad weather condition happened. However, covering material shall not get in touch with concrete before its curing.
(7) Specially-assigned person shall be arranged to check the stability of support, formwork, reinforcement and embedded parts etc, during casting. Any parts becoming loose,out of shape or shifting shall be fixed at once.
(8) Construction record shall be made while casting concrete.
6,Concrete Curing and Decoration
(1) Concrete Curing
A, As to concrete curing in site, the details of curing scheme shall be made and strictly adhere to according to construction works, environment, cement type, admixture and concrete performance.
B, Concrete shall be covered and watered after contraction. Formwork shall keep wet during curing.
C, the time of concrete curing and mixing is the same.
D, concrete shall be cured 7days normally, and the period could prolong or shorten according to air humidity, temperature, cement types and admixture. Watering time shall be subject to the condition of keeping surface moist.
E, Gunny bag covering and watering shall be applied to concrete curing.
F, No pedestrian, transport machine and formwork shall be loaded before concrete strength reached to 2.5Mpa.
(2) Concrete Decoration
Concrete surface finish in different parts are dissimilar. The exposed surfa