James E. Roberts Bridge
Encyclopedia
The James E. Roberts Memorial Bridge is a 1,400 foot two-lane highway bridge on California State Highway 120, in Tuolumne County, California. The bridge spans the Tuolumne River just north of Lake Don Pedro, near the community of Chinese Camp
. It opened in 1971.
Originally named the Tuolumne River Bridge, it was renamed in 2007 in honor of James E. Roberts
by legislative resolution. Roberts was the California Department of Highways (now, Caltrans) project manager, his first project management assignment as a senior bridge engineer. The cost to create new highway signs was raised by private donations.
, as lead design engineer; M. Comacho, PE, as details and quantities engineer, George Amaro, PE, as specifications engineer; and R. J LeBeau, PE, and K. C. Blechinger, PE, as independent design checkers. Herbert K. Jensen, PE, was Resident Engineer for Bridge Construction, and John F. Harrington, PE, was assistant resident engineer.
This bridge, located north of Yosemite, was necessitated by a new highway alignment the resulted from creation of the new Don Pedro Dam
reservoir. James Roberts laid out the bridge on a horizontal curve with a 1,200 foot radius curve to meet the requests of the highway engineers. Large bridges of this size were normally built straight, and California bridges required a detailed seismic analysis.
Normal weight concrete was used for foundations or bridge piers and lightweight concrete
was used for the bridge deck. The superstructure was painted steel curved girders trucked into the site.
The bridge had to be completed prior to the filling of the reservoir. The tallest column is about 230 feet high, so falsework
for concrete
superstructure was not practicable. The highway engineers requested that the bridge have a capability to be widened from 2-lanes of traffic to 4-lanes, as planning at the time assumed that a wider highway would be necessary by 1995. The columns and foundation system were thus designed to support a second superstructure. The highway and bridge remain at two lanes wide today. A the majority of the north south freeway traffic is on I-5
or Highway in the relatively flat farming valleys. Highway 49 is a winding, scenic highway that follows the profile of the foothills to the Sierra Nevada Mountain range.
The top 70 feet of the bridge columns have an equilateral triangular shape to support the four lanes of proposed superstructure. The initial 2-lanes were placed on the outside radius, so eccentric loading analysis of the columns was necessary. The foundation was excavated rock and is essentially hexagonal in shape to stabilize the column. The column is reasonably complicated and attractive.
canyon walls. Custom steel column forms were manufactured at an on site concrete batch plant. The San Jose Steel Company was the steel superstructure fabricator. Pieces were brought in by rail and truck. After column completion, steel girders were erected from the canyon floor, lifted from the cantilevered tips of the north and south girders.
The bridge opened to traffic in 1971. The designers received an AISC
Medium Span Steel Bridge award in 1972 and a James F. Lincoln Arc Welding Foundation Award. The AISC jurors wrote "this gracefully sweeping bridge fits beautiful into it’s setting. The clean curving superstructure and the sculptured piers are very pleasing."
2. Roberts, James E., Dokken Richard A., Golden Gate of the Motherload, Modern Welded Structures, Volume VI, James F. Lincoln Arc Welding, Cleveland, OH, ( 1st Edition, Nov 1980) pp A-67 to A-70.
3. AISC, AISC Prize Bridges -1972, American Institute of Steel Construction
pages 8 & 9, 1972 pp 33
4. Roberts, James E., Effects of curing and falsework support periods on dead load deflections of reinforced concrete slab bridges: final report / prepared in cooperation with the U.S. Dept. of transportation, Federal Highway Administration 1972 California Department of Highways Caltrans
5. Roberts, James E., Esthetics in concrete bridge design / editors, Stewart C. Watson, M.K. Hurd. American Concrete Institute
6. Roberts , James E., Marquez, T., Huang, C, Mangus A., Dykes, B., Marlow S., Rea1igning Ca1ifornia’s 1-880 Freeway. Concrete International January 2000 pp. 22–27.
7. Roberts, James E.,, Maroney Brian Chapter 40 Seismic Retrofit Practice, Bridge Engineering Handbook, 1St ed., Chen, Wai-Fah, Duan Lian Ed., CRC Press, Boca Raton Florida, (1999).
8. Roberts, James E., Maloney Brian, Theory of California seismic bridge design and analysis for the beginner (Division of Structures, California Dept. of Transportation.
9. Alden, Don, et al. Oral History James E Roberts, California Department of Transportation
Caltrans, pp
10. Kempton, Will, Land Richard, et al. James E. Roberts Memorial, California Department of Transportation, [Caltrans], DVD, 59 minutes
11. Roberts, James E., 50-Years as bridge engineer History James E Roberts, California Department of Transportation [Caltrans], DVD, March 14, 2001
11. Wilson, Bill, Nothing Earth-Shattering –Roebling Medal, Roads & Bridges Magazine, August 2001, www.ROADSBRIDGES.com pp 24–25
Chinese Camp, California
Chinese Camp is a census-designated place in Tuolumne County, California, United States. The population was 126 at the 2010 census, down from 146 at the 2000 census. It lies in the grassy foothills of the Sierra Nevada near the southern end of California's Gold Country.-History:Chinese Camp is the...
. It opened in 1971.
Originally named the Tuolumne River Bridge, it was renamed in 2007 in honor of James E. Roberts
James E. Roberts
James E. Roberts was a noted American civil engineer. He was recognized with industry and government awards for his leadership in bridge engineering, especially in the area of seismic retrofit. He was the state bridge engineer at Caltrans during the Loma Prieta Earthquake and Northridge Earthquake...
by legislative resolution. Roberts was the California Department of Highways (now, Caltrans) project manager, his first project management assignment as a senior bridge engineer. The cost to create new highway signs was raised by private donations.
Designers
Key members of the Tuolumne River Bridge project, in addition to Mr. Roberts, were Richard “Dick” Dokken, PEProfessional Engineer
Regulation of the engineering profession is established by various jurisdictions of the world to protect the safety, well-being and other interests of the general public, and to define the licensure process through which an engineer becomes authorized to provide professional services to the...
, as lead design engineer; M. Comacho, PE, as details and quantities engineer, George Amaro, PE, as specifications engineer; and R. J LeBeau, PE, and K. C. Blechinger, PE, as independent design checkers. Herbert K. Jensen, PE, was Resident Engineer for Bridge Construction, and John F. Harrington, PE, was assistant resident engineer.
This bridge, located north of Yosemite, was necessitated by a new highway alignment the resulted from creation of the new Don Pedro Dam
Don Pedro Dam
The Don Pedro Dam, since 1971 also known as the Old Don Pedro Dam, was a dam across the Tuolumne River in Tuolumne County, California. The structure is currently flooded underneath Don Pedro Reservoir, which is formed by the New Don Pedro Dam....
reservoir. James Roberts laid out the bridge on a horizontal curve with a 1,200 foot radius curve to meet the requests of the highway engineers. Large bridges of this size were normally built straight, and California bridges required a detailed seismic analysis.
Normal weight concrete was used for foundations or bridge piers and lightweight concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
was used for the bridge deck. The superstructure was painted steel curved girders trucked into the site.
The bridge had to be completed prior to the filling of the reservoir. The tallest column is about 230 feet high, so falsework
Falsework
Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself...
for concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
superstructure was not practicable. The highway engineers requested that the bridge have a capability to be widened from 2-lanes of traffic to 4-lanes, as planning at the time assumed that a wider highway would be necessary by 1995. The columns and foundation system were thus designed to support a second superstructure. The highway and bridge remain at two lanes wide today. A the majority of the north south freeway traffic is on I-5
Interstate 5
Interstate 5 is the main Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific Ocean coastline from Canada to Mexico . It serves some of the largest cities on the U.S...
or Highway in the relatively flat farming valleys. Highway 49 is a winding, scenic highway that follows the profile of the foothills to the Sierra Nevada Mountain range.
The top 70 feet of the bridge columns have an equilateral triangular shape to support the four lanes of proposed superstructure. The initial 2-lanes were placed on the outside radius, so eccentric loading analysis of the columns was necessary. The foundation was excavated rock and is essentially hexagonal in shape to stabilize the column. The column is reasonably complicated and attractive.
Contractor
Peter Kiewit and Sons built the bridge as general contract with a gravel access road using switchbacks into the sides of the Tuolumne RiverTuolumne River
The Tuolumne River is a California river that flows nearly from the central Sierra Nevada to the San Joaquin River in the Central Valley...
canyon walls. Custom steel column forms were manufactured at an on site concrete batch plant. The San Jose Steel Company was the steel superstructure fabricator. Pieces were brought in by rail and truck. After column completion, steel girders were erected from the canyon floor, lifted from the cantilevered tips of the north and south girders.
The bridge opened to traffic in 1971. The designers received an AISC
American Institute of Steel Construction
The American Institute of Steel Construction, often abbreviated AISC, is a not-for-profit technical institute and trade association for the use of structural steel in the construction industry of the United States. It is headquartered in Chicago, IL. Their mission is to make structural steel the...
Medium Span Steel Bridge award in 1972 and a James F. Lincoln Arc Welding Foundation Award. The AISC jurors wrote "this gracefully sweeping bridge fits beautiful into it’s setting. The clean curving superstructure and the sculptured piers are very pleasing."
Selected References
1. Dokken Richard A., Salveson Matthew, James E. Roberts – More than an Engineer’s Engineer. ASCE Structure Magazine, Feb 2009, pp 48–492. Roberts, James E., Dokken Richard A., Golden Gate of the Motherload, Modern Welded Structures, Volume VI, James F. Lincoln Arc Welding, Cleveland, OH, ( 1st Edition, Nov 1980) pp A-67 to A-70.
3. AISC, AISC Prize Bridges -1972, American Institute of Steel Construction
American Institute of Steel Construction
The American Institute of Steel Construction, often abbreviated AISC, is a not-for-profit technical institute and trade association for the use of structural steel in the construction industry of the United States. It is headquartered in Chicago, IL. Their mission is to make structural steel the...
pages 8 & 9, 1972 pp 33
4. Roberts, James E., Effects of curing and falsework support periods on dead load deflections of reinforced concrete slab bridges: final report / prepared in cooperation with the U.S. Dept. of transportation, Federal Highway Administration 1972 California Department of Highways Caltrans
5. Roberts, James E., Esthetics in concrete bridge design / editors, Stewart C. Watson, M.K. Hurd. American Concrete Institute
American Concrete Institute
The American Concrete Institute is a non-profit technical society and standard developing organization . ACI was founded in 1904 and its headquarters are currently located in Farmington Hills, Michigan, USA.- ACI History :1904-1929:...
6. Roberts , James E., Marquez, T., Huang, C, Mangus A., Dykes, B., Marlow S., Rea1igning Ca1ifornia’s 1-880 Freeway. Concrete International January 2000 pp. 22–27.
7. Roberts, James E.,, Maroney Brian Chapter 40 Seismic Retrofit Practice, Bridge Engineering Handbook, 1St ed., Chen, Wai-Fah, Duan Lian Ed., CRC Press, Boca Raton Florida, (1999).
8. Roberts, James E., Maloney Brian, Theory of California seismic bridge design and analysis for the beginner (Division of Structures, California Dept. of Transportation.
9. Alden, Don, et al. Oral History James E Roberts, California Department of Transportation
California Department of Transportation
The California Department of Transportation is a government department in the U.S. state of California. Its mission is to improve mobility across the state. It manages the state highway system and is actively involved with public transportation systems throughout the state...
Caltrans, pp
10. Kempton, Will, Land Richard, et al. James E. Roberts Memorial, California Department of Transportation, [Caltrans], DVD, 59 minutes
11. Roberts, James E., 50-Years as bridge engineer History James E Roberts, California Department of Transportation [Caltrans], DVD, March 14, 2001
11. Wilson, Bill, Nothing Earth-Shattering –Roebling Medal, Roads & Bridges Magazine, August 2001, www.ROADSBRIDGES.com pp 24–25