Self-prestressed glued laminated timber beam embedded with iron-based shape memory alloy and preparation method thereof

Abstract

The present invention discloses a self-prestressed glued laminated wood beam embedded with an iron-based shape memory alloy and a preparation method, which includes two wood laminates and a number of prestressing tendons; the two wood laminates are formed into a whole through bonding and pressing; a number of prestressing tendons are uniformly arranged along the width direction between the pressing and bonding surfaces of the two wood laminates; each prestressing tendon is installed at a set position on the pressing and bonding surface of one of the wood laminates through a U-shaped nail; each prestressing tendon includes an iron-based shape memory alloy wire and a flame-retardant tube sleeved on the outer periphery thereof. The present invention uses a pressing device to press the iron-based shape memory alloy wire and the two-side wood laminates to make a glued laminated wood beam, and finally, by energizing the iron-based shape memory alloy wire, the self-recovery characteristic thereof will generate prestress in the glued laminated wood beam. Through the pressing action of the wood laminates, the iron-based shape memory alloy wire will be firmly embedded in the glued laminated wood beam, and it is convenient to prepare in vivo prestressed glued laminated wood beams arranged in a straight line or a curve.

Description

Technical Field

[0001] The present invention relates to the technical field of prestressed structures, in particular to a self-prestressed glued laminated timber beam embedded with iron-based shape memory alloy and a preparation method thereof. Background Art

[0002] The main load-bearing members of modern timber structures are wooden columns and wooden beams. As the most commonly used timber structure member, the glued laminated timber beam often suffers from tensile brittle failure during use, resulting in the inability to exert the strength of the wood in the compression zone and insufficient utilization of material properties. With the country's call for energy conservation and carbon reduction, the construction industry has higher and higher requirements for the durability of building structures and the utilization rate of their materials. At present, some people in China have achieved prestressed glued laminated timber beams by grooving and embedding prestressing tendons or steel strands in the glued laminated timber beam, so as to improve the bearing capacity of the timber structure and the material properties of the wood. However, its grooving requires high precision, and anchoring and tensioning are required when applying prestress, and the steps are very cumbersome, which undoubtedly greatly increases the preparation difficulty.

[0003] Iron-based shape memory alloy can be applied to the field of prestress reinforcement of civil engineering structures due to its shape memory effect. The shape memory effect refers to the situation where, under pre-tension, through some excitation means, its temperature is increased, and the residual deformation generated during pre-tension will be restored after cooling. When the restoration of its residual deformation is blocked, a compressive stress can be generated on the obstacle. Therefore, when using iron-based shape memory alloy as a prestress material, mechanical tensioning is not required. So when applying prestress to a structure through iron-based shape memory alloy, no complex mechanical tensioning equipment is needed, and the efficiency is very high.

[0004] Although some people have embedded prestressing tendons in glued laminated timber beams for reinforcement, there are still the following deficiencies to be improved:

[0005] 1. During the embedding process, it is necessary to groove the glued laminated timber veneer, and the grooving accuracy requirement is high.

[0006] 2. During the prestress application process, a tensioning device is required to tension the prestressing tendon, and the anchoring equipment will also remain on the glued laminated timber beam, increasing the structural self-weight, and the advantages of the lightweight of the timber structure cannot be fully exerted.

[0007] Therefore, there is still a need to develop a method for conveniently and efficiently introducing prestress into glued laminated timber beams. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a self - prestressed glued laminated timber beam embedded with a ferrous - based shape memory alloy and a preparation method in view of the deficiencies of the above - mentioned prior art. The self - prestressed glued laminated timber beam embedded with a ferrous - based shape memory alloy and the preparation method can introduce prestress into the glued laminated timber beam through the self - recovery performance of the ferrous - based shape memory alloy without anchoring, and realize mechanical tensioning. Moreover, batch production can be completed in the factory, reducing on - site working hours.

[0009] To solve the above - mentioned technical problem, the technical solution adopted by the present invention is as follows:

[0010] A self - prestressed glued laminated timber beam embedded with a ferrous - based shape memory alloy includes two wood laminates and a number of prestressing tendons.

[0011] The two wood laminates are formed into a whole through bonding and pressing.

[0012] A number of the prestressing tendons are evenly arranged along the width direction between the pressing and bonding surfaces of the two wood laminates.

[0013] Each prestressing tendon is installed at a set position on the pressing and bonding surface of one of the wood laminates through a number of U - shaped nails.

[0014] Each prestressing tendon includes a ferrous - based shape memory alloy wire and a flame - retardant tube sleeved on the outer periphery of the ferrous - based shape memory alloy wire.

[0015] Each prestressing tendon is straight or curved.

[0016] A preparation method of a self - prestressed glued laminated timber beam embedded with a ferrous - based shape memory alloy includes the following steps.

[0017] Step 1, cutting: Cut the pre - stretched ferrous - based shape memory alloy wire according to a set length; wherein, the set length of the ferrous - based shape memory alloy wire is at least 100 mm longer than the length of the glued laminated timber beam.

[0018] Step 2, sleeving the flame - retardant tube: Sleeve a flame - retardant tube on the outer periphery of each cut ferrous - based shape memory alloy wire to form a prestressing tendon; wherein, the length of the flame - retardant tube needs to be greater than the length of the glued laminated timber beam.

[0019] Step 3, fixing the prestressing tendon: Fix the prestressing tendon formed in Step 2 at a set position on the pressing and bonding surface to be bonded of one of the wood laminates by using U - shaped nails.

[0020] Step 4, applying adhesive: Apply adhesive on the bonding surface to be bonded of the wood laminate.

[0021] Step 5, Pressing: Use a wooden beam pressing device to press two wooden laminates together; wherein, the wooden beam pressing device includes several wooden beam pressing tooling fixtures, and each wooden beam pressing tooling fixture includes a reaction steel frame, a pressure plate, an upper screw rod, a lower screw rod, and a fastening nut; the reaction steel frame and the pressure plate are arranged vertically and parallel; the upper screw rod and the lower screw rod are arranged horizontally and parallel between the reaction steel frame and the pressure plate, and one end of the upper screw rod and the lower screw rod is clamped to the reaction steel frame; the other ends of the upper screw rod and the lower screw rod extend out from the pressure plate and are respectively sleeved with fastening nuts.

[0022] The pressing method for two wooden laminates specifically includes the following steps:

[0023] Step 5A, Layout of the tooling position: Place several wooden beam pressing tooling fixtures along the length direction of the wooden laminate and determine the placement position of each wooden beam pressing tooling fixture.

[0024] Step 5B, Assembly of the lower screw rod: At the placement position of each wooden beam pressing tooling fixture, arrange the corresponding reaction steel frame and the pressure plate vertically and parallel, clamp one end of the lower screw rod in the reaction steel frame, let the other end extend out from the pressure plate, and sleeve a fastening nut on the extended end of the lower screw rod.

[0025] Step 5B, Placement of the wooden laminates: Place the two wooden laminates on the lower screw rods between the reaction steel frame and the pressure plate, and place the adhesive-coated surfaces to be bonded facing each other and in a vertical state.

[0026] Step 5C, Assembly of the upper screw rod: At the placement position of each wooden beam pressing tooling fixture, place the upper screw rod on the top of the two laminates, clamp one end of the upper screw rod in the reaction steel frame, let the other end extend out from the pressure plate, and sleeve a fastening nut on the extended end of the upper screw rod.

[0027] Step 5D, Pressing: Rotate the fastening nut, and the pressure plate will move towards the bonding surface of the wooden laminate, thereby pressing the two wooden laminates to a set depth, so that all the prestressing tendons are completely embedded inside the two wooden laminates, forming a glued wooden beam.

[0028] Step 6, Demolish the pressure plate: When the bonding surface of the two wooden laminates reaches the set bonding strength, screw out all the fastening nuts from the corresponding upper screw rod or lower screw rod, and demolish the pressure plate.

[0029] Step 7, Apply prestress: Apply an electric heating excitation to each iron-based shape memory alloy wire. Due to the generation of the shape memory effect, the iron-based shape memory alloy wire will retract and become shorter. However, since the iron-based shape memory alloy wire is firmly embedded in the glued wooden beam, the iron-based shape memory alloy wire will in turn apply in-body prestress to the wooden beam, forming a self-prestressed glued wooden beam.

[0030] In Step 7, the excitation temperature for heating each iron-based shape memory alloy wire by energization needs to be determined according to the recovery stress range of the iron-based shape memory alloy wire.

[0031] In Step 7, the recovery stress range of the iron-based shape memory alloy wire is associated with the shape of the iron-based shape memory alloy wire; the shape of the iron-based shape memory alloy wire is determined according to the set position during the fixation of the prestressed tendon in Step 3.

[0032] When the iron-based shape memory alloy wire is straight, the maximum recovery stress σ of a single iron-based shape memory alloy wire Fe-SMA,max has the following calculation formula:

[0033]

[0034] In the formula, f t is the tensile strength of the top wood fiber at the mid-span of the glued laminated timber beam, which is a known value.

[0035] b is the width of the cross-section of the glued laminated timber beam, and h is the height of the cross-section of the glued laminated timber beam.

[0036] e is the distance from the iron-based shape memory alloy wire to the center point at the mid-span of the glued laminated timber beam.

[0037] n is the number of iron-based shape memory alloy wires;

[0038] A Fe-SMA is the cross-sectional area of the iron-based shape memory alloy wire.

[0039] When the iron-based shape memory alloy wire is curved, the maximum recovery stress σ of a single iron-based shape memory alloy wire Fe-SMA,max has the following calculation formula:

[0040]

[0041] In the formula, f is the vertical distance from the center point at the mid-span of the glued laminated timber beam to the iron-based shape memory alloy wire.

[0042] l is the length of the glued laminated timber beam.

[0043] θ is the angle between the extending direction of the end of the curved iron-based shape memory alloy wire and the length direction of the glued laminated timber beam.

[0044] In Step 5D, when there are no gaps around the contact surface of the two wood laminates, it is considered that the two wood laminates have been pressed to the set depth. The present invention has the following beneficial effects:

[0045] 1. The present invention can solve the defect that in traditional wooden beams, the performance of the wood in the compression zone cannot be utilized due to brittle failure in the tensile zone, and greatly increases the material utilization rate of the wood.

[0046] 2. The present invention does not require mechanical equipment for tensioning. It only needs to heat the iron-based shape memory alloy to a predetermined temperature, with simple and convenient operation. It can be prefabricated in large quantities in the factory, greatly shortening the construction time.

[0047] 3. The present invention does not require high precision and has simple operation, which can avoid losses caused by improper operation.

[0048] 4. Since the present invention does not require anchoring equipment for prestress application, the advantages of the light weight of the wooden structure can be fully utilized.

[0049] 5. The present invention does not require manual tensioning and anchoring, which can greatly save construction costs.

[0050] 6. The wooden beam pressing device adopted by the present invention can press a large number of wooden laminates and iron-based shape memory alloys, greatly improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a side view during the preparation of a self-prestressed glued wooden beam with an embedded iron-based shape memory alloy according to the present invention.

[0052] Figure 2 is a sectional view during the preparation of a self-prestressed glued wooden beam with an embedded linear iron-based shape memory alloy according to the present invention.

[0053] Figure 3 is a sectional view during the preparation of a self-prestressed glued wooden beam with an embedded curved iron-based shape memory alloy according to the present invention.

[0054] Figure 4 is a top view during the installation of the screw, reaction steel frame and pressure plate in the present invention.

[0055] Figure 5 are schematic diagrams of the calculated dimensions of two glued wooden beams; among them, Figure (a) shows a schematic diagram of the dimensions of a self-prestressed glued wooden beam with an embedded linear iron-based shape memory alloy; Figure (b) shows a schematic diagram of the dimensions of a self-prestressed glued wooden beam with an embedded curved iron-based shape memory alloy.

[0056] Among them: 1. wooden laminate; 2. iron-based shape memory alloy wire; 3. flame retardant pipe; 4. U-shaped nail; 5. reaction steel frame; 6. screw; 7. fastening nut; 8. pressure plate. DETAILED DESCRIPTION OF THE INVENTION

[0057] The present invention will be further described in detail below in conjunction with the drawings and specific preferred embodiments.

[0058] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second", etc. do not represent the importance of components, so it cannot be understood as a limitation to the present invention. The specific dimensions adopted in this embodiment are only for illustrating the technical solution by way of example and do not limit the protection scope of the present invention.

[0059] As Figures 1 to 3 shown, a self-prestressed glued laminated timber beam embedded with iron-based shape memory alloy includes two wood laminates 1 and a number of prestressing tendons.

[0060] The two wood laminates are formed into a whole by bonding and pressing.

[0061] A number of prestressing tendons are uniformly arranged along the width direction between the pressing and bonding surfaces of the two wood laminates.

[0062] Each prestressing tendon is installed at a set position on the pressing and bonding surface of one of the wood laminates through a number of U-shaped nails 4.

[0063] Each prestressing tendon includes an iron-based shape memory alloy wire 2 and a flame-retardant tube 3 sleeved on the outer periphery of the iron-based shape memory alloy wire.

[0064] The flame-retardant hose 3 is used to prevent the iron-based shape memory alloy threaded bar 2 from heating up and damaging the surrounding wood laminate 1, and the length of the flame-retardant hose 3 should be greater than the length of the glued laminated timber beam to prevent the exposed position of the iron-based shape memory alloy wire 2 from being damaged by high temperature.

[0065] The above U-shaped nails 4 are preferably nailed on the wood laminate 1 through a pneumatic rivet gun to fix the iron-based shape memory alloy wire 2. The fixed positions of the straight or curved iron-based shape memory alloy wire 2 should be pre-drawn on the glued laminated timber beam in advance. The U-shaped nails 4 can also increase the bonding strength between the flame-retardant hose 3 and the iron-based shape memory alloy threaded bar 2.

[0066] Each prestressing tendon is in the form of a straight line as Figure 2 shown or a curved line as Figure 3 shown.

[0067] In the present invention, the iron-based shape memory alloy wire 2 generates a recovery stress through temperature rise excitation. Due to the pressing of the wood laminate 1, it cannot recover, thus introducing prestress into the glued laminated timber beam.

[0068] A preparation method of a self-prestressed glued laminated timber beam embedded with iron-based shape memory alloy includes the following steps.

[0069] Step 1, cutting: Cut the pre-stretched iron-based shape memory alloy wire to a set length; wherein, the set length of the iron-based shape memory alloy wire is at least 100 mm longer than the length of the glued laminated timber beam, preferably 200 mm longer, leaving the length required for heating excitation.

[0070] Step 2, sleeving a flame-retardant pipe: Sleeve a flame-retardant pipe around each cut iron-based shape memory alloy wire to form a prestressed tendon; wherein, the length of the flame-retardant pipe needs to be greater than the length of the glued laminated timber beam.

[0071] Step 3, fixing the prestressed tendon: Preferably use a pneumatic rivet gun to drive out U-shaped nails 4 and fix the prestressed tendon formed in Step 2 at a set position on the bonding surface to be pressed of one of the wooden laminates.

[0072] Step 4, applying an adhesive: Apply an adhesive to the bonding surface to be glued of the wooden laminate.

[0073] Step 5, pressing

[0074] The present invention uses a wooden beam pressing device to press two wooden laminates together.

[0075] The above-mentioned wooden beam pressing device includes a number of wooden beam pressing workpieces, and each wooden beam pressing workpiece includes a reaction steel frame 5, a pressure plate 8, an upper screw, a lower screw and a fastening nut 7.

[0076] The above-mentioned upper screw and lower screw are collectively referred to as screw 6.

[0077] The reaction steel frame and the pressure plate are arranged vertically and parallel; the upper screw and the lower screw are arranged horizontally up and down between the reaction steel frame and the pressure plate, and one end of the upper screw and the lower screw is clamped with the reaction steel frame; the other ends of the upper screw and the lower screw extend out of the pressure plate and are respectively sleeved with fastening nuts.

[0078] Further, the reaction steel frame 5 has a groove, and the screw 6 is clamped on the groove of the reaction steel frame 5 through the protruding end. At this time, after the glued laminated timber beam is cut and the iron-based shape memory alloy threaded bars are fixed, a strong adhesive is applied to both sides to be pressed. Half of the glued laminated timber beam with the iron-based shape memory alloy threaded bars fixed is attached to the reaction steel frame 5, and the lower side is the screw 6 placed in advance. Then the other half of the glued laminated timber beam is placed on the screw 6.

[0079] One end of the screw 6 is clamped on the reaction steel frame 5, and the other end extends out of the pressure plate 8. The fastening nut 7 is used to press the glued laminated timber beam.

[0080] The fastening nut 7 needs to be pre-tightened when the glued laminated timber beam is placed, and the position is adjusted to ensure that the positions of the two half glued laminated timber beams coincide.

[0081] The pressure plate 8 is provided with a long hole through which the screw rod 6 can extend. By tightening the fastening nut 7 screwed on the screw rod 6, pressure is applied to the pressure plate, and the pressure plate 8 further presses the glued laminated timber beam. When the crack between the two halves of the glued laminated timber beam can no longer be observed, maintain this pressure state. After it reaches the strength, the pressure plate can be removed to complete the internal reinforcement of the prestressed glued laminated timber slab.

[0082] The pressing method for two wood slabs specifically includes the following steps.

[0083] Step 5A, arranging the tooling position: Place several wood beam pressing toolings along the length direction of the wood slab and determine the placement position of each wood beam pressing tooling.

[0084] Step 5B, assembling the lower screw rod: At the placement position of each wood beam pressing tooling, arrange the corresponding reaction steel frame and pressure plate vertically and parallelly, and snap one end of the lower screw rod into the reaction steel frame, with the other end extending from the pressure plate, and sleeving a fastening nut on the extending end of the lower screw rod.

[0085] Step 5B, placing the wood slabs: Place both wood slabs on the lower screw rod between the reaction steel frame and the pressure plate, and place the adhesive-coated bonding surfaces facing each other and in a vertical state.

[0086] Step 5C, assembling the upper screw rod: At the placement position of each wood beam pressing tooling, place the upper screw rod on the top of the two slabs, and snap one end of the upper screw rod into the reaction steel frame, with the other end extending from the pressure plate, and sleeving a fastening nut on the extending end of the upper screw rod.

[0087] Step 5D, pressing: Rotate the fastening nut, and the pressure plate will move towards the bonding surface of the wood slab, thereby pressing the two wood slabs to the set depth, so that all prestressing tendons are completely embedded inside the two wood slabs to form a glued laminated timber beam. Among them, when there is no gap around the contact surface of the two wood slabs, it is considered that the two wood slabs have been pressed to the set depth.

[0088] Step 6, removing the pressure plate: When the bonding surface of the two wood slabs reaches the set bonding strength, unscrew all the fastening nuts from the corresponding upper screw rod or lower screw rod, and remove the pressure plate.

[0089] Step 7, applying prestress: Apply current to heat and excite each iron-based shape memory alloy wire. Due to the generation of the shape memory effect, the iron-based shape memory alloy wire will retract and become shorter. However, since the iron-based shape memory alloy wire is firmly embedded in the glued laminated timber beam, therefore, the iron-based shape memory alloy wire will in turn apply internal prestress to the wood beam to form a self-prestressed glued laminated timber beam.

[0090] Among them, the excitation temperature for heating each iron-based shape memory alloy wire by energization needs to be determined according to the recovery stress range of the iron-based shape memory alloy wire.

[0091] The recovery stress range of the above-mentioned iron-based shape memory alloy wire is associated with the shape of the iron-based shape memory alloy wire; the shape of the iron-based shape memory alloy wire is determined according to the set position during the fixing of the prestressed tendon in step 3.

[0092] When the iron-based shape memory alloy wire is straight, the maximum recovery stress σ of a single iron-based shape memory alloy wire (i.e., a single prestressed tendon) Fe-SMA,max has the following calculation formula:

[0093]

[0094] In the formula, f t is the tensile strength of the top wood fibers at the mid-span of the glued laminated timber beam, which is a known value.

[0095] b is the width of the cross-section of the glued laminated timber beam, and h is the height of the cross-section of the glued laminated timber beam.

[0096] e is the distance from the iron-based shape memory alloy wire to the center point at the mid-span of the glued laminated timber beam.

[0097] n is the number of iron-based shape memory alloy wires (i.e., prestressed tendons).

[0098] A Fe-SMA is the cross-sectional area of the iron-based shape memory alloy wire.

[0099] When the iron-based shape memory alloy wire is curved, the maximum recovery stress σ of a single iron-based shape memory alloy wire (i.e., a single prestressed tendon) Fe-SMA,max has the following calculation formula:

[0100]

[0101] In the formula, f is the vertical distance from the center point at the mid-span of the glued laminated timber beam to the iron-based shape memory alloy wire.

[0102] l is the length of the glued laminated timber beam.

[0103] θ is the angle between the extending direction of the end of the curved iron-based shape memory alloy wire and the length direction of the glued laminated timber beam.

[0104] The in-body prestress to be applied to the glued laminated timber beam is specifically determined according to the load that the glued laminated timber beam needs to bear, and try to make the two offset each other. Then, according to the in-body prestress to be applied to the glued laminated timber beam, the optimal recovery stress of a single iron-based shape memory alloy wire (i.e., a single prestressed tendon) is determined; finally, according to the optimal recovery stress, the optimal excitation temperature is calculated. Among them, the optimal recovery stress should not be greater than σ Fe-SMA,max .

[0105] Step 8: Glue the pressed wooden laminate 1 and the ordinary wooden laminate to make a glued laminated beam. When needed, only by heating and exciting both ends of the exposed iron-based shape memory alloy wire 2, the prestress can be introduced into the glued laminated beam.

[0106] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy, characterized in that: It includes two wooden laminates and several prestressing tendons; The two wooden laminates form an integral body through bonding and pressing; the two wooden laminates can be pressed to a set depth so that all the prestressing tendons are completely embedded inside the two wooden laminates; A number of the prestressing tendons are evenly arranged in the width direction between the pressing and bonding surfaces of the two wooden laminates; Each prestressing tendon is installed at a set position on the pressing and bonding surface of one of the wooden laminates through a number of U-shaped nails; Each prestressing tendon includes a ferrous-based shape memory alloy wire and a flame-retardant tube sleeved on the outer periphery of the ferrous-based shape memory alloy wire.

2. The self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy according to claim 1, characterized in that: Each prestressing tendon is linear or curved.

3. A preparation method of the self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy according to any one of claims 1 - 2, characterized in that: It includes the following steps: Step 1, Cutting: Cut the pre-stretched ferrous-based shape memory alloy wire according to a set length; wherein, the set length of the ferrous-based shape memory alloy wire is at least 100 mm longer than the length of the glued laminated timber beam; Step 2, Sleeving the flame-retardant tube: Sleeve a flame-retardant tube on the outer periphery of each cut ferrous-based shape memory alloy wire to form a prestressing tendon; wherein, the length of the flame-retardant tube needs to be greater than the length of the glued laminated timber beam; Step 3, Fixing the prestressing tendon: Fix the prestressing tendon formed in Step 2 at a set position on the pressing and bonding surface to be bonded of one of the wooden laminates by using U-shaped nails; Step 4, Smearing the adhesive: Smear the adhesive on the bonding surface to be bonded of the wooden laminate; Step 5, Pressing: Use a wooden beam pressing device to realize the pressing of the two wooden laminates; wherein, the wooden beam pressing device includes a number of wooden beam pressing toolings, and each wooden beam pressing tooling includes a reaction steel frame, a pressure plate, an upper screw rod, a lower screw rod and a fastening nut; the reaction steel frame and the pressure plate are arranged vertically and parallelly; the upper screw rod and the lower screw rod are arranged vertically and parallelly between the reaction steel frame and the pressure plate, and one ends of the upper screw rod and the lower screw rod are both clamped with the reaction steel frame; the other ends of the upper screw rod and the lower screw rod both extend out of the pressure plate and are respectively sleeved with fastening nuts; Then the pressing method of the two wooden laminates specifically includes the following steps: Step 5A, Arranging the position of the tooling: Place a number of wooden beam pressing toolings along the length direction of the wooden laminate and determine the placement position of each wooden beam pressing tooling; Step 5B, Assembling the lower screw rod: At the placement position of each wooden beam pressing tooling, arrange the corresponding reaction steel frame and the pressure plate vertically and parallelly, clamp one end of the lower screw rod in the reaction steel frame, extend the other end out of the pressure plate, and sleeve a fastening nut on the extended end of the lower screw rod; Step 5B, Placing the wooden laminates: Place the two wooden laminates on the lower screw rods between the reaction steel frame and the pressure plate, and the bonding surfaces to be bonded smeared with the adhesive face each other and are in a vertical state; Step 5C, Assembling the upper screw rod: At the placement position of each wooden beam pressing tooling, place the upper screw rod on the top of the two laminates, clamp one end of the upper screw rod in the reaction steel frame, extend the other end out of the pressure plate, and sleeve a fastening nut on the extended end of the upper screw rod; Step 5D, Pressing: Rotate the fastening nut, and the pressure plate will move towards the bonding surface of the wooden laminate, so as to press the two wooden laminates to a set depth, so that all the prestressing tendons are completely embedded inside the two wooden laminates to form a glued laminated timber beam; Step 6. Remove the pressure plate: When the bonding surfaces of the two wooden laminates reach the set bonding strength, unscrew all the fastening nuts from the corresponding upper screws or lower screws, and remove the pressure plate. Step 7. Apply prestress: Electrify and heat each iron-based shape memory alloy wire for excitation. Due to the shape memory effect, the iron-based shape memory alloy wire will retract and become shorter. However, since the iron-based shape memory alloy wire is firmly embedded in the glued laminated timber beam, the iron-based shape memory alloy wire will in turn apply in-body prestress to the wooden beam, forming a self-prestressed glued laminated timber beam.

4. The preparation method of the self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy according to claim 3, characterized in that: In Step 7, the excitation temperature for electrifying and heating each iron-based shape memory alloy wire needs to be determined according to the recovery stress range of the iron-based shape memory alloy wire.

5. The preparation method of the self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy according to claim 4, characterized in that: In Step 7, the recovery stress range of the iron-based shape memory alloy wire is associated with the shape of the iron-based shape memory alloy wire; the shape of the iron-based shape memory alloy wire is determined according to the set position during the fixation of the prestressing tendon in Step 3.

6. The preparation method of the self - prestressed glued laminated wood beam embedded with an iron - based shape memory alloy according to claim 5, characterized in that: When the iron-based shape memory alloy wire is straight, the maximum recovery stress σ of a single iron-based shape memory alloy wire Fe-SMA,max is calculated by the formula: where f t is the tensile strength of the top wood fibers at the mid-span of the glulam beam, a known value; b is the cross-sectional width of the glued laminated timber beam, and h is the cross-sectional height of the glued laminated timber beam; e is the distance from the iron-based shape memory alloy wire to the center point of the mid-span of the glued laminated timber beam; n is the number of iron-based shape memory alloy wires; A Fe-SMA is the cross-sectional area of the iron-based shape memory alloy wire.

7. The preparation method of the self-prestressed glued laminated timber beam embedded with an iron-based shape memory alloy according to claim 6, characterized in that: When the iron-based shape memory alloy wire is curved, the maximum recovery stress σ Fe-SMA,max of a single iron-based shape memory alloy wire is calculated by the following formula: In the formula, f is the vertical distance from the center point of the mid-span of the glued laminated timber beam to the iron-based shape memory alloy wire; l is the length of the glued laminated timber beam; θ is the angle between the extending direction of the end of the curved iron-based shape memory alloy wire and the length direction of the glued laminated timber beam.

8. The preparation method of the self-prestressed glued laminated timber beam embedded with an iron-based shape memory alloy according to claim 3, characterized in that: In Step 5D, when there is no gap around the contact surface of the two wooden laminates, it is considered that the two wooden laminates have been pressed to the set depth.

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