Roadway/traffic delineator

Abstract

A post designed for sign or guide marker use having sufficient longitudinal rigidity to withstand a force driving it into the ground and sufficient elasticity to permit nondestructive deformation upon impact by a moving object, with subsequent restoration to an original, upright position. Various construction materials .Iadd.including fiber reinforced plastics, .Iaddend.and/or structural configurations are disclosed for obtaining this dual character without incurring high production and material costs.

I claim: .[.1. A delineator having concurrent characteristics of a sufficiently high modulus of elasticity for withstanding buckling loads applied during static conditions along its longitudinal axis during installation and a sufficiently low moment of inertia to establish elastic character in an exposed section of said delineator to permit nondestructive deformation upon impact by a moving object and subsequent immediate restoration to an original, upright orientation, said delineator including: 
     
        to minimize weathering effects thereon..]. .[.12.  A delineator as defined in claim 1, further comprising a removable rigid-body casing for enclosing a portion of said delineator during installation, said casing having sufficient inner surface conformity with said delineator to restrain bending movement of said portion when said driving load is applied..]. .[.13. A delineator as defined in claim 12, wherein said casing further comprises a impactable cap for receiving said driving force and for retaining said casing at an upper portion of said delineator..]. .[.14. A delineator as defined in claim 1, wherein said web structure is laterally contoured with varying web thickness and relative nonplanar web structure to increase moment of inertia and rigidity along said longitudinal axis, said delineator comprising: a nonplanar web including a first longitudinal section of thermosetting resin attached to a second longitudinal section of thermoplastic resin, said first section providing higher elastic modulus for drivability and said second section providing a low moment of inertia and improved transverse flexibility to obtain lateral angular contortion of said delineator during bending to cause a reduction in moment of inertia..]. .[.15. A delineator as defined in claim 14, wherein said nonplanar web is concave in structure having lateral longitudinal sections of thermosetting resin and a central longitudinal section of thermoplastic resin..]. .[.16. A delineator as defined in claim 1, further comprising a network of microspherical voids within said web structure to reduce moment of inertia and provide differentiating response to a static, longitudinal load and a dynamic bending force..]. .[.17. A delineator as defined in claim 1, wherein said web structure is concavo-convex at the forward and rearward faces thereof..]. .[.18. A delineator as defined in claim 17, further comprising longitudinal rib structure at side edges of said web structure, said rib structure adding additional longitudinal rigidity to withstand said buckling loads occurring during installation of said delineator..]. .[.19. A delineator having concurrent characteristics of a sufficiently high modulus of elasticity for withstanding buckling loads applied during static conditions along its longitudinal axis during installation and a sufficiently low moment of inertia to establish elastic character in an exposed section of said delineator to permit nondestructive deformation upon impact by a moving object and subsequent immediate restoration to an original, upright orientation, said delineator including:   an elongate web structure comprising a combination of traversing and longitudinally oriented fibers imbedded in 20 to 40% (w) resin binder, said fiber combination being comprised of at least 7% but not more than 60% fiber in traversing arrangement to provide transverse flexibility and tensile strength, and said longitudinal orientation of fiber comprising the remaining percentage of total fiber content to provide longitudinal   
     
     
        rigidity during said static conditions..]. .[.20.  A delineator including: a web structure of unibody construction having a tapered base to facilitate insertion thereof into a hard surface and being constructed of a material composition substantially uniform along the length of said delineator which develops a modulus of elasticity (E) sufficiently high, when taken in combination with the moment of inertia (I) of said web structure, to develop a maximum buckling load (P E ) in accordance with a delineator length parameter (L) as defined by the relation P E  =(π 2  EI/L 2  wherein the resulting buckling load (P E ) is capable of withstanding an impact force to be applied near the top of a longitudinal axis of said delineator during static installation conditions at said hard surface;   said product of EI being variable in response to deformation of said delineator by a lateral impact force which modifies said geometric structure to decrease the moment of inertia (I) and develop a delineator bending radius (R) as defined by the relationship R=EI/M, wherein M is the bending moment of said delineator, said bending radius being sufficiently low to permit passage of a vehicle over said delineator, said material composition having sufficient elasticity to restore to its upright orientation upon dissipation of said impact force;   said geometric structure comprising a nonplanar impacting surface of said web structure which responds with angular contortion upon occurrence of said impact, thereby decreasing the moment of inertia of said delineator during bending motion, reducing said EI product from a longtudinal rigid structure to a flexible structure during deformation..]. .[.21. A delineator as defined in claim 20, wherein said material composition includes material selected from the group consisting of thermosetting resins, thermoplastic resins and combinations thereof..]. .[.22. A delineator as defined in claim 20, wherein said web structure comprises a planar section with at least one longitudinal rib extending forward therefrom..]. .[.23. A delineator as defined in claim 22, wherein said web structure includes two longitudinal ribs extending forward from the respective sides of said delineator, with a third longitudinal rib extending rearward from a central area of a backside of said delineator..]. .[.24. A delineator as defined in claim 20, wherein the web structure comprises a concavo-convex structure for the front and backside of said delineator..]. .[.25. A delineator as defined in claim 24, further comprising a longitudinal rib to increase longitudinal rigidity..]. .[.26. A delineator as defined in claim 24, wherein longitudinal ribs extend from   
     
     
        sides of said concavo-convex web structure..]. .Iadd.27.  An upright delineator of an impact-resistant, elongate web structure consisting of fiber-reinforced synthetic material for driving into hard ground, characterized in that said structure has concurrent driveability and flexibility characteristics wherein the product of EI (E=elastic modulus; I=moment of inertia) for the delineator is chosen such that it withstands buckling loads supplied at the delineator top during installation and that it establishes elastic character in an exposed section of said delineator to permit non-destructive deformation upon impact to permit passage of a moving vehicle over said delineator and subsequent immediate restoration to an original, upright condition, said elongate web structure comprising a combination of random or transversing and longitudinally oriented fibers embedded in 20 to 40 percent (w) resin binders, said fiber combination being comprised of at least 7 percent, but not more than 60 percent, fiber in random or transversing arrangement to increase tensile strength thereby to enable transverse flexibility, and said longitudinal orientation of fiber comprising the remaining percentage of total fiber content to provide longitudinal rigidity during said static conditions..Iaddend. .Iadd.28. A delineator as defined in claim 27, wherein the selected value of E within the EI product is large to withstand the buckling loads applied along the longitudinal axis, and the selected value of I within the EI product is minimal to improve the bendability of the delineator to 
     
     
        achieve a low radius of curvature..Iaddend. .Iadd.29.  A delineator as defined in claim 27 which is geometrically configured to develop a reversibly variable product of EI by causing a change in the value of I from its value in a static condition to a lower value under dynamic bending conditions such as occur upon lateral impact of the delineator by a moving object, the original value of I being restored following dissipation of impact energy and return of the delineator to its static condition..Iaddend. .Iadd.30. A delineator as defined in claim 27, wherein said web structure is concavo-convex at the forward and rearward faces thereof..Iaddend. .Iadd.31. A delineator as defined in claim 30, further comprising longitudinal rib structure at side edges of said web structure, said rib structure adding additional longitudinal rigidity to withstand said buckling loads occurring during installation of said 
     
     
        delineator..Iaddend. .Iadd.32.  A delineator as defined in claim 27, wherein the web structure includes a planar surface extending along its full length and adapted for installation toward the direction of oncoming traffic along roadside, a said web structure including rib structure formed integrally therewith at each side and protruding slightly forward of the planar surface to extend the thickness of the web structure and thereby increase the moment of inertia for greater longitudinal rigidity needed to withstand driving forces applied during installation of the delineator, the increased thickness being limited to slight protrusion to avoid excessive stress resulting in longitudinal shearing which would otherwise occur during dynamic bending if the extent of protrusion were too great, said rib structure including longitudinal reinforcing fibers to further increase the elastic modulus of the web structure for withstanding a greater driving force applied at the top of the delineator..Iaddend. .Iadd.33. A delineator as defined in claim 32, wherein the product of EI within the delineator rib structure provides the primary load bearing structure required to withstand impacts applied along the length of the delineator at its top during installation; the thinner, more flexible web being the primary load bearing element responsive to stress forces arising during bending contortions occurring upon lateral impact..Iaddend. 
     
     
        .Iadd.  .  A delineator as defined in claim 32, wherein EI of the rib structure during dynamic bending requires the delineator to deform in accordance with a radius of curvature (R) defined by the relationship R=EI/M wherein M is the bending moment applied to the delineator during impact by a vehicle..Iaddend. .Iadd.35. A delineator as defined in claim 34, wherein the radius of curvature is approximately equal to or less than the distance from ground level to the lowest part of the underside of a motor vehicle for which impact is anticipated..Iaddend. .Iadd.36. A delineator as defined in a claim 35, where the radius of curvature is 
     
     
        approximatley 18 inches or less..Iaddend. .Iadd.37.  A delineator as defined in claim 36, wherein the large values of E are achieved by the incorporation of reinforcing, longitudinal fibers along the length of the delineator, the random or transverse fiber being incorporated within the delineator to establish tensile strength and to contribute to the proper balance between rigidity and flexibility..Iaddend. .Iadd.38. A delineator as defined in claim 32, wherein the web and rib structure are geometrically configured to develop a reversibly variable product of EI by causing a change in the value of I from its value in a static condition to a lower value under dynamic bending conditions such as occur upon lateral impact of the delineator by a moving object, the original value of I being restored following dissipation of impact energy and return of the delineator to its static condition, lateral contortion being developed because of the greater flexibility of the thinner web section as compared 
     
     
        to the more rigid ribs..Iaddend. .Iadd.39.  A delineator as defined in claim 38, wherein the reversible change in the value of I results from the combined rib structure and thinner, planar web which are further adapted to deform upon impact by lateral, angular contortion about the longitudinal axis of the delineator toward its neutral axis in a rearward direction, decreasing the value of C in the expression f b  =MC/I, wherein M is equal to the bending moment, C is the distance from the neutral axis to the point of stress, and f b  is the bending stress, said angular contortion further reducing the effective thickness of the delineator cross-section, along with the value of I, and decreasing the bending radius R in accordance with the expression R=EI/M, thereby increasing the flexibility of the delineator in impact, said angular contortion being developed by (i) greater stiffness of the ribs compared to the greater flexibility of the thinner web between said ribs and (ii) higher value of C where the bending stress is measured at the ribs, in view of protrusion of the ribs forward of the planar web surface..Iaddend. 
     
     
        .Iadd.40.  A delineator as defined in claim 38, wherein the reversible change in the value of I results from the combined rib structure and thinner, planar web which are further adapted to deform upon impact by lateral angular contortion of the rib structure about the longitudinal axis of the delineator toward its neutral axis in a rearward direction, decreasing the effective thickness of the delineator cross-section, decreasing the value of I, and developing a reduced bending radius defined by the expression R=EI/M, said angular contortion being developed by (i) greater stiffness of the ribs compared to the greater flexibility of the thinner web between said ribs and (ii) higher value of C where the bending stress is measured at the ribs, in view of protrusion of the ribs forward 
     
     
        of the planar web surface..Iaddend. .Iadd.41.  A delineator as defined in claim 32 wherein the delineator further comprises an additional protruding rib located on an opposing side of the web structure from the planar surface adapted to face the oncoming traffic and extending rearward of the delineator, said rearward rib being formed integrally with the web structure and being limited to slight protrusion therefrom to avoid excessive stress which would otherwise result in longitudinal shearing and destructive deformation during dynamic bending of the delineator, said slightly protruding rib providing additional thickness to the web structure, thereby increasing the value of I; said rearward rib structure further including longitudinal reinforcing fibers to provide increased value of elastic modulus for withstanding a greater driving load at the top of said delineator..Iaddend. .Iadd.42. A delineator as defined in claim 41 wherein the rearward rib is centrally   
     
     
        located at the rearward side of the web structure..Iaddend. .Iadd.43.  A delineator as defined in claim 41 wherein EI of the rib structure during dynamic bending requires the delineator to deform in accordance with a radius of curvature (R) defined by the relationship R=EI/M wherein M is the bending moment applied to the delineator during impact by the vehicle..Iaddend. .Iadd.44. A delineator as defined in claim 41, wherein the opposing side of the web structure comprises a second planar surface 
     
     
        from which the rearward rib protrudes..Iaddend. .Iadd.45.  A delineator as defined in claim 44 wherein the rearward rib is centrally located at the rearward side of the web structure..Iaddend. .Iadd.46. A delineator as defined in claim 44, wherein the reversible change in the value of I results from the combined rib structure and thinner, planar web which are further adapted to deform upon impact by lateral angular contortion of the rib structure about the longitudinal axis of the delineator toward its neutral axis in a rearward direction, decreasing the effective thickness of the delineator cross-section, decreasing the value of I, and developing a reduced bending radius defined by the expression R=EI/M, said angular contortion being developed by (i) greater stiffness of the ribs compared to the greater flexibility of the thinner web between said ribs and (ii) higher value of C where the bending stress is measured at the ribs, in view of protrusion of the ribs from the planar web surfaces..Iaddend.