Civil Engineering Reference
In-Depth Information
are common or where a lower amount of cover is required on pre-cast
elements.
Pre-cured NSM rod/shape systems can generally be used as an alternative
for reinforcing concrete and masonry structures similar to surface laminates.
NSM rods/shapes provide a more discrete solution to strengthening structures
in that they generally are inserted into the masonry or concrete structure via
slot or saw cuts. Generally, shapes can vary in size depending on application
but typically are provided in round and rectangular cross-sections. The
shapes are manufactured in the system supplier's facility and shipped to the
job site. The shapes generally feature a surface treatment to facilitate bond
between the FRP and adhesive or grout. An epoxy adhesive or cementitious
grout is used to bond the pre-cured rods in the groove cut into the surface.
Adhesive selection is critical in that the adhesive provides for the proper
transfer of load between the wall and the cured reinforcement. A cosmetic
surface can then be added to completely hide the strengthening system.
Since the products are embedded into the substrate and bonded on three
sides of the FRP shape, development lengths for NSM strengthening may be
shorter. NSM rods/shapes may also be anchored into adjacent members and
the opportunity of upgrading elements in their negative-moment region is
opened up, as the FRP shape is not exposed to potential mechanical damage
typical of floor or deck systems. FRP rods/shapes using the NSM technique
