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precast_welded connection

Popular mechanical connections for precast members are welding and steel anchor bolts systems. Those connections need pockets in the precast member to do connection work such as welding or fastening bolts, etc., and such pockets need to be filled with additional mortar or concrete at a later stage.
Additionally, welding requires special care so that welding heat does not affect the expansion of welded plates and parts which would cause cracks in the concrete, resulting in subsequent water intrusion into the cracked area causing rusting of the steel parts.

The NMB Splice Sleeve is designed for precast concrete instant connection which completely embeds itself in the precast concrete member so that no pocket is required. The system only leaves very small patch-work for inlet/outlet ports on the concrete surface for Post-Grout System or even no ports are required for Pre-Grout System. This system has significantly contributed to the speed of precast concrete construction without skilled workers.
For example, The first NMB project, a 38-story Ala Moana Hotel, was able to cut 8 months off the projected schedule thanks to the NMB Splice Sleeve. Generally, consumers report a 20% difference in terms of saved time if using precast concrete verses cast-in-place.

precast_splicing connection
precast_splicing Alabama DOT column

Splicing the rebars to connect the precast concrete structural members by way of NMB Splice Sleeve Systems is the emulative detail. The connection of the structural performance is equivalent to that of a continuous member or a monolithic connection by the cast-in-place concrete design. (ref. ACI550.1R). Therefore, NMB systems are widely used for various types of precast connections of columns, beams, and walls even in seismic zones.