Five years after a fully loaded locomotive and 26 coal cars chugged over a 30-ft-long, 17-ft-wide span comprising eight hybrid composite beams (HCB) in Colorado, the technology has been used in nine states.
An HCB consists of a glass-fiber-reinforced plastic shell with high-strength continuous steel fibers placed along the bottom flange and filled with self-consolidating concrete (ENR 4/12/10 p. 34). Like the Bridge-in-a-Backpack (BIAB)—another non-traditional construction technology largely developed and pioneered in Maine (see p. 12)—HCB aims to provide portability, ease of installation and, ultimately, an extremely long and durable bridge life.