Florida State University Pedestrian Bridges Tallahassee, FL
Installing CHANCE® Helical Pulldown® Micropiles for four (4) Pedestrian Bridge Foundations at the Haskins Circus Complex on the campus of Florida State University.
The bridge foundations needed to be designed on deep foundations due to the presence of underground concrete box culverts adjacent to the foundations.
Two (2) new pedestrian bridges were being constructed over a low area of campus with high foot traffic. The bridge foundations where to be constructed within inches of two (2) existing concrete box culverts. CHANCE® Helical Pulldown® Micropiles (HPM) were selected to support the foundations and transfer this load below the culverts, to ensure too great a load was not placed upon the sides of the culverts.
CHANCE® Helical Pulldown® Micropiles were selected for this project because of the limited access that was available at the site, as well as the need for a deep foundation that could be installed without hammering, augering, or using large construction equipment, as noise and vibration needed to be held to a minimum. Two pre-production load tests were conducted, one on a vertical pile and one on a pile installed on a 15 degree batter. Even at 120 kips, which was 3 times the design load, pile movement was less than 1/2 inch. During the project, the piles were installed with a 10,000 lb. excavator and 12,000 ft-lb Eskridge drive head. (48) SS200 piles with a 10/12/14 helix and a 7 in. grout column were installed to depths of 35 - 40 feet and torque values from 5,000 ft-lbs. to 8,000 ft-lbs. Pile installation took five days to complete.
Vertical Load Test
Installation of the helical lead section
Battered Load Test
View of completed pile system
- Limited Access
- Quick installation
- Low to no vibration/noise
- Standard equipment for installation
- Lower mobilization costs - smaller equipment
- Time to install faster than concrete
- Labor savings - smaller crews