Eccentric punching tests on column bases ‐ Influence of column geometry

Structural Concrete, vol. 23, pp. 1316–1332

Abstract

Abstract Experimental investigations on centrically loaded column bases provide the basis for current punching shear design provisions. However, this symmetric loading condition represents an exception in daily engineering practice since usually load eccentricities occur leading to uneven shear stress distributions along the control perimeter. To account for this effect, design approaches define different factors to either increase the acting shear force or to decrease the punching shear resistance in design. New punching test results of 14 eccentrically loaded and four centrically loaded column bases now allow the evaluation of design approaches depending on different geometric boundary conditions. In this new test series, the load eccentricities were systematically graded to analyze their influence on the punching behavior. Strain measurements in the multiaxial compression zone of the concrete in the column‐footing connection reveal new insights on the punching failure of column bases. As a result, a correlation between tangential concrete strains and the reduction of punching shear strength can be recognized for increasing load eccentricities. The comparison of experimentally determined load increase factors with the design results according to Eurocode 2, Model Code 2010 and the stable version of the next generation of Eurocode 2 reveals optimization potential for deriving more advanced design provisions in the future.

Authors 3

1. Jan Ungermann corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University/Institute of Structural Concrete Aachen Germany

   RWTH Aachen University/Institute of Structural Concrete Aachen Germany

2. Philipp Schmidt
   Affiliation as printed

   Thomas & Bökamp Ingenieurgesellschaft mbH Münster Germany

3. Josef Hegger Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University/Institute of Structural Concrete Aachen Germany

   RWTH Aachen University/Institute of Structural Concrete Aachen Germany