Clinker silo steel structure – Case Study

Project scope: The erection of steel structures on a clinker silo such as the ring beam, rafter frames, penthouse, and conveyor galleries. Equipment used: Liebherr 110t mobile crane, Liebherr 250t mobile crane, Liebherr 450t mobile crane, Kobelco 250t crawler crane, IHI CCH2500 – 250t crawler crane, Demag 650t crawler crane. Load details: Penthouse assembly (150t), Ring beam assembly (70t), Rafter assembly (25t), Conveyor Gallery (48t)

Project execution: A 650t crane was rigged up and lifted the ring beam assembly above the silo. Stay cables were used to secure the ring beam at 44m. Two 250t cranes are used to connect the rafter assembly (25t each). Once the rafters have been assembled, the silo's load is gradually released. The entire penthouse set (150t) of dimensions (15m x 15m x 22m) is lifted and placed on top of the ring beam with a rafter. As per the scope we initially lifted the 40m long conveyor in tandem with 450t and 250t cranes and erected it over the existing column and silo.

Challenges of the project:

The main crane had to hold the ring beam above the silo for 15 days. During these days, the rafters and purlins were installed, increasing the load from 70t to 135 tons.
The rigging arrangement of the penthouse assembly was designed to lift the load with minimal stress on the steel structure. Detailed load analysis was done, and counterweights were added to the structure to ensure the COG of the load remained at the centre of the structure.
Since the site is near a mountain, the wind speed created a tunnel effect, and the load surface area is also large, we had to calculate the permissible wind speed.
To complete the project, a complex rigging system was created.

Penthouse structure at JSW cement – Case Study

Project scope: The erection of clinker silo structures such as the ring beams, rafter frames, penthouse, and conveyor galleries. Equipment used: Liebherr 110t mobile crane, Liebherr 250t mobile crane, Liebherr 450t mobile crane, Kobelco 250t crawler crane, IHI CCH2500 – 250t crawler crane, Demag 650t crawler crane. Load details: Penthouse assembly (150t), Ring beam assembly (70t), Rafter assembly (25t), Conveyor Gallery (48t)

Project execution: A crane has been rigged up and lifted the ring beam assembly above the silo. The ring beam was secured with stay cables at 44m. Then with the help of 2 x 250t cranes, the rafter assembly (25t each) is connected. The silo's load is gradually released once the complete rafters have been assembled. After the ring beam is erected with a rafter, the entire penthouse set (150t) of dimensions (15m x 15m x 22m) is lifted and placed on top. As per the scope we initially lifted the 40m long conveyor in tandem with 450t and 250t cranes and erected it over the existing column and silo.

Challenges of the project:

The main crane had to hold the ring beam above the silo for 15 days. During this day, the rafters and purlins were installed, increasing the load from 70t to 135 tons.
The rigging arrangement of the penthouse assembly was designed to lift the load with minimal stress on the steel structure detailed load analysis was done, and counterweights were added to the structure to ensure the COG of the load remained at the centre of the structure.
As the site was near to maintain the wind speed was high which created a tunnel effect and the load surface area is also high, we had to calculate the permissible wind speed to mitigate the tunnel effect.
A complex rigging system

Al Faris recently installed a Steam Box at a new Waste to Energy Plant in Dubai.

Due to Industry reputation and expertise involving high complexity in planning and execution, Al Faris were recently awarded this project.

This challenging installation was done at a height of 2.8m using our specialized in-house modular towers and other skidding equipment.

The Steam Box was delivered in two parts, the bottom part weighing 27t and the top part weighing 40t. The top part was tandem lifted for top and tail operation using our 250t and 200t mobile cranes. It was then placed onto skid tracks and skidded into a temporary position. Thereafter the bottom part was placed on the skid tracks. The top part was then lifted in order to allow the bottom to be skidded underneath. Once the bottom part was skidded into final position, the top part was lowered onto the bottom part and both parts of the Steam Box were joined together for final installation.

Challenges: The clearance while skidding was only 30mm. All measurements and markings were done precisely during the operation.

The COG of the top part of the steam box was away from both the lifting points during the lifting of the load from the trailer which could have caused the load to slide. In order to avoid this situation, we made a temporary packing arrangement of stools at the corner of the steam box.

A project of this nature requires exceptionally detailed planning to orchestrate the complex activities necessary for ensuring uninterrupted safe services; from detailed planning to ensuring utmost safety during all lifts. The technical support documentation, execution plans and HSE protocols were prepared in-house and discussed with the client prior to project execution.

Manufacturing

Loading and transportation of DRI cooler vessel

Top and tailing of flanging machine in confined space