Road structure – process – or apparatus – Traffic steering device or barrier
Patent
1996-01-17
1997-12-16
Lisehora, James
Road structure, process, or apparatus
Traffic steering device or barrier
256 131, E01F 1500, E01D 1910
Patent
active
056977280
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a guardrail of the so-called New Jersey type, and in particular to such a guardrail, which will be prevalently installed on the lateral overhangs of bridges having a reduced resistance to loads.
BACKGROUND ART
Guardrails of the New-Jersey type, made of concrete and generally obtained from monolithic elements which are 6 metres in length, has been known since several years. These guardrails initially had a weight of about 850 kg/m (kilograms per meter), and this weight was sometimes too great for the lateral overhangs of bridges and also for the lateral beams of bridges. Later on, the weight was reduced by employing lightened concrete (640 kg/m), or by realizing lightening recesses (440 kg/m). In order to further reduce the weight, guardrails entirely made of steel have been used afterwards (linear specific weight: 130-150 kg/m).
The single parts of the guardrail of the New Jersey type are connected to each other, forming a chain, which at every connection point can yield and move backwards towards the outside, as a result of the collision with a motor vehicle.
Furthermore, ductile anchor means connecting the guardrail to the kerbstone, allow the moving backward of a single part or element of the guardrail onto which the collision occurs, and said ductile anchor means will break only after they have absorbed an amount of energy, so that they do not transfer too large stresses to the underlying structure.
DISCLOSURE OF INVENTION
An object of the present invention is to realize a guardrail having a New Jersey profile, providing a controlled and distributed yielding, and which doesn't transfer excessive stresses to the underlying structure, whereby the guardrail because of its reduced weight (130-150 Kg/m), may also be installed on older type bridges which are not able to resist to excessive loads on the lateral overhangs of the bridge and on the lateral beams.
Another object of the present invention is that of realizing a guardrail which can be assembled at the place where it is installed, without the need of transporting monolithic blocks, and of cranes for lifting the blocks of the guardrail, when said blocks have been brought to the place of installation of the guardrail. Adequate acoustic insulation structures may be introduced inside the guard-rail, if desired, in order to increase the deadening effect which is already produced by the guardrail.
Still another object of the present invention, is to provide stiffening and connecting plates fixed by bolts or the like, to the uprights of the barrier, on their rear sides, and also connecting means which allow a variation of the reciprocal distance of the two neighbouring junction uprights, which variation is due to temperature oscillations.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example only, making reference to the annexed drawings, which show a particular embodiment thereof. Each figure shows individually:
FIG. 1, a transversal cross-sectional view of the New Jersey-guardrail anchored to the kerbstone of the bridge;
FIG. 2, the New Jersey-guardrail anchored to the kerbstone of the bridge, according to a transversal cross-sectional view, at the junction point between two spans of the bridge;
FIG. 3, a rear view of a segment of the New Jersey guardrail, according to the present inventions;
FIG. 4, a rear view of a segment of the New Jersey guardrail, according to the present invention, at the junction point between two spans of a bridge;
FIG. 5a, a lateral view of an upright of the New Jersey guardrail according to the present invention;
FIG. 5b, a rear view of the upright of FIG. 5a;
FIG. 6a, a lateral view of an upright of the guardrail of the present invention, to be installed at the junction point between two spans;
FIG. 6b, a rear view of the upright of FIG. 6a;
FIG. 6c, a rear view of an upright similar to the upright of FIG. 6b, and which is installed in a position adjacent to the latter at the junction point between two spans;
FIG. 7a, a connection plat
REFERENCES:
patent: 2181703 (1939-11-01), McCracken
patent: 3262240 (1966-07-01), Schuman et al.
patent: 3276750 (1966-10-01), Ridder
patent: 4954009 (1990-09-01), Kellison
patent: 4989689 (1991-02-01), Berlin
patent: 5145278 (1992-09-01), Lohrmann
Bruschi Stefano
Camomilla Gabriele
Malgarini Mauro
Autostrade Concessioni e Costruzioni Autostrade S.p.A.
Lisehora James
LandOfFree
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