dismantling- crane inside lift

Raymond Tang, Product Manager APAC

Potain MCi 85 Tower Crane ( Internal)-Dismantling

By Anil K Mishra

MC i85 A/ B Specifications

Model Mci 85 a/b, External Crane( Inside lift shaft)

Base Mast – 7.5m

Jib – 50 Mtrs

Height Under Hook – 49.5 Mtrs

Maximum Capacity – 5 Tons

Load at 50 Mtrs – 1.3 Tons

Method statements:- Dismantling

•Preparation &Removal of Telescopic cage•Position of Derrick for counter weights•Removal of cabin•Position of derrick for main jib•Position of derrick for removing cat head, mast and anchorage frames•Position of Gantry for lowering the material.•Provision of storage on ground for shipping•General provisions

Potain Asia Range

Preparation for dismantling

•Ensure Crane is positioned approx 6 meters above the top slab to facilitate removal of telescopic cage (if fitted)

•Remove telescopic Cage using standard method

Potain Asia Range

Removal of Counter Weights using Special Frame or Derricks

Special FrameInstalled on counter jib

3 counter weights removedone by one

One counter weight will remainInstalled until main jib is removed

Operator’s Cabin Removal

Same winch is used with Derrick / Pulleys to remove and lower the cabin

Position of Derrick for main jib removal

MAIN JIB

LENGTH CG ( HOOK POSITION) WEIGTH (+_5%)

50M 17.5M 6488 KGS

45M 16.2M 6237 KGS

40M 14M 5584 KGS

35M 12.87M 5351 KGS

CG ( DERRICK HOOK POSITION) FOR 50M JIB LENGTH

Derrick Hook


HOOK

CG ( DERRICK HOOK POSITION) FOR 35 M JIB LENGTH

HOOK

Tentative location of Derrick for main jib dismantling

D- position of Derrick for Main jibD for CJ- Derrick position for Counter jib

D for CJ

Potain Asia Range

Removal of Main jib using special Derrick

Special derrick is positioned as per actual site condition to balance the load / CG as per jib length in use

Special Derrick

Lowering of Main jib on Top Slab

Main jib is rested on the top slab ensuring safety, Joining Pins are removed with load supported on slab

Making the main jib free

Tie Bar Pins removed to makejib Free from main structure

Removing of Control Panel and Hoist motor

Hoist Motor and Electrical control panel is removed using Chain Pulleys/ derrick as required

Main Jib dismantled into small parts and lowered to groundusing same winch or routing through derrick/ pulleys

Removal of Counter Jib- Using Derrick

Removing of Counter jib using Derrick – Position as per actual position

Counter Jib

Positioning of Derrick for Removing Vertical Structure

Derrick

Position

Vertical Structure with Cat head

Removing Cat head

Removing vertical Structure- Using Derrick

Cat is removed and all masts pulled up one by one using derrick and Hoist winch

Bringing down to Zero level

All Materials are brought down to Zero level with Derrick or gantry Crane which is positioned near edge of building on top

General Provisions

• All Precautions are taken to ensure crane is balanced and safe before start of work.

• At any given point, all derrick, pulleys and wire rope are inspected fully for any possible damage.

• Necessary safety is ensured at every stage of work

• Loads on hook, pulley, wire rope and number of falls calculated for each stage of work.

• Safety precautions for site specific is also followed by work and team

• Actual position of Derrick/ gantry may vary as per site condition and load CG.

• Site Support is essential for smooth and safe operation for dismantling

dismantling- crane inside lift

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