1950’s, an extensive program of research on the hydraulics of culverts, bridges, and storm sewers was undertaken, largely by contract with various universities and other Federal agencies.
The infamous Silver Bridge over the Ohio River at Point Pleasant, W. Va.
In 1959 a Hydraulic Branch was established in the Public Roads Bridge Division. The functions of this Branch were to initiate and participate in hydraulic research, to disseminate the practical application of hydraulic design to bridge engineers and to review hydraulic features of Federal-aid structures. Studies were also made on stream pollution from highway and bridge construction and guidelines were issued on reduction of such pollution.
One of the most important contributions in this area was BPR’s Hydraulic Engineering Circulars and Hydraulic Design Series Bulletins. These publications, still in use, provide practical methods for applying research results to designs and are widely used by Federal, State and consulting engineers.
Other areas of bridge related research and development included safety measures, with particular emphasis on:
- Elimination or neutralization of hazardous fixed objects along the roadside including bridge piers, abutments, parapets, and culvert headwalls.
- Strengthening of bridge guardrail designs and the new concept of a strong beam (rail) with a weak post that would yield partially and redirect the errant vehicle safely back to the road.
- Breakaway sign supports and lighting poles that break when hit by a vehicle, thereby reducing the injury to vehicle and occupants on collision. In collisions, the vehicle usually passes under the sign or pole before it falls. These concepts were developed at Texas A&M through State and Federal funding.
Gore[N 1] protection devices to protect out-of-control vehicles at the diverging point of ramp exits and branching roadways. These rapidly reduce the speed of an out-of-control vehicle by the absorption of energy by using springs, crushing of drums, displacement of water or sand or related methods.
New criteria for design of sign supports, including new recommedations for certain aluminum alloy design stresses, accepted and published by AASHO in 1961.
- ↑ The elongated triangular area where one-way roadways begin to separate.
The Scene Today
The State transportation agencies, the Federal Highway Administration, the highway industry and research groups have achieved a finely tuned, cooperative highway program. It is difficult to say that any one group is responsible for new developments, since each concerned group has played a part. This is the way it has been with the latest developments in bridge design, ultimate strength design (USD) for concrete and load factor design for steel. The Bureau of Public Roads supported these developments vigorously and was in the forefront of this movement when it published the Strength and Serviceability Criteria—Reinforced Concrete Bridge Members—Ultimate Design in 1966. This helped bring the bridge specifications up to the American Concrete Institute (ACI) Building Code Requirements for Reinforced Concrete which had adopted USD in 1963. A Tentative Criteria for Load Factor Design of Steel Highway Bridges, with
440
