Patent Publication Number: US-2023135646-A1

Title: Replaceable and fatigue-avoided orthotropic plate structure and replacing method thereof

Description:
TECHNICAL FIELD 
     The present invention relates to the technical field of civil engineering, in particular to a replaceable and fatigue-avoided orthotropic plate structure and a replacing method thereof. 
     BACKGROUND 
     A steel orthotropic plate is a load-bearing structure composed of vertical and horizontal stiffening ribs (or diaphragm) and a steel roof plate. The self-weight of the steel orthotropic plate is about ¼-⅕ of the self-weight of the reinforced concrete bridge deck or the precast prestressed concrete bridge deck; and the transportation and erection of the steel orthotropic plate is convenient and the construction period is short. 
     Kurpfalz bridge, which was built in 1950 using the orthotropic steel bridge deck technology proposed in 1930s, is the first steel structure bridge in the world that takes the steel orthotropic plate structure as a part of the main girder to bear stress, and simultaneously as the bridge deck to bear the local traffic load. Since then, the technology has been widely used in steel structure bridge engineering. 
     However, since it&#39;s been in use for nearly 70 years, the steel orthotropic bridge deck exposes some problems: firstly, due to the welding of U rib and steel roof plate and the existence of weld joint and welding stress, U rib, steel roof plate, and the weld joint between the U rib and the steel roof plate are prone to fatigue cracking; secondly, because the side of U rib is welded with diaphragm, the diaphragm near the U rib and the weld joint between the U rib and the diaphragm are prone to fatigue cracking. 
     Once the above fatigue crack damage occurs, it is difficult to repair or replace, and the damage may become a stubborn issue affecting the use of steel orthotropic bridge deck. The main reason is that the small steel box is formed after the U rib and the steel roof plate are welded, which is subjected to the torsion around the longitudinal axis and the vertical bending around the transverse axis under the wheel load. During the torsion, the external torque needs to be balanced with the bending moment at the joint between the U rib and the steel roof plate, resulting in a large relative deformation at the joint between the U rib and the steel roof plate. Moreover, the geometric stiffness is discontinuous at the joint, and a relatively large cyclic stress is produced at the joint under the reciprocating load, which easily leads to the fatigue cracking at the weld joint between the U rib and the steel roof plate, as shown in  FIG.  1   . 
     Meanwhile, when the U rib undergoes the vertical bending around the transverse axis, the repeated out-of-plane bending of the diaphragm will occur under the external reciprocating load due to the welding of the U rib and the diaphragm, thereby leading to the fatigue cracking at the weld joint between the U rib and the diaphragm, as shown in  FIG.  2   . 
     SUMMARY 
     In view of the shortcomings in the prior art, the present invention provides a replaceable and fatigue-avoided orthotropic plate structure and a replacing method to solve the problems that the orthotropic plate is prone to fatigue damage and the damage is not easy to repair in the prior art. 
     In order to solve the above technical problems, the present invention adopts the following technical solution. 
     A replaceable and fatigue-avoided orthotropic plate structure is provided, including a plurality of U rib components detachably arranged. Each of the plurality of U rib components includes a U rib, and an upper end of the U rib is fixedly connected to a roof plate in a non-welded manner; undertaking plates are attached on outer sides of both sides of the U rib, and the undertaking plate abuts against and is connected to a side-inclined limiting component; the side-inclined limiting component includes a connecting plate detachably installed on a diaphragm, and a limiting plate is arranged vertically on the connecting plate; a friction plate matched with the undertaking plate is installed on the limiting plate, and the friction plate and the undertaking plate are closely against each other to form a friction pair; two sides of a bottom of the U rib are symmetrically fixedly arranged with vertical limiting components, and an upper end of the vertical limiting component abuts against and is connected to a lower end of the limiting plate. 
     The present invention also provides a method for replacing the replaceable and fatigue-avoided orthotropic plate structure, including the following steps: 
     S1, when a structural abnormality is detected in a predetermined U rib component, sequentially removing connecting pieces between the connecting plate corresponding to the target component and the diaphragm; 
     S2, pulling out the connecting plate corresponding to the target component and the limiting plate corresponding to the target component in a direction perpendicular to the diaphragm; 
     S3, sequentially removing connecting pieces between the upper end of the U rib corresponding to the target component and the roof plate; 
     S4, installing a U rib component for replacement at a position corresponding to the target component with the connecting pieces obtained in S3; 
     S5, installing the connecting plate and the limiting plate obtained in S2 at the original position with the connecting pieces obtained in S1, to complete a replacement of the orthotropic plate structure. 
     The main advantages of the replaceable and fatigue-avoided orthotropic plate structure provided by the present invention are as follows: 
     For the fatigue-avoided orthotropic plate structure provided by the present invention, the friction plate tightly abuts against the undertaking plate on each side of the U rib to form a friction pair. When the U rib is vertically bent around the transverse axis, the fatigue damage of the diaphragm is avoided because a non-welded connection is used between the U rib and the diaphragm, the side-inclined limiting component constrains the vertical deformation of the U rib through the friction pair connection, and the U rib can be bent freely around the transverse axis without the out-of-plane bending of the diaphragm. 
     The U rib and the roof plate are fixedly connected in the non-welded manner, as a result, the welding stress caused by welding at the joint is relieved and meanwhile the resultant fatigue cracking of the weld joint and base material is eliminated. Furthermore, the torsional constraint of the diaphragm on the U rib around the longitudinal axis is effectively weakened, the stress at the connecting portion between the U rib and the roof plate is greatly reduced, and the fatigue of the U rib is avoided. 
     Through the cooperation of the side-inclined limiting component and the undertaking plate, the transverse position of the U rib can be limited and the U rib is not needed to be welded with the diaphragm. As such, the constraint of the diaphragm on the vertical bending of the U rib around the transverse axis is released, and the repeated out-of-plane bending of the diaphragm caused by the bending of the U rib is eliminated, so that the fatigue cracking of the weld joint between the U rib and the diaphragm and the fatigue cracking of arc-shaped notch are eliminated. Meanwhile, the vertical downward movement of the U rib is limited. 
     By setting the vertical limiting component at the lower part of the U rib, the upper end of the vertical limiting component abuts against and is connected to the limiting plate to form a limit when the U rib moves upward, thus limiting the vertical upward movement of the U rib. 
     The cooperation of the side-inclined limiting component and the vertical limiting component has a synergetic effect of restricting the movement of a workpiece in the vertical plane. 
     The U rib is only detachably connected to the roof plate, tightly abuts against and connected to the vertical limiting component, and is not fixedly connected to any other component, therefore, it is convenient to remove the U rib. Even if fatigue damage of the U rib component occurs, the damaged modular U rib component can also be wholly replaced. 
     The side-inclined limiting component and the diaphragm are connected in a detachable method, which facilitates replacement. The U rib component, the side-inclined limiting component, and the vertical limiting component are mutually detachable, thus able to be made into standardized components to facilitate manufacture, installation, and replacement. 
     When using the method for replacing the replaceable and fatigue-avoided orthotropic plate structure provided by the present solution, the connecting plate and the limiting plate are horizontally removed, conducive to extracting the side-inclined limiting component for reuse. Moreover, the components for connection are reused, thus prolonging the service life of each structure and saving cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of the lateral deformation of the existing orthotropic bridge deck under wheel load. 
         FIG.  2    is a schematic diagram of the vertical deformation and diaphragm bending of the existing orthotropic bridge deck under wheel load. 
         FIG.  3    is a structural diagram of the fatigue damage-avoided orthotropic plate structure. 
         FIG.  4    is a schematic diagram showing an overall structure of a welded U rib with a top cover plate. 
         FIG.  5    is a schematic diagram showing an overall structure of a welded U rib with an inner transverse rib. 
         FIG.  6    is a structural schematic diagram of a vertical limiting component in an L shape. 
         FIG.  7    is a schematic diagram showing an overall structure of a U rib when the vertical limiting component is a limiting bolt. 
         FIG.  8    is an overall side view of an orthotropic plate structure. 
         FIG.  9    is an overall top view of the orthotropic plate structure. 
         FIG.  10    is a schematic diagram of the lateral deformation of the orthotropic plate structure of the present invention under wheel load. 
         FIG.  11    is a flow chart showing a method for replacing the replaceable and fatigue-avoided orthotropic plate structure. 
     
    
    
     In the drawings:  100 , U rib component;  101 , U rib;  102 , undertaking plate;  200 , side-inclined limiting component;  201 , connecting plate;  202 , limiting plate;  203 , friction plate;  300 , vertical limiting component;  301 , arc-shaped flange;  400 , roof plate;  500 , diaphragm. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present invention is further illustrated below in combination with the drawings. 
       FIG.  3    shows a structural schematic diagram of a replaceable and fatigue-avoided orthotropic plate structure. 
     The detachable and fatigue-avoided orthotropic plate structure of the present invention includes a plurality of U rib components  100  which are detachably arranged. The U rib component  100  includes the U rib  101 , and two sides of the U rib  101  are inclined edges. An upper end of the U rib  101  is fixedly connected to the roof plate  400  in a non-welded manner. Preferably, the U rib  101  and the roof plate  400  are connected by a method including a bolted connection or a riveting connection. 
     Outer sides of the two sides of the U rib  101  are affixed with the undertaking plate  102 , and the undertaking plate  102  is connected to and abuts against the side-inclined limiting component  200 . The side-inclined limiting component  200  includes the connecting plate  201  removably installed on the diaphragm  500 , the limiting plate  202  vertically arranged on the connecting plate  201 , and the friction plate  203  matched with the undertaking plate  102  is installed on the limiting plate  202 . The vertical limiting components  300  are symmetrically fixedly arranged on two sides of a bottom of the U rib  101 , and an upper end of the vertical limiting component  300  is connected to and abuts against a lower end of the limiting plate  202 . The limiting plate  202  is set to support the friction plate  203 , thereby enhancing the force bearing capacity of the side-inclined limiting component  200 . 
     Specifically, the thickness of the upper end of the vertical limiting component  300  is greater than the sum of the thicknesses of the undertaking plate  102  and the friction plate  203 . When the U rib  101  moves upward, the vertical limiting component  300  is driven to upward squeeze the limiting plate  202 , and the upward vertical movement of the U rib  101  is effectively restricted under the action of the limiting plate  202  and the connecting plate  201  fixed on the diaphragm  500 . 
     The distance between upper ends of the limiting plates  202  on two sides is less than the distance between two sides of the upper end of the U rib  101 . In this way, the limiting plate  202  can not only bear the transverse deformation force of the U rib  101 , but also withstand the longitudinal force caused by the roof plate  400 . 
     Preferably, the vertical limiting component  300  is arc-shaped, as shown in  FIG.  6   , and is fitted with bending parts on the two sides of the bottom of the U rib  101 . The upper end of the vertical limiting component  300  is provided with the arc-shaped flange  301  which is connected to and abuts against a bottom of the limiting plate  202 . The vertical limiting component  300  and the U rib  101  are connected by a method including a bolting connection, a welding connection, a riveting connection and a high-strength adhesive connection, which ensures the consistency of the force bearing on the vertical limiting component  300  and the U rib  101 . 
     Optionally, the vertical limiting component  300  is a limiting bolt fixed on the U rib  101 , as shown in  FIG.  7   . The limiting bolt is installed on the bottom of the side of the vertical limiting component  300 , and an upper side of the limiting bolt is connected to and abuts against the lower end of the limiting plate  202 , which also has the effect of restricting the upward movement of the U rib  101 . 
     Preferably, the upper end of the U rib  101  is provided with an extended flange, and the extended flange and the roof plate  400  are fixedly connected in the non-welded manner, as shown in  FIG.  3   . 
     Optionally, the upper end of the U rib  101  is provided with a top cover plate fixedly connected to the roof plate  400  by welding, as shown in  FIG.  4   . 
     Optionally, an inner transverse rib plate is arranged at a position on an inner side of the U rib  101  and adjacent to the diaphragm  500 , as shown in  FIG.  5   , so as to increase the structural stiffness of the U rib component  100 . 
     Further, the U rib is a structure modularly prefabricated by the process of rolling, stamping, and cold bending; the side-inclined limiting component  200  and the vertical limiting component  300  are also standardized modular components, which facilitates manufacturing, installation, and replacement. 
     Preferably, the undertaking plate  102  is a stainless steel plate, and the friction coefficient between the friction plate  203  and the undertaking plate  102  is less than 0.3. The friction plate  203  and the undertaking plate  102  are closely against each other to form a friction pair to restrain the vertical deformation of the U rib  101 . 
     The following is the working principle of the present technical solution: 
     Through a non-welded connection between the U rib component  100  and the roof plate  400 , the vertical downward displacement of the U rib component  100  is limited by the inclined clamping action of the side-inclined limiting component  200 , and the vertical upward displacement is limited by both the vertical limiting component  300  and the roof plate  400 . Additionally, the transverse displacement is limited by the side-inclined limiting component  200 . 
     As shown in  FIG.  10   , when the U rib component  100  is torsional around the longitudinal axis, the fatigue damage is avoided and will not occur on the U rib  101 , the steel roof plate, nor at the weld joint between the U rib  101  and the steel roof plate due to the utilization of the high-strength bolt connection instead of welding between the U rib  101  and the steel roof plate. 
     Meanwhile, when the U rib  101  is vertically bent around the transverse axis, the fatigue damage of the diaphragm  500  is avoided because a non-welded connection is used between the U rib  101  and the diaphragm  500 , the side-inclined limiting component  200  constrains the vertical deformation of the U rib  101  through the friction pair connection, and the U rib  101  can be bent freely around the transverse axis without the out-of-plane bending of the diaphragm  500 . 
     Further, as shown in  FIGS.  8  and  9   , since the U rib component  100  is a modular component and not connected to the diaphragm  500 , and the U rib component  100  and the roof plate  400  are connected by the bolted connection or riveting connection, the U rib component  100  and the roof plate  400  are easily disassembled even if the fatigue cracking damage occurs on the U rib component  100  or the connection bolt or rivet, as a result, the modular U rib component  100  can be wholly replaced after the disassembly. 
     The present solution also provides a method for replacing the replaceable and fatigue-avoided orthotropic plate structure, as shown in  FIG.  11   , including the following steps: 
     S1, when a structural abnormality is detected in the predetermined U rib component  100 , connecting pieces between the connecting plate  201  corresponding to the target component and the diaphragm  500  are removed in sequence; 
     A method for the detection includes a visual inspection, ultrasonic inspection, etc. during conventional periodical inspection. 
     S2, the connecting plate  201  corresponding to the target component and the limiting plate  202  corresponding to the target component are pulled out in a direction perpendicular to the diaphragm  500 , which facilitates the removal of the side-inclined limiting component  200 , avoids compressing and affecting the adjacent U rib component  100  and vertical limiting component  300 , and simplifies operation simultaneously. 
     S3, connecting pieces between the upper end of the U rib  101  corresponding to the target component and the roof plate  400  are removed in sequence; 
     When the connecting pieces are the high-strength bolts, the connecting pieces can be quickly removed with a bolt extractor and collectively placed for recycling. 
     S4, the U rib component  100  for replacement is installed at a position corresponding to the target component with the connecting pieces obtained in S3; 
     Further, the U rib  101  for replacement is pre-affixed with the undertaking plate  102 . The combined structure of the undertaking plate  102  and the U rib  101  is prefabricated in the factory to facilitate rapid replacement on site. 
     S5, the connecting plate  201  and the limiting plate  202  obtained in S2 are installed at the original position with the connecting pieces obtained in S1, to complete a replacement of the orthotropic plate structure. 
     The side-inclined limiting component  200  is reused to save cost and facilitate maintenance operation. 
     The specific embodiments of the present invention are described above to facilitate the technicians in the art to understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, various changes, as long as within the spirit and scope of the present invention defined and determined by the appended claims, are apparent. All inventions conceived based on the present inventive concept are included in the scope of protection.