The Button Block Building, located at 500 North Water Street in Milwaukee, is an historic, masonry and timber building founded on timber piles. This building is somewhat unique in Milwaukee due to its use of sandstone as a cladding material, which gives the building a salmon color. Like many buildings in and around the Third Ward area of Milwaukee, the Button Block building suffered from deterioration of the uppermost portion of its timber piles. This problem became evident over time as the corner column at the main (southwest) entry began to settle and tilt out of plumb. The out of plumb condition increased the stress level in both the granite shaft and the sandstone base to the point that they began to crack and spall. The stone pieces at the head of the openings on each side of the column also began to crack. These cracks were monitored, and eventually the degree of movement was such that corrective action was initiated.
In order to fully address the situation, a number of elements required replacement. Among these were the granite shaft, sandstone base, and below-grade pier. The City historic review board insisted that the replacement shaft and base match the original in regard to material type, color, and shape. Thus, these became long lead-time items. The existing pile cap was removed, and new helical piers were installed to supplant the original timber piles. A substantial “temporary” shoring system was built, consisting of piles, concrete piers, wide flange steel beams, and a steel framed “cradle”. The cradle was filled with grout in order to support the bowl-shaped element atop the original columns. Throughout the entire process, the building movement was continuously monitored in real time using sophisticated gauges and digital recording equipment.
