The TxDOT US 77 project in Victoria, TX will convert 2.5 miles of US 77 from a two-lane roadway to a full freeway section. The project consists of seven bridges and concrete paving. The Guadalupe River Bridge has two spans of 170’ Type TX70 Pre-stressed Concrete Girders. The project has a significant amount of environmental commitments.
The project requires the Contractor to use a nondestructive testing (NDT) method, termed Thermal Integrity Profiler (TIP) testing. The method obtains records of the heat generated by the curing cement (hydration energy) to assess the quality of drilled shafts. TIP measurements that are colder than normal indicate necks, Inclusions, or poor quality concrete, while warmer than normal measurements are indicative of bulges. Variations of temperatures between tubes reveal cage eccentricity.
One of the major challenges on the project has been Mother Nature. An abnormal amount of rainfall has caused delays and major cleanup on the project. As a result of the weather and concerns for safety, the Contactor continues to look for ways to help expedite the project. SBI supports the approach by providing an expeditious review of the Contractor’s proposals and schedule and processes a Change Order to document any major revision.
The two spans of 170’ Type TX70 Pre-stressed Concrete Girders were placed beginning on November 28, 2016. The fourteen beams were placed within a three-day period. Placement of the beams required special bracing details due to the length of the beams, a complete road closure, and monitoring of wind speed.
To date, one shaft was found to be out of specification. Said drill shaft was evaluated using the results from the high strain dynamic load testing and analyses. The shaft was tested using the GRL APPLE 2 pile load testing system to evaluate bearing capacity and integrity. An 8G Model, Pile Driving Analyzer® (PDA) acquired and processed the dynamic test data. The CAPWAP® computer program was used to further evaluate static capacity including the soil resistance distribution along the shaft and at the toe.