own their own fleet; others subcontract this work. It can be beneficial for the design reviewer to check the voyage bracing prior to shipping. There are other operational considerations, such as where hatch covers are stored; the use of dual trollies; and how many containers the crane can lift: single 40 ft., twin 20 ft., tandem 40 ft., quad 20 ft., etc. All things considered the planning phase has great variance. Sometimes it starts at the wharf design stage, other times the wharf is already designed, and existing cranes are being replaced. Depending on the level of customization, once a crane is awarded, it can be up to three years before delivery. Phillips, who himself conducts peer
reviews of contractors’ crane designs, including some of the largest container cranes in the world, pointed to CP&A’s crane base anti-seismic isolation system (BASIS), which is built on nonlinear time history analysis (NLTHA) and can protect a crane’s main structure from damage even in contingency level earthquakes. “We are always improving our
software,” said Phillips. “Our crane analysis software can be thought of
CP&A peer review of a set of rubber-tired gantry cranes for Global Container Terminals.
as a custom workbench specifically made for cranes. There is a much larger market for buildings and bridge design, so the commercial software packages tend to focus on larger markets such as those [see below]. That led CP&A to create our own crane code checking
software. One example is that we have incorporated wind tunnel test data into our pre-processor, which develops the wind load forces on a crane. Obviously, a commercial building will not have integrated wind tunnel data for container cranes.” Interestingly, due to the geological
and environmental hazards, cranes should be treated more like bridges and skyscrapers instead of mass produced cars and airplanes. However, for cars and airplanes, there are crash tests and full-scale testing, which is impractical with cranes. ASCE 7-16 1.3.1.3.4 covers minimum design loads and associated criteria for buildings and other structures; this particular clause covers peer reviews for significant structures. Phillips added: “When you start thinking about how bridges, stadiums, and skyscrapers are designed it starts to become clear. For significant structures the [AISC 7] code requires a peer review. Are cranes significant structures? In our opinion they are; however, it is up to the local jurisdiction to make that decision.” Even at the time of going to press,
CP&A was wrapping up peer review and procurement assistant projects related to rubber-tired gantry, rail-mounted gantry, and ship-to-shore cranes. Are your procurement processes for these hulking container cranes up to standard?
CP&A performed a peer review of a set of
ship-to-shore container cranes for Georgia Ports Authority.
Dockside Lift & Move Supplement | August 2024 | xv
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