An aluminum alloy truss structure and design method, a spliced highway emergency bridge, and a splicing method

Abstract

The present invention relates to the technical fields of bridge truss structures and emergency bridges, and specifically relates to a truss structure and design method, a spliced emergency bridge, and a splicing method, which include the following steps: constructing an aluminum alloy truss structure, where the truss structure includes assembled truss segments, cross beams, and panels, and through the force analysis of the truss structure, adjusting the positions and dimensions of each component of the truss structure; designing a stiffness adjustment mechanism in the aluminum alloy truss structure, and calculating the influence of the pre-tightening force of the stiffness adjustment mechanism on the deflection of the aluminum alloy truss; calculating the maximum deflection of the aluminum alloy truss structure based on the influence of the pre-tightening force of the stiffness adjustment mechanism. Compared with the prior art, the beneficial effects of the present invention are: the present invention designs an assembled aluminum alloy truss structure, and the emergency bridge spliced by this structure has the characteristics of light self-weight, low erection technical requirements, and high assembly efficiency. The assembled truss structure can be carried by manual or small machinery, which is beneficial to quickly restoring bridge traffic.

Description

Technical Field

[0001] The present invention relates to the technical fields of bridge truss structures and emergency bridges, and particularly relates to an aluminum alloy truss structure and a design method thereof, a spliced highway emergency bridge, and a splicing method thereof. Background Art

[0002] When a bridge is damaged or impassable due to various geological disasters, traffic on the bridge is usually closed, and a detour plan is formulated. An emergency bridge is erected on a suitable passing section. Most existing emergency bridges are made of steel. Although steel structures have high strength, good plasticity and toughness, they also have disadvantages such as large self-weight, poor mobility, and high labor intensity in erection operations. For example, the assembled steel bridge truss Bailey sheet has heavy components, requires lifting equipment for erection, and has low splicing efficiency. It has high requirements for the number, physical strength, and collaborative cooperation ability of erection personnel, is not conducive to short-term and rapid erection, and cannot meet the current mobile support tasks. Therefore, a bridge structure that is lightweight, high-strength, and easy to erect is needed.

[0003] Aluminum alloy materials meet the characteristics of being lightweight and high-strength. In existing emergency bridges, a small part also uses aluminum alloy materials. However, the disadvantages of aluminum alloy material bridges are as follows: The elastic modulus of aluminum alloy is only one-third of that of steel, and it is easy to cause deformation of components. Excessive deflection of the aluminum alloy truss structure under load will cause deformation of the bridge body, affecting the safety of bridge use.

[0004] Therefore, developing an aluminum alloy truss structure and a design method thereof, a spliced highway emergency bridge, and a splicing method thereof not only has urgent research value, but also has good economic benefits and industrial application potential. This is the motivation and basis for the completion of the present invention. Summary of the Invention

[0005] In order to overcome the defects of the above-mentioned prior art pointed out, the inventor of the present invention has conducted in-depth research and completed the present invention after a large amount of creative labor.

[0006] Specifically, the technical problem to be solved by the present invention is: by providing an aluminum alloy truss structure with adjustable stiffness, and splicing the truss structure into an emergency bridge, to solve the technical problem that the deflection cannot be reduced after the existing bridge is lightened.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An aluminum alloy truss structure design method includes the following steps:

[0009] (1) Construct an aluminum alloy truss structure, and the truss structure includes assembled truss segments, cross beams, and panels;

[0010] (2) Preset a stiffness adjustment mechanism in the aluminum alloy truss structure, and calculate the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure;

[0011] (3) Adjust the parameters of the stiffness adjustment mechanism based on the design requirements of the truss structure stiffness, and install the adjusted stiffness adjustment mechanism in the aluminum alloy truss structure;

[0012] Among them, calculating the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure includes:

[0013] 1) Calculate the structural deflection adjusted by the stiffness adjustment mechanism;

[0014] 2) Calculate the maximum deflection of the truss structure after the stiffness adjustment mechanism is adjusted;

[0015] 3) Establish the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure based on the relationship between deflection and stiffness.

[0016] In the present invention, as an improvement, the preset stiffness adjustment mechanism includes:

[0017] Select the stiffness adjustment position based on the bridge span as the stiffness adjustment direction;

[0018] Select the adjustment points of the stiffness adjustment mechanism at the stiffness adjustment position based on the adjustment characteristics of the stiffness adjustment mechanism;

[0019] Install the stiffness adjustment mechanism at the stiffness adjustment position based on the adjustment points.

[0020] In the present invention, as an improvement, the truss segment includes upper and lower chord rods and vertical web members connected between the two. The upper and lower chord rods both include symmetric trough-shaped rods installed on the inner and outer sides at the ends of the vertical web members with the notch facing outward. The stiffness adjustment mechanism is installed in the inner and outer troughs of the lower chord rod, and both ends of the high-strength anchoring screw in the stiffness adjustment mechanism are anchored between the vertical web members connected to both ends of the lower chord rod.

[0021] In the present invention, as an improvement, the following formula is used to calculate the structural deflection adjusted by the stiffness adjustment mechanism:

[0022]

[0023] Among them, N p is the tension of the high-strength anchoring screw, e p is the distance from the anchoring position of the high-strength anchoring screw to the neutral axis of the truss structure, is the distance from the centroid axis of the truss structure to the bottom of the truss structure, E is the elastic modulus of the aluminum alloy, and I is the moment of inertia of the aluminum alloy truss structure.

[0024] In the present invention, as an improvement, the calculation of the maximum deflection of the truss structure after the stiffness adjustment mechanism is adjusted is as follows:

[0025] w = f1 + f2 - f3

[0026] Wherein, f1 is the deflection generated by the self-weight of the truss structure, and f2 is the deflection generated by the vehicle load;

[0027] Among them, the deflection f1 generated by the self-weight of the truss structure is as follows:

[0028]

[0029] The calculation of the deflection f2 generated by the vehicle load is as follows:

[0030]

[0031] Wherein, q represents the self-weight line load, l represents the structural length of the truss structure, E represents the elastic modulus of aluminum alloy, I represents the moment of inertia of the aluminum alloy truss structure, and k q represents the equivalent line load of the live load.

[0032] In the present invention, as an improvement, the calculation of the moment of inertia I of the aluminum alloy truss structure is as follows:

[0033]

[0034] Wherein, A is the cross-sectional area of the channel bar at the installation position of the anchor screw, A s is the cross-sectional area of the high-strength anchor screw, h is the distance from the center of the upper chord to the center of the lower chord, h1 is the distance from the center of the lower chord to the bottom of the truss structure, I C is the moment of inertia of the channel bar cross-section, I s is the moment of inertia of the anchor screw cross-section;

[0035] The calculation of the distance from the centroid axis of the truss structure to the bottom of the truss structure is as follows:

[0036]

[0037] The calculation of the distance from the anchoring position of the anchor screw to the neutral axis of the truss structure is as follows:

[0038]

[0039] Wherein, f c is the design strength of aluminum alloy for tension and compression, and f s is the design value of the bearing capacity of the anchor screw.

[0040] In the present invention, as an improvement, the stiffness of the aluminum alloy truss is the ratio of deflection to span, and the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure is obtained based on the maximum deflection w of the truss structure.

[0041] An aluminum alloy truss structure, the truss structure includes assembled truss segments, cross beams and panels. The truss segments include upper chord bars and lower chord bars arranged along the bridge span direction. Vertical web bars and diagonal web bars are connected between the upper chord bars and the lower chord bars. Both the upper and lower chord bars are composed of symmetrical channel bars installed on the inner and outer sides of the ends of the vertical web bars with the notch facing outwards. Two groups of stiffness adjustment mechanisms are respectively installed in the notches of the channel bars on the inner and outer sides of the lower chord bars;

[0042] The cross beam includes an upper cross bar and a lower cross bar. Vertical bars and diagonal bars are connected between the upper cross bar and the lower cross bar. Both ends of the upper cross bar and the lower cross bar are provided with screw holes opened along the rod body extension direction. The vertical web bar is provided with through holes matching the screw holes. Bolts pass through the through holes and the screw holes to connect the upper cross bar and the lower cross bar with the vertical web bar. The upper cross bar is connected to the middle of the vertical web bar;

[0043] The panel is a multi-chamber aluminum alloy plate. Buckle plates are arranged at both ends of the panel. Adjacent panels are connected through the buckle plates;

[0044] The stiffness adjustment mechanism includes high-strength anchor bolts and anchor plates. The anchor plates are vertically arranged at both ends in the lower chord bar groove. The end of the screw rod is anchored to the anchor plate through bolts.

[0045] A spliced highway emergency bridge, the bridge is spliced by multiple truss structures. Among them, the splicing ends of the truss segments are located at the ends of the upper and lower chord bars. The splicing chord bars of two adjacent segments are spliced through splicing holes and bolts arranged at the ends. Buckle plates are arranged at the ends of the panel. Adjacent panels are connected through the buckle plates.

[0046] A splicing method for a spliced highway emergency bridge, including:

[0047] Place a cross beam at the vertical web bar between two truss segments, and align the cross beam screw rod with the through hole of the vertical web bar;

[0048] Connect the cross beam and the vertical web bar into a whole through bolts to form a segment splicing module;

[0049] Splice the splicing ends of the upper chord bar and the lower chord bar of two adjacent segment splicing modules through bolts;

[0050] Repeat the adjacent module splicing steps to build the bridge framework;

[0051] Lay and splice the panels section by section, and connect two adjacent panels through the buckle plates;

[0052] According to the passing load requirements, adjust the tension of the anchor screws section by section to make the structural deflection meet the specification requirements. After the tension reaches the target load, anchor both ends of the screws to the anchor plates respectively.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] (1) The present invention designs an assembled aluminum alloy truss structure. The emergency bridge spliced by this structure has the characteristics of light self-weight, low erection technical requirements, and high assembly efficiency. The assembled truss structure can be carried by manual or small machinery, which is beneficial to quickly resume bridge traffic.

[0055] (2) The present invention adds a stiffness adjustment mechanism to the truss structure. By adjusting the deflection of the aluminum alloy truss through the stiffness adjustment mechanism, the structural stiffness is increased to meet the structural stiffness requirements, avoiding deformation of the truss components, thereby improving the safety of the entire emergency bridge. The overall structure of the aluminum alloy truss is designed according to the stiffness adjustment needs, achieving lightweight while improving the structural stiffness.

[0056] (3) The assembled aluminum alloy truss structure of the present invention forms modules with crossbeams and spliced segment bridge decks. Positioning holes are reserved in the upper and lower main trusses, which can quickly realize module splicing, improve the splicing efficiency and accuracy, and can quickly assemble an emergency bridge through this splicing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0058] Figure 1 is the structural schematic diagram of the aluminum alloy truss structure of the present invention;

[0059] Figure 2 is the structural schematic diagram of the truss segment of the present invention;

[0060] Figure 3 is the structural schematic diagram of the crossbeam of the present invention;

[0061] Figure 4 is the structural schematic diagram of the stiffness adjustment mechanism of the present invention;

[0062] Figure 5 is the schematic diagram of the calculation parameters of the stiffness adjustment mechanism of the present invention;

[0063] Figure 6 is the connection schematic diagram of the aluminum alloy truss structure of the present invention;

[0064] Figure 7 isFigure 6 Structural sectional view in the A-A direction;

[0065] Figure 8 Schematic diagram of the parameters of the trough-shaped rod in Embodiment 1;

[0066] Figure 9 Schematic diagram of the emergency bridge assembly structure in Embodiment 1;

[0067] In the figure, 1. Truss segment, 2. Cross beam, 3. Panel, 11. Upper chord rod, 12. Lower chord rod, 13. Vertical web member, 14. Diagonal web member, 16. Anchor screw, 17. Anchor plate, 21. Upper cross bar, 22. Lower cross bar, 23. Vertical rod, 24. Diagonal rod. Specific implementation mode

[0068] Hereinafter, embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0069] An assembled aluminum alloy truss structure with adjustable stiffness, as Figure 1 shown, the aluminum alloy truss structure includes assembled truss segments 1, cross beams 2 and panels 3. The truss segments 1 are symmetrically arranged on both sides. The cross beams 2 are connected between the two truss segments 1, and a plurality of cross beams 2 are arranged in parallel along the laying direction of the truss segments 1. The panel 3 is laid on the plurality of cross beams 2. Among them, as Figure 2 shown, the truss segment 1 includes an upper chord rod 11 and a lower chord rod 12 arranged along the bridge span direction. Vertical web members 13 and diagonal web members 14 are connected between the upper chord rod 11 and the lower chord rod 12. A plurality of vertical web members 13 are evenly arranged along the chord rod. The diagonal web members 14 are obliquely installed between the two vertical web members 13. The upper and lower chord rods are both trough-shaped rods, and are installed at the ends of the vertical web members 13 on the inner and outer sides with the trough openings facing outward. The two upper and lower chord rods, the vertical web members 13 and the diagonal web members 14 are all connected by high-strength bolts. The stiffness adjustment mechanism is installed in the inner and outer troughs of the lower chord rod 12.

[0070] As Figure 3 shown, the cross beam 2 includes an upper cross bar 21 and a lower cross bar 22. Vertical rods 23 and diagonal rods 24 are connected between the upper cross bar 21 and the lower cross bar 22. The two ends of the upper cross bar 21 and the lower cross bar 22 have screw holes extending inward and opened in the rod body. The vertical web member 13 has through holes matching the screw holes. Bolts pass through the through holes and the screw holes to connect the upper cross bar 21 and the lower cross bar 22 to the vertical web member 13.

[0071] As shown in the figure, the panel 3 is a multi-chamber aluminum alloy plate. Clasps are provided at both ends of the panel 3 for connecting two adjacent panels 3 during segment assembly.

[0072] As Figure 4As shown in the figure, the stiffness adjustment mechanism includes a high-strength anchor screw 16 and an anchor plate 17. The anchor plate 17 is vertically arranged at both ends inside the groove of the lower chord 12. The screw 16 is arranged along the length direction of the chord. The end of the screw 16 is anchored to the anchor plate 17 by bolts. The anchor plate 17 is welded inside the groove along the notch section, and two pieces are arranged in parallel. The end of the screw 16 extends to the outside of the anchor plate 17 and is locked by a nut.

[0073] The design method of an assembled aluminum alloy truss with adjustable stiffness includes:

[0074] (1) Construct the above aluminum alloy truss structure, including connecting the cross beam between the vertical web members of the two side truss segments, laying the panel on the cross beam, and through the structural design of the cross beam, making the panel be laid in the middle of the truss segment, adjusting the dimensions of the truss segment and the cross beam so that they can cooperate with the stiffness adjustment mechanism to meet the stiffness adjustment requirements;

[0075] (2) Preset a stiffness adjustment mechanism in the aluminum alloy truss structure and calculate the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure. Among them, the preset stiffness adjustment mechanism includes:

[0076] Based on the bridge span as the stiffness adjustment direction, conduct a force analysis on the truss structure, and select the lower chord in the truss segment as the stiffness adjustment position;

[0077] Through the force analysis of the aluminum alloy truss structure, the most position for deflection adjustment of the truss structure is at the bottom of the structure. Based on the bridge span as the stiffness adjustment direction, select the bottom end of the truss structure as the stiffness adjustment position, set the tension end point of the stiffness adjustment mechanism at the end of the lower chord segment between the two side vertical web members. After determining the installation position, calculate the influence of the pre-tightening force of the stiffness adjustment mechanism on the deflection of the aluminum alloy truss, that is, the structural deflection adjusted by the stiffness adjustment mechanism;

[0078] (3) Calculate the maximum deflection of the aluminum alloy truss structure. At this time, the maximum deflection of the adjusted aluminum alloy truss structure is equal to the total deflection generated by the self-weight of the truss structure and the vehicle load minus the structural deflection adjusted by the stiffness adjustment mechanism;

[0079] (4) The stiffness of the truss structure is the ratio of the deflection to the span length. Based on this relationship, obtain the relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the adjusted truss structure;

[0080] (5) Design the parameters of the stiffness adjustment mechanism in the assembled aluminum alloy truss structure based on the relationship between the parameters of the stiffness adjustment mechanism and the adjusted stiffness.

[0081] The formula for calculating the structural deflection adjusted by the stiffness adjustment mechanism is as follows:

[0082]

[0083] Among them, N p is the tensile force of the high-strength anchoring screw, and e p is the distance from the anchoring position of the high-strength anchoring screw to the neutral axis of the truss structure. is the distance from the centroid axis of the truss structure to the bottom of the truss structure, E is the elastic modulus of aluminum alloy, and I is the moment of inertia of the aluminum alloy truss structure.

[0084] Through the cooperative design of the aluminum alloy truss structure, the moment of inertia I of the truss structure is calculated as follows:

[0085]

[0086] Among them, A is the cross-sectional area of the channel bar, and A s is the area of the high-strength anchoring screw, h is the distance from the center of the upper chord bar to the center of the lower chord bar, h1 is the distance from the center of the lower chord bar to the bottom of the truss structure, and I C is the moment of inertia of the channel bar cross-section, and I s is the moment of inertia of the anchoring screw cross-section.

[0087] As Figure 5 shown, the distance from the centroid axis of the truss structure to the bottom of the truss structure is calculated as follows:

[0088]

[0089] The distance e from the anchoring position of the anchoring screw to the neutral axis of the truss structure p is calculated as follows:

[0090]

[0091] Among them, fc is the design strength of aluminum alloy for tension and compression, and fs is the design value of the bearing capacity of the anchoring screw.

[0092] The neutral axis refers to the intersection line of the neutral layer of the beam and the cross-section. In the cases of plane bending and skew bending, the normal stress values of all points on the intersection line of the cross-section and the stress plane are zero, and this intersection line is called the neutral axis.

[0093] If the product of inertia Ixy of the cross-sectional graph with respect to any pair of orthogonal coordinates is 0, then this pair of coordinate axes is called the principal inertia axis, simply referred to as the principal axis. If this pair of coordinate axes passes through the centroid of the cross-section, it is called the centroid axis.

[0094] The maximum deflection of the aluminum alloy truss structure is calculated as follows:

[0095] w = f1 + f2 - f3

[0096] Among them, f1 is the deflection caused by the self-weight of the truss structure, and f2 is the deflection caused by the vehicle load. From this, the influence of the pre-tightening force of the stiffness adjustment mechanism on the maximum deflection of the aluminum alloy truss structure is obtained, and then the influence law of the stiffness adjustment mechanism parameters on the deflection is obtained. According to the relationship between deflection and stiffness (stiffness is the ratio of deflection to span length, ) the relationship between the stiffness adjustment mechanism parameters and the adjusted stiffness can be obtained.

[0097] In the calculation of the maximum deflection of the aluminum alloy truss structure, the calculations of f1 and f2 are as follows:

[0098]

[0099] Among them, q represents the self-weight line load, l represents the length of the assembled aluminum alloy structure, E represents the elastic modulus of aluminum alloy, I represents the moment of inertia of the assembled aluminum alloy truss structure, and k q represents the equivalent line load of the live load.

[0100] From the above calculations, it can be seen that in this application, in the design of the aluminum alloy truss structure, by adjusting the distance between the upper and lower chord bars, the overall structure height and the centroid position, the adjustment parameters of the stiffness adjustment mechanism can be changed. At the same time, the installation position and tension parameters of the stiffness adjustment mechanism also affect the stiffness adjustment effect. Therefore, in this application, the stiffness of the truss structure is adjusted integrally from the structural design and the cooperation with the stiffness adjustment mechanism to meet the stiffness requirements of the aluminum alloy truss structure.

[0101] The spliced highway emergency bridge is composed of the above-mentioned aluminum alloy truss structures. Among them, as Figure 6 and Figure 7 shown, the splicing ends of the truss segments are located at the ends of the upper and lower chord bars. The splicing chord bars of two adjacent segments are spliced through the splicing holes and bolts provided at the ends. The end of the panel is provided with a buckle plate, and the adjacent panels are connected through the buckle plate. The splicing method is as follows:

[0102] Place a cross beam at the vertical web member between two truss segments, and align the cross beam screw with the through hole of the vertical web member;

[0103] Connect the cross beam and the vertical web member into a whole through bolts to form a segment splicing module;

[0104] Splice the splicing ends of the upper and lower chord bars of two adjacent segment splicing modules through bolts;

[0105] Repeat the adjacent module splicing steps to build the bridge framework;

[0106] Lay and splice the panels section by section, and connect two adjacent panels through the buckle plate;

[0107] According to the passing load requirements, adjust the tension of the anchor bolts section by section to make the structural deflection meet the specification requirements. After the tension reaches the target load, anchor both ends of the bolts to the anchor plate respectively.

[0108] Example 1:

[0109] Build a highway emergency bridge with a span of 15 m, a width of 3 m, and a passing vehicle load of 30 t. Select 5 sections of aluminum alloy truss structures according to the span, as Figure 8 shown. In the truss structure, the upper and lower chord bars are made of channel aluminum, and the designed tensile and compressive strengths are 215 MPa. The cross-section form is as Figure 8 shown. Select the anchor bolts with a diameter of 27 mm, the designed bearing capacity is 232 kN, the tension of a single anchor bolt is 225 kN, the self-weight line load is 1.3 kN / m, and the equivalent line load of the live load is 12 kN / m.

[0110] According to the structural form and materials, the values of each parameter are shown in the following table:

[0111] Structural parameter values

[0112]

[0113] Combined with the above table parameters, the calculation parameters of the stiffness adjustment mechanism are as follows:

[0114] I = 4.175×10 9 (mm 4 );e p = 547 mm

[0115] The influence of the pre-tightening force of the stiffness adjustment mechanism on the deflection of the aluminum alloy truss is as follows:

[0116]

[0117] The deflection generated by the self-weight of the truss structure is:

[0118]

[0119] The deflection generated by the vehicle load is:

[0120]

[0121] Therefore, it can be known that the maximum deflection w of this assembled aluminum alloy truss structure is 6.1 mm, and the structural stiffness is 6.1 / 15000, and its value is 4.1e-4.

[0122] When the high-strength anchor bolts are not set, the maximum deflection of the aluminum alloy truss structure is 53.79 mm, and the structural stiffness is 53.79 / 15000, with a value of 3.58e-3. Therefore, setting the high-strength anchor bolts enhances the structural stiffness of the aluminum alloy truss.

[0123] The emergency bridge splicing is as follows:

[0124] Assemble a single truss structure; three vertical web members are arranged along the chord members in the truss segment, three cross beams are connected between the vertical web members of the two side truss segments, the panel is laid on the cross beam, and the stiffness adjustment mechanism is installed at the lower chord member;

[0125] As Figure 9 shown, splice 5 truss structures in sequence; splice the upper and lower chord members with bolts in sequence. After splicing, the adjacent panels are connected by buckle plates;

[0126] Stiffness adjustment mechanism adjustment; adjust the tension of the anchor bolts in segments so that the deflection of each truss structure meets the specification requirements. The tension adjustment per level does not exceed 20 kN. After reaching the target load, anchor the two ends of the anchor bolts to the inner and outer anchor plates respectively to complete the assembly of the emergency bridge.

[0127] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A design method for an aluminum alloy truss structure. The designed aluminum alloy truss structure includes prefabricated truss segments, cross beams, and panels, and is characterized in that, It has the following steps: (1) By analyzing the forces on the truss structure, adjust the positions and dimensions of the components of the truss structure to construct an aluminum alloy truss structure; (2) Preset a stiffness adjustment mechanism in the aluminum alloy truss structure, and calculate the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure; (3) Based on the design requirements of the truss structure stiffness, adjust the parameters of the stiffness adjustment mechanism, and install the adjusted stiffness adjustment mechanism in the aluminum alloy truss structure; Among them, calculating the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure includes: 1) Calculate the structural deflection adjusted by the stiffness adjustment mechanism; 2) Calculate the maximum deflection of the truss structure after the stiffness adjustment mechanism is adjusted; 3) Establish the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure from the relationship between deflection and stiffness; The formula for calculating the structural deflection adjusted by the stiffness adjustment mechanism is as follows: Among them, N p is the high-strength anchoring screw tension, e p is the distance from the anchoring position of the high-strength anchoring screw to the neutral axis of the truss structure, E is the elastic modulus of the aluminum alloy, I is the moment of inertia of the aluminum alloy truss structure, and l represents the structural length of the truss structure; The moment of inertia I of the aluminum alloy truss structure is calculated as follows: Among them, A is the cross-sectional area of the grooved rod at the installation position of the anchor screw, A s is the cross-sectional area of the high-strength anchor screw, h is the distance from the center of the upper chord to the center of the lower chord, h1 is the distance from the center of the lower chord to the bottom of the truss structure, I C is the moment of inertia of the cross-section of the grooved rod, I s is the moment of inertia of the cross-section of the anchor screw, is the distance from the centroid axis of the truss structure to the bottom of the truss structure; The distance from the centroid axis of the truss structure to the bottom of the truss structure is calculated as follows: The distance from the anchoring position of the anchoring screw to the neutral axis of the truss structure is calculated as follows: Among them, f c is the design strength of the aluminum alloy for tensile and compressive strength, and f s is the design value of the bearing capacity of the anchor screw; The truss segment includes upper and lower chord bars and vertical web members connected between the two. The upper and lower chord bars both include symmetric channel bars with the inner and outer sides installed at the ends of the vertical web members and the notch facing outward. The stiffness adjustment mechanism is installed in the inner and outer slots of the lower chord bar, and both ends of the high-strength anchoring screw in the stiffness adjustment mechanism are anchored between the vertical web members connected to both ends of the lower chord bar.

2. The aluminum alloy truss structure design method according to claim 1, characterized in that The preset stiffness adjustment mechanism includes: Based on the bridge span as the stiffness adjustment direction, select the stiffness adjustment position; Based on the adjustment characteristics of the stiffness adjustment mechanism, select the adjustment points of the stiffness adjustment mechanism at the stiffness adjustment position; Install the stiffness adjustment mechanism at the stiffness adjustment position with the adjustment point as the reference.

3. The aluminum alloy truss structure design method according to claim 1, characterized in that The maximum deflection of the truss structure after the stiffness adjustment mechanism is adjusted is calculated as follows: w = f1 + f2 - f3 Among them, f1 is the deflection generated by the self-weight of the truss structure, and f2 is the deflection generated by the vehicle load; Among them, the deflection f1 generated by the self-weight of the truss structure is as follows: The deflection f2 generated by the vehicle load is calculated as follows: Wherein, q represents the self-weight line load, E represents the elastic modulus of the aluminum alloy, I represents the moment of inertia of the aluminum alloy truss structure, and k q represents the equivalent line load of the live load.

4. The aluminum alloy truss structure design method according to claim 3, characterized in that The stiffness of the aluminum alloy truss is the ratio of the deflection to the span. Based on the maximum deflection w of the truss structure, the adjustment relationship between the parameters of the stiffness adjustment mechanism and the stiffness of the truss structure is obtained.

5. An aluminum alloy truss structure designed by the design method according to claim 1, the truss structure comprising prefabricated truss segments, cross beams and panels, the truss segments including upper chord bars and lower chord bars arranged along the bridge span direction, with vertical web members and diagonal web members connected between the upper chord bars and the lower chord bars, characterized in that: The upper and lower chord bars are both composed of symmetric channel bars with the inner and outer sides installed at the ends of the vertical web members and the notch facing outward. Two sets of stiffness adjustment mechanisms are respectively installed in the slots of the inner and outer channel bars of the lower chord bar; The cross beam includes an upper cross bar and a lower cross bar. A vertical bar and a diagonal bar are connected between the upper cross bar and the lower cross bar. The two ends of the upper cross bar and the lower cross bar have screw holes opened along the rod body extension direction. There are through holes at the vertical web member that match the screw holes. Bolts pass through the through holes and the screw holes to connect the upper cross bar and the lower cross bar to the vertical web member. The upper cross bar is connected to the middle of the vertical web member; The panel is a multi-chamber aluminum alloy plate. Buckle plates are provided at both ends of the panel. Adjacent panels are connected through the buckle plates; The stiffness adjustment mechanism includes a high-strength anchoring screw and an anchoring plate. The anchoring plates are vertically arranged at both ends in the slot of the lower chord bar, and the end of the screw is anchored to the anchoring plate through a bolt.

6. A highway emergency bridge assembled by splicing the aluminum alloy truss structure described in claim 5, characterized in that: The bridge is composed of multiple truss structures spliced together. Among them, the splicing ends of the truss segments are located at the ends of the upper and lower chords. The spliced chords of two adjacent segments are spliced through the splicing holes and bolts provided at the ends. A buckle plate is provided at the end of the panel, and adjacent panels are connected through the buckle plate.

7. A splicing method for the spliced highway emergency bridge according to claim 6, characterized in that, Including: Place a cross beam at the vertical web member between two truss segments, and align the cross beam screw with the through hole of the vertical web member; Connect the cross beam and the vertical web member into a whole through bolts to form a segment splicing module; Splice the splicing ends of the upper chord and the lower chord of two adjacent segment splicing modules through bolts; Repeat the adjacent module splicing steps to build the bridge framework; Lay and splice the panels section by section, and connect two adjacent panels through the buckle plate; According to the requirements of the passing load, adjust the tension of the anchor screws section by section to make the structural deflection meet the specification requirements. After the tension reaches the target load, anchor the two ends of the screw to the anchor plate respectively.

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