August 31 - Lifting Gear Hire (LGH) has provided 16 wireless compression load cells from Straightpoint for the benchmark weighing of ten ship-to-shore cranes at the Port of Los Angeles, USA.

The 150-tonne capacity load cells combined to weigh one Noell ship-to-shore container handling crane, originally estimated to have a weight of 1,350 tonnes, and provide benchmark data before the cranes were raised to accommodate larger ships calling at the port.

The project, managed by ZPMC North America, involved raising the cranes 10 m and inserting longer leg sections, which were constructed at ZPMC's Shanghai facility.

Rick Pope, vice president at ZPMC North America, explained that the benchmark weighing was required to determine the new, as-built weight and centre of gravity of the raised crane.

"From this data, ZPMC calculated the required concrete ballast that needed to be added to establish the crane's operational centre of gravity and stability," added Pope.

The weighing procedure included lifting the crane utilising ZPMC's self-propelled modular trailers (SPMT), placing the load cells in pairs under the eight intermediate gantry equalisers on specially designed pedestals, and lowering the crane down to rest on the load cells. The crane was lifted off the load cells between trials to allow for three distinct weighing phases.

The initial as-built weight of the crane was 1,185 tonnes. Post-construction weighing indicated the longer leg sections added 193 tonnes, while the concrete ballast resulted in a total weight of 1,414 tonnes and a shift in the operational centre of gravity by approximately 1 m towards the rear of the crane.

Centre of gravity software collected data over the three trials and generated a report which included each load cell's load, location, calculated centre of gravity and standard deviation of weight data.