1. Offsite manufactured Bridges
IDEAS FOR FAST, SAFE AND EFFICIENT
BRIDGE CONSTRUCTION
Tomas Garcia
Principal Bridge Engineer at CH2M

2. Index
OVERVIEW
DESCRIPTION
CONSTRUCTION
EXAMPLES

3. OVERVIEW

4. Industry:
Shortage of skills
High demand

5. ...Is there any other way? Fast Simple Inexpensive ...but Maintenance?
Typical case
Fast
Simple
Inexpensive
...but
Maintenance?
Aesthetics?
Functionality?
...Is there any other way?

7. 2. DESCRIPTION

8. Different way to build continuous precast decks

9. Main characteristics of BSST precast continuous bridges
Continuous U-beam bridge decks, made up of:
Precast prestressed spliced U-beams
(pretensioned and/or post-tensioned)
Cast-in-place reinforced and/or post-tensioned concrete top slab,
using free-standing planks.
Three main elements:
- U-girder (close the span between supports, its shape enables to have enough space inside to do the continuity in an easy way, and other possibilities that we will see after),
- free-standing precast-planks (structurally not relevant, but very important to get an easy & fast construction process)
- cast-in-place concrete slab (it makes possible the composite action of all elements, and also to get easly the final top surface. The concrete poured over the planks, it is also an economical material to work with on site)

10. 3. CONSTRUCTION

11. Simple planks for
Two U-girder section
Enhanced planks for
long spans

12. Description of BSST system
Continuity by means of post-tensioning:
tendon or bar

13. Continuity by
unbounded elements

14. UPPER SLAB by FREE-STANDING PLANKS and pouring fresh concrete on site.
Construction sequence of BSST
UPPER SLAB by FREE-STANDING PLANKS and pouring fresh concrete on site.
- get a fast surface to work on it
- increase of safety on top slab tasks

15. 4. EXAMPLES

16. Alternative arrangements
If required, monolithic connection to piers.

17. Alternative arrangements
Monolithic cross head,
in extreme skewed crossings.
Precast capping beam + two U-girders at each side, with post-tensioning through them.

18. Constant/variable depth or width
(straight or curved haunches)
Straight or curved beams

21. Design and construction solutions for complex geometries:
“Fork” type decks
Decks with a great variable width

22. QUESTIONS ?

23. THANK YOU !!