Quay to Success!
Cement

Quay to Success!

K Ramkrishna, General Manager, IMCL; PS Sengupta, Vice President, ITD Cementation; and Jayanta Basu, Vice President, ITD Cementation, take us through the design and construction of the marine liquid jetty and allied marine structures at Ennore Port.

Every challenge can be overcome with the right game plan. Proof of this is the design and construction of the marine liquid jetty at Ennore Port by ITD Cementation from 2007 to 2009.

The blueprint

The liquid jetty was designed in association with an external design firm based in Kolkata. The requirements:
  • To meet all operational needs for the 360 m long berthing structures with final dredged level of 21 m in front of the berth. Structures to withstand all mooring, berthing and materials handling loads likely to be experienced by the vessel.
  • To meet all operational needs for supporting product pipelines and one carriageway from shore to jetty of a length of about 1,200 m. It required strong point structures at three locations to withstand the horizontal drag from the liquid carrying pipelines.  
  • To design the approach trestle with abutment partially suspended in existing breakwater.
Planning and design

The jetty was planned with continuous deck arrangement. All possible environmental and ship operational loads were considered as per tender stipulation and codal requirements. Also, for the design and analysis of structure state, an art software programme was used. Major elements included the marine piles, reinforced concrete members and pre-stressed post-tension girder; bored cast-insitu piles of 1,200 mm diameter were used for the jetty head. Piles were of long cantilever type for dredged level of 21 m CD. Other structural components include pile muff, RCC cross beams, longitudinal beams and deck slab. The pipeline trestle was about 1,200 m. Moreover, for economy and ease of construction, pre-stressed concrete 'I' girders were used.

Key elements

Major activities included the construction of a 360 m x 30 m berthing jetty; a 1,200 m pipeline trestle; 130 m approach trestle; and a 450 sq m fire pump house. Structural elements were required for the bored cast-insitu piles (392); product jetty (214); pipeline trestle (150); approach trestle (14); fire pump house (14); pre-stressed concrete girders each 20 m long (212); and RCC precast units (2,125); with a total concrete volume of about 35,000 cu m.

The challenges

Completion of marine piling on time was critical. The challenges included the long spacing of pile grid at 20 m c/c for pipe trestle and loose and fine sand strata beneath the seabed for large depth. To address these, a large cantilever piling gantry of 60 m length with 20 m hanging in front was used. Owing to such large cantilevering, the piling gantry structure required deep lattice main girders with builtup plate girders at the bottom. The gantry rolled on a 180 tonne articulated rollerwheel assembly supported on four completed piles. A  
10 tonne electric winch was used to pull the gantry.

As the 1,200 m long pipe trestle is in curvilinear alignment, three sharp bends had to be provided at three strong point locations. It was an enormous technical challenge to negotiate the movement of such large cantilever platforms at those sharp bends. Part of the pipe trestle piles were installed using a specially designed jackup piling platform. The platform was fabricated and launched at site. The spud operation was done with hydraulic jacks and centrally controlled. The jackup was designed engaging an external consultant, while the entire mehanical arrangement for the spud movement as well as the fabrication of the structural modules of the jackup were undertaken using inhouse resources.

The 1,200 mm diameter marine piles for product jetty were installed from three piling gantries, each with piling rigs. All the piles were lined with a permanent steel liner up to the bottom of the loose and fine sand (about 20 m CD). The main jetty piles had a deep founding level at 43 m CD; thus the length of each pile was 57 m from the top of the piling gantry. Pile boring was done by percussive method with a sludge pump and cross chisel; 7.5 tonne capacity bored pile winches were used. Strict control on bentonite was followed with a proper QA/QC system in place. The tremie concrete was laid in piles with concrete supplied by the concrete pump. The other major aspect of pile installation was pile bracing. This was extremely critical for the pipe trestle as the spacing was large. A set of bracings was fabricated at site that were to move below the gantry as it was impossible to remove the bracing all the time and refix it. Pile bracing was provided to cater to the horizontal load on pile from current, wind and wave, as well as while shifting the piling platform from one bent to the next.

Casting, handling and transporting

Another key aspect was to cast, handle, and transport 20 m long PSC girders for the pipe. Around 212 girders with another 2,100 RCC precast units were cast at the yard along the shoreline in a limited space. As the yard was square in shape, it was also difficult to use one handling EOT gantry covering a large length. The solution: manoeuvring the gantry on rails in any direction. Thus, one gantry with a 20 m span was able to cover several precast beds laid parallel by moving along both directions. At the junction of the rails, a diamond crossing was introduced and a wheel rotated 90°. The girders were transported to the location with specially designed tyre mounted wheel bogies and pulled with a tractor.

All the girders were launched by a site-fabricated laun­ching truss by the endon method. The operation required a skilled team. The launching commenced from shore and progressed further inside the sea. A temporary track was laid to shift the girders to the launching truss location. Now, for the most critical part to have better control on the concrete finish, the entire fender-supporting concrete unit was cast at the yard, transported through water through a special pontoon and erected at position with a 60 tonne hoist and special gantry.
Indeed, this was a landmark project, unique in its challenges. But, it was executed to perfection by the efforts of the project team and inhouse design unit of ITD Cementation.

To share your industry experiences with us, write in at feedback@ASAPPmedia.com

K Ramkrishna, General Manager, IMCL; PS Sengupta, Vice President, ITD Cementation; and Jayanta Basu, Vice President, ITD Cementation, take us through the design and construction of the marine liquid jetty and allied marine structures at Ennore Port. Every challenge can be overcome with the right game plan. Proof of this is the design and construction of the marine liquid jetty at Ennore Port by ITD Cementation from 2007 to 2009.The blueprintThe liquid jetty was designed in association with an external design firm based in Kolkata. The requirements:To meet all operational needs for the 360 m long berthing structures with final dredged level of 21 m in front of the berth. Structures to withstand all mooring, berthing and materials handling loads likely to be experienced by the vessel. To meet all operational needs for supporting product pipelines and one carriageway from shore to jetty of a length of about 1,200 m. It required strong point structures at three locations to withstand the horizontal drag from the liquid carrying pipelines.  To design the approach trestle with abutment partially suspended in existing breakwater. Planning and designThe jetty was planned with continuous deck arrangement. All possible environmental and ship operational loads were considered as per tender stipulation and codal requirements. Also, for the design and analysis of structure state, an art software programme was used. Major elements included the marine piles, reinforced concrete members and pre-stressed post-tension girder; bored cast-insitu piles of 1,200 mm diameter were used for the jetty head. Piles were of long cantilever type for dredged level of 21 m CD. Other structural components include pile muff, RCC cross beams, longitudinal beams and deck slab. The pipeline trestle was about 1,200 m. Moreover, for economy and ease of construction, pre-stressed concrete 'I' girders were used.Key elementsMajor activities included the construction of a 360 m x 30 m berthing jetty; a 1,200 m pipeline trestle; 130 m approach trestle; and a 450 sq m fire pump house. Structural elements were required for the bored cast-insitu piles (392); product jetty (214); pipeline trestle (150); approach trestle (14); fire pump house (14); pre-stressed concrete girders each 20 m long (212); and RCC precast units (2,125); with a total concrete volume of about 35,000 cu m.The challengesCompletion of marine piling on time was critical. The challenges included the long spacing of pile grid at 20 m c/c for pipe trestle and loose and fine sand strata beneath the seabed for large depth. To address these, a large cantilever piling gantry of 60 m length with 20 m hanging in front was used. Owing to such large cantilevering, the piling gantry structure required deep lattice main girders with builtup plate girders at the bottom. The gantry rolled on a 180 tonne articulated rollerwheel assembly supported on four completed piles. A  10 tonne electric winch was used to pull the gantry.As the 1,200 m long pipe trestle is in curvilinear alignment, three sharp bends had to be provided at three strong point locations. It was an enormous technical challenge to negotiate the movement of such large cantilever platforms at those sharp bends. Part of the pipe trestle piles were installed using a specially designed jackup piling platform. The platform was fabricated and launched at site. The spud operation was done with hydraulic jacks and centrally controlled. The jackup was designed engaging an external consultant, while the entire mehanical arrangement for the spud movement as well as the fabrication of the structural modules of the jackup were undertaken using inhouse resources.The 1,200 mm diameter marine piles for product jetty were installed from three piling gantries, each with piling rigs. All the piles were lined with a permanent steel liner up to the bottom of the loose and fine sand (about 20 m CD). The main jetty piles had a deep founding level at 43 m CD; thus the length of each pile was 57 m from the top of the piling gantry. Pile boring was done by percussive method with a sludge pump and cross chisel; 7.5 tonne capacity bored pile winches were used. Strict control on bentonite was followed with a proper QA/QC system in place. The tremie concrete was laid in piles with concrete supplied by the concrete pump. The other major aspect of pile installation was pile bracing. This was extremely critical for the pipe trestle as the spacing was large. A set of bracings was fabricated at site that were to move below the gantry as it was impossible to remove the bracing all the time and refix it. Pile bracing was provided to cater to the horizontal load on pile from current, wind and wave, as well as while shifting the piling platform from one bent to the next.Casting, handling and transportingAnother key aspect was to cast, handle, and transport 20 m long PSC girders for the pipe. Around 212 girders with another 2,100 RCC precast units were cast at the yard along the shoreline in a limited space. As the yard was square in shape, it was also difficult to use one handling EOT gantry covering a large length. The solution: manoeuvring the gantry on rails in any direction. Thus, one gantry with a 20 m span was able to cover several precast beds laid parallel by moving along both directions. At the junction of the rails, a diamond crossing was introduced and a wheel rotated 90°. The girders were transported to the location with specially designed tyre mounted wheel bogies and pulled with a tractor.All the girders were launched by a site-fabricated laun­ching truss by the endon method. The operation required a skilled team. The launching commenced from shore and progressed further inside the sea. A temporary track was laid to shift the girders to the launching truss location. Now, for the most critical part to have better control on the concrete finish, the entire fender-supporting concrete unit was cast at the yard, transported through water through a special pontoon and erected at position with a 60 tonne hoist and special gantry. Indeed, this was a landmark project, unique in its challenges. But, it was executed to perfection by the efforts of the project team and inhouse design unit of ITD Cementation.To share your industry experiences with us, write in at feedback@ASAPPmedia.com

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