1	Proposed Benchmark Problem Structural Response of a Concrete Interface Subjected to Reverse Cyclic Load Prof. Victor E. Saouma University of Colorado, Boulder/Politecnico di Milano Eric Puntel Politecnico di Milano
2	Background During his leave of absence from the University of Colorado at the Politecnico of Milano, Prof. Saouma performed tests on large jointed concrete specimens subjected to reverse cyclic loading. Tests were performed by Mr. Eric Puntel as part of his PhD thesis in the Structural Engineering Laboratory of Politecnico. Computational Enthusiasts are invited/challenged to provide a numerical prediction for those tests. Results will be compiled and presented at a forthcoming international event.
3	Experiments on cyclic behaviour of concrete joints
4	Experimental apparatus (1)
5	Experimental apparatus (2)
6	Specimen preparation
7	Surface Roughness
8	Free body diagram
9	Simplified 2D geometry
10	Boundary conditions and material properties Plane stress Concrete: E=25 GPa n=0.2 Compressive strength: 30 MPa Steel E=206 GPa n=0.2 Imposed cyclic vertical load Amplitude: 40 mm Period: 16 minutes
11	Anticipated Response
12	REQUESTED DATA Perform an analysis for 10 cycles. Provide the following Mesh Details (picture, element types, number of nodes/elements). FE Model (Program name, constitutive model, details of analysis). Results (COD and CSD across the interface in the center of the crack in terms of external axial load) plotted, and in excel format. Preferred formats: Power-Point. Send results to saouma@civil.colorado.edu before June 2005. Additional test information can be obtained from eric@stru.polimi.it