Stambaugh Stadium is a 20,000-seat football stadium with a multipurpose gymnasium and locker facilities. The structure consists of cast-in-place concrete buttresses and beams, post-tensioned concrete floor slabs, precast concrete double tees, hollow-core planks and stadium risers, and various configurations of waterproofing. The main concourse level includes precast concrete double tees with a direct-applied concealed liquid polyurethane membrane system, insulation, and a concrete wearing surface.
Shortly after completion, water infiltration into the multipurpose gymnasium, locker rooms, and offices occurred. Cracking and spalling distress exhibited in the post-tensioned concrete slabs and some of the precast concrete member connections.
RRJ was retained by the waterproofing contractor to investigate the causes of the leakage problems. Field investigation revealed leakage under each of the waterproofing systems. The membrane underneath the massive concourse area (above the gymnasium) was leaking through tears at the precast double tee joints and ends and could not accommodate the relative movements occurring between the double tees and the cast-in-place concrete frame. Precast roofing areas exhibited leakage and movement problems as well.
RRJ’s structural analyses revealed that the stadium design incorporated insufficient accommodation for expansion and contraction. A series of small joints with welded connections had been used without the benefit of defined expansion joints, resulting in excessive movements that tore the waterproofing systems and cracked the concrete connections. Review of the architectural drawings indicated that the majority of the waterproofing details were poorly conceived for the anticipated environment.
