An expansion joint in which by means of movability of expansion shim assemblies in a sustaining pedestal and a stepped bench unit formed of a pair of benches at different elevation disposed beneath the sustaining pedestal so as to withstand vibration of roadway or bridge and instantly rescue the roadway or bridge from collapsing.  
     Before construction of the same, a specially designed H configurated clearance gage is used for determining clearances of adjacent component parts of the expansion joint resulting in getting an accurate and effective structure of the expansion joint.

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to vibration resistive instant responding roadway or bridge expansion joint and construction method of the same, in particular, to a roadway or bridge expansion joint in which by means of movability of expansion shin assembly in a sustaining pedestal to withstand vibration of roadway or bridge and instantly rescue the roadway or bridge from collapsing, moreover, a H configurated clearance gage is provided for determining clearances of adjacent component parts in constructing the expansion joint.  
           [0003]    2. Description of the Prior Art  
           [0004]    In selecting a well-suited expansion joint, in addition to effectiveness, other factors such as durability, econo-my, maintainability , and water drainage must also be taken in account.  
           [0005]    Conventional roadway or bridge expansion joint, like one which was patented by Pat. No. 414820 in Taiwan is essentially a pre-buried elastic expansion joint element, this element restores its elastic property functionable as an expansion joint after the concrete dries which has been squeezing the element from the moment of pouring on. However, it has unsolvable problems of no way to expel water contained therein, and this expansion joint is only applicable for a short span roadway or bridge.  
           [0006]    Another expansion joint disclosed by Pat. No. 382376 in Taiwan is essentially a sliding plate joint having an intricated structure which is susceptible to being filled with rubbish and loosing its effectiveness, on the other hand, its intricated structure gives rise of a high construction cost and difficulty in repairing. Besides, and expansion joint made of metallic material is inevitably corrosive.  
           [0007]    Another well known conventional technology in the field of vibration resistive instant responding expansion joint is represented by so called “Finger Plate Joint” which is in the form of two piece of serrated steel plates. The serrated teeth of the two steel plates are staggeringly crossing one another so as to avoid squeezing each other when been stressed, and a drain ditch equipped beneath the expansion joint for draining water on the roadway or bridge surface. With this structure, the expansion joint is strongly constructed with steel plates formed with mutually staggered serration teeth to alleviate bouncing vibration imparted by heavy traffic, and at the same time, expel the water trickling down from the bridge or roadway surface. On the contrary, it has been reported that this expansion joint has disadvantages of high production cost, expensive repairing cost, and difficult to install.  
           [0008]    In all, those aforementioned well known techniques about expansion joint have a common shortcoming of in complete vibration resistive property that the allowable clearance of the joint is insufficient to absorb the large verticall vibration deformational stress which might be caused by a severe earthquake resulting in catastrophic ruination of bridge and roadway and further leads to lives and property losses of human being.  
           [0009]    Besides, in conventional techniques, some are want of assembly tools, while some are in need for special and complicated extra tools for assembly, both expensive labor cost and precious time are involved.  
           [0010]    In view of the foregoing situation, the inventor of the invention herein conducted intensive research based on many years of experience gained through professional engagement in the manufacturing and construction of related products, with continuous experimentation and improvement culminating in the development of the improved structure for vibration resistive instant responding roadway or bridge expansion joint and construction method of the same herein.  
         SUMMARY OF THE INVENTION  
         [0011]    It is an object of the present invention to provide a vibration resistive expansion joint having horizontally displaceable and turnable expansion shims which are replaceable one by one for defected shims, while the configuration of the shims can be changed according to specific requirements, moreover a proper clearance between two adjacent shims is reserved so as to cope with possible asymmetrical displacement of roadway or bridge surface separated by an expansion joint.  
           [0012]    It is another object of the present invention to provide a vibration resistive expansion joint having stepped bench unit whose thickness and tilted angle is well-fitted to the grade of the roadway or bridge.  
           [0013]    It is still another object of the present invention to provide a vibration resistive expansion joint equipped with a water receptacle beneath the expansion joint for releasing the water twickled down from the roadway or bridge surface.  
           [0014]    It is one more object of the present invention to provide method for constructing an expansion joint having aforementioned effects.  
           [0015]    For achieving these and other objects, the expansion joint of the present invention comprises a sustaining pedestal which is further formed of two sustasiming U shaped members, the top edge of each member is formed into a hinge bracket with a hinge hole, several expansion shim assemblies each formed of a bifurcated tooth like shim hinged to both side sustaining members are indented one antoher with those hinged at opposite member. Eash expansion shim assembly includes an independent tongue piece hinged to the sustaining member and is interposed in a gap of the bifurcated expansion shim and indented each other with opposite one. A hinge pin is used to connect each sustaining member with each expansion shim assembly. A foundation formed of two L shaped side members having a slide surface at each bottom surface thereof is provided with several fins at both outer side surfaces, and a guide rail is formed along each outer edge of the slide surface. A stepped bench unit formed of a pair of benches disposed at different elevation is slidably mounted on both side surfaces of the side foundation members. A water receptacle made of watertight material and having flanges along both side edges is inlaid in the both guide rails of the foundation to collect the water coming form the roadway or bridge surgace and trickling the water away thereform.  
           [0016]    In the present invention, the sustaining pedestal, the stepped bench unit, and the foundation are engaged with screws at proper positions.  
           [0017]    In the present invention, the contact edge of the respective expansion shim can be made into an arcuate shape or the like according to actual requirement.  
           [0018]    In case it is considered necessary, the sustaining members can be reinforced with several reinforcement ribs.  
           [0019]    As for the construction, a specially designed clearance gage is utilized for precisely determining clearance between two foundation members of expansion joint. The clearance gage is a supporting saddle with two parallelly erected plates at both sides. The construction steps are: Setting the clearance gage on the slide surfaces of the foundation to check the precise distance between the two foundation members, and then removing the clearance gage. Setting the bottom of the stepped bench unit on the slide surfaces. Setting the sustaining pedestal on the stepped bench unit. Connecting the expansion shim assemblies and the sustaining pedestal with both hinge pins and adjusting mutual positional relation. Engaging the sustaining pedestal, the stepped bench unit, and the foundation with tightening screws. Installing the water receptacle.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    To enable a further understanding of the innovative and technological content of the invention herein, refer to the detailed description of the invention and the accompanying brief description of the drawings appended below:  
         [0021]    [0021]FIG. 1 is a three dimensional assembly view of the expansion joint of the present invention.  
         [0022]    [0022]FIG. 2 is an exploded view of the expansion joint of the present invention.  
         [0023]    [0023]FIG. 2A is a constructional view of the water receptacle of the present invention.  
         [0024]    [0024]FIG. 3A is an illustrative view showing that roadway or bridge surface is relatively displaced in vertical direction at two sides of the expansion joint.  
         [0025]    [0025]FIG. 3B is an illustrative view showing that roadway or bridge surface is relatively displaced in horizontal direction at two sides of the expansion joint.  
         [0026]    [0026]FIG. 4 is an illustrative view showing the structure of an expansion-shim assembly of the present invention.  
         [0027]    [0027]FIG. 5 is an illustrative view of the stepped bench unit of the present invention.  
         [0028]    [0028]FIG. 6A is a view showing normal state of expansion shim assemblies in the expansion joint of the present invention.  
         [0029]    [0029]FIG. 6B is a view showing variation in relative position of components of expansion shim assemblies in case a relative displacement of roadway or bridge surface occurs at two sides of the expansion joint.  
         [0030]    [0030]FIG. 7 is a three dimensional view illustrating how the clearance gage is applied in construction of an expansion joint at the site.  
         [0031]    [0031]FIG. 8 is a side cross sectional view of FIG. 7. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    For understanding the structure of the present invention, reference should be made to FIGS. 1 and 2, which respectively show a three dimensional assembly view and an exploded view of the expansion joint according to the present invention. The expansion joint comprises a sustaining pedestal  1  which is further formed of two sustaining L shaped members  111  and  112 . The top edge of each sustaining member  111  or  112  is formed into a hinge bracket  114  or  115  with a hinge hole. Several expansion shim assemblies  12  each containing a bifurcated tooth like shim  121  hinged to both side sustaining members  111  and  112  are indented one another with those arrayed at opposite member. Each expansion shim assembly  12  includes an independent tongue piece  122  hinged to the sustaining member  111  or  112  and is interposed in a gap  121  of the bifurcated expansion shim S and indented each other with opposite one. The contact edges of the respective expansion shims S can be made into an arcuate shape or the like according to actual requirement. A hinge pin  12 A or  12 B is used to connect each hinge bracket  114  or  115  of the sustaining member  111  or  112  with a lug  117  or  118  of the expansion shim assembly  12  such that the expansion shim assemblies  12  are turnably connected to the sustaining members  111  and  112 .  
         [0033]    The sustaining members  111  and  112  can be reinforced with several reinforcement ribs  113  in case it is considered necessary. A foundation  3  formed of two L shaped side members having a slide surface  33  or  34  at each bottom surface thereof is provided with several fins B with several holes A at both outer sidesurfaces, and a guide rail  31  or  32  is formed along each outer edge of the slide surface  33  or  24 . A stepped bench unit  2  formed of a pair of benches disposed at different elevation is slidably mounted on both side surfaces of the foundation  3 . A water receptacle  4  made of watertight material and having flanges  41  and  42  along both side edges is inlaid the flanges  41  and  42  into the guide rails  31  and  32  of the foundation  3  respectively to collect the water coming from the roadway or bridge surface and twickling the water away therefrom (see FIG. 2A). The sustaining pedestal  1 , the stepped bench unit  2 , and the foundation  3  are engaged with screws M at proper positions thus completing an entire expansion joint assembly.  
         [0034]    For understanding rapid response of the expansion joint of the present invention to deformation of road way or bridge in vertical direction, reference should be made to FIG. 3A. When a roadway or bridge surface C is displaced in vertical direction, the deformation of roadway or bridge is maintained within an allowable limit E without collapsing by coorperated function of the independent tongue pieces  122  in the gaps  121  and the expansion shims S with the aid of the expansion shim assemblies  12  turning about the hinge pins  12 A and  12 B. At this time, the water tightness of the water receptacle  4  is free from destruction as it is made of watertight material.  
         [0035]    For understanding rapid response of the expansion joint of the present invention to deformation of roadway or bridge in horizontal direction, reference should be made to FIG. 3B. When a roadway or bridge surface is displaced in horizontal direction by an external force exceeding the engaging strength of the screws M, the screws M may possibly be broken by a shearing force produced among the sustaining pedestal  1 , stepped bench unit  2  and the foundation  3 . As a result, sustaining pedestal  1  may slip on the stepped bench unit  2 , or the stepped bench unit  2  may slip on the slide surfaces  33  and  34 . In this version it is helpful for readjusting and repairing the roadway or bridge surface C without affecting its strength. Similarly, the water receptacle  4  is able to remain its normal function as it is made of a water tight material.  
         [0036]    [0036]FIG. 4 is an illustrative view showing the structure of an expansion shim assembly  12  of the present invention. As shown in FIG. 4, the contact edge of the respective expansion shim can be made into an arcuate shape or the like according to actual requirement. An expansion shim  13  contains a gap  131  and a tongue piece  132 . The lugs  137  and  138  at each end of the expansion shims  13  are turnably conjoined with hinge pins  12 A and  12 B.  
         [0037]    [0037]FIG. 5 is an illustractive view showing the stepped bench unit  2   a  of the present invention. The tilted angle D between the benches  21   a  and  22   a  can be determined according to the grade of the roadway or bridge.  
         [0038]    For understanding how the expansion shim assemblies work in case asymmetrical deformation of roadway or bridge surface occurs, reference shoulb be made to FIGS. 6A to  6 B, As shown in FIG. 6B, variation in state of expansion shim assemblies is clearly observed where the expansion shims S still rewain the allowable limit. In this version, the deformed expansion joint is repairable and reusable.  
         [0039]    For understanding how a clearance gage H is used for construction of an expansion joint of the present invention, reference should be made to FIGS. 7 and 8. The clearance gage H is actually a supporting saddle H 1  with two parallely erected plates H 21  and H 22  spacing in predetermined distance at both sides. The through holes A on the fins B of the foundation  3  can be strung together before pre-burying the foundation  3  in the roadway or bridge so as to intensify binding force therebetween.  
         [0040]    Referring to FIGS. 2, 7 and  8 , the construction of the expansion joint comprises the steps of: 1. Setting the clearance gage H on the slide surfaces  33  and  34  of the foundation  3  to check the precise distance between the two foundation members, and removing the clearance gage H. 2. Setting the bottom of the stepped bench unit  2  on the slide surfaces  33  and  34 . 3. Setting the sustaining pedestal  1  on the stepped bench unit  2 . 4. Connecting the expansion shim assemblies  12  and the sustaining pedestal  1  with hinge pins  12 A and  12 B and adjusting mutual positional relation. 5. Engaging the sustaining pedestal  1 , the stepped bench unit  2 , and the foundation  3  with tightening screws M. 6. Installing the water receptacle  4 .  
         [0041]    It emerges from the description of the above example that the invention has several noteworthy advantages, in particular:  
         [0042]    1. The expansion joint of the present invention is simply constructed, easy for installation and maintenance thereby cutting down the necessary cost.  
         [0043]    2. It is applicable to horizontal, verticall and asymmetrical deformation of roadway and bridge, especially effective in prolonging bridge lifetime.  
         [0044]    3. Using a specially designed clearance gage to determine the related precise dimensions in construction at site results in getting an accurate and effective structure for an expansion joint.  
         [0045]    Those who are skilled in the art will readily perceive how to modify the invention. Therefore, the appended claims are to be construed to conver all equivalent structures which fall within the true scope and spirit of the invention.