As engineers navigate the design process of buildings and other structures, there is a factor that is rarely, if ever, accounted for: relocation. As a result, the relocation of buildings and other structures is a specialized facet of the industry. Relocations can occur for a number of reasons, including historic preservation, construction purposes, and fixing errors. Since relocations have been occurring for hundreds of years, there are a number of standard practices that have developed, which have since been enhanced by the development of modern technology and engineering practices. The knowledge and hands-on experience of building relocation companies in conjunction with the technical expertise of structural engineers is critical for a successful relocation.
General Overview
Figure 2: Building relocation utilizing push jacks in Washington DC. Photo Credit: Holbert Apple Associates
The relocation process generally involves shoring and supporting the structure on steel framing in addition to properly bracing it inside and out to preserve its current state. The steel frame consists of “mains” which support the cross beams and rest on the roll beams. Bracing can consist of numerous combinations of interior bracing, such as temporary infill of wall openings, shear walls, and diagonal bracing, and exterior bracing, such as tension cables. A series of hydraulic leveling jacks (Figure 3), located between the “mains” and the roll beams, are utilized to keep the structure level throughout the relocation, which is an intensive process. The jacks are controlled by a Unified Jacking Machine, which enables to structure to be lifted uniformly regardless pressure or load. Meanwhile, the structure is shifted by either using push-jacks (Figure 4) to slide the “mains” along the roll beams (Figure 2) or moving the roll beams on a set of dollies (Figure 1) in unison towards the desired location. Careful calculations and preparation are necessary not only to properly determine the loads when designing the steel frame and bracing, but also to create an appropriate zoning configuration for the leveling jacks. Maintaining the levelness of the structure during relocation is critical for limiting unintentional stresses, which could cause cracking. In the event that the structure needs to be transported along a roadway, further attention has to be paid to ensure that size and weight limitations are met and that the intended relocation method is acceptable.
Figure 3: "Mains" (yellow) resting on hydraulic jacks on top of roll beams. Photo Credit: Holbert Apple Associates
Figure 4: Hydraulic push jacks. Photo Credit: Holbert Apple Associates
Case Studies:
Cape Hatteras Lighthouse
In addition to the more common occurrence of moving houses and small commercial structures, it is sometimes necessary to move much larger and complex structures. One such case is that of the Cape Hatteras Lighthouse.
Harrowing and daunting in its nature, the relocation of the Cape Hatteras Lighthouse was essential for the preservation of the historic beacon situated in the Outer Banks of North Carolina. Initially completed in 1870, the lighthouse sat 1,500 feet from the coast, where it remained until 1999 when it was moved 2,900 feet inland (Figure 5) to its current location (AACE 2000) due to its threatened status. Perpetual erosion of the shoreline resulted in only 120 feet separating the lighthouse from the waters of the Atlantic Ocean by 1970, threatening the tallest brick lighthouse in the United States (NPS 2001). After numerous attempts to preserve the lighthouse in its original location, the National Park Service began planning and fundraising to move the Cape Hatteras Lighthouse, ultimately receiving funding from Congress in 1998. Relocation efforts involved not only the lighthouse itself, but also the set of accompanying historic structures, resulting in an $11,800,000 overall budget (Schierhorn 1999). Funding was provided in two separate fiscal years, 1998 and 1999, causing the design to be completed a year prior to construction. International Chimney Corporation worked in conjunction with Expert House Movers to design and execute the relocation of the Cape Hatteras Lighthouse. The National Park Service also hired Wiss, Janney, Elstner Associates (WJE) as a consultant to aid in the preservation of the lighthouse during the relocation by monitoring cracks and stresses, conducting tests on materials, supervising the construction of the new lighthouse base, and executing final condition surveys (WJE). The Cape Hatteras Lighthouse Relocation Team was rounded out by Masonry Building Corporation, a historic architect and masonry consultant, which was responsible for the erection of the masonry foundation at the lighthouse’s final location (Scheirhorn 1999).
Figure 6: Cape Hatteras Lighthouse Relocation. Photo Credit: National Park Service
The Cape Hatteras Lighthouse Relocation began with the lengthy process of excavating and shoring the structure in place so the steel framing grid could be constructed. Once completed, the load of the structure was progressively transferred from the shoring structure to the steel framing through the use of the hydraulic jacks. Once everything was set, push-jacks were used to move the lighthouse five feet at a time. A three-zone scheme was utilized with the Unified Jacking System to ensure slight changes in the soil surface could be addressed while keeping the lighthouse level (Tice 2000). On June 17, 1999, the 4,830 ton Cape Hatteras Lighthouse began its twenty-three day journey to its new location. Once in place, the load was transferred from the steel frame to another set of shoring structures, which allowed the roll beams, “mains”, and cross beams to be removed and the construction of the new brick foundation on top of a concrete pad. The selection of a brick foundation was made based in part for efficiency and economy, but also because it enabled the lighthouse to be supported continuously throughout its footprint. After a lengthy and tedious relocation process, the Cape Hatteras Lighthouse was operational again in November 1999.
Concrete Building in Israel
The construction of the residence for the Japanese ambassador to Israel began in March 2000 (Telem 2006). Despite being a residence, reinforced concrete was selected as the structural system. During construction, a surveyor realized the building location on the site did not match the project drawings and building permits. The residence was built 190 cm (approx. 6’ – 2”) east of its proper spot, protruding into site setback. Because the reinforced concrete structure was nearly finished, it was determined that moving the building would be the best solution to preserve the completed work and provide the intended design to the client. Other options were considered, such as cutting off the protruding segment or lifting the building with cranes. However, the client required that the building match the original plans and the building weight exceeded the capacity of available cranes that could also fit in the surrounding area. The Ghiora Mehler Company consulted with various relocation experts in North America and Europe, and eventually selected a Dutch engineering company, Mammoet.
After conducting in-depth soil tests and evaluating the structural limits, the team decided to utilize six hydraulic push jacks to shift the building and developed a jack placement plan. As part of the relocation planning and design, the impact of forces on the building structure in addition to the surrounding area had to be considered. As a result, a concrete retaining wall with 90 cm (approx. 3’) diameter vertical piers was constructed on the east side of the site to avoid damaging utilities along the site that could be stressed by the reaction forces of the push jacks. In addition, a leveling mat was cast along the west side of the structure to provide a sliding surface during the move. The relocation was conducted in five stages of roughly 50 cm (approx.. 1’-7.5”) and 20 minutes each. However, as the building was pushed, a wedge of soil was created due to the leveling mat causing the front side of the building to lift up 2.5 cm (approx.. 0’-1”). The leveling mat was subsequently removed and the building returned to its proper elevation following the next push. Following the completion of the pushes, a survey confirmed the building was in the correct location and that no structural damage was present.
American Association of Medical Colleges - Washington, DC
In order to make way for the new eleven story office building for the American Association of Medical Colleges (AAMC), six existing buildings were uprooted, five of which were returned close to their original locations (Block 2012). These buildings were protected despite not being designated as historic structures, due to the efforts of the DC Preservation League and its collaboration with Douglas Development. Expert House Movers executed the building relocation in conjunction with International Chimney Corporation. By relocating the buildings, the new building could be constructed and the existing buildings could be re-purposed house restaurants and shops.
Figure 7: AAMC Building Relocation. Photo Credit: Todd Holbert
Hongxing Mansion
The 13-story high-rise building in China was translocated 26 m (approx. 85’-4”) to accommodate urban planning and widening of streets (Gou 2013). The relocation was particularly challenging due to the urban setting and the 3.5 height to width ratio. Evaluation of the options revealed that moving the structure would only cost a quarter to a third of the cost to demolish and rebuild. The design team elected to use anchor-jacked piles to support the rail beams. Unlike the other case studies, the rail beams were cast-in-place reinforced concrete used with steel rollers. The rail system was broken up into regions for the original foundation, the transition area, and the new foundation. The Hongxing Mansion relocation utilized a combination of push and pull processes, in the form of jacks and tendons, to increase the efficiency and stability of the system. A synchronic control system was used to monitor the status of the building during the move with displacement gauges and pressure sensors and make adjustments to the hydraulic jacks, oil pumps, and servo-valves. New connections had to then be constructed to attach the superstructure to the new foundations, while maintaining the gravity loading and seismic capabilities of the original structure.
465 NY Avenue - Washington, DC
Figure 8: 465 NY Ave. Building Relocation. Photo Credit: Todd Holbert
To facilitate the construction of the new 13-story Homewood Suites hotel, a three story building built in 1902 was shifted on the lot at 465 NY Avenue in Washington DC (Courtney 2014). The historic townhouse, constructed with stone and brick and designed by L. F. Stutz, was approved for relocation as part of a redevelopment plan submitted to the Historic Preservation Review Board (Calcott 2012).
To prepare the building for the move, bracing was added in the form of infilling openings, wood shear walls, and external cabling, in addition to existing internal diagonal bracing that had been installed previously. The building was cut at the basement to install the steel support frame.
Due to the townhouse being tight against the newer Yale Laundry Condominiums, analysis had to be conducted to evaluate the impact of the building movement on Yale Laundry's concrete foundation walls. In addition, the site layout impacted the design and placement of the steel undercarriage, as Expert House Movers could not access the east side of the building prior to lifting and moving the building. This relocation was conducted using two methods. First, push jacks were utilized to move the building along the roll beams off of its original foundation, at which point dollies were placed
under the roll beams to relocate the building across the site (Figures 8 and 12). The move across the
site involved both laterally moving and rotating the building (Figure 9).
Figure 10: 465 NY Ave. Building Relocation. Photo Credit: Holbert Apple Associates
Next, the dollies were removed and the building was shifted using the push jacks to its final location: a set of piles resting only inches from an adjacent historic building (Figure 10). The piles then supported the building as excavation for a new two-level sub-grade parking garage was conducted (Hotel 2012). The historic structure was planned to be refurbished into apartments following relocation.
Figure 9: 465 NY Ave. Building Relocation. Photo Credit : Holbert Apple Associates
Figure 11: Portion of Drawing for 465 NY Ave. Building Relocation. Courtesy of Holbert Apple Associates
Figure 12: 465 NY Ave. Building Relocation. Photo Credit: Todd Holbert
Conclusion
The relocation of buildings and other structures is a specialized niche of the industry that facilitates the preservation of historic structures, correction of construction errors, and alteration of the urban fabric. Although various methods are utilized, the most prevalent one is lifting the building with hydraulic leveling jacks and moving it with hydraulic push jacks along roll beams or with sets of dollies.The accurate estimation of the structural loads and determination of the proper lift points and main beam locations is critical. In addition, proper shoring and bracing is important for laterally stabilizing the structure during relocation. The success of relocating buildings relies on the collaboration between relocation companies and structural engineers to ensure that the building can be moved efficiently and safely.
Annotated Bibliography
Block, Melissa. (June 28, 2012). “Moving Buildings To Save D.C.’s Historic Foundation.” National Public Radio. Washington, DC. Web. (September 14, 2014).
Story about the preservation and relocation of several buildings on K Street in Washington, DC as part of the construction of the Association of American Medical Colleges.
Calcott, Steve. (July 26,2012). Staff Report and Recommendation. Historic Preservation Review Board. Washington, DC. (September 12, 2014).
Historic Preservation Review Board meeting minutes regarding 465 New York Avenue, the site of a new hotel and relocation of an existing structure.
CapeHatterasLighthouse Articles and Photos. (2001). “Moving the Cape Hatteras Lighthouse”. National Park Service. Cape Hatteras, National Seashore, N.C. Web. <**http://www.nps.gov/caha/historyculture/movinglighthouse.htm**> (September 12, 2014).
Discussion of the necessity and execution of the Cape Hatteras Lighthouse relocation in 1999.
“Cape Hatteras Lighthouse Move.” (2000). American Association of Cost Engineering. 42(4). (October 3, 2014).
The article discusses the execution of moving the Caper Hatteras Lighthouse away from the shore.
Gou, T., Li, A., Wei, L., and Gu, Y. (2013). “Horizontal Translocation of a High-Rise Building: Case Study.” J. Perform. Constr. Facil., 27(3), 235-243. (October 1, 2014).
Case study of a building relocation in China to accommodate urban planning, while preserving the high-rise structure.
“Hotel Planned for 400 Block of New York Avenue, NW”. Blog post. EastShawDC. (July 30, 2012). Web. <http://eastshawdc.blogspot.com/2012/07/new-hotel-for-400-block-of-new.html> (September 12, 2014).
Discussion of a new hotel to be built on a site in Washington, DC that includes an existing 3-story building that will be relocated to a new area on the site. The developer’s submission to the Historic Preservation Review Board is included.
Schierhorn, Carolyn. (1999). “Rescuing the Cape Hatteras Lighthouse.” The Aberdeen Group. (October 14, 2014).
Article about the relocation of and construction of a new foundation for the Cape Hatteras Lighthouse.
Telem, D., Shapira, A., Goren, Y., and Schexnayder, C. (2006). “Moving a Reinforced-Concrete Building: Case Study.” J. Constr. Eng. Manage., 132(2), 115-124. (September 14, 2014).
This case study details the process of shifting a concrete building in Israel to correct a construction error.
Tice, J. Allan, and Knott, Randy A. (2000). “Relocation of the Cape Hatteras Light Station: Move Route Design and Construction.” Soil-Cement and Other Practices in Geotechnical Engineering: pp. 51-66. (September 12, 2014).
Article about the geotechnical engineering for and relocation of the Cape Hatteras Light Station.
Guidelines for Building and Structure Relocation
An Overview and Select Case StudiesTodd Holbert, B.A.E./M.A.E., The Pennsylvania State University, Class of 2015
Table of Contents
Introduction
As engineers navigate the design process of buildings and other structures, there is a factor that is rarely, if ever, accounted for: relocation. As a result, the relocation of buildings and other structures is a specialized facet of the industry. Relocations can occur for a number of reasons, including historic preservation, construction purposes, and fixing errors. Since relocations have been occurring for hundreds of years, there are a number of standard practices that have developed, which have since been enhanced by the development of modern technology and engineering practices. The knowledge and hands-on experience of building relocation companies in conjunction with the technical expertise of structural engineers is critical for a successful relocation.General Overview
Case Studies:
Cape Hatteras Lighthouse
In addition to the more common occurrence of moving houses and small commercial structures, it is sometimes necessary to move much larger and complex structures. One such case is that of the Cape Hatteras Lighthouse.Harrowing and daunting in its nature, the relocation of the Cape Hatteras Lighthouse was essential for the preservation of the historic beacon situated in the Outer Banks of North Carolina. Initially completed in 1870, the lighthouse sat 1,500 feet from the coast, where it remained until 1999 when it was moved 2,900 feet inland (Figure 5) to its current location (AACE 2000) due to its threatened status. Perpetual erosion of the shoreline resulted in only 120 feet separating the lighthouse from the waters of the Atlantic Ocean by 1970, threatening the tallest brick lighthouse in the United States (NPS 2001). After numerous attempts to preserve the lighthouse in its original location, the National Park Service began planning and fundraising to move the Cape Hatteras Lighthouse, ultimately receiving funding from Congress in 1998. Relocation efforts involved not only the lighthouse itself, but also the set of accompanying historic structures, resulting in an $11,800,000 overall budget (Schierhorn 1999). Funding was provided in two separate fiscal years, 1998 and 1999, causing the design to be completed a year prior to construction. International Chimney Corporation worked in conjunction with Expert House Movers to design and execute the relocation of the Cape Hatteras Lighthouse. The National Park Service also hired Wiss, Janney, Elstner Associates (WJE) as a consultant to aid in the preservation of the lighthouse during the relocation by monitoring cracks and stresses, conducting tests on materials, supervising the construction of the new lighthouse base, and executing final condition surveys (WJE). The Cape Hatteras Lighthouse Relocation Team was rounded out by Masonry Building Corporation, a historic architect and masonry consultant, which was responsible for the erection of the masonry foundation at the lighthouse’s final location (Scheirhorn 1999).
The Cape Hatteras Lighthouse Relocation began with the lengthy process of excavating and shoring the structure in place so the steel framing grid could be constructed. Once completed, the load of the structure was progressively transferred from the shoring structure to the steel framing through the use of the hydraulic jacks. Once everything was set, push-jacks were used to move the lighthouse five feet at a time. A three-zone scheme was utilized with the Unified Jacking System to ensure slight changes in the soil surface could be addressed while keeping the lighthouse level (Tice 2000). On June 17, 1999, the 4,830 ton Cape Hatteras Lighthouse began its twenty-three day journey to its new location. Once in place, the load was transferred from the steel frame to another set of shoring structures, which allowed the roll beams, “mains”, and cross beams to be removed and the construction of the new brick foundation on top of a concrete pad. The selection of a brick foundation was made based in part for efficiency and economy, but also because it enabled the lighthouse to be supported continuously throughout its footprint. After a lengthy and tedious relocation process, the Cape Hatteras Lighthouse was operational again in November 1999.
Concrete Building in Israel
The construction of the residence for the Japanese ambassador to Israel began in March 2000 (Telem 2006). Despite being a residence, reinforced concrete was selected as the structural system. During construction, a surveyor realized the building location on the site did not match the project drawings and building permits. The residence was built 190 cm (approx. 6’ – 2”) east of its proper spot, protruding into site setback. Because the reinforced concrete structure was nearly finished, it was determined that moving the building would be the best solution to preserve the completed work and provide the intended design to the client. Other options were considered, such as cutting off the protruding segment or lifting the building with cranes. However, the client required that the building match the original plans and the building weight exceeded the capacity of available cranes that could also fit in the surrounding area. The Ghiora Mehler Company consulted with various relocation experts in North America and Europe, and eventually selected a Dutch engineering company, Mammoet.After conducting in-depth soil tests and evaluating the structural limits, the team decided to utilize six hydraulic push jacks to shift the building and developed a jack placement plan. As part of the relocation planning and design, the impact of forces on the building structure in addition to the surrounding area had to be considered. As a result, a concrete retaining wall with 90 cm (approx. 3’) diameter vertical piers was constructed on the east side of the site to avoid damaging utilities along the site that could be stressed by the reaction forces of the push jacks. In addition, a leveling mat was cast along the west side of the structure to provide a sliding surface during the move. The relocation was conducted in five stages of roughly 50 cm (approx.. 1’-7.5”) and 20 minutes each. However, as the building was pushed, a wedge of soil was created due to the leveling mat causing the front side of the building to lift up 2.5 cm (approx.. 0’-1”). The leveling mat was subsequently removed and the building returned to its proper elevation following the next push. Following the completion of the pushes, a survey confirmed the building was in the correct location and that no structural damage was present.
American Association of Medical Colleges - Washington, DC
In order to make way for the new eleven story office building for the American Association of Medical Colleges (AAMC), six existing buildings were uprooted, five of which were returned close to their original locations (Block 2012). These buildings were protected despite not being designated as historic structures, due to the efforts of the DC Preservation League and its collaboration with Douglas Development. Expert House Movers executed the building relocation in conjunction with International Chimney Corporation. By relocating the buildings, the new building could be constructed and the existing buildings could be re-purposed house restaurants and shops.Hongxing Mansion
The 13-story high-rise building in China was translocated 26 m (approx. 85’-4”) to accommodate urban planning and widening of streets (Gou 2013). The relocation was particularly challenging due to the urban setting and the 3.5 height to width ratio. Evaluation of the options revealed that moving the structure would only cost a quarter to a third of the cost to demolish and rebuild. The design team elected to use anchor-jacked piles to support the rail beams. Unlike the other case studies, the rail beams were cast-in-place reinforced concrete used with steel rollers. The rail system was broken up into regions for the original foundation, the transition area, and the new foundation. The Hongxing Mansion relocation utilized a combination of push and pull processes, in the form of jacks and tendons, to increase the efficiency and stability of the system. A synchronic control system was used to monitor the status of the building during the move with displacement gauges and pressure sensors and make adjustments to the hydraulic jacks, oil pumps, and servo-valves. New connections had to then be constructed to attach the superstructure to the new foundations, while maintaining the gravity loading and seismic capabilities of the original structure.465 NY Avenue - Washington, DC
To prepare the building for the move, bracing was added in the form of infilling openings, wood shear walls, and external cabling, in addition to existing internal diagonal bracing that had been installed previously. The building was cut at the basement to install the steel support frame.
Due to the townhouse being tight against the newer Yale Laundry Condominiums, analysis had to be conducted to evaluate the impact of the building movement on Yale Laundry's concrete foundation walls. In addition, the site layout impacted the design and placement of the steel undercarriage, as Expert House Movers could not access the east side of the building prior to lifting and moving the building. This relocation was conducted using two methods. First, push jacks were utilized to move the building along the roll beams off of its original foundation, at which point dollies were placed
under the roll beams to relocate the building across the site (Figures 8 and 12). The move across the
site involved both laterally moving and rotating the building (Figure 9).
Next, the dollies were removed and the building was shifted using the push jacks to its final location:
a set of piles resting only inches from an adjacent historic building (Figure 10). The piles then supported
the building as excavation for a new two-level sub-grade parking garage was conducted (Hotel 2012).
The historic structure was planned to be refurbished into apartments following relocation.
Conclusion
The relocation of buildings and other structures is a specialized niche of the industry that facilitates the preservation of historic structures, correction of construction errors, and alteration of the urban fabric. Although various methods are utilized, the most prevalent one is lifting the building with hydraulic leveling jacks and moving it with hydraulic push jacks along roll beams or with sets of dollies.The accurate estimation of the structural loads and determination of the proper lift points and main beam locations is critical. In addition, proper shoring and bracing is important for laterally stabilizing the structure during relocation. The success of relocating buildings relies on the collaboration between relocation companies and structural engineers to ensure that the building can be moved efficiently and safely.Annotated Bibliography
Block, Melissa. (June 28, 2012). “Moving Buildings To Save D.C.’s Historic Foundation.” National Public Radio. Washington, DC. Web. (September 14, 2014).
Story about the preservation and relocation of several buildings on K Street in Washington, DC as part of the construction of the Association of American Medical Colleges.
Calcott, Steve. (July 26,2012). Staff Report and Recommendation. Historic Preservation Review Board. Washington, DC. (September 12, 2014).
Historic Preservation Review Board meeting minutes regarding 465 New York Avenue, the site of a new hotel and relocation of an existing structure.
Cape Hatteras Lighthouse Articles and Photos. (2001). “Moving the Cape Hatteras Lighthouse”. National Park Service. Cape Hatteras, National Seashore, N.C. Web. <**http://www.nps.gov/caha/historyculture/movinglighthouse.htm**> (September 12, 2014).
Discussion of the necessity and execution of the Cape Hatteras Lighthouse relocation in 1999.
“Cape Hatteras Lighthouse Move.” (2000). American Association of Cost Engineering. 42(4). (October 3, 2014).
The article discusses the execution of moving the Caper Hatteras Lighthouse away from the shore.
Courtney, Shaun. (May 21, 2014). “Rolling Stones: Moving Historic Mt. Vernon Home to New Location.” District Source. Web. < **http://districtsource.com/2014/05/rolling-stones-moving-historic-mt-vernon-home-to-new-location/**> (October 2, 2014)
Article about the relocation of a 100+ year old home being relocated at 465 New York Avenue for a new hotel.
Gou, T., Li, A., Wei, L., and Gu, Y. (2013). “Horizontal Translocation of a High-Rise Building: Case Study.” J. Perform. Constr. Facil., 27(3), 235-243. (October 1, 2014).
Case study of a building relocation in China to accommodate urban planning, while preserving the high-rise structure.
“Hotel Planned for 400 Block of New York Avenue, NW”. Blog post. EastShawDC. (July 30, 2012). Web. <http://eastshawdc.blogspot.com/2012/07/new-hotel-for-400-block-of-new.html> (September 12, 2014).
Discussion of a new hotel to be built on a site in Washington, DC that includes an existing 3-story building that will be relocated to a new area on the site. The developer’s submission to the Historic Preservation Review Board is included.
Schierhorn, Carolyn. (1999). “Rescuing the Cape Hatteras Lighthouse.” The Aberdeen Group. (October 14, 2014).
Article about the relocation of and construction of a new foundation for the Cape Hatteras Lighthouse.
Telem, D., Shapira, A., Goren, Y., and Schexnayder, C. (2006). “Moving a Reinforced-Concrete Building: Case Study.” J. Constr. Eng. Manage., 132(2), 115-124. (September 14, 2014).
This case study details the process of shifting a concrete building in Israel to correct a construction error.
Tice, J. Allan, and Knott, Randy A. (2000). “Relocation of the Cape Hatteras Light Station: Move Route Design and Construction.” Soil-Cement and Other Practices in Geotechnical Engineering: pp. 51-66. (September 12, 2014).
Article about the geotechnical engineering for and relocation of the Cape Hatteras Light Station.
Wiss, Janney, Elstner Associates. “Project Profile: Cape Hatteras Lighthouse.” Web. <**www.wje.com/assets/pdfs/projects/Cape_Hatteras_Lighthouse.pdf**> (October 14, 2014)
Project description of the Cape Hatteras Lighthouse by a preservation consultant.