Combined guardrail and cable safety systems

A combined guardrail and cable safety system is disclosed. In one aspect, a safety barrier incorporating the teachings of the present disclosure may include a plurality of cable posts spaced from each other and disposed adjacent to a roadway. At least two cables may be releasably engaged with and supported by the cable posts. The cable posts and the at least two cables may cooperate with each other to prevent a vehicle from leaving the roadway. A plurality of guardrail posts may also spaced from each other and disposed adjacent to the roadway longitudinally spaced from the plurality of cable post. A box beam guardrail beam may be attached to the plurality of guardrail posts. The at least two cables may operably extend from the cable posts to engage respective cable anchor brackets attached to the box beam guardrail beam.

TECHNICAL FIELD

The present disclosure is related to highway barriers and safety systems and more particularly to combined guardrail and cable safety systems and associated posts.

BACKGROUND OF THE DISCLOSURE

Guardrails are traffic barriers placed along roadsides to screen errant vehicles from hazards behind the barrier. A common guardrail in the U.S. is constructed using a standard steel W-beam or three-beam mounted on spaced wood or steel posts. Alternative guardrail installation designs incorporate a box beam rail member wherein the rail member may be a tubular beam member having a square or rectangular cross-section. Box beam guardrails are often popular in geographical locations that receive significant amounts of snow, as the use of box beam guardrails permits wider support post spacing and greater ground clearance as compared to W-beam and three-beam rail systems, and thus may reduce snow drift problems.

Another type of highway safety device is cable safety systems and cable barriers, which have been installed along edges of roadways and highways for many years. Cable safety systems and cable barriers have also been installed along medians between roadways and/or highways. Cable safety systems generally include one or more horizontal cables attached to support posts. For some applications cable safety systems and cable barriers may reduce damage to an impacting vehicle and/or injury to occupants of the impacting vehicle as compared with other types of highway safety systems and highway barriers.

Cable safety systems are often designed and installed with at least one cable mounted horizontally on a plurality of generally vertical support posts. The number of cables may vary depending on various factors such as the type of vehicles using the associated roadway and the hazard which required installation of the cable safety system. The length of a cable safety system is generally determined based on the adjacent roadside hazard. Each cable is typically installed at a selected height relative to the ground and with selected vertical spacing between adjacent cables. Associated support posts are installed with desired horizontal spacing between adjacent posts.

One recognized limitation of many cable safety systems is excessive deflection of associated cables during a vehicle impact. Deflection associated with a cable safety system may be larger than deflection of a conventional guardrail when subjected to the same type of vehicle impact. Such deflection frequently determines maximum allowed spacing between adjacent posts for satisfactory performance of the cable safety system. Large deflection during a vehicle impact also increases the risk of the vehicle running over the cables and being exposed to the hazard that required installation of the cable safety system. Calculating performance of many cable safety systems is often difficult due to unpredictable interactions between associated posts and cables during a vehicle impact. Depending upon car type, speed and angle of impact, cables may release as far as ten (10) or most posts spaced ahead of the impact location. Cable release from posts often causes much larger deflections than expected or calculated.

From full scale crash testing and from real life experience, it has been determined that keeping the length of unsupported cables as short as possible will generally reduce deflection. The longer the distance between adjacent posts supporting associated cables, the larger the deflection will generally be during a vehicle impact. An increased number of posts (shorter post spacing) will generally decrease deflection. However, shorter spacing between posts affects total cost of a cable safety system, not only material, but also installation cost.

During the past several years, cable safety systems have been used as an alternative to traditional guardrail systems. These cable safety systems address some of the weaknesses of prior cable safety systems by using pre-stretched cables and/or reducing spacing between adjacent posts to reduce deflection to an acceptable level. A consultant report “Dynamic Analysis of Cable Guardrail” issued in April 1994 by an ES-Consult in Denmark, established a model for various parameters, which affect performance and design considerations for acceptable deflection of cable safety systems.

Standards have been developed within the European standardization body, CEN (Commite Europeen de Normalisation), for impact tests performed on safety systems and barriers. These barrier impact tests are described in CEN 1317, Road Restraint Systems. According to the CEN standards, safety systems and barriers are to be impact tested at different containment levels. The elongation or deformation of a barrier is also measured to determine a safe working width. The environment in which the barrier is to be constructed generally determines appropriate containment level as well as permissible working width. The CEN standard generally requires that the risk of injury in a collision with the barrier is minimized (injury risk class). CEN standards are used in the European countries and several countries near Europe, among others.

NCHRP stands for the National Cooperative Highway Research Program, a program developed by the Transportation Research Board of the National Research Council, USA. Report 350 is entitled “Recommended Procedures for the Safety Performance Evaluation of Highway Features” and may be commonly referred to as the NCHRP 350 Standard. The standard describes how impact tests should be conducted. Test results may be used to determine elongation or deformation and safe working widths. This standard is used mainly in the USA and is predominately used in Australia and New Zealand.

SUMMARY OF THE DISCLOSURE

In accordance with teachings of the present disclosure, a combined guardrail and cable safety system is provided which may overcome many disadvantages and problems associated with prior guardrail safety systems, cable safety systems and cable barriers.

According to one embodiment of the present disclosure, a safety barrier incorporating the teachings of the present disclosure may include a plurality of cable posts spaced from each other and disposed adjacent to a roadway. At least two cables may be releasably engaged with and supported by the cable posts. The cable posts and the at least two cables may cooperate with each other to prevent a vehicle from leaving the roadway. A plurality of guardrail posts may also spaced from each other and disposed adjacent to the roadway longitudinally spaced from the plurality of cable post. A box beam guardrail beam may be attached to the plurality of guardrail posts. The at least two cables may operably extend from the cable posts to engage respective cable anchor brackets attached to the box beam guardrail beam.

According to another embodiment of the present disclosure, a method of forming a combined guardrail and cable safety system is provided. At least one cable from a cable safety system set along a roadway may be extended. The at least one cable may be operable to engage a portion of a guardrail safety system. A first end of the at least one cable may be secured with a cable anchor bracket coupled to a box beam rail that forms part of the guardrail safety system.

According to a further embodiment of the present disclosure, a combined guardrail and cable safety system may include a guardrail safety system extending along a roadway, the guardrail safety system having a plurality of guardrail posts. Each guardrail post may be operably coupled to a box beam guardrail beam. The system may also include at least one cable extending from a cable safety system and at least one cable anchor bracket fastened to a portion of the guardrail safety system. The at least one cable anchor bracket may be operable to receive and secure the at least one cable such that sufficient tension is applied to the respective cable.

According to yet another embodiment of the present disclosure, a safety barrier may include a plurality of cable posts spaced from each other and disposed adjacent to a roadway. Three cables may be releasably engaged with and supported by the cable posts. The cable posts and the cables may cooperate with each other to prevent a vehicle from leaving the roadway. The safety barrier may also include a plurality of guardrail posts spaced from each other and disposed adjacent to the roadway. The plurality of guardrail posts may be spaced from the plurality of cable posts. A plurality of box beam guardrail beams may be coupled to the plurality of guardrail posts. The guardrail posts and the box beam guardrail beams may cooperate with each other to prevent a vehicle from leaving the roadway. The first end of each cable may engage with a respective cable anchor bracket attached to a portion of the safety barrier system.

According to yet another embodiment of the present disclosure, a cable anchor bracket for use in a safety barrier system may include an elongated member having an inward side and an outward side. A first flange and a second flange each may be formed substantially perpendicular to and on the inward side of the elongated member. The elongated member, the first flange, and the second flange may be sized and configured to be attached to a box beam guardrail beam.

Technical benefits of the present disclosure include providing a combined box beam guardrail and cable safety system that maintains adequate barrier protection during a transition between cable and box beam guardrail safety systems. Because the cables may be coupled directly to associated guardrail beams, the cable may have adequate tension adjacent to the junction between the cable system and the guardrail system. Additionally, attaching the cables directly to the beams may transfer forces from an impacting vehicle to both the cable safety system and the guardrail safety system.

Additional technical benefits of the present disclosure include a combined guardrail and cable safety system that has cables with less tension and greater spacing between associated support posts. Due to the transition between the cable safety system and the box beam guardrail safety system, the combined guardrail and cable safety system maintains satisfactory deflecting characteristics.

Further technical benefits of the present disclosure include an economical design and the employment of component parts. Repairs or replacement of damaged components may often be more easily accomplished after a vehicle impact due to each component's design. The need for periodic re-tensioning of cables may be reduced or eliminated by the present disclosure.

Further technical benefits of the present disclosure include a flexible transition junction between a box beam guardrail safety system and cable safety system. Because cables extending from the cable safety system may be attached with associated guardrail beams, a smoother transition is possible from the cable the system to the guardrail safety system. Thus, designers have more flexibility in design and installation of cable and/or guardrail safety systems as determined by specific highway and roadway conditions.

The present disclosure allows differences in design and performance of cable and guardrail safety systems to be combined into an appropriate safety system for a wide variety of highways and roadways. The present disclosure provides a smooth transition between a box beam cable safety system and a guardrail safety system. The present disclosure provides a combination of guardrail and cable safety system designs which assists in joining or bridging the two safety systems.

All, some, or none of these technical advantages may be present in various embodiments of the present disclosure. Other technical advantages will be apparent to one skilled in the art from the following figures, descriptions, and claims.

DETAILED DESCRIPTION OF THE DISCLOSURE

Preferred embodiments of the disclosure and its advantages are best understood by reference toFIGS. 1 through 14wherein like reference numbers indicate like features.

The terms “safety system” or “safety systems” and “barrier” or “barriers” may be used throughout this disclosure to include any type of safety system and/or barrier which may be formed at least in part using cables, guardrails and support posts incorporating teachings of the present disclosure. The term “roadway” may be used throughout this disclosure to include any highway, roadway or path satisfactory for vehicle traffic. Safety systems and barriers incorporating teachings of the present disclosure may be installed in median strips or along shoulders of highways, roadways or any other path which is likely to encounter vehicular traffic. The term “upstream” may be used throughout this disclosure to refer to the direction from which an impacting vehicle would be expected to approach. The term “downstream” may be used throughout this disclosure to refer to the opposite direction, i.e., the direction toward which an impacting vehicle would be expected to travel.

Various aspects of the present disclosure will be described with respect to combined guardrail and cable safety systems15. However, teachings of the present disclosure may be used to form a wide variety of safety systems and barriers.

Referring toFIGS. 1 and 2, combined guardrail and cable safety systems15may be installed adjacent to a roadway (not expressly shown) to prevent motor vehicles (not expressly shown) from leaving the roadway and to redirect vehicles away from hazardous areas without causing serious injuries to the vehicle's occupants or other motorists.

Combined guardrail and cable safety system15may be satisfactorily used as a median, a single barrier installation along the edge of a roadway and at merge applications between adjacent roadways. For some applications, combined guardrail and cable safety systems15may satisfactorily withstand a second impact before repairs have been made after a first impact. For many applications, combined guardrail and cable safety systems15may be described as generally maintenance free except for repairs required after a vehicle impact.

Combined guardrail and cable safety system15may include a plurality of support posts for cables, namely cable posts30, and support posts for guardrail beams, namely posts20, that are anchored adjacent to the roadway. Posts20and30may be anchored with the ground using various techniques. As shown inFIG. 1, concrete foundation32may be provided with holes to allow relatively quick and easy insertion and removal of cable posts30. The number, size, shape and configuration of posts20and30may be significantly modified within teachings of the present disclosure. Optimum spacing between posts20and30may be designed in accordance with teachings of the present disclosure.

Guardrail beams24may be mounted on a plurality of posts20using bolt23and angle bracket22(as depicted inFIG. 6). Posts20may be made from wood, metal or other suitable types of material satisfactory for highway safety systems. The types of material which may be satisfactorily used to manufacture posts with the desired strength and/or breakaway characteristics appropriate for a specific guardrail system, location of each post and roadside hazard include, but are not limited to, wood, metal (e.g., steel), composite materials and other various types of plastics. In the depicted embodiments, posts20may comprise I-beam posts. Posts20may be connected to guardrail beam24adjacent to the roadway facing the oncoming traffic. Guardrail beams24may couple directly to posts20but may also include a block out structure (not expressly shown) disposed between post20and guardrail beam24. When used, block outs may provide a lateral offset between a respective post20and guardrail beam24during a rail-face impact. The distance and direction of such lateral offsets may be selected to prevent the wheels (not shown) of a vehicle from striking one or more posts during a rail face impact.

In one particular application, posts20may be installed in foundation tubes (not shown). Other applications, for example in flared end terminals, two (2) posts20may be installed in the foundation tubes. The remaining posts may be installed adjacent to the highway without the use of any foundation tubes as such they are buried directly in the ground.

The total length of guardrail beam24measured from leading edge to trailing edge may be approximately twenty-five (25) feet. Other lengths of guardrail section including, but not limited to one-half lengths, or twelve and one-half foot members, may also be provided within teachings of the present disclosure. The overall geometry of guardrail beam24may allow combining guardrail beam24and conventional or standard box beam guardrails within a single guardrail system, to maintain the benefits described herein. Accordingly, guardrail beams24may be incorporated into existing guardrail systems as needed, and an entire retrofit of any particular guardrail system may not be required in order to recognize the benefits of the present disclosure. In fact, the overall geometry of guardrail beam24may be configured to accommodate a close fit between conventional or standard box beam guardrails.

Guardrail beam24, formed in accordance with teachings of the present disclosure, provides improved safety performance and protection of the general public. Recently, increased interest in the need for more stringent safety requirements has culminated in the issuance of the National Cooperative Highway Research Program Report 350 (NCHRP 350). The performance standards of NCHRP 350 require all new safety hardware to be tested with larger vehicles than required by previous standards. NCHRP 350 evaluates all safety hardware within three areas: structural adequacy, occupant risk, and vehicle trajectory. Each area has corresponding evaluation criteria. The Federal Highway Administration (FHWA) officially adopted these new performance standards and has ruled that all safety hardware installed after August of 1998 will be required to meet the new standards.

Various types of guardrail beams, cables and/or wire ropes may be satisfactorily used to form a combined guardrail and cable safety system15in accordance with teachings of the present disclosure. Cables34,36and38, as shown inFIGS. 3A and 3B, may be substantially identical. However, for some applications each cable of safety system15formed in accordance with teachings of the present disclosure may have different characteristics. Cable safety systems may be described as flexible, substantially maintenance free systems with designed low deflection of cables34,36and38during a vehicle impact. In some embodiments of the present disclosure, cable safety systems may minimize damage during a vehicle impact with posts30and/or cables34,36and38.

Guardrail end terminal assembly21may be provided to minimize or eliminate the potential for a serious accident from a head on collision with the end of guardrail safety system facing oncoming traffic. As such, the present disclosure may be used with either energy absorbing end terminals or non-energy absorbing end terminals. In some embodiments, guardrail end terminal assembly21may include kinetic energy absorbing assembly (not expressly shown) which may prevent guardrail safety system from piercing the vehicle and passenger compartment or causing a vehicle to either roll over or vault the guardrail safety system. In the event of a collision between a vehicle and the end of the guardrail safety system, a kinetic energy absorbing assembly may dissipate the impact energy of the vehicle without creating an unduly dangerous condition.

Guardrail end terminal assembly21may include post21connected by cross member21b. Post21aand cross member21bmay be made from wood or other suitable types of breakaway material. The types of material which may be satisfactorily used to manufacture posts with desired strength and/or breakaway characteristics appropriate for the specific guardrail system, location of each post and roadside hazard include but are not limited to wood, steel, composite materials and various types of plastics.

Various guardrail designs and end terminal assemblies have been developed to minimize consequences resulting from impact between a vehicle and the end of a guardrail. These designs include tapering the end of the guardrail into the ground to eliminate potential contact with the end of the guardrail. Other types of end terminal assemblies include breakaway cable terminals (BCT), slotted rail terminals (SRT), sequential kinking terminals (SKT), vehicle attenuating terminals (VAT), end terminal assemblies (ET), flared end terminals (FET) including flared energy absorbing terminals (FLEAT), the Sentre end treatment, and breakaway end terminals (BET).

It is desirable for guardrail end terminal assembly21to be usable at either end of a guardrail as a means of both attenuating a head on impact as well as providing an effective anchor for an impact along the side of the guardrail downstream from the end terminal assembly. Examples of such end terminal assemblies are shown in U.S. Pat. No. 5,391,016 entitled “Metal Beam Rail Terminal”, and U.S. Pat. No. 7,185,882 entitled “Box Beam Terminals”.

FIG. 4Ais an enlarged schematic drawing showing an isometric view with portions broken away of cable post30and cables34,36and38incorporating teachings of the present disclosure. As shown in this embodiment of the present disclosure, cable post30may include a generally C-shaped cross section defined in part by web43with respective legs44and45extending therefrom.

Typically, the extreme edges of each leg44and45opposite from attached web43may be rounded or bent inward to eliminate any sharp edges being exposed. Cable post30may have a “rounded” or “soft” profile. For some applications, cable post30may be formed using roll forming techniques.

Slot40may be formed in web43extending from first end31atowards second end31b(as shown below in more detail). The length of slot40may be selected in part based on desired vertical spacing of cable38relative to the adjacent roadway. The length of slot40may also be selected to accommodate the number of cables which may be installed therein and desired vertical spacing between each cable. Slot40may have a generally elongated U-shaped configuration defined in part by first edge41, second edge42and bottom47(shown below in more detail). In some embodiments, first edge41and second edge42may have a generally smooth profile and extend generally parallel with each other. Forming slot40within web43of cable post30may eliminate requirements for bolts, hooks or other mechanical attachments to releasably secure cables34,36and38with cable post30.

For some applications, cable post30may be formed from metal sheet having a thickness of 4 millimeters, a length varying approximately from 700 millimeters to 1,600 millimeters and a width of approximately 350 millimeters. The metal sheet may weigh approximately 7.8 kilograms per meter (kg/m). For other applications, cable post30may be formed from a metal sheet having a thickness of 4 millimeters, a length varying approximately from 700 millimeters to 1,600 millimeters, a width of approximately 310 millimeters and a weight of less than 4.5 kg/m.

In some aspects, cable post30may be installed in a tube sleeve (not expressly shown) that is driven directly into the soil.

One aspect of the present disclosure includes forming one or more restrictions within slot40to help retain associated cables within the respective slot when a vehicle impacts the associated safety barrier. Cable post130as shown inFIG. 4Bmay retain cables34,36and38within slot40aby restrictions formed along edges41aand42a. As a result of the restrictions formed within slot40a, cables34,36and38may be retained within slot40awhen cable post130impacted by a vehicle and is bent at an angle from vertical, which typically causes the release of cable34,36and38from slot40of cable post30.

FIG. 4Bis an enlarged schematic drawing showing another example of cable post130having slot40aform thereon with a plurality of restrictions and/or projections formed in each edge41aand42a. For the embodiment of the present disclosure as shown inFIG. 4Bthe location and configurations of the restrictions formed in edges41aand42amay be selected to correspond generally with the desired location for associated cables34,36and38.

Restrictions61,62and63of slot40amay be defined in part by respective projections61a,61b,62a,62b,63a,63band bottom47a. Edges41aand42aof slot40amay include alternating tapered or sloping surfaces which form respective projections61a,61b;62a,62band63a,63b. The same tapered or sloping surfaces also form respective enlarged openings70a,70band70cwithin slot40a. The location of enlarged openings70a,70band70cmay be selected to correspond with approximate desired locations for cables34,36and38. The gap or spacing formed between respective projections61aand61b,62aand62band63aand63bis generally selected to be greater than the outside diameter of cables34,36and38.

Specific dimensions between the respective projections are selected to provide optimum resistance to disengagement between cables34,36and38as cable post130with slot40ais bent from a generally vertical position towards a horizontal position and still allow easy installation of cables34,36and38in slot40a.

FIG. 5is a schematic drawing in elevation with portions broken away showing one example of cable post30and attached cables34,36and38incorporating teachings of the present disclosure. Respective cap49may be placed on first end31of each cable post30. Retaining band or bands49amay be placed on the exterior of one or more cable posts30to provide additional strength. Cap49and retaining bands49amay be formed from various types of metals, elastomeric materials and/or composite materials.

For some applications, retaining band49amay be formed from a relatively strong steel alloy to provide additional support to allow cable post30to handle forces imposed on edges41and42by cables34,36and38during a vehicle impact with combined guardrail and cable safety system15, cable38may be disposed within slot40resting on bottom47therein. Since cable post30has a partially closed cross section defined in part by the bend or rounded edges of legs44and45, a relatively simple first spacer46may be inserted or dropped into cable post30to rest on cable38opposite bottom47. Spacer46may be a block having a generally rectangular configuration with a thickness satisfactory for insertion within the cross section of cable post30. The height of spacer46may be selected to correspond with desired vertical spacing between cables38and36.

Cable36may be inserted into slot40after spacer46has been disposed onto cable38. Spacer48may then be installed within slot40with one end resting on cable36opposite from the spacer46. The height of spacer block48may be selected to correspond with desired vertical spacing between cables36and34. Spacer48may be a block having a generally rectangular configuration with a thickness satisfactory for insertion within the cross section of cable post30.

Cable34may then be installed within slot40resting on spacer48opposite from cable36. One or more retaining bands49amay be secured with the exterior of cable post30between cables34and36and/or cables36and38. Cap49may be placed over first end31of cable post30after installation of cables34,36and38and spacers46and48.

For some applications, second end32aof each cable post30may be installed in concrete foundation32or footing (not expressly shown). In other applications, a flip plate (not expressly shown) may be attached to second end32aof each cable post30for use in bolting or otherwise securely attaching cable post30with a larger flip plate (not expressly shown) that has been cast into a concrete foundation or similar structure adjacent to a roadway. Alternatively, second end32amay be inserted directly into the ground. One or more soil plates (not expressly shown) may be attached to cable post30proximate respective second ends32awhen cable post30are installed directly into the ground adjacent to a roadway.

In other embodiments of the present disclosure, cable safety system may be formed using a low-tensioned cable system such as cable systems including I-beam posts and hook bolts (not expressly shown).

FIG. 6is a schematic drawing taken along lines6-6ofFIG. 2. In one embodiment, post20may be coupled to and support guardrail beam24using bolt23and angle bracket22. Cables34,36and38may be run longitudinally with guardrail beam24. As illustrated, cables34,36and38may extend from cable safety system to run near one or more faces of guardrail beam24. For example, cable34may run near the top of beam24, cable36may run near the side of beam24facing traffic, and cable38may run near the bottom of beam24. Also as depicted, cable anchor bracket assemblies50, each configured to receive one of cables34,36and38, may be coupled to guardrail beam24, as shown in greater detail inFIG. 9.

FIG. 7is a schematic drawing taken along lines7-7ofFIG. 2. Cables34and36are shown running longitudinally with guardrail beam24. As illustrated, cable38is not shown, as it is coupled to a cable anchor bracket assembly50upstream of lines7-7ofFIG. 2.

FIG. 8is a schematic drawing taken along lines8-8ofFIG. 2. As depicted, cables34,36and38may be terminated into a cable anchor bracket assembly50at different locations along guardrail beam24. For example, as illustrated inFIGS. 1,2and3A and3B, cables34and36may be attached along other sections of combined guardrail and cable safety system15such that cable38is the remaining cable to be coupled to guardrail beam24via a cable anchor bracket assembly50, as shown inFIG. 8. Accordingly, cables36and38are not shown inFIG. 8, as they may be coupled to cable anchor bracket assemblies50upstream of lines8-8ofFIG. 2.

As depicted inFIGS. 1,2,3B,6,7, and8, brackets50may be attached to guardrail beam24such that each cable34,36, and38terminates adjacent to a different face of guardrail beam24. For example, cable34may terminate adjacent to the top face of guardrail beam24, cable36may terminate adjacent to the lateral face of guardrail beam24facing traffic, and cable38may terminate adjacent to the bottom face of guardrail beam24.

FIG. 9is an enlarged schematic drawing showing an isometric view of an example embodiment with portions broken away of combined guardrail and cable safety system15and cable anchor bracket assembly50incorporating teachings of the present disclosure. Cable anchor bracket assembly50may include cable anchor bracket80that is attached to the top, bottom or side face of guardrail beam24.

Cable anchor bracket80may include elongated member81having a first flange84and a second flange86. Each of first flange84and second flange86may be formed substantially perpendicular to elongated member81, and may be configured to attached cable anchor bracket80to guardrail beam24. Elongated member81, first flange84and second flange86may cooperate with each other to define a generally U-shaped cross section sized to receive guardrail beam24.

First flange84and second flange86may each include holes91and may be used to couple cable anchor bracket80to guardrail beam24via bolts93extending through guardrail beam24and secured with washers94and nuts92. Bolts93and nuts94may be arranged longitudinally along guardrail beam24to mount and couple cable anchor bracket80thereto. Although the present embodiment is illustrated with two washers94, the present disclosure may be practiced with more or less number of washers including but not limited to various types of washers such as a flat washer or a lock washer. In the some embodiments of the present disclosure, bolts93may be hex bolts. However, bolts93may include a variety of fastening devices such as carriage bolts, rivets, screws or any other type of connector.

Cable anchor bracket80may include cable receiving channel82coupled to elongated member81. Cable receiving channel82may have a first channel member74and second channel member76formed adjacent and longitudinally to elongated member81. First channel member74and second channel member76may be substantially parallel to each other and substantially perpendicular to elongated member81. Cable channel82may also include third channel member73formed adjacent and longitudinally to each of first channel member74and second channel member76. Cable channel82may also include plate85formed perpendicular to each of first channel member74, second channel member76, and third channel member73. Plate85may be configured to engage cable34,36or38. As depicted, first channel member74, second channel member76, third channel member73, plate85, and elongated member81may cooperate with each other to form cable channel82with openings71and87. In certain embodiments, cable channel82may have a generally square- or rectangular-shaped cross section.

As illustrated, an end of cable36may inserted through bracket channel82formed in cable anchor bracket80for attachment to cable anchor bracket assembly50. The end of cable36may extend into opening71of cable anchor bracket80that is mounted onto guardrail beam24and may feed through opening87of plate85for attachment to cable anchor bracket80. Threaded cable termination88may be provided on an end portion of cable36to allow for connection to cable anchor bracket assembly50. Once extended through opening87, a washer94and nuts89may be used in conjunction with threaded cable termination88and plate85to fasten cable36to cable anchor bracket80. In some embodiments, cable tension of cable38may be adjusted by turning nuts89against washer94adjacent to plate85. Cable anchor bracket assembly50and the respective attachments and cables of the present disclosure may meet National Highway Safety requirements and allow reducing the manufacturing costs of the associated connections and mountings as compared with other end terminal assemblies.

As shown inFIG. 9, in some embodiments opening71may be angled such that edge71bformed by third side73may be located downstream relative to edge71aformed by elongated member81, and the edges71cand71dof opening71formed by each of first side74and second side76may be appropriately tapered or angled from edge71ato edge71b. In certain embodiments, the angle formed by an imaginary line substantially parallel to elongated member81and each of edge71cand71dmay be approximately 30 degrees. This manner of angling opening71in a downstream manner may reduce the likelihood of an impacting vehicle snagging or catching on cable anchor bracket50, thus potentially reducing damage to the impacting vehicle or injury to the occupants thereof.

FIG. 10Aillustrates a cross-sectional upstream view of the cable anchor bracket80bolted to a guardrail beam24incorporating teachings of the present disclosure.FIG. 10Billustrates a cross-sectional downstream view of the cable anchor bracket80bolted to a guardrail beam24incorporating teachings of the present disclosure. In some embodiments, cable anchor bracket80may form a generally rectangular cross-section to allow for the insertion of end of cable34,36and38having a end terminal connections such as threaded cable termination88mounted on the end of the cable for attaching the cable to the assembly.

As shown, first flange84may extend along the same direction and same angle as a first face95of guardrail beam24to allow bolts93to extend therethrough and couple using nut92and washer94. Similarly, second flange86may extend along the same angle as a second face96of guardrail beam24for coupling using bolt93with washers94and nut92. In some embodiments, first face95and second face96may be substantially parallel to each other. Depending on design criteria, cable anchor bracket80may include more or less mounting bolt connections.

FIG. 11is a schematic drawing in section showing one example of a cable60satisfactory for use in forming a cable safety system in accordance with teachings of the present disclosure. For some applications cables34,36and38may be formed from seven strand wire rope. Other types of wire ropes and cables may also be used. A plurality of cables34,36and38may be attached to support posts30in accordance with teachings of the present disclosure. Support posts30may maintain associated cables34,36and38in substantially horizontal positions extending along an edge of the roadway. Support posts30may allow relative quick and easy repair of combined guardrail and cable safety systems15after a vehicle impact.

Cable safety systems may be relatively narrow as compared to conventional W-beam, three beam, and box beam guardrail systems. The length of cables34,36and38may extend up to 3,000 meters from below-ground anchor100. For other applications the length of cable34,36and38may exceed 3,000 meters without an intermediate anchorage. Cable posts30may maintain desired vertical spacing between cables34,36and38and desired vertical spacing of each cable relative to the ground. Cable safety system including cable posts30formed in accordance with teachings of the present disclosure may be designed in accordance with teachings of the present disclosure to meet or exceed the criteria of NCHRP Report 350 Test Level 3 requirements.

Cables34,36and38may be disposed in slot40of each cable post30. Each cable34,36and38may be disposed at different heights relative to the ground and relative to each other. Varying the vertical spacing between cables34,36and38may provide a much wider lateral catch area for vehicles impacting with combined guardrail and cable safety system15. The vertical spacing between cables34,36and38may be selected to satisfactorily contain both pickup trucks and, to some extent, even larger vehicles with a relatively high center of gravity, as well as vehicles with a low front profile and low center of gravity.

Cables34,36and38may be prefabricated in approximately three hundred (300) meter lengths with desired fittings attached with opposite ends of each cables34,36and38. Tailor made cables34,36and38may then be delivered to a desired location for installation adjacent to a roadway.

Alternatively, cables34,36and38may be formed from a single cable stored on a large drum (not expressly shown). Cables stored on drums may often exceed three thousand (3,000) meters in length. Cables34,36and38may be cut in desired lengths from the cable stored on the drum. Appropriate fittings (not expressly shown) may be swaged or otherwise attached with opposite ends of the respective cable34,36and38at an onsite location. In one embodiment, cables34,36and38may be installed between below ground anchors100and cable anchor bracket assembly50with approximately twenty thousand Newtons of tension over a length of approximately three thousand (3,000) meters.

Cable60as shown inFIG. 11may be formed from three groups of seven strand wire rope. Cable60may be used in forming combined guardrail and cable safety system15. Cable60may have a modulus of elasticity of approximately 8,300 kilograms (kg) per square millimeter (mm). The diameter of each strand used to form cable60may be approximately three (3) mm. The diameter of cable60may be approximately nineteen (19) mm. Cable60may be pre-stretched to approximately fifty percent (50%) of designed or rated breaking strength. One or more cables60may be used to replace cables34,36, and/or38of combined guardrail and cable safety system15.

FIG. 12shows one example of below-ground anchor100which may be satisfactorily used with a combined guardrail and cable safety system15incorporating teachings of the present disclosure. Below-ground anchor100may be set approximately ten feet from cable post30. Respective holes107may be formed in the ground at desired locations for below-ground anchor100. A portion of each hole107may be filled with concrete foundation108.

Anchor plate109may be securely engaged with concrete foundation108using various types of mechanical fasteners, including, but not limited to, a plurality of bolts, such as concrete anchor bolts103, and nuts104. Anchor plate109may be formed at an appropriate angle to accommodate the design of combined guardrail and cable safety system15. Also multiple slots and/or openings (not expressly shown) may be formed in anchor plate109to receive respective threaded cable termination102extending from each cable34,36and38.

For the embodiment of the present disclosure as shown inFIG. 12, threaded cable termination102of cable32may be engaged with anchor plate109. Threaded cable termination102may use nuts104to coupled on both sides of anchor plate109to maintain a fixed position in relation to anchor plate109. Various types of anchor assemblies and cable end fittings such as threaded cable termination102may be satisfactorily used with a combined guardrail and cable safety system incorporating teachings of the present disclosure. The present disclosure is not limited to below-ground anchor100or threaded cable termination102as shown inFIG. 12.

FIG. 13is an enlarged schematic drawing showing an isometric view with portions broken away of one embodiment of cable post30asatisfactory for use with a combined guardrail and cable safety system incorporating teachings of the present disclosure. Cable posts30amay be interchangeable with cable posts30. Cable posts30amay be associated with various types of mounting structures such as a foundation tube such as concrete tube32or a soil plate (not expressly shown) for direct placement in the ground.

As shown inFIG. 13, cable post30amay include a generally I-beam cross section defined in part by web111. Connecting flanges113and114are formed on opposite ends of web111such that flanges113and114generally extend perpendicular to web111. Typically, flanges113and114are arranged substantially parallel to each other allowing cables34,36and38to couple to flanges113and/or114at respective heights from the ground level. As such, flanges113and114may be mounted and/or installed parallel to a highway or roadway (not expressly shown).

In order to maintain or alter the position of cables34,36and38, with respect to ground level, cable post30amay further include cable retainers115. Each cable retainer115may be associated with a respective cable34,36and38to maintain its position relative to ground level on cable post30a. Cable retainers115may include a variety of attachment retainers such as u-bolt clamps, cable clamps or other mechanical devices that may retain cable34,36or38to cable post30a. In one embodiment, cable retainer115includes cable lock bolt117and nut116that fasten respective cables34,36and38at associated openings112.

Openings112are typically formed in cable post30aalong the edges of flanges113and114. As shown in the embodiment, two openings112are formed to receive respective ends of cable lock bolt117such that nut116attaches to at least one end of cable lock bolt117to couple one of cables34,36or38to cable post30a. Openings112are generally formed in columnar groups such that cable height may be varied based on the selection of different openings112.

For example, six openings112may be formed in a substantially columnar group extending from top110of cable post30atoward ground level along one edge of cable post30a. By associating cable retainer115with two openings112near top110, cable34may couple to cable post30aat a respective position from ground level. Alternatively, cable retainer115may be associated with lower openings112for coupling cables36or38to a position closer to ground level.

FIG. 14shows one example of cable terminal assembly118, which may be satisfactorily used with a combined guardrail and cable safety system incorporating teachings of the present disclosure. In addition to below-ground anchor100, cable terminal assembly118may also be used to terminate a cable safety system.

As shown in the example embodiment, cable posts30bmay couple to foundation tubes such as concrete tubes32such that cable posts30bmay be formed as breakaway posts. Cables34,36and38may be attached to respective cable posts30band may be secured with cable bracket post assemblies120. Each cable post30bmay be associated with one cable bracket post assembly120that secures a respective cable. For example, in a cable safety system having three cables, cable terminal assembly118may include three cable post30beach used to secure one of the three cables.

Each cable34,36and38may include a cable termination such as threaded cable termination125that permits cable34,36and38to couple to their respective cable posts30b. Threaded cable termination125of each cable may extend through an slot or opening (not expressly shown) in cable post30ballowing for connection to cable bracket post assembly120. Cable bracket post assembly120may include bracket123, washer122and nuts121.