Historical Background of Strut-and-Tie Model (STM)

The idea of the strut-and-tie method came from the truss analogy method introduced independently by Ritter and Mörch in the early 1900s for shear design of B-Regions. This method employs the so-called truss model as its design basis. The model was used to idealize the flow of force in a cracked concrete beam. In parallel with the increasing availability of experimental results and the development of limit analysis in plasticity theory, the truss analogy method has been validated and improved considerably in the form of full member or sectional design procedures. The truss model has also been used as the design basis for torsion. Excellent summary of the development of truss model for shear design of B-Regions can be found in Ref. 1. The strut-and-tie method came after Marti [2] and Schlaich et al. [3,4] promoted the use of truss model in D-Regions.

 Reference:
1) ASCE-ACI Committee 445 on Shear and Torsion, "Recent Approaches to Shear Design of Structural Concrete," Journal of Structural Engineering, ASCE, Vol. 124, No. 12, December 1998, pp. 1375-1417.
2) Marti, P., "Basic Tools of Reinforced Concrete Beam Design," ACI Journal, Proceedings, Vol. 82, No. 1, January-February 1985, pp. 45-56.
3) Schlaich, J., Schäfer, K., and Jennewein, M., "Toward a Consistent Design of Structural Concrete," Journal of the Prestressed Concrete Institute, Vol. 32, No. 3, May-June 1987, pp. 74-150.
4) Schlaich, J. and Schäfer, K., "Design and Detailing of Structural Concrete Using Strut-and-Tie Models," The Structural Engineer, Vol. 69, No. 6, March 1991, pp. 113-125.

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