S&F Ref: 909007 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Allen Taylor & Company Ltd, of Applicant: an Australian company ACN 000 003 056, of 89 St. Hilliers Road, Auburn, New South Wales, 2144, Australia Actual Inventor(s): Peter Robinson Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Modular bridge Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2008904205 15 Aug 2008 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(2131734_1) 1 Modular Bridge Technical Field 5 The present invention relates to a bridge construction method. More particularly, this invention relates to a modular bridge incorporating a plurality of prefabricated modular bridge sections. Background of the Invention 10 Bridges are well known in the prior art. Typically, a bridge structure includes a plurality of longitudinally extending girders and concrete webbing supported by the girders. 15 The construction of a bridge can be a time-consuming undertaking when the girders of the bridge are to be erected on site. In such instances the concrete webbing must be poured in place between the girders at an elevated height. This operation requires that multiple customized foris be positioned on top of the girders for containing and supporting concrete after it is poured. After the concrete webbing has set, the forms must 20 be removed leaving in place the concrete webbing supported by the girders. The use of pre-cast slab panels in the construction of bridges has been suggested as an alternative to the above-described method. One of the most significant advantages gained in the use of pre-cast slab panels is the savings in construction time and labour 25 which reduces the cost of the structure. However, a cast-in-place concrete topping may be required to achieve a smooth and/or level surface at the joins between adjacent panels. Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled 30 in the art to which the invention relates, at the priority date if this application.
2 Object of the Invention It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages. 5 Summary of the Invention The present invention provides a modular bridge having a longitudinal axis and a bridge span of a length, the modular bridge including a modular bridge superstructure; the modular bridge superstructure including a plurality of prefabricated modular bridge 10 sections, each said prefabricated modular bridge section including: at least one deck panel supported on two or more girders, said girders being aligned substantially parallel to the longitudinal axis of the bridge; said prefabricated modular bridge sections being placed side by side to form a bridge deck that spans the length of the bridge span, and attachment means for securing the said at least one deck panel and the girders together against 15 relative displacement. The prefabricated modular bridge section can include a plurality of deck panels supported on two or more girders, said girders being aligned substantially parallel to the longitudinal axis of the bridge; the deck panels being transversely disposed side by side in 20 an abutting relationship to form a portion of the bridge deck, each said deck panel spanning transversely across the prefabricated modular bridge section; and attachment means for securing the deck panels and the girders together against relative displacement. Preferably, the modular bridge superstructure includes at least three prefabricated 25 modular bridge sections, the arrangement being such that the prefabricated modular bridge sections are substantially uniformly spaced horizontally from one another to define an expansion gap between two adjacent sections. The deck panel can be secured to the girders by a layer of an adhesive. 30 Mechanical attachment means may additionally be used to secure the deck panel to the girders. Preferably, the deck panel is an engineered composite timber panel. More preferably, the deck panel is made of plywood. 35 3 Preferably, the girder is comprised of vertically oriented laminated veneer lumber. The modular bridge can include a pair of abutments arranged in spaced 5 relationship with each other to define a bridge, said abutments being adapted to support the prefabricated modular bridge section at opposite ends thereof The modular bridge can include at least two connecting spans, and the prefabricated modular bridge section can be supported by a supporting structure at a 10 junction of said connecting spans of the modular bridge. The modular bridge can include a plurality of bearing pads attached to the abutments, said bearing pads being disposed at specified intervals, said bearing pads being adapted to support end portions of the girders. 15 Preferably, the abutment is a precast concrete abutment. An end portion of the girder can be provided with an end cap, said end cap being adapted to distribute and transmit loads to a supporting structure. 20 Preferably, the bearing pad includes a layer of elastomeric rubber to allow for longitudinal and rotational movement of the bridge superstructure. The modular bridge can further include one or more of the following: a guardrail 25 system; a handrail system; an edge distributor beam; a load distributor; a deck wearing surface. In another aspect, the present invention provides a method for constructing a modular bridge assembled from a plurality of prefabricated modular bridge sections. 30 In a preferred embodiment, the method includes the following steps: arranging at least a pair of abutments, the abutments defining a bridge span; providing bearing pads at specified intervals; disposing at least two prefabricated modular bridge sections on top of said bearing pads to span the distance between the abutments, the arrangement being such 35 that the girders are aligned substantially parallel to a longitudinal axis of the bridge and 4 the prefabricated modular bridge sections are placed side by side to form a bridge deck; and providing a deck wearing surface to improve the wear and tear resistance of the bridge deck. 5 Brief Description of the Drawings A preferred embodiment of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: Figure 1 is a schematic perspective view of a portion of a bridge superstructure io according to a first embodiment of the present invention; Figure 2 is a schematic elevation view of an end portion of a bridge incorporating a bridge superstructure according to a second embodiment of the present invention; Figure 3 is a plan view of the end portion of Fig. 2; is Figure 4 is a schematic end view of the bridge superstructure of Fig.2; Figure 5 is a plan view of a center section according to a preferred embodiment of the present invention; Figure 6 is a cross-sectional view taken along section lines A-A of Figure 5; Figure 7 is a plan view of an end section according to a preferred embodiment of 20 the present invention; Figure 8 is a cross-sectional view taken along section lines A-A of Figure 7; Figure 9 is a schematic plan view of a skew bridge; Figure 10 is a schematic perspective view of a portion of a bridge section of the bridge superstructure of Fig. 1; 25 Figure 11 is a schematic perspective view of an embodiment of assembled bearing plates; Figure 12 is a schematic perspective view of another embodiment of assembled bearing plates; Figure 13 is a plan view of the assembly of Fig. 12; 30 Figure 14 is a cross-sectional view taken along section lines A-A of Fig. 13; and Figure 15 is a cross-sectional view taken along section lines B-B of Fig. 13. Detailed Description of the Preferred Embodiments As shown in Figs. 1-4, a bridge 10 includes a modular bridge superstructure 20 35 and a pair of abutments 30 arranged in spaced relationship with each other to define a 5 bridge span. In a preferred embodiment of the present invention, the abutments 30 are precast concrete or timber abutments. Attached to the abutments 30 is a plurality of bearing pads 40 adapted to support 5 the modular bridge superstructure 20. The bearing pads 40 are disposed at specified intervals, the arrangement being such that the modular bridge superstructure 20 is supported by the abutments 30 at opposite ends thereof. In a preferred embodiment of the present invention, the bearing pads 40 include a layer of elastomeric rubber to allow for longitudinal and rotational movement of the bridge superstructure 20. 10 As shown in Fig. 1, the bridge superstructure 20 includes a plurality of prefabricated modular bridge sections 20.1, 20.2, and 20.3 extending in the longitudinal direction L of the bridge 10. The bridge sections 20.1, 20.2, and 20.3 are disposed side by side to form a bridge deck 50 having a width W. The bridge sections 20.2 and 20.3 are is substantially uniformly spaced horizontally from one another such that an expansion gap (not shown) is left between the adjacent sections (20.1, 20.2) and (20.1, 20.3). Preferably, the bridge superstructure 20 includes a centre section 20.1 and two side sections 20.2 and 20.3. However it should be apparent to one of ordinary skill in the 20 art, that it is within the scope of the present invention to utilize a plurality of bridge sections 20.1. In a preferred embodiment of the present invention, each bridge section 20 has a nominal width of 2400 mm and a length up to 15000 mm. In another preferred embodiment, the bridge superstructure 20 includes two end 25 sections 20.2 and 20.3, as is illustrated in Figs. 3 and 4. As best shown in Fig.4, the bridge sections 20.2 and 20.3 are spaced horizontally from one another to define an expansion gap 60 between the bridge sections 20.2 and 20.3. 30 As illustrated in Fig.4, 7 and 8, each side section 20.2 and 20.3 includes a cantilevered portion 70.1, 70.2 extending laterally in a direction perpendicular to the longitudinal axis L of the bridge. The cantilevered portions 70.1 and 70.2 can be used to 6 extend the width of the bridge 10. In a preferred embodiment of the present invention, the cantilevered portions 70.1, 70.2 have a width of 300 mm. As best shown in Fig.3-8, each bridge section 20 includes three girders 80.1, 5 80.2, 80.3. In use, the girders 80.1, 80.2, 80.3 are aligned substantially parallel to the longitudinal axis L of the bridge 10, approximately in the direction of the flow of traffic. The adjacent girders 80 of the center section 20.1 are spaced apart a distance of 1048 mm. The adjacent girders of the side sections 20.2, 20.3 are spaced apart a distance of 898 mm. 10 As illustrated in Fig. 2, an end portion of the girder 80 can be provided with an end cap 82 adapted to distribute and transmit loads to the bearing pad 40. On top of the girders 80.1, 80.2, 80.3, there is placed a plurality of deck panels 90 of substantially uniform thickness, the deck panels 90 being transversely disposed side is by side in an abutting relationship to form a portion of the bridge deck 50. In a preferred embodiment, the deck panel 90 has a nominal width of 1200 mm and a length of 2400 mm. Typically, between six and thirteen deck panels are required for each of the 4 layers of the bridge section 20 with the length (2400 mm) being placed 20 perpendicular to the longitudinal axis L of the bridge 10. As shown in Figs. 1, 5, 7, the deck panels 90 have a generally rectangular outline. It will be appreciated by those skilled in the art that the deck panels 90 can be configured to form a skew bridge 95, as is illustrated in Fig. 9. 25 The bridge section 20 further includes attachment means for securing the deck panels 90 and the girders 80 together against relative displacement. In this specification, the words "attachment means" should be interpreted broadly and include a combination of attachment means. 30 In a preferred embodiment of the present invention, the deck panels 90 are mounted on the girders 80 without gaps therebetween. A resourcinol formaldehyde adhesive (or other suitable adhesive) can be applied between seams 100 of the deck panels 90 to allow the deck panels 90 to act as a unitary structure. 35 7 A resourcinol formaldehyde adhesive is applied between the bottom surface of the deck panels 90 and the girders 80 to form a permanent bond that will not deteriorate under wet conditions, heat or cold. Preferably, a resourcinol formaldehyde (RF) bond is used (eg, "A" Bond as defined and specified in AS 2754). As shown in Figs.6 and 8, apertures 110 are drilled through the girder 80 at specified intervals therealong and in a straight line. In a preferred embodiment, the interval is 1200 mm. 10 Similarly, the deck panels 90 are provided with apertures 120 at predetermined positions. For fixing the girder 80 and the deck panels 90 integrally, bolts 130 may be inserted into the apertures 110, 120. When nuts 150 are tightened, the girders 80 and the deck panels are held firmly together. Preferably, M20 bolts with 75x75x16 square washers 140 are used. As a result, the deck panels 90 and the girders 80 are mutually 15 fixed and assembled into an integral unit adapted to resist the stresses and strains of bridge traffic. This step results in an increase in stiffness of the bridge section 20 which in turn reduces displacements due to loads applied to the bridge deck 50. Preferably, the bolts 130, the washers 140, and the nuts 150 are hot dip 20 galvanized to provide corrosion protection. Any other corrosion resistance methods can be used. In a preferred embodiment of the present invention, the deck panel 90 is made of an engineered timber (e.g. structural grade plywood manufactured to AS/NZS 25 2269:2004). As best shown in Fig.6 and 8, the deck panel 90 includes a plurality of horizontally oriented layers 90.1, 90.2, 90.3, 90.4. Preferably, the deck panel 90 includes 4 layers of 2400x1200x27 mm structural grade plywood. 30 It will be understood by those skilled in the art that any number of layers may be used to form the deck panel 90. Furthermore, it will be appreciated by those skilled in the art that the deck panel 90 can be engineered such that a desired mode of failure and/or maximum load capacity is achieved. 35 8 In a preferred embodiment, each layer 90 is a two-directional laminate including a face-veneer ply and a substrate-veneer ply bonded to each other to provide stability and strength. s Preferably, the face veneer has a thickness of about 3 mm, and the substrate ply has a thickness ranging from 27 to 33 mm. However, it will be appreciated by those skilled in the art that it within the scope of the present invention to utilize any thickness selected for the face ply or the substrate ply. 10 In a preferred embodiment, all plywood is ACQ (or equivalent) veneer treated to H4 in accordance with AS/NZS 1604.3:2004. A layer of an adhesive material is positioned between adjacent layers 90.1, 90.2, 90.3, 90.4. Preferably, "A" bond is used. The layers 90.1, 90.2, 90.3, 90.4 are glued 15 together with the grain of adjacent plywood layers at parallel to thereby form a cross laminated deck panel 90. In a preferred embodiment, plywood butt joins in the deck 50 are offset by 400 mm. 20 Typically, the loads transferred to the deck panels 90 are very abrasive to the surface of the deck panels 90. A durable deck wearing surface (eg, Asphaltic Concrete coating, a bitumen/aggregate system etc, not shown) can be provided to improve the wear and tear resistance of the deck panels 90. 25 As best shown in Figs. 1, 5, 7 , the girder 80 is an axially extending member including a plurality of layers of thin wood bonded together to form a unitary structure. The girder 80 is generally elongate and has primary bending stiffness along a longitudinal axis. 30 It will be appreciated by those skilled in the art that the girder 80 may have various cross-sections. In a preferred embodiment, the girder 80 has a generally rectangular cross-section (304x300, 304x400, 304x450, 304x600 mm) and is comprised of vertically oriented laminated veneer lumber (LVL) made by gluing wood veneers 35 together with the grains of all plies parallel to each other.
9 Preferably, the girder 80 is manufactured from 30-33 mm-thick LVL laminations wherein the face veneer of LVL has a thickness of about 3 mm, and the substrate ply has a thickness ranging from 27 to 33 mm, more preferably 30 mm. 5 Similarly to the deck panels 90, the girders 80 are ACQ (or equivalent) veneer treated to H4 in accordance with AS/NZS 1604.3:2004. As shown in Figs. 10-15, a pair of girder bearing plates 200.1 and 200.2 can be io used to support an end portion of the girder 80. Bolts 202 are provided to couple the bearing plates 200.1 and 200.2 to the girder 80. Preferably, M20 bolts with 75x75x 16 squire washers 204 are used. When nuts 206 are tightened, the girder 80 and the bearing plates 200.1 and 200.2 are mutually fixed and assembled into an integral unit. is In a preferred embodiment, each girder bearing plate 200.1 and 200.2 includes an L-shaped structural member 208 (150x90x8 mm) welded to a base plate 210 (150x90x8 mm). Preferably, a 4 mm continuous fillet weld is used to attach the member 208 to the base plate 210. Preferably, the height of the member 208 is about 280 mm. 20 It will be appreciated by those skilled in the art that the bearing plates 200 may be in the form of other structural members. As shown in Figs. 12, 14 and 15, in a preferred embodiment, a girder support bolt 212 is bolted to a support structure (not shown) to secure the deck panels 90, the 25 girders 80 and the support structure against relative displacement. It will be appreciated by those skilled in the art, that the bridge superstructure 20 can further include a guardrail system 160, a handrail system, an edge distributor beam, a load distributor (not shown). 30 The present invention provides a method for constructing a modular bridge from prefabricated modular bridge sections. The method includes the following steps: fabricating a plurality of deck panels; fabricating a plurality of girders; drilling a plurality of locking apertures through the deck panels and girders; integrally attaching the deck 35 panels and the girders to form a modular bridge section.
10 The modular bridge sections are then shipped to a jobsite for quick assembly. A method of building a bridge using the above-described prefabricated modular 5 bridge sections includes the following steps: arranging at least a pair of abutments, the abutments defining a bridge span; providing bearing pads at specified intervals; arranging centre pilons in multi-span bridges; disposing at least two prefabricated modular bridge sections on top of said bearing pads to span the distance between the abutments, the arrangement being such that the girders are aligned substantially parallel to a bridge io longitudinal axis and the modular bridge sections are placed side by side to form a bridge deck. The method can further include the step of providing a deck wearing surface to improve the wear and tear resistance of the bridge deck. 15 Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of'. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear. 20 While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative 25 and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.