Important Facts on the Methods of Statement for Precast Deck Slab Installation are given below:
1. Scope:
This Method Statement describes the sequence to be followed during the installation of precast ‘ deck slab for the various culverts.
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2. Summary of Activities:
Transportation and offloading of Precast deck slabs.
ADVERTISEMENTS:
Installation
Precast slab connections.
Opening to traffic
3. Procedures:
ADVERTISEMENTS:
Transportation and Off Loading of Precast Deck Slabs:
(i) Cured Precast deck slabs shall be loaded on the trailer using embedded hooks on slab by crane.
(ii) Precast slabs shall be kept on top of the wooden battens and necessary side packing shall also be provided to avoid damages.
(iii) Transport all the precast slabs required to cover one full culvert and offload them using embedded hooks, slings and crane.
ADVERTISEMENTS:
(iv) The offloading of precast slabs shall be carried out as shown on the attached sketches.
(v) Precast slabs shall be kept on top of the wooden batten placed on the level and firm ground.
Installation:
(i) Temporary decking system shall be provided over the pipelines prior to the installation of precast slabs.
(ii) Line, level and dimensional check shall be carried out for the walls prior to the commencement of Precast slabs installation.
(iii) Precast slab installation shall be carried out between the abutment wall and first internal wall.
(iv) Installation of Precast slab in first bay shall be completed prior to proceed to the second bay.
(v) Installation shall be started from one side to the other side of the bay by installing first end slab with kerb.
(vi) Precast slab installation details shall be strictly followed as shown on the attached sketch. Adequate care will be taken such that while lifting the slab, the boom of the crane will move within the limits of the crash deck area only and not above the pipelines.
(vii) Precast slab installation for the longer culverts shall be carried out from both sides of the culverts.
Precast Slab Connections:
(i) Complete the installation of precast slabs as per the approved drawings.
(ii) Provide additional 20mm dia bars by opening the links and insert the extra bars. All the extra bars shall be kept in proper position and tied with links.
(iii) Insert 16 mm dia connection bar through the loop bars, which protruded from the precast slab.
(iv) All the vertical bars in Abutment wall kept straight shall be bent and lapped with the slab bars. All the links shall be open and inset the bars then close to the original position.
(v) Necessary shuttering shall be provided to close the open sides of the area to be stitched.
(vi) Concrete casting shall be carried out with 10mm aggregate, concrete in order to get free flow.
(vii) Proper compaction shall be provided with needle vibrations.
(viii) The temporary decking system shall be removed after 3 days curing of the stitched concrete.
Opening to Traffic:
(i) All the gap between the precast slabs shall be closed with rich cement mortar.
(ii) Earth filling behind the abutment wail shall be carried out in layers of 300 mm thick with proper compaction.
(iii) Approach slab shall be concreted as shown on the drawing and allow for curing for 7 days.
(iv) Small concrete ramp shall be provided temporarily to make connection with existing road and culvert slab.
(v) Allow the traffic on the culverts temporarily.
(vi) Temporarily close the traffic to provide the asphalt-wearing course, when the first group culverts (4 culverts) are ready to receive wearing course.
(vii) Provide asphalt wearing course on the culvert and reopen for the permanent traffic.