TOMORROW'S ROADS TODAY - Maryland State Highway ...

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or Bethlehem Steel types would be acceptable. The metal beams and girders also could be
ordered by length and weight depending on the bridge design requirements (length and width of
bridge, traffic volumes, crossing type). Unlike the bridges from the 1930s, the new bridge
parapets were higher and closed so that drivers would be less distracted by looking through the
parapets at the scenery beyond the bridge.
However, since 1965, many of these bridges have also been altered by widening or
redecking with new parapets. In the 1980s, many bridges had the parapet endposts replaced with
trapezoidal shapes to increase driver safety at the approaches to the bridges. Another change was
to add safety fencing across the bridges. The SRC made all of these changes in response to
growing traffic and concern for driver safety on the associated highways. These types of
alterations preclude these bridges from being able to convey their significance as mid-twentieth
century bridges.
By the 1950s, standardization was not a new innovation and did not result in a markedly
different bridge design from those bridges built in the 1930s. The SRC began to use Standard
Plans for its bridge designs in 1912 with plans for concrete slab and metal girder bridges. By the
1930s and early 1940s, the SRC did not rely on the earlier Standard Plans, but began using
standardized bridge elements to design and construct rolled and plate girder bridges for crossings
that did not require a specialized solution. One change from the 1930s was that the bridges were
no longer encased in concrete. Instead, the metal beams would be exposed but painted. Not
using additional concrete enabled the SRC to further reduced the cost of bridge construction. In
the case of concrete bridges, the SRC continued using reinforced concrete to design and
construct slab, beams, girders and rigid frame bridges for crossings that did not require a
specialized solution. These bridges were less expensive to construct because they were not the
decorative arched bridges that were frequently built during the early part of the twentieth
century. Prestressed concrete bridges were first built during the 1948-1965 period, but not
universally incorporated into all concrete bridges on the state system.
Bridge building was one of the most expensive undertakings for the transportation
agency, and standardizing as much of the process helped to control the costs and construction
time. Through the post-war period, SRC continued its earlier practices from the 1930s and 1940,
building plate and rolled girders and reinforced concrete bridges that enabled the agency to
produce similar designs for many new crossings. The large number of similar bridges
demonstrates how the SRC made practical use of standardization to build the new highway
system.
The mid-century bridges were not constructed as the single most important element of the
highway system, nor were they unusual designs. Rather, the bridges were constructed as an
integral part of the associated highway, and there were many bridges on each highway that
crossed other roads, railroads, and bodies of water along the route. Although the SRC
constructed many bridges and highways during this period, that is not an exceptional event.
During this same period, other state Departments of Transportation such as Delaware, New
Jersey, Virginia, Nebraska, Tennessee, Oregon and California were constructing similar bridges
and highways in order to keep up with growing traffic on state highways. The steel beam and
girder bridges and reinforced concrete bridges constructed during this period by the SRC became
a common resource found on every highway in the state and in many other states as well.