Colgate Campus Project Wins ACI Award

Klepper, Hahn & Hyatt’s replacement of the Willow Path Bridge on the Colgate University campus earned a Bronze Award for Excellence in Masonry Design and Installation from the American Concrete Institute - Central New York Chapter.

Taylor Lake, the Willow Path, and Willow Path Bridge are iconic elements of the celebrated beauty of the Hamilton, New York, campus. According to the timeline on the University’s web site, Taylor Lake and Willow Path were added to the Colgate landscape in 1905. Professor James Morford Taylor, head of the mathematics department, interested a group of alumni in building a lake on the campus to provide more space for ice skating. A swamp area was drained and excavated by hand to form the five-acre lake. A resulting embankment was lined with golden Russian willows, and the pathway was connected across the stream with a bridge. The “Stone Bridge” was a gift of Sidney and Colonel Austen Colgate. It was constructed in 1913-1914, and cost between $4,000 and $5,000.

The stone piers and the concrete deck of the century-old bridge were deteriorating, and the bridge had been closed to vehicular traffic (maintenance vehicles) for quite some time. This project focused on repairing and rebuilding the bridge with materials matching the original construction.

KHH presented the University with four design schemes, the most costly of which was to replace the bridge “in kind,” as originally designed. The three alternative schemes, while saving money, would have significantly altered the appearance of the bridge. University officials agreed that maintaining the distinctive structure in its archetypal form was worth the added investment. Thus the bridge was slated for replacement with no change in appearance, salvaging the decorative railing for repair and reuse.

The scope of work included the construction of concrete abutments, piers, and walls, and the installation of new stone facing material. A new precast concrete bridge deck was also installed. Since the bridge was originally constructed with a thin stone coping with no flashing, which led to deterioration of the walls, the engineers improved on the detailing of the new construction to extend the life of the structure.

“Holbert Ashler Bluestone” proved to be an acceptable match, in color and profile/texture, for the existing “Lenroc” stone veneer. Mortar materials included Rosendale No. 12M Natural Cement Mortar, a very durable mortar in wet locations.

Reconstructed, Willow Path Bridge reposes in its pastoral setting like a structural work of art, for the use and delight of present and future generations of the Colgate campus community.

Two ACI Awards Highlight Firm’s Diversity

Klepper, Hahn & Hyatt earned two awards from the American Concrete Institute - Central New York Chapter which showcase the firm’s professional diversity.

The Gold Award for Excellence in Masonry Design and Installation was given to the Spear House Masonry Facade Restoration for Colgate University in Hamilton, New York. An Award of Merit for Excellence in Concrete Design and Installation went to the East Hills Senior Living Center in Binghamton, New York. Spear House involved exterior restoration for an 1835 stone masonry building, while East Hills was new construction involving sustainable criteria for concrete installation. These are both project types for which KHH has considerable expertise.

Spear House was built by the Baptist Education Society in 1835, and purchased by faculty member Philetus Bennett Spear in 1838. “Claremont,” as it was then known, was a faculty residence and fraternity house for a full century, before being gutted and renovated in 1935. It housed the Samuel Colgate Baptist Historical Collection until 1947, when it was again renovated for university offices. It currently houses the Center for Career Services.

Spear House is a solid stone masonry, bearing wall building with a wood framed roof structure. The wood floors were replaced with steel and concrete in 1935. The exterior walls consist of rubble stone masonry with traditional lime putty mortar. This facade restoration project focused on investigating the causes of problems which had become evident in the facade, and finding the best way to correct those issues to preserve the building and ensure its longevity.

The building’s relative antiquity mandated a sympathetic use of materials which replicated the original, applied with current methods and craftsmanship. Project work included:

• Removing and rebuilding the high stone parapets on the east and west sides
• Repairing wall cracks and open joints on all elevations, plus cracked stone sills, lintels, and water tables
• Rebuilding of bulging wall sections where voids were created when chimneys were removed in the 1930s
• Repair of rotted timber roof beams.

KHH chose natural hydraulic lime as the repointing mortar. It has greater strength and durability than lime putty mortar, while also providing a high moisture transmission rate, similar to the original lime mortar.

Viau Construction, the masonry contractor, further enhanced the project through skillful practices and applications.

East Hills Living Center in the City of Binghamton was one of several projects which boosted the number of affordable senior developments in Broome County. The development consists of 32 townhouse-style, one- and two-bedroom units within seven residential buildings, plus an eighth building which serves as a Community Center.

The single-story buildings have wood-framed roofs and superstructure walls. Foundation walls and footings are conventional cast-in-place concrete, as are the slab on grade floors. Design and materials for the concrete installation employed sustainable green building criteria. The project architect was Bearsch Compeau Knudson.

While the concrete foundation design is quite conventional, the edge of the slab incorporates a fairly unusual detail. The top of the rigid insulation, which is vertically up against the inside face of the foundation walls, has a 45-degree bevel with the top extending up to the slab finish elevation. This is a detail that is in compliance with the New York State Energy Conservation Construction Code; however, it is not done very often due to various concerns about potential problems. This project showed that this detail can be successfully implemented.

A surprisingly high level of building heat escapes out of an uninsulated slab edge, even though this area represents a relatively small percentage of the building envelope’s total surface area. The thermal mass of concrete is very high; a large amount of heat is stored in the interior slabs. When the slab edge is not insulated, it is thermally connected with the exterior, and the heat is continually drawn out of the building. This is evident in images taken with thermal cameras, and can be quantified with good building energy modeling programs. When a building’s walls and roofs are tight and well insulated, a higher percentage of heat loss occurs at uninsulated slab edges. Thus it is even more important to have good foundation insulation details.

The large thermal mass of interior concrete - both slabs on grade and building structures - can be very advantageous in maintaining uniform temperature levels if the concrete is kept inside a properly-insulated building envelope, especially adjacent to the concrete elements. Studies have shown that concrete buildings are, in fact, more energy efficient than buildings built with materials of lower thermal mass, when both buildings are equally insulated.

Although the detail with the beveled top insulation edge seems awkward, it is the most practical way to provide effective insulation at the slab edge for a foundation wall that is insulated on the inside face. If this detail were not used, the buildings would have a large amount of heat loss through the tops of the foundation walls during heating seasons for the entire service life of the buildings.

All of the concrete that was used in this construction had 20 percent of its Portland cement content reduced by the use of fly ash. This included the footings, foundation walls, and interior and exterior slabs on grade. The incorporation of fly ash reduces the production of Portland cement, which in turn reduces the amount of carbon dioxide emitted into the atmosphere.