Research at structural concrete laboratory

Design philosophy and code-writing

Over the past decades, technical design codes have become increasingly complex and hard to apply. For simple cases in particular, of for the verifications of non-controlling load cases, this can lead to a significant waste of time for practicing engineers. For complex structures, however, or for the checking of existing structures that are critical, the design rules proposed by codes are often not detailed enough or may include higher than needed safety margins, with the consequence that hard-to-execute and costly strengthenings may become necessary.
The levels-of-approximation approach was developed to address this problem. Detailed physical models (that can be applied for complex cases or for the verification of critical existing structures) are simplified to define design rules at several levels of approximation. This concept was adopted by the Swiss design codes SIA 262 (2003 and 2013) and by the fib 2010 Model-Code.

reference publications

  • Muttoni A., Fernández Ruiz M., Niketic F Design versus Assessment of Concrete Structures Using Stress Fields and Strut-and-Tie Models, ACI, Structural Journal, Vol. 112 n°5, Farmington Hills, USA, 2015, pp. 605-616.
  • Muttoni A., Fernández Ruiz M., The levels-of-approximation approach in MC 2010: application to punching shear provisions, Structural Concrete, Vol. 13, 2012, pp. 32-41.
  • Muttoni A., Fernández Ruiz M., Levels-of-approximation approach in codes of practice, Structural Engineering International, Vol. 22, n° 2, 2012 pp. 190-194.
  • Muttoni A., Fernández Ruiz M., Bentz E. C., Foster S. J., Sigrist V., Background to the Model Code 2010 Shear Provisions - Part II Punching Shear, Structural Concrete, Switzerland, 2013.