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原文传递 Strength Evaluation of Connectors for Intermodal Containers

题名：	Strength Evaluation of Connectors for Intermodal Containers
作者：	H. S. Lew Fahim Sadek Erik D. Anderson
关键词：	container; comer fittings; interbox connectors; latch locks; twistlocks; vertical tandem lifts
摘要：	Intermodal containers are used widely in marine cargo handling. In order to facilitate unloading of empty containers from ship to shore, two containers are frequently lifted in tandem. This operation is referred to as ‘Vertical tandem lifting.” In this lifting process, the lower container is attached to the upper container by means of interbox connectors at the four comers of the container. During the vertical tandem lifting operation, if one or more connectors are disengaged, the bottom container may be separated from the upper container, thereby creating an unsafe condition to workers below. This safety concern prompted the Occupational Safety and Health Administration (OSHA) to request the National Institute of Standards and Technology (NIST) to study the suitability of interbox connectors for vertical tandem lifting. The NIST study included site visits to port facilities and laboratory tests of interbox connectors. Test specimens included semi-automatic twistlocks and latch locks. The experimental program included testing of twistlocks in tension, twistlock and latch lock assemblies with comer fittings in tension and compression, and shafts of twistlocks in tension to obtain the stress-strain relationship. In addition, measurements were made of the bearing area of the top and bottom cones of twistlocks and the latch on the inner surface of the comer fitting. The study indicated that the tensile edacity of the connection is governed by the strength of the comer fitting. The study also shows that the bearing area of latch locks on the comer fitting is less than that required by the ISO standards
报告类型：	科技报告