Pittsburgh-Des Moines Steel Co.
Pittsburgh-Des Moines Steel Co. was an American steel fabricator known for water tanks, bridges, major structural steelwork, and the fabrication and erection of the Gateway Arch.
Last updated August 26, 2026
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Overview
Pittsburgh-Des Moines Steel Co., commonly called Pitt-Des Moines Steel or PDM, was an American steel fabrication and engineering company whose roots went back to the Des Moines Bridge and Iron Company, established in 1892. The business was founded by William H. Jackson and Berkeley M. Moss, graduates of Iowa State College. Edward W. Crellin, who operated a small fabrication shop in Des Moines, Iowa, subsequently joined the venture. The company initially arranged for steel tanks to be fabricated by Keystone Bridge Company in Pittsburgh, while it developed a broader business supplying engineered steel structures for municipalities, utilities, transportation projects, and industrial customers. Its early product range included elevated water tanks, standpipes, waterworks equipment, bridges, structural members, and steelwork for electric plants. Steel stock was shipped from Pittsburgh to Iowa for fabrication, reflecting the company’s original geographic and commercial connection to both cities. A fabrication plant opened in Warren, Pennsylvania, in 1900. Berkeley M. Moss left the enterprise around 1905, after which the company continued expanding its manufacturing and contracting activities. The company adopted the Pittsburgh-Des Moines Steel Company name in 1916 and opened a new headquarters in Pittsburgh. It remained a partnership until incorporation in 1956. Corporate naming later changed to Pittsburgh-Des Moines Corporation in 1980 and to Pitt-Des Moines, Inc. in 1985. The company had registered the PDM trademark by 1930, and the abbreviated name was widely used in business and project references. PDM’s historical importance rests in part on the public infrastructure that it fabricated or erected. Its work included numerous steel bridges and municipal water towers, many of which were later listed on the National Register of Historic Places. The company was also the steel fabricator and erector for the Gateway Arch in St. Louis, constructed from 1963 to 1965. During the 1960s it fabricated the distinctive forked columns used in the World Trade Center complex in New York. These projects placed the company among the major American specialists in large-scale structural steel fabrication. The company experienced significant operational disruption in the late twentieth and early twenty-first centuries. In July 1993, flooding from Iowa’s Raccoon River damaged the original Des Moines site and fabrication works beyond salvage. The facility, then known as the Des Moines Heavy Bridge Division, was permanently closed and later sold. In 2001, the Chicago Bridge & Iron Company acquired the company’s principal assets and operations, while Reliance Steel & Aluminum Co. acquired its steel distribution unit. The original Pittsburgh-Des Moines corporate entity therefore ceased operating as an independent business at approximately the beginning of the 2000s, although facilities, assets, and successor operations continued under other ownership. Chicago Bridge & Iron, later known as CB&I, closed the Warren, Pennsylvania, plant in early 2009. In 2013, PDM steel plants in Eau Claire and Wausau, Wisconsin, and Palatka, Florida, were sold to Veritas Steel LLC. A later PDM-related headquarters relocation to Elk Grove, California, was reported in 2016, reflecting the continued use of the PDM name in successor or reorganized operations rather than the uninterrupted existence of the original independent company. The historic brand is consequently best understood as a defunct American steel-fabrication company whose legacy survives through landmark structures, preserved bridges and waterworks, and successor businesses.
History
Pittsburgh-Des Moines Steel Co. originated in 1892 as the Des Moines Bridge and Iron Company. William H. Jackson and Berkeley M. Moss, both graduates of Iowa State College, established the venture and initially contracted with Keystone Bridge Company of Pittsburgh to fabricate steel tanks. Edward W. Crellin, proprietor of a small Des Moines fabrication shop, soon joined the partnership. The business combined Pittsburgh steel supplies with Iowa fabrication capacity and began producing engineered structures for water systems, bridges, waterworks, and electric plants. The company’s early work was closely tied to the growth of municipal infrastructure in the United States. It manufactured elevated metal tanks, standpipes, bridge components, and other steel structures that could be shipped and assembled in communities across the country. A new fabrication plant opened in Warren, Pennsylvania, in 1900. Moss left the business around 1905, after the Warren facility had been established, while the company continued to develop its manufacturing and contracting network. In 1916, the enterprise adopted the Pittsburgh-Des Moines Steel Company name and opened a headquarters in Pittsburgh. The new name reflected the company’s two principal geographic associations: steel and industrial connections in Pittsburgh and its original fabrication base in Des Moines. The partnership structure lasted until 1956, when the company was incorporated. It later became Pittsburgh-Des Moines Corporation in 1980 and Pitt-Des Moines, Inc. in 1985. The company also used PDM as a registered trademark from at least 1930. Across the twentieth century, PDM became known for large-scale steel fabrication and erection. Its projects included numerous road and pedestrian bridges, elevated water tanks, water-pumping facilities, and industrial structures. Many surviving examples are listed on the National Register of Historic Places, documenting the company’s contribution to regional infrastructure and the development of American steel construction. The company’s most prominent architectural assignment was the Gateway Arch in St. Louis. From 1963 to 1965, Pittsburgh-Des Moines served as the steel fabricator and erector for the stainless-steel monument. The company also fabricated the forked columns used in the World Trade Center during the 1960s. The Des Moines works suffered a decisive setback in July 1993 when flooding from the Raccoon River destroyed the original site and fabrication works beyond salvage. The facility, then operating as the Des Moines Heavy Bridge Division, was permanently closed and later sold. This event removed the company’s historic Iowa manufacturing base and contributed to the restructuring of its operations. In 2001, Chicago Bridge & Iron Company acquired Pittsburgh-Des Moines and its principal assets. In the same year, Reliance Steel & Aluminum Co. acquired the company’s steel distribution unit. These transactions effectively ended the original company’s independent operating history, generally placed at approximately 2002, although its facilities and business activities continued through successor ownership. CB&I later closed the Warren plant in early 2009. In 2013, Veritas Steel LLC acquired former PDM plants in Eau Claire and Wausau, Wisconsin, and Palatka, Florida. Reference material also reports a PDM headquarters relocation to Elk Grove, California, in 2016, apparently reflecting a continuing or successor operation using the PDM name. The company’s legacy is therefore divided between a historical corporate identity and the physical works it produced. Historic bridges, water towers, waterworks, and major landmarks remain evidence of its engineering and fabrication role. The Gateway Arch and the former World Trade Center columns are especially prominent examples, while many smaller municipal structures illustrate the company’s long-running role in supplying durable steel infrastructure throughout the United States.
- 2013
Former PDM plants are sold to Veritas Steel
[1]Veritas Steel acquired former PDM facilities in Wisconsin and Florida.
- 2001
Assets are divided among successor owners
[1]Chicago Bridge & Iron acquired the principal company assets, while Reliance Steel & Aluminum acquired the steel distribution unit.
- 1993
Des Moines plant permanently closes after flooding
[1]The Raccoon River flood destroyed the Des Moines Heavy Bridge Division beyond salvage.
- 1985
Corporate name shortened to Pitt-Des Moines, Inc.
[1]The corporation changed its name to Pitt-Des Moines, Inc.
- 1980
Corporate name changes to Pittsburgh-Des Moines Corporation
[1]The company adopted the Pittsburgh-Des Moines Corporation name.
- 1963
Gateway Arch fabrication and erection begins
[1]Pittsburgh-Des Moines fabricated and erected the steelwork for the Gateway Arch project, completed in 1965.
- 1956
Partnership becomes a corporation
[1]After operating as a partnership for decades, the company was incorporated.
- 1930
PDM trademark registered
[1]The company registered the abbreviated PDM mark, which became a commonly used identifier.
- 1916
Company adopts the Pittsburgh-Des Moines Steel name
[1]The business changed its name and opened a headquarters in Pittsburgh.
- 1900
Warren, Pennsylvania, fabrication plant opens
[1]The company opened a new fabrication plant in Warren, expanding beyond its original Des Moines base.
Products and positioning
An engineering-led American steel fabricator serving infrastructure, municipal utilities, transportation, industrial construction, and landmark architectural projects.
Water infrastructure · 1892
Municipal water tanks and towers
Water tanks, elevated towers, and standpipes were among the company’s foundational products. PDM supplied steel structures for municipal water storage and distribution systems, including numerous surviving installations in Midwestern and Southern communities. Several examples attributed to the company or its predecessor names are listed on the National Register of Historic Places.
Transportation infrastructure · 1892
Bridges
Pittsburgh-Des Moines fabricated and erected steel highway, railroad, viaduct, and pedestrian bridges. Its bridge portfolio included structures in Iowa, Texas, Arkansas, Vermont, Arizona, and other states. The work ranged from local crossings and historic highway bridges to major urban and regional transportation structures.
Structural steel fabrication · 1892
Industrial and utility steelwork
The company produced engineered steelwork for waterworks, electric plants, pumping stations, industrial facilities, and other public utilities. Its capabilities covered fabrication, shipment, assembly, and erection, allowing it to deliver complete structural packages rather than only raw steel products.
Architectural landmark fabrication · 1963
Gateway Arch steelwork
For the Gateway Arch in St. Louis, Pittsburgh-Des Moines served as the steel fabricator and erector between 1963 and 1965. The assignment involved manufacturing and assembling the monument’s complex stainless-steel structural sections and remains the company’s best-known architectural project.
Building structural components · 1960
World Trade Center forked columns
During the 1960s, PDM fabricated the distinctive forked columns used in the World Trade Center complex. These components formed part of the innovative structural system of the original towers and demonstrated the company’s capacity to manufacture large, specialized members for major buildings.
Brand decisions
2001
Sale of principal assets to Chicago Bridge & IronM&ABackground
After decades as an independent steel fabricator, Pittsburgh-Des Moines entered an ownership transition at the beginning of the 2000s.
Action taken
Chicago Bridge & Iron acquired the company’s principal assets and operations. Reliance Steel & Aluminum separately acquired the steel distribution unit.
Aftermath
The original company ceased operating independently, and its facilities and business lines subsequently passed through successor ownership.
1993
Permanent closure of the Des Moines fabrication siteOtherBackground
The company’s original Des Moines works were severely damaged by flooding from the Raccoon River in July 1993.
Action taken
The Des Moines Heavy Bridge Division was closed permanently after the facility was damaged beyond salvage.
Aftermath
The historic Iowa site was later sold, shifting the company’s operating footprint away from its original location.
Sources1 sources
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