Downtown San Antonio's first high-rise in 30 years completed with help of key geotechnical and materials services

Client

Confidential

Location

San Antonio, Texas

Challenge

The 24-story Frost Bank Tower is the first high-rise added to San Antonio’s downtown skyline in 30 years. With generational projects come generational challenges, and Terracon’s local San Antonio office was prime to meet them. On the geotechnical side, the combination of large construction equipment and limited space meant that near continuous pre-task planning was essential to safely complete our scope of work. Our materials professionals, meanwhile, were tasked with gathering the testing and observation data critical to verifying the intended performance and safety of the structure.

Solution

Geotechnical services are critical to making sure projects are built on a solid foundation. Our team performed many critical services, including investigating subsurface soil and groundwater conditions, foundation design and construction, and building pad and subgrade preparation. Geotechnical engineering services included the use of downhole testing with a pressuremeter.

The analysis of the data collected from this in situ testing allowed our geotechnical engineers to provide much higher bearing pressures and skin friction values, as compared to the data generated from typical lab testing, for the design of the deep drilled pier foundations. When the geotechnical work was done and the tower started to take shape, our materials team stepped in.

Accurate materials testing data is essential to safety of a structure and the people within it. Testing of cylinders made from the high-strength, 10,000 psi concrete used in Frost Bank Tower required special procedures. The San Antonio office provided temperature-controlled curing containers at the site and purchased a piece of lab equipment to plane flat the ends for each cylinder. Investing in the equipment enabled us to provide accurate data faster. It also helps us meet this need for our clients on future projects.

Results

Our client was wise to invest in pressuremeter testing in the geotechnical phase. The data concluded the sizes of the steel reinforced concrete piers could be reduced, resulting in less time required to complete the drilling, less reinforcing steel, less concrete and lower costs, all done with proper safety factors. The result: a very high Return on Investment related to the additional cost of the pressuremeter testing.

The 460,000 square-feet of office space is located less than a mile from San Antonio Sports and Entertainment District and will be ready to help meet the growing needs of downtown San Antonio.