Vibration Data Collection
Collection of vibration data utilizing Geocomp’s S-lynks wireless measurement nodes
Scroll Down
The Challenge
- Measure and analyze deck, tower, and cable stay vibrations
The Fred Hartman Bridge (1995) is a twin-deck cable-stayed bridge with a main span unit of 2,475 ft. carrying 2.6 miles between Baytown and La Porte, TX. Each of the decks is 79 ft. wide and consists of precast concrete slabs on steel girders and floor beams. The decks are supported by a total of 192 cables, arranged in four inclined planes originated at each of the two double diamond shaped towers. The towers are 436 ft. tall. The stays range from 194 to 649 ft. in length, with varying diameters.
The project required establishing the existing dynamic behavior of the cable-stayed bridge by measuring and analyzing the deck, tower, and cable stay vibrations.
The Solution
Geocomp deployed S-lynks wireless vibration measurement and data analysis solution. S-lynks allowed us to collect vibration data from Southbound deck, Southbound North Tower, and all of the 192 stay cables under operational and ambient loads with minimal impact to traffic. Following the fieldwork, Geocomp conducted data analysis utilizing its Operational Modal Analysis (Snap-D) and Cable Tension Estimation (CTE) software developed in-house and provided the final report. The reported information included:
- ~ Identification of the resonant frequencies, mode shapes, and damping ratios of the bridge deck and towers
- ~ Estimation of cable resonant frequencies, cable forces, and overall cable damping
- ~ Comparison of measured cable tension with historical cable tension records from symmetrically positioned cables
- ~ Documentation of the coupled behavior between the deck and the cables for determining a complete picture of the global dynamic behavior
- ~ Establishment of the dynamic baseline of the bridge to be compared with future conditions
