The Influence of Tension Cables on the Structural Behavior of Tedesko’s Haverford Shell

Abstract

Restoration is a sustainable building practice, in addition to being important for cultural preservation. In particular, this is valid for 20th century reinforced concrete shell structures known for their efficiency, economy, and elegance. They represent an engineer’s creative side and the leeway for play in design. They are not as common to design and build anymore and therefore it is important to restore the existing ones for future generations to study, use, and be inspired by them. The Ardmore Rink (in Haverford, Pennsylvania, U.S.A, Anton Tedesko, built 1938) was one of the first large span thin shell structures built in the U.S.A. The rink, maintained over the years, is structurally in good shape mostly needing cosmetic restoration. The semi-cylindrical reinforced concrete shell has both tension cables and buttresses to resolve the shell’s horizontal forces at its extremities. This research explores the necessity of the tension cables considering the presence of the buttresses for the strength, stiffness, and stability of the shell. Results obtained using finite element analysis software suggest that the tension cables assist in reducing the horizontal reaction at the two-hinges although the inclusion of cables does not affect the deflection or stresses of the shell. Evaluating the thrust line of the structure through graphic statics confirms that the horizontal forces, the ties provide at the supports, are critical for shell’s behavior. This paper is of interest to structural and architectural engineers as well as building historians and its findings support restoration and preservation efforts that enable a more sustainable built environment.