Construction Optimization

Large civil structures typically require many years of extensive construction effort. Due to the heat of hydration, the placement of large volumes of concrete can generate high internal temperatures that may lead to thermally induced cracking and residual stresses. Such cracking leads to maintenance issues related to water penetration and flow characteristics.

As an expert in mass concrete construction, ANATECH, a Structural Integrity Associates company – has developed effective modeling programs that provide an in-depth understanding of optimal construction methods and those that may potentially lead to thermally induced cracking.

Using coupled thermal-stress analysis based on nonlinear and time-dependent characterizations, our modeling programs can evaluate the heat of hydration, concrete aging, shrinkage, creep, and cracking. These programs can also analyze: a) the effect of embedded cooling coils to control internal temperatures during concrete placement; b) the effect of curing and final cooling in arch dams to open contraction joints; and c) the effect of residual stress fields that might cause fatigue cracking at welded connections.

Our proven modeling programs implement optimal engineering designs that mitigate the effects of thermal-induced cracking in the following applications:

  • Conventional mass concrete with formwork
  • Innovative float-in, pre-cast concrete segments with tremie in-fill
  • Innovative lift-in, pre-cast concrete shells with tremie in-fill
  • Coffer Box with wet tremie foundation layer
  • Embedded cooling coils in mass concrete
  • Roller compacted concrete

We are recognized in the U.S. Army Corp of Engineers (USACE) NISA Guidance, ETL 1110-2-365, for our Nonlinear Incremental Structural Analysis (NISA) for structural performance during construction. The NISA methodology evaluates thermal-induced cracking by calculating time-dependent thermal gradients relative to the restraints against thermal expansion in the structure. The analytic simulation tracks the history of the material behavior from a few hours of age until approximately one year after final lift placement.

Advanced analytical techniques must rely on material modeling and computational simulation methods that are capable of predicting severe damage states and structural failures. The development of such advanced methods have been a continuous activity for nearly four decades.

We are a leader in providing innovative engineering solutions for real-world applications, and our experience includes a diverse range of projects. We frequently provide structural engineering support for civil infrastructure applications, such as bridges, locks, and dams. We are also especially active in applications related to the nuclear power industry.

 

 
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