Building the Bridges of Connecticut
Connecticut's bridges have changed markedly since the time when some colonists first laid rough-hewn timbers over a stream. Better materials, new technologies, and the rise of professional engineering all played a part in the story. But equally important were the changing transportation needs of Connecticut's citizens. The farming communities of the Colonial period needed only the most rudimentary structures, but modern industrialized society, with its dependence on automobiles and trucks, requires much more. Not surprisingly, the arena of transportation decisions has changed as fully as the bridges themselves, from local government, to state government, to the federal-state partnership that accounts for much of the bridge building in our own time.
Bridges in Colonial Connecticut
In the Colonial period, bridges were the responsibility of Connecticut's individual towns. Each year people at the town meeting elected several highway surveyors, who then took charge of the roads and bridges in particular sections of town. Money for construction and repairs came from the town's annual highway tax, levied on households according to how much land they owned. Residents who were short of cash could pay all or part of their highway tax by working on the roads, by providing the town with a team of oxen, or by furnishing timber for bridges.
Most of these early bridges were short spans built of wood. Except for stone slabs used to cross run-off ditches and other small streams, masonry bridges were too expensive. The timber bridges of the Colonial period, even when braced by simple truss forms such as the king-post truss, were limited to a length of about fifty feet. Wider streams had to be bridged by a series of spans resting on intermediate stone piers, and ferries provided the principal means of crossing the state's largest rivers, including the Connecticut, Housatonic, Naugatuck, and Thames.
Few towns planned ahead or took a broad view of their transportation requirements. Instead, bridge construction and maintenance responded to petitions from townspeople, and it was carried out at the lowest possible cost. Such localized, informal planning was appropriate for a society made up largely of farmers. Most people had to travel only to a few neighboring farms, to the gristmill, to the meetinghouse, and occasionally to a store. The system worked less well when many bridges had to be replaced or repaired at once, such as in 1795, when a spring flood washed out dozens of bridges in the Farmington Valley. The towns responded by doubling the highway tax, creating a hardship for many families.
Toward the end of the 18th century, people began to recognize the need for improved overland transportation. During the Revolutionary War, British control of Long Island Sound had forced the colonists to move troops and provisions over woefully inadequate Connecticut roads. Also, Connecticut's growing commerce in agricultural produce and timber products, while relying primarily on water-borne transportation, still had to be carried in wagons for the first part of the journey. Several large bridges were built over major rivers in this period, most by private companies that had received a charter from the legislature permitting them to build a bridge and charge tolls. The magnitude of these projects often required special financing. In 1782, to pay for a bridge across the Quinebaug River in Canterbury, the General Assembly authorized a lottery, the most common method of raising capital for major public construction projects.
The Era of Turnpikes and Canals
In the 1790s and early 1800s, Connecticut's General Assembly authorized many turnpikes, which were toll roads of supposedly superior quality built and operated by private companies. The legislative charter for each turnpike specified the general route and the allowable tolls. Then the company surveyed and constructed the road subject to approval from the General Assembly. That approval process provided citizens the chance to protest planned routes and suggest alternatives, as many did. In 1803, for instance, the villages of West Britain and New Cambridge, in the town of Bristol, vied to be on the route of a proposed turnpike. Both villages feared economic stagnation if the turnpike passed them by, but they debated the route in terms of efficient transportation and the cost of construction. The residents of West Britain claimed that the route closer to them was on "hard firm soil, destitute of sand, the hills not tedious, and [had need of] fewer expensive bridges." Nevertheless, New Cambridge won out by paying for the survey of an alternative route and promising to build two bridges for the turnpike, which roughly followed what is today Route 6. More than 120 companies received turnpike charters and, while not every one managed to complete a road, turnpikes crisscrossed the state by 1820. Like town bridges, most of the hundreds of bridges built by the turnpikes were wood, but the ability to raise money from investors and charge tolls allowed more stone-bridge construction.
The towns continued to exercise authority over bridges, particularly when concern over a structure's adequacy caused citizens to complain. In 1797, a bridge on the Hartford-Albany turnpike came under scrutiny when the town of Farmington appointed a committee to examine the bridge. Their report found the bridge "so far decayed that we consider it unsafe and hazardous." The public was assured that it would be replaced "as soon as the season and the nature of the business permit." The town did not want to be held liable for any mishap connected with the old bridge, and to fulfill its obligation to the traveling public, placed a notice in the Connecticut Courant:
Travellers and others will therefore do well to stop, consider, and look before they leap, as the town will not expect to be responsible for any loss or injury that may be sustained in consequence of the insufficiency of the present bridge.
At the same time that turnpike companies were improving roads, the legislature chartered several toll-bridge companies to build and operate large bridges. In 1807, a company was authorized to build a new bridge over the mouth of the Housatonic River between Stratford and Milford (aided by a lottery), and in 1808 the state's first bridge across the Connecticut River was built at Windsor. Two years later, despite considerable opposition from ferrymen, a second toll-bridge was completed at Hartford. It lasted only eight years before being swept away in the spring of 1818. It was then replaced by a covered bridge which stood for more than 75 years.
These bridges were able to take advantage of improvements in timber bridge building that had only recently been developed. The Hartford bridge of 1818 consisted of six arch-trusses over 150 feet in length, built according to a design patented by Theodore Burr in 1804. The Burr design used a web of king-post trusses reinforced by an arch. Burr's design allowed for span lengths far greater than that of simple-truss timber bridges, and when roofed over to protect the bridge from the elements, it made a durable structure.
Although more economical than comparable spans in stone, Burr trusses still required expensive, specialized labor in their construction. That problem was addressed by Ithiel Town, who patented his design for a lattice truss in 1820. After his youth on a Connecticut farm, Town studied in Boston with Asher Benjamin, one of the nation's most accomplished architects, then moved to New Haven to run a building contracting business. In partnership with Isaac Damon, Town constructed three bridges over the Connecticut River before 1820, including the Burr truss at Hartford. In Town's lattice design, the truss consisted of simple planks set diagonally between top and bottom chords and joined at their intersections with "treenails," or wooden pins. The Town lattice truss saved on material because it did not require massive timbers, and on labor because it did not use intricate mortise-and-tenon joints. Town promoted the bridges through pamphlets and traveling sales agents. By 1834, lattice trusses had been built throughout the New England and Middle Atlantic states and as far away as Alabama. Two of the three wooden covered bridges remaining in Connecticut are Town-lattice trusses.
Another significant development in Connecticut transportation occurred in the 1820s, when two canals were built. The Enfield, or Windsor Locks, Canal bypassed dangerous rapids on the Connecticut River, thereby opening up navigation between Hartford and the upper Connecticut Valley. The Farmington Canal linked New Haven with Northampton, Massachusetts. None of the numerous wooden bridges built to carry farm roads over the canals have survived.
Bridges in the Industrial Age
Railroads completely supplanted canals in Connecticut during the 1840s. Like canals, they were self-contained transportation systems that nonetheless had enormous impact on highways in the surrounding communities. Where high embankments carried the tracks, passages had to be cut through for local road traffic, often by means of arched masonry tunnels. Two such crossings can be seen today in eastern Connecticut, along the route first built in the late 1840s by the Hartford, Providence and Fishkill Railroad. Rail access also transformed the character of numerous quiet villages, causing massive increases in commercial feeder traffic and stimulating the development of local industries. To cope with such growth, towns needed to build more bridges and replace old ones with stronger spans.
Railroad construction stimulated further developments in bridge technology. A timber truss patented in 1840 by Massachusetts millwright William Howe incorporated wrought-iron vertical tension members that could be tightened with turnbuckles. For ten years it was the standard truss used in railroad bridges, and survived even longer for highway bridges. The covered bridge across the Salmon River between Colchester and East Hampton is a Howe truss. Railroads, however, soon turned to all-iron trusses for bridges which could meet the demands of heavier rolling stock and higher speeds. The first practical iron trusses, which would transform the nation's bridge technology, were developed by two engineers working for the Baltimore and Ohio (B & O) Railroad, Wendel Bollman and Albert Fink. Like timber trusses, their designs were based on the principle of using diagonal members to transmit vertical load from the center of the bridge to the abutments. The B & O used iron trusses extensively for spans of up to one hundred feet as it extended or improved its western routes.
Bollman also led the way in establishing the structural fabrication industry as an enterprise independent from the railroads. He left the B & O in 1858 to start his own bridge firm, which (except for suspending operations during the Civil War) flourished until his death in 1884. The pattern repeated itself throughout the United States after the war, as dozens of railroad engineers either started firms or allied with iron works to pursue the growing bridge market.
At first, metal-truss bridges were primarily used on railroads. But by 1870 they increasingly found favor with local highway officials, who were seeking bridges that would be stronger and more durable than wooden trusses (which probably lasted less than 25 years on average) and cheaper than masonry construction. From the late 1860s through end of the 19th century, intense competition pervaded the bridge industry. Rival sales agents often touted the particular qualities of their firm's patented designs, such as less material and lower cost, greater strength, or even more handsome appearance. Berlin Iron Bridge Company, Connecticut's only major bridge fabricator, was one of the pre-eminent examples of a company that used a distinctive product as an aid in marketing.
Berlin Iron Bridge Company had its origin in the sheet-metal industry of central Connecticut, which in turn had grown out of the tinware trade. The direct predecessor of Berlin Iron Bridge was the Corrugated Metal Company, a manufacturer of roofing material. In the mid-1870s, the firm moved into fabricating iron roof trusses, which were needed to support its heavy corrugated roofing. Meanwhile, William Douglas of Binghamton, New York, had developed an American version of the lenticular or parabolic bridge truss that had been used in Europe since the 1850s. Douglas hired a young Yale graduate, Charles Jarvis, to help with production, and engaged Corrugated Metal to handle the fabrication. The firm may have begun selling the bridges as early as 1877, a year before Douglas received a patent for the design. Active marketing began in earnest in 1878, particularly in the region near the factory in East Berlin. Waterbury's Washington Avenue Bridge, erected during the summer of 1878, was one of the earliest sales, and is the oldest lenticular truss known to survive.
The Douglas truss has a lens-shaped profile, with the bottom chord curving upward to meet the top chord at the end posts. This distinctive appearance, and an advantage in cost because the lenticular truss used 10 percent less metal than the more common types, were the principal selling points exploited by the agents. Bridges soon became the firm's major product, and in 1883 the name was changed to Berlin Iron Bridge Company.
Not every sale to town officials depended on claims of technical superiority or cost efficiency. Collusion and bid-rigging were an integral part of commerce in the 19th century. An agent for the Groton Bridge Company of New York recalled one such circumstance involving local highway officials in Vermont who solicited bids from his firm, from King Iron Bridge in Ohio, and from Berlin Iron Bridge:
Well, they opened the bids and the Ohio man was way high. Next was our bid -- $908.14. And when they opened Berlin's bid it was exactly the same, right to the penny! The Berlin man and I were flabbergasted, but the commissioners thought it was funny. Finally one of 'em pulled out a shiny silver dollar and we flipped for the bridge contract. The Berlin man won and they built it. Later I met up with him again over East, under just about the same circumstances. That time our bid was just eighteen cents under his and we got the job. Bridge business was fun in those days.
Berlin Iron Bridge did not completely monopolize the iron-bridge market in Connecticut, but the inherent economy in transportation to in-state locations made the firm a formidable competitor. Of more than 1,000 lenticular trusses built by the firm, nearly 10 percent were sold to Connecticut municipal governments. In addition to its lenticular trusses, the firm built spans designed by city engineers and railroads, such as the Pratt truss on Chapel Street in New Haven and the plate-girder span carrying the railroad over Asylum Street in Hartford.
Even while the lenticular truss achieved its peak of popularity in the late 1880s, two simpler trusses had already established themselves as the preferred types among engineers, fabricators and customers. The Pratt and Warren trusses and their variants had simplicity as their main advantage over the lenticular and other exotic trusses. It was easier to calculate the load capacity for these trusses, and the less complicated joints considerably eased the fabricating process.
Until the early 1890s, truss bridges of every pattern shared two important characteristics. First, their connections featured large pins, up to three inches in diameter, that passed through holes drilled in the ends of the members. Pins were favored due to ease of assembly, even though engineers realized that riveted connections offered superior rigidity. In the 1890s, innovations in pneumatic field riveting overcame the cost advantage of pinned joints, and riveting became standard. Secondly, most trusses before 1895 were made from wrought iron.
Although an all-steel railroad had been built as early as 1879, many engineers and fabricators distrusted the material, especially for tension members. With the perfection of the open-hearth process of steelmaking around 1890, the performance of steel was no longer a serious question, and the common structural shapes (plates, channels, angles) soon became available at prices competitive with wrought iron. By 1895, as one eminent bridge engineer recalled, steel's "adoption for bridges was practically universal, and the production of wrought iron in large quantities was a thing of the past."
Economic consolidation in the bridge fabricating industry helped make standard the technological changes that had occurred. In a classic case of market dominance through financial manipulation, the banker J. P. Morgan in 1900 formed the American Bridge Company. In its first year American Bridge purchased 24 bridge companies (including Berlin Iron Bridge) and thereby controlled half the nation's fabricating capacity. In 1901 American Bridge was itself purchased by U.S. Steel, the largest producer of structural steel. This combination achieved immediate control of the bridge market, leaving the survivors to fight over scraps from the giant's table. In a pattern frequently repeated, executives of Berlin Iron Bridge left the new monopoly after a short time and started over in their original home area. Like the rest of the smaller firms, the new Berlin Construction Company (later renamed Berlin Steel Construction Company) competed in a regional market by capitalizing on existing contacts with local highway officials and whatever advantage in transportation cost it could offer over American Bridge.
Although hundreds of small metal trusses were built on Connecticut highways in the period 1870 to 1910 (some towns bought more than a dozen from Berlin Iron Bridge alone), they did not completely supersede timber and masonry bridge construction. In two projects in the decade following the Civil War, the towns of Watertown and Colchester both considered iron bridges, but instead built a stone arch and a wooden covered bridge. Stone and timber bridges had the advantage of using easily available materials and local labor.
Many towns chose stone bridges because they were especially strong and durable. As industries proliferated in Connecticut, the danger of flooding increased. During periods of heavy rains, mill dams would burst, washing out all the bridges downstream. When a storm in October of 1869 caused waters to rise, so many dams failed in Glastonbury that seventeen of the town's eighteen bridges were destroyed; most were replaced with stone arches.
Stone bridges were also favored for their beauty. Many arched bridges, even in the smaller towns, had carefully cut ring stones and other decorative features that served an aesthetic rather than functional purpose. In the early 1900s, many cities and large towns chose to build impressive stone arches as part of civic-improvement programs. The "City Beautiful" movement, as it was called, so favored stone-arch construction that even after reinforced concrete became the dominant material for bridges, the sides of the arches and the railings were often finished with stone for the sake of appearance.
The Connecticut State Highway Department
In 1895, the State of Connecticut took the first step toward centralized transportation planning and administration by establishing the Office of the Connecticut Highway Commissioners. Because of disproportional representation, the Connecticut Legislature was controlled by rural towns, and the Highway Commissioners' Office explicitly set out to benefit farmers, who even then were a minority of the state's population. The Highway Commissioners' main function was to distribute a modest state appropriation of $75,000 to towns for widening rights-of-way, eliminating steep hills, improving drainage, and resurfacing roads with packed-gravel pavement. The average grant was less than $900, and the towns had to match the state contribution. In 1897 the legislature reduced the number of Commissioners from three to one and added a small professional staff to the agency, thereby creating the State Highway Department.
The size of the program's grants precluded substantial bridge work on most projects. However, the Commissioner's office did promulgate technical standards for state-aided bridges, such as a minimum width of 12 feet. Also, through competitive evaluation of applications for state aid, the Commissioner was able to encourage the towns to build stronger bridges. "The makeshift toy bridges of the past will not be tolerated in the days to come," declared the Department in 1899.
The bridges most in need of improvement were those that carried major highways over the state's larger rivers. But because of its rural orientation and its reliance on town initiative, the State Highway program did little for the main through routes, then called "trunk lines," that connected the state's urban centers. In fact, Commissioner James A. MacDonald opposed spending money on such roads because he thought they siphoned off the economic vitality of farming areas into the cities. Even Connecticut's busiest highway, the Boston Post Road, he insisted, could be improved by the individual towns through which it passed, given the engineering expertise and matching funds available from the state program.
The limited role staked out by the State Highway Department in the 1890s changed abruptly in response to pressures brought by a new mode of transportation--the automobile. Packed-gravel pavements were unsuitable for motor-vehicle traffic, as were the lightly constructed, narrow bridges being erected by the towns. Moreover, as motor trucks captured some of the long-distance freight formerly monopolized by the railroads, business and industry came to depend on good-quality highways. These interests made themselves heard in the General Assembly, which in 1905 created the state's trunk-line system, and gave the Highway Commissioner direct authority over the state's fourteen major through highways. Besides the Post Road (now U.S. Route 1), the trunk lines followed the approximate course of present-day Routes 2, 4, 6, 7, 8, 9, 10, 11, 12, 14, 15, 34 and 44. In addition to money for distribution to the towns, the State Highway Department was now authorized spend money directly to improve and maintain the trunk lines.
The Highway Department's goals had undergone a fundamental change from just eight years before. The Commissioner now responded to the interests of commerce and the internal-combustion engine, and the conservatism of small-town governments stood in the way. MacDonald argued that trunk lines suffered because the towns did not initiate enough projects or appropriate sufficient money. The General Assembly complied with his request to eliminate the annual cap on state expenditure in any single town.
Bridges necessarily became a major component of trunk-line improvement. The Boston Post Road crossed several large rivers on town-operated or private ferries that charged tolls. The Commissioner recommended for the short term that the state take over the ferries, and again the legislators complied. Meanwhile, the Department began the planning for several large bridge projects.
In 1907 the department also started promoting a relatively new structural material, reinforced concrete. A few towns had already adopted concrete, notably West Hartford, which built one of the state's first concrete-arch bridges in 1901 and added several more in the next few years. The Connecticut Society of Civil Engineers examined concrete construction in 1903 and enthusiastically endorsed the new material for bridges. Comparing concrete arches with steel trusses, the engineers favored the unobstructed roadway, faster construction and lower maintenance cost of the arches.
The Highway Commission urged towns to adopt concrete and printed standard designs in its 1907 report, but it still lacked the funding needed to undertake major bridge projects on its own. Conservative spending remained the order of the day, especially after the recession of 1907. From 1909 through 1913 the General Assembly would not even fund the printing of the Highway Commissioner's annual report. Instead of a coordinated bridge program, the legislature authorized the construction of important bridges on a case-by-case basis, creating a special commission to build each bridge and requiring the towns that were directly affected to pay most of the cost.
Charles J. Bennett assumed charge of the State Highway Commission in 1913. He spent two years improving relations with the legislature and reorganizing the office. After receiving the first increase in administrative expenses since 1907, he hired additional professional staff to head the new operational divisions he established within the office: construction, maintenance, and accounting. Bennett also divided the state into seven highway districts, and assigned to each an engineer who was responsible for reviewing all state-aided local road projects. He adopted as a primary goal the complete upgrade of the trunk-line system to make it suitable for automobiles and trucks.
In 1915, Bennett convinced the General Assembly to grant his office authority over all the state's bridges. Construction money was still very limited, however, and it was restricted to a handful of critical crossings rather than a general appropriation for a statewide bridge program. The first structure designed and constructed by the Highway Commission was a concrete-beam bridge carrying Boston Post Road over the Saugatuck River in downtown Westport. Following that, the state engineers designed the concrete-arch span over the Housatonic River between Derby and Shelton.
In 1916 the Highway Department gained a powerful ally--the United States government. The Federal Aid Road Act made a limited amount of federal matching funds available to support the state's overall construction program. The Highway Department apportioned the money according to its own priorities, and federal officials approved the allocations and designs. Bennett devoted most of the federal cost-share to the two trunk-line programs: bridge reconstruction and removal of dangerous conditions (poor paving, sharp curves, hills). Federal money allowed the Highway Department to pursue the long-deferred goal of improving the river crossings on Boston Post Road, which remained the most heavily used route in the state. Planning for Washington Bridge, over the Housatonic, began in 1917 but construction was delayed by the allocation of steel to military purposes during World War I, and the bridge was not completed until 1921. The following year, the bridge over the Mystic River between Groton and Stonington completed the upgrade of the road to serve the needs of burgeoning automotive traffic.
Many of the Post Road projects incorporated the latest in movable bridge technology. Shoreline communities such as Westport, Stratford, and Mystic were all located on rivers that were navigable, at least by small craft, and the new bridges had to provide clearance for maritime traffic. Most used a bascule, a modern version of the medieval drawbridge, which in the early 20th century was reaching the peak of its technological development.
The Federal Aid Road Act and subsequent amendments encouraged participating states to establish technical specifications for road and bridge construction. Partly in response, and partly to minimize the engineering work on the 15,000 miles of roads in the state, the Connecticut legislature in 1924 directed the Highway Commissioner to establish and distribute "Standard Specifications" for construction. In 1927 the Commissioner's office issued these specifications, which have been updated every two to five years since. The specifications did not include any specific bridge designs, but they did indicate a strong preference for concrete bridges and effectively limited metal trusses to the Pratt and Warren designs that had become standard in the bridge industry. By also stipulating such items as methods of materials analysis, rivet spacing for trusses, and surface finishes for concrete spans, the Commissioner's office set the character of the bridges that would be built throughout Connecticut. Even those bridges designed by private engineering firms, or paid for by individual towns, followed the Commission's standards.
Despite the continual expansion of its responsibility and budgets in the 1920s, the Office of the Highway Commissioner struggled to build and maintain roads and bridges that would be adequate for constantly increasing traffic. In the early 1930s the Department assumed the additional responsibility of long-term planning, made possible in part by general-obligation bonding for highway and bridge construction. Bonding helped the program by spreading out the cost of improvements over a period of years.
In addition to exercising a supervisory role, the engineers in the Commissioner's office themselves designed some of the state's largest bridges of the period. These monumental structures include a number of open-spandrel concrete arches, such as the 1930 Reynolds Bridge in Thomaston, the 1930 Cornwall Bridge, and the 1934 Hammonassett River Bridge, and several large steel through trusses, such as the 1934 Lake Zoar bridge and the 1936 Butts Bridge in Canterbury.
The highway between New York and New Haven continued to demand the attention of State Highway officials. Despite an improvement program in the mid-1920s, it was still the most frequently jammed and accident-prone road in the state. The Highway Department's Warren M. Creamer described the situation in a 1936 address to the Connecticut Society of Civil Engineers:
It is certain that many of you have occasion to use the Post Road; have doubtless in your journey from Bridgeport to New York City been confronted by an amazing succession of traffic lights . . . have passed through the city and town streets . . . ultimately arriving in the city, nerves on edge and facing exhaustion.
To alleviate the jangled nerves of shoreline travelers, the Department undertook construction of a four-lane parkway from Greenwich to the Housatonic River at Stratford. Completed in 1938, the Merritt Parkway was designed by the department's staff under Creamer. The project also involved several consulting engineers, landscape architects, and architect George Dunkelburger, who designed the decorative details and finishes for some 60 concrete bridges. The Merritt was widely hailed as the epitome of American parkway construction, a uniquely well-fulfilled combination of effective traffic-carrying capacity and aesthetically pleasing design. Also in 1938, the department reported the completion of the largest single structure it had ever undertaken -- the steel-arch Arrigoni Bridge over the Connecticut River at Middletown.
Bridge work in Connecticut in the 1930s benefited not only from ordinary federal-aid appropriations but also from the numerous New Deal programs enacted during the presidency of Franklin Roosevelt. The Works Progress Administration built many new bridges in local and state parks, often using picturesque stone construction, and the Civilian Conservation Corps rehabilitated the Salmon River covered bridge. After the Hurricane of 1938 destroyed dozens of bridges, federal work-relief funds allowed the state and towns to undertake speedy reconstruction.
Today the State Highway Department's successor, the Connecticut Department of Transportation, is engaged in another program of major improvements to the state's roads and bridges. In partnership with the Federal Highway Administration, the Department is continuing its long tradition of providing safe and efficient transportation. At the same time, the Department's planners and engineers are confident that through proper planning, the program can preserve many of the historic highway bridges that stand as monuments to the state's transportation and engineering heritage.