Moffatt & Nichol (M&N) has been involved with the development of port facilities for more than 60 years and, over that period of time, has seen the size of equipment grow. The company faced the task of designing yard improvements for a portion of the backland areas at the Georgia Port Authority’s Garden City Terminal. The rehabilitation project required the installation of new highmast lighting and provisions for fiber optic security lines.
Handling the Load
The equipment operating within the project limits consisted of rubber-tired gantry cranes that generate loads of more than 100,000 lb. Maintenance personnel wanted a cover, then, that was easily accessible and that met those extra heavy-duty loads. M&N had experience at several other port facilities that utilized spring-assisted lids made of various metals. The majority of the spring-assisted covers on the market, however, were being deformed because of heavy wheel loads.
While maintenance department crews enjoyed the spring-assisted lids’ accessibility, the deformation from over-loading often caused the vaults to get filled with water and other maintenance issues. Deformation at the corners also posed a tripping hazard. Finding and implementing an easy access cover that was heavy enough to withstand the loads became critical.
M&N asked Neenah Foundry Co. about the development of a lid that would meet load requirements and still provide a spring-assisted opening. M&N selected the 36 x 36-in. spring-assist manholes for the electrical and fiber optic pull boxes associated with making necessary connections at each highmast light pole.
The covers are aircraft-rated and easy to open and latch, and the seal keeps most water out. Field personnel had only good things to say about the new covers.
Teaming Up for Engineering Success
This was the not the only port facility collaboration between M&N and Neenah . For another port project, M&N asked Neenah to develop an extra heavy-duty trench grate system that would be easily utilized in a cast-in-place or precast application.
The company needed a system that could retain the grate without any small parts but still be removable for cleaning. There had been instances where standard trench grates’ bolts were left out after maintenance work and equipment bounced the grates out of the frame—a dangerous condition that could cause a serious accident.
M&N shared these concerns with Neenah , who answered them with the LiftMate trench grate system. The new frame allowed the system to be fully integrated into the structure of the trench and made it easier for contractors to get the bearing required to accommodate heavy wheel loads associated with moving containerized goods. The new trench grate system retains the frame even if the bolts are removed.