APTI Conference Kansas City, Missouri CS04 Archaic Systems, Modern Needs

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1 APTI Conference Kansas City, Missouri CS04 Archaic Systems, Modern Needs Suitability of Techniques of FRP Retrofit for Historic URM Buildings Presenter: Sara Alinia Student Scholar - Southern Illinois University Edwardsville Advisor: Donald Friedman, PE, FAPT FRP (fiber reinforced polymer) composite retrofit is a practical method for increasing the strength of historic URM buildings. Several types of FRP upgrading are now available, including using glass, aramid, basaltic, and carbon fiber FRP. Each of these types has strengths and weaknesses for use in historic buildings, related to durability, mechanical compatibility, ease of installation, chemical suitability, seismic ductility, strength, reversibility, and cost. This presentation will describe the differences between the various methods of FRP retrofit used for historic building strengthening, show case studies of FRP installation and performance for historic buildings, and recommend guidelines for FRP retrofit in relation to the Standards for Historic Preservation by the National Park Service. The main purpose of this presentation is to introduce different materials and techniques that are used in FRP retrofitting for URM buildings. It will outline their advantages and disadvantages and measure how each of them makes changes in the building. The presenter will suggest an approach that meets National Park Service standards for retrofitting historic unreinforced masonry buildings. I. Introduction A. Historic Unreinforced Masonry B. Conventional Methods of Retrofitting C. National Park Service Preservation Standards II. Fiber Reinforced Polymer (FRP) A. Introduction of FRP B. Fiber Materials 1. Carbon 2. Glass 3. Aramid 4. Basalt C. Resin Materials 1. Epoxy 2. Polyester 3. Vinylester III. Techniques of Application of FRP A. Externally Bonded (EB) B. Near Surface Mounted (NSM) C. Other Techniques D. Comparison of the Two Main Techniques with Regard to NPS Standards for Preservation E. Details of Application for Near Surface Mounted Method (NSM) F. Advantages and Disadvantages of NSM method IV. Conclusion

2 St. Elizabeths: Progression of structural systems between 1850 and 1910 Presenter: Rachel Will, PE and Timothy Crowe RA, SE, PE The period between circa 1850 and 1910 represents a time of evolution for the building industry, with structural systems being no exception. Technological advancements exhibited through the construction history of St. Elizabeths Hospital West campus present an interesting example of the state of building technology utilized to respond to the call of developing the first federal mental institution of the United States. St Elizabeths Hospital, pioneered by social reformer Ms. Dorothea Dix, and later recognized by Congress in 1855, was constructed in several phases into the early-twentieth century. During the Civil War, the property was employed to house wounded soldiers, and into the more recent history, over 70 structures surrounded the cultural landscape that provide a glimpse of early planning strategies for treatment of mental illness in this country. The campus was designated a National Historic Landmark in 1990 around which time the hospital functions had mostly transferred to the east campus where newer and more updated facilities were provided, on the opposite side of Martin Luther King Drive. By 2000, the west campus buildings had been mostly mothballed and in 2008, the campus development projects were underway to reuse selected structures on behalf of the Department of Homeland Security (DHS). The landmark status necessitated that HSRs be prepared for affected buildings prior to any retrofit or reuse efforts. Program demands imposed on these buildings included, blast load requirements, lateral load upgrades, increased floor loads, and strict energy enhancements that created unique challenges in the adaptive reuse effort of these historic structures. This presentation will examine the evolution of structural systems at the St. Elizabeths West Campus through its early history and the solutions to unique challenges encountered during the structural adaptations to comply with the DHS/GSA criteria for building improvements. 1. Introduction a. Brief historical overview of the St. Elizabeths Campus b. Building construction and conditions encountered c. The nature of the HSRs and corresponding objectives 2. Design requirements a. Overview on building design needs presented in adaptive reuse project b. Challenges presented by the design team program schedules and client requirements c. Structural upgrades including blast design requirements and increased floor loading to 130 year old buildings d. Maintaining and stabilizing buildings through major alterations 3. Site challenges and opportunities a. Soil issues associated with new and existing foundation requirements b. Stabilization of hidden soil conditions c. Underpinning needs to accommodate site and design conditions d. Endeavoring to conceal site improvements that retain the historic landscape 4. Conclusion a. Discussion regarding lessons learned during the accelerated pace of HSR development to construction document preparations b. Assessment of challenges/risks with losing historically significant elements during adaptive reuse projects

3 New Structure: Historic Building Presenters: Jessica Reske, AIA, LEED AP and Ian Glaser, PE At times, historic buildings fall short of meeting today s requirements for continued use. In some cases, calculated deficiencies may limit the use of the building. Some deficiencies are a result of under-sized original structural components; others are a result of material deterioration and natural weathering. In both cases, interventions are required to strengthen the original structural system while retaining as much original historic material as possible and minimizing the visual impact of the structural interventions on the historic buildings if more modern load criteria is to be satisfied. At the Crested Butte Depot, in Crested Butte, Colorado, deficiencies in the original structure were evident at the roof lines of the building. The original 1883 structure was not adequately designed to meet the heavy snow loads in this mountain community. As a result, visible deflections were occurring in the roof, which had necessitated unsightly temporary measures to support the roof, and led to damage to original exterior and interior finishes. In order to meet the load requirements for the building, steel components were employed to bolster the original wood structural members. These components were sized to fit within the existing wall assemblies and within the existing roof structure. Complexities were encountered where structural components were exposed on the exterior of the building, such as large brackets supporting the roof overhang. At these locations, materials were altered to hide the steel within them. Careful removal and re-installation of exterior and interior finishes was required to minimize the alteration of the historic appearance of the building. The end result of the project is a new steel structure, completely concealed within the original historic building s materials. At the Church of the Holy Redeemer, in Denver, Colorado, deterioration of original masonry resulted in compromised bearing capacity of an exterior wall of the church. Several repair strategies were studied. Many of these strategies were eliminated from consideration due to the desire to conceal the modern interventions as much as possible. To address the issue, masonry repairs were required, as was insertion of a steel beam to assist the wall in carrying the roof load. The steel beam was inserted in a cavity between the roof structure and the sanctuary ceiling in such a manner that it is not visible from the interior or exterior. The affected area has been adequately strengthened for years to come, while retaining the historic appearance and materials. Both of these case studies which are to be presented are examples of successfully completed projects which required close coordination between the structural engineer and architect to achieve the project goals. In both cases, the Secretary of the Interior s Standards were followed. Continued use is key to the preservation of historic buildings; and ensuring the structural integrity of the building is critical to this continued use. 1. Introduction and General session overview strengthen the historic structural system while retaining the original appearance and materials 2. Examination of Crested Butte Depot a. Original building appearance & detailing weaknesses of original design b. Deterioration & failures over time including temporary stabilization measures taken c. Details of permanent structural repairs required d. Coordination with architectural finishes and historic appearance e. Final appearance and long-term performance of repairs 3. Examination of Church of the Holy Redeemer

4 a. Original appearance including historic interior mural b. Structural shortcomings & required interventions c. Design options and owner preferences for repairs d. Final appearance and long-term performance of repairs 4. Lessons learned review regarding the critical nature of: a. The need for coordination between engineer, architect, and owner required b. Application of the Secretary of the Interior s Standards Presidio Officers Club: Rehabilitation of San Francisco s Oldest Building Focus: seismic upgrade and repair of adobe walls Christina Wallace LEED AP BD+C Conservator The Officers Club was originally constructed as the Spanish commandancia by the De Anza party, who settled and founded the el presidio of San Francisco in In the 1840 s the Presidio became an army base, and served in that capacity until base closure in The Officers Club has remained in use, in various capacities, since 1776 and represents one of the oldest remaining structures in the boundaries of the city of San Francisco. The original walls were adobe, and the structure was enlarged in the 1870 s with the addition of a wood, balloon frame, assembly hall. Over the years the building continued to grow with new additions constructed whenever the army needed more space. This culminated in the 1970 s when a two-story, post-tensioned reinforced concrete structure was constructed, and marked the end of the original building campaign. In 2008 the Presidio Trust, stewards of the Presidio of San Francisco National Historic Landmark District, embarked on a full building rehabilitation and seismic upgrade project, including all new building systems, life safety and accessibility upgrades. The repair and seismic upgrade of the original adobe walls proved to be the most challenging aspect of the project. This paper details the non-destructive evaluation techniques that were used to determine the condition of the adobe, and the process of seismic strengthening adobe walls. It also describes other structural upgrades that stitched the multiple building construction types together. The Presidio Officers Club reopened one year ago when the 20 million dollar, 4 year construction project, was completed. The building has, once again, assumed the position as the main social and cultural center of the Presidio. 1. Introduction A. The Presidio, location in San Francisco and California i. Brief overview of history of Presidio B. Significance of Officers Club (Building 50) and Site i. Oldest building in Presidio ii. 1776, De Anza party, Spanish commandancia iii. Most significant archaeology zone in Presidio 2. Officers Club: Building 50 - Description of Building A. Major periods of construction i. Adobe era; s focus on this period of construction ii. Victorian era, Assembly Hall addition, wood balloon frame: 1884 (brief)

5 iii. iv. Mission revival era, additions, wood frame; 1930 s s (brief) Modern era, 2 story addition, post-tensioned reinforced concrete, 1972 (brief) 3. Rehabilitation Project - Planning & Design to 2010 A. Feasibility Studies, Historic Structure Report B. Non Destructive Evaluation of Adobe Surfaces i. Infra-red thermography, impulse radar, moisture tests ii. Recommendations C. Structural recommendations for seismic upgrade i. Adobe wings; center core, stainless steel rods, mesh 4. Construction Process to 2014 A. Adobe repair, center core, foundation repairs, wall encapsulation- main focus B. Installation of braced frames- Moraga Room, Arguello Room C. General construction: costs, duration, complexity, challenges, successes 5. Grand Opening, October 4, 2014 A. Before and after images