Patent Publication Number: US-2023159744-A1

Title: Polymer blend cradle for cable-stayed bridge

Description:
TECHNICAL FIELD/FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to structural construction components and specifically to cradles for cable stayed bridges. 
     BACKGROUND OF THE DISCLOSURE 
     Cable-stayed bridges typically include a pylon, a deck, and one or more cable stays extending between the deck and the pylon such that the deck is supported from the pylon by the cable stays. Typical cable-stayed bridges anchor the cable stays at the deck and the pylon. 
     SUMMARY 
     The present disclosure provides for a cable-stayed bridge. The cable-stayed bridge may include a pylon. The pylon may include a passage formed therethrough. The cable-stayed bridge may include a polymer blend cradle extending through the passage of the pylon. The cable-stayed bridge may include a deck. The cable-stayed bridge may include a cable stay. The cable stay may be coupled to the deck at each end of the cable stay. The cable stay may pass through the passage through the pylon via the polymer blend cradle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    is a side elevation view of a cable-stayed bridge including a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
         FIG.  2    is a cross-section view of the pylon of the cable-stayed bridge of  FIG.  1   . 
         FIG.  3    is a perspective view of a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
         FIG.  4    is an end view of a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
         FIG.  5    is an end view of a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
         FIG.  6    is an end view of a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
         FIG.  7    is an end vies of a polymer blend cradle consistent with at least one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
       FIG.  1    depicts cable-stayed bridge  10 . Cable-stayed bridge  10  may include pylon  12  and deck  14 . Deck  14  may be mechanically coupled to pylon  12  by cable stays  16 . In some embodiments, cable stays  16  may be anchored to deck  14 . In some embodiments cable stays  16  may be anchored at each end to deck  14  and may pass through passages  18  extending through pylon  12 . 
     In some such embodiments, as shown in  FIG.  2   , each passage  18  may be formed by positioning polymer blend cradle  100  through pylon  12 . In an embodiment in which pylon  12  is formed from concrete, polymer blend cradle  100  may be positioned within the form for pylon  12  with the concrete poured and cast around polymer blend cable  100 . 
     In some embodiments, as shown in  FIG.  3   , polymer blend cradle  100  may be tubular. In some embodiments, polymer blend cradle  100  may be arcuate in profile such that a cable stay  16  positioned therethrough enters and exits substantially straight from polymer blend cradle  100  as shown in  FIG.  2   . Such an arrangement may, for example and without limitation, reduce stress concentration due to bending of cable stay  16  as cable stay  16  extends through polymer blend cradle  100  when installed to cable-stayed bridge  10 . 
     In some embodiments, polymer blend cradle  100  may be formed from a blended polymer material. By forming polymer blend cradle  100  from a selected blended polymer, the friction between cable stay  16  and polymer blend cradle  100  may be increased when compared with the friction between cable stay  16  and a metal cradle. Without being bound to theory, polymer blend cradle  100  may, for example and without limitation, deform more than a metal cradle, therefore increasing the surface area between cable stay  16  and polymer blend cradle  100  while also conforming to the outer profile of cable stay  16 . Additionally, forming polymer blend cradle  100  from a blended polymer material may, for example and without limitation, reduce manufacturing costs and reduce the likelihood that corrosion of cable stay  16  occurs compared to a metal cradle. For example, by forming polymer blend cradle  100  from a non-conductive polymer, galvanic corrosion caused by dissimilar metals in cable stay  16  and a metal cradle may be prevented. 
     In some embodiments, polymer blend cradle  100  may be formed from a blend of one or more of polyethylene, high-density polyethylene, polypropylene, high-stiffness grades of polypropylene, and nylon. In some embodiments, polymer blend cradle  100  may be formed with glass-filled, fiber-filled, mineral bead-filled, or sand-filled polymer. In some embodiments, polymer blend cradle  100  may be at least partially formed from carbon fiber. 
     In some embodiments, as shown in  FIG.  4   , polymer blend cradle  100  may be circular in cross-section. In other embodiments, polymer blend cradle  100  may be formed such that the cross-sectional profile includes one or more friction-enhancing features. 
     For example,  FIG.  5    depicts polymer blend cradle  100   a  having V-shaped section  101   a  positioned on the concave lower surface of polymer blend cradle  100   a . In such an embodiment, V-shaped section  101   a  may further increase the friction between polymer blend cradle  100   a  and cable stay  16  and further enhance the friction-increasing properties of the blended polymer material. In some embodiments, the interior of polymer blend cradle  100   a  may be large enough to permit cable stay  16  to pass therethrough relatively unencumbered to allow for construction of cable-stayed bridge  10 . In some embodiments, as the weight of deck  14  is taken up by cable stay  16 , cable stay  16  is pulled downward into V-shaped section  101   a , thereby increasing the friction between polymer blend cradle  100   a  and cable stay  16 . 
     As another example,  FIG.  6    depicts polymer blend cradle  100   b  having keyway section  101   b  positioned on the concave lower surface of polymer blend cradle  100   b . In such an embodiment, keyway section  101   b  may further increase the friction between polymer blend cradle  100   b  and cable stay  16  and further enhance the friction-increasing properties of the blended polymer material. In some embodiments, the interior of polymer blend cradle  100   b  may be large enough to permit cable stay  16  to pass therethrough relatively unencumbered to allow for construction of cable-stayed bridge  10 . In some embodiments, as the weight of deck  14  is taken up by cable stay  16 , cable stay  16  is pulled downward into keyway section  101   b , thereby increasing the friction between polymer blend cradle  100   b  and cable stay  16 . 
     As another example,  FIG.  7    depicts polymer blend cradle  100   c . Polymer blend cradle  100   c  may have a cross-section that includes upper circular path  101   c  and lower circular path  103   c . Upper circular path  101   c  and lower circular path  103   c  may be intersecting such that upper circular path  101   c  and lower circular path  103   c  together form the interior of polymer blend cradle  100   c . In some embodiments, the diameter of upper circular path  101   c  may be large enough to permit cable stay  16  to pass therethrough relatively unencumbered to allow for construction of cable-stayed bridge  10 . In some embodiments, the diameter of lower circular path  103   c  may be smaller than the diameter of upper circular path  101   c  such that as the weight of deck  14  is taken up by cable stay  16 , cable stay  16  is pulled downward from upper circular path  101   c  into lower circular path  103   c , thereby increasing the friction between polymer blend cradle  100   c  and cable stay  16 . 
     The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.