Geotechnical construction contractor Hayward Baker (HB) received the Keystone Award from the Associated General Contractors of St. Louis (AGC). The award was presented to HB in the “Specialty Contractor/Subcontractor Project Under $1 Million” category for performing micropile and compaction grouting work on the St. Louis Central Library, an 100-year-old historic structure located in downtown St. Louis.

The Keystone Award honors the achievements of St. Louis-area construction firms and their employees in building the facilities that support and enhance the quality of life in greater St. Louis. Recipients display excellence in providing solutions to unique obstacles and challenges specific to their projects.

The award was presented to senior engineer Jeffrey R. Hill, PE, and area manager Gregory A. Terri, PE, of Hayward Baker's St. Louis office at AGC's 2013 Construction Awards Gala held on Nov. 14, 2013 in downtown St. Louis.

Current fire code requirements mandated renovations to the St. Louis Library structure, as did the planned shift from a traditional library to an interactive media center. Due to the historic features of the library, special considerations were required to ensure that activities and vibrations from construction did not disturb the structure.

Prior to construction, asbestos was found, delaying the project by four months. Despite this, the finish date could not change as the owner planned to re-open the library on the building’s centennial anniversary. Other challenges that contributed to the project’s difficulty included the unknown geometry and conditions of the existing foundations.

HB’s use of micropiles and compaction grouting supported new structural loads and prevented damage to the existing building throughout the renovation. High-capacity micropiles were constructed after the demolition of wrought iron book stacks to support the new space – essentially creating a new building within the existing historic shell.

Settlement of one of the library’s trademarks, the east perimeter stone balustrade, also required attention. Compaction grouting gently lifted and stabilized the balustrade without the need to excavate or connect to the foundation. This technique reduced the risk of further damage to the structure.

The existing grillage foundations were not always defined – and the proposed elevator tower foundations needed to connect seamlessly to them – resulting in a variety of earth retention systems used to safely support the excavation beneath the library for the construction of mechanical suites and new elevators.
A pit of +/- 6 feet was required below the planned elevator’s bottom floor that would undermine the grillage foundation, which would result in movement of the existing load bearing walls. Hayward Baker designed a system to underpin the grillage foundation and take the full vertical load of the masonry wall. Shotcrete and soil nails were then utilized to prevent the fill soils from caving into the elevator pit excavation.

Hill said, “It was a privilege to work on such a unique and historic structure, and to be part of a transformation of a state-of-the-art media center and gathering place for the citizens of St. Louis.”

Winners of the award are selected based on the complexity and uniqueness of construction, their solutions to challenges, the innovative use of manpower and technology, safety, project communications, workforce diversity, the quality of construction, schedule and budget adherence as well as the carbon footprint of the project’s life.

For more information on the St. Louis Central Library project in St. Louis and the ground improvement capabilities and services provided by Hayward Baker, contact Hill at

Hayward Baker has worked in ground modification and site improvement for 60 years, and offers a range of foundation support and rehabilitation services. For more information, visit