Information for Contractors
The HCB comes in several different forms depending on the needs of the project. They are:
- Single-web box beam, usually 2 feet wide by the required depth. These beams can span up to 85 feet.
- Double-web box beam – a trapezoidal box beam for spans 90 feet and longer or heavy loads.
- Triple-web box beam for railroad loadings.
- The HCB Pier Cap – 3 feet or 4 feet wide, designed to set on two or more piles or columns
- All of these different shapes can be pre-filled either on-site prior to setting or at a precast facility near the jobsite.
- The HCB Prefabricated Bridge Module – Ideal for Accelerated Bridge Construction, these pieces are pre-filled and include a concrete deck. In addition, parapets, railings or other appurtenances can be added to greatly reduce the overall construction time.
- Empty HCBs are very light, and multiple beams are normally shipped on one trailer.
- Pre-filled HCBs must be supported at the bearings for delivery. Two or more beams are usually shipped on one trailer, but longer beams (over 90 feet) may require trailing dollies.
- Prefabricated HCB modules are normally shipped one per trailer.
- One or two small cranes are normally used to set the beams in place depending on site conditions, on-site equipment, etc. Excavators and forklifts have also been used.
- Empty HCBs can be picked at points similar to rolled steel girders. Due to their light weight, oftentimes a telescoping boom forklift can off-load a trailer. Nylon straps around the beam are normally used for picking and handling empty HCBs.
- Pre-filled HCBs must be picked from the ends, similar to prestressed concrete girders using installed prestressed strand lift loops or nylon straps. Minimum sling angle should be 60 degrees.
- Prefabricated modules must be picked from the ends, similar to prestressed concrete girders using prestressed strand lift loops or recessed anchors and equalizers on each end to balance the load.
Filling Empty Beams
- All styles of HCBs are filled with self-consolidating concrete (SCC). The SCC is placed using either a concrete pump, gravity feed hopper fed directly from a truck or bucket.
- HCBs can be fabricated with top flanges that extend the overall width to eliminate the need for deck forms.
- On-site Deck Forming:
- Overhangs re formed using standard overhang bracket with hangers attached to shear connectors. The bottom foot of the bracket should be 3 inches above the bottom of the beam.
- Interior bays are formed using stay-in-place (SIP) forms (prestressed panel, FRP Panels, etc.) or removable forms with standard hangers attached to the shear connectors
- Supports for bridge deck finishing equipment is normally set at the center of the exterior girders.
HCB Field Installation Manual
The HCB Field Installation Manual is an invaluable guide to engineers and contractors for installing HCBs. It answers many questions on how to install HCBs, form decks and incorporate scuppers, railings, etc.