COMMAND Center Used to Meet Tight Construction Deadline on Dallas High-Rise
Photo courtesy of Braun Intertec.
The Terraces at Douglas Center is a new 12-story office tower in Dallas with a two-level basement parking garage. It’s made of concrete structural elements and has a steel-framed roof level area. The building is named for the upper floor balconies which feature an open view of north Dallas.
Braun Intertec—a geotechnical engineering, environmental consulting, and testing firm—provided construction materials testing and special inspections for the project. Braun Intertec is committed to innovating for clients and delivering highly valued engineering, consulting, testing and design solutions. They initiated the use of COMMAND Center concrete temperature and maturity meters on the Terraces at Douglas Center project to measure concrete strength in real-time in order to expedite post-tension stressing and meet a tight construction deadline.
In-situ strength estimation is often achieved through flexural or compressive strength tests of beam or cylinder specimens in accordance with standard test methods. It’s assumed the test specimens are representative of the same concrete that is placed in the field. If testing of the specimens determines design strength has been achieved, then it is assumed that strength has been achieved in the field, as well. However, assuming that concrete in the field gains strength at the same rate as test specimens is not always the case.
To mitigate the disparity between laboratory test specimens and actual in-place concrete, construction teams can use COMMAND Center to monitor the maturity of in-place concrete as a supplement to standard strength tests. COMMAND Center allows teams to know in real-time when adequate concrete strength is achieved in the field, so you can move on to post-tensioning and form and shore removal as soon as the in-place concrete is ready.
Implementing maturity has other advantages, as well. The method is not dependent on how well an acceptance cylinder or beam was cast and handled, and it does not rely on how well load was applied to the acceptance specimen to determine strength. It is a simple test that requires portable equipment. When implemented correctly, the maturity method has been shown through countless research efforts to work well as a tool for estimating early-age concrete strength gain in the field.