Semi-fabricated durable small-deformation combined guardrail and construction method thereof

Abstract

The invention relates to a semi-fabricated durable small-deformation combined guardrail and a construction method thereof.The guardrail comprises an upper steel structure part and a lower concrete structure part, and the steel structure part comprises stand columns, longitudinal beams, friction beams, n-shaped steel, cross beams, connecting pieces and supporting blocks; the concrete structure part comprises an external protective layer (UHPC material), internal filling body concrete (common concrete with slump of more than 200mm), a connecting rod, a support frame, connecting glue and an end head. The guardrail mounting method comprises the following steps: step 1, surveying and setting out, and preparing materials; 2, the connecting face of the external protective layer is coated with connecting glue, and the connecting rod and the supporting frame are welded; step 3, splicing an external protective layer; 4, end heads are installed; 5, installing the stand columns and the cross beams; sixthly, internal filling body concrete is poured; and 7, mounting the longitudinal beams and the friction beams. The method has the following advantages that installation is easy and convenient, and construction efficiency is high; the installation linearity on a concrete guardrail road section is uniform, and the appearance quality is good; the maximum dynamic external invasion equivalent value after the vehicle is collided can be effectively reduced, and the vehicle and an obstacle behind the guardrail are protected; the guardrail is high in durability, and the whole life cycle cost of the guardrail is saved.

Description

Technical Field

[0001] This invention relates to the field of protective fence design and construction technology, specifically to a semi-assembled, durable, low-deformation composite guardrail and its construction method. Background Technology

[0002] Highway guardrails are crucial traffic safety facilities, effectively protecting drivers. When obstacles such as ETC gantries lie behind the guardrails, it is essential to ensure a sufficient safety distance between the guardrails and these obstacles. The "Design Specifications for Highway Traffic Safety Facilities" (JTG D81—2017) stipulates that concrete guardrails should be used for median barriers in road sections with a high proportion of large vehicles. However, existing concrete guardrails have a large maximum dynamic outward tilt equivalent value, which is insufficient to effectively protect against obstacles. Simply widening the concrete guardrail at the obstacle location is time-consuming and labor-intensive, and in actual design, the width of the median strip often limits its widening. Therefore, specially designed guardrails with small deformation capacity are needed in these sections.

[0003] Currently, steel guardrails are the main type of guardrail with small deformation capacity on the market. When concrete guardrails are used in the median strip, a transition section needs to be designed between the small deformation steel guardrail and the standard concrete guardrail, resulting in inconsistent guardrail linearity and poor aesthetics. When using composite guardrails, the concrete part of the guardrail requires on-site formwork and rebar tying, making the guardrail installation complex and requiring a large number of on-site workers. Furthermore, ordinary concrete has weak freeze-thaw resistance and low durability, making it susceptible to corrosion and deterioration from freezing, carbonization, and de-icing agents. This causes the guardrail surface to loosen and peel off, and the internal rebar to be exposed and corroded, significantly shortening its service life. It also requires frequent application of protective paint for maintenance, increasing maintenance costs. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a semi-assembled, durable, low-deformation composite guardrail and its construction method.

[0005] A semi-assembled, durable, low-deformation composite guardrail includes an upper steel structure and a lower concrete structure.

[0006] The steel structure includes columns, longitudinal beams, friction beams, Z-shaped steel, crossbeams, connectors, and support blocks. The columns are composed of vertical square steel pipes with a horizontal square steel pipe welded to the top. The horizontal square steel pipes, Z-shaped steel, and longitudinal beams, along with the friction beams, effectively extend the upper impact surface of the guardrail to reduce the maximum dynamic outward intrusion equivalent value of a vehicle after impact. The columns, longitudinal beams, friction beams, Z-shaped steel, crossbeams, and connectors all have bolt holes and are connected to each other by bolts and welding. Preferably, the steel structure is made of Q355 grade low-alloy high-strength structural steel, and all surfaces are galvanized.

[0007] The concrete structure includes an outer protective layer, an inner filling concrete, connecting rods, a support frame, adhesive, and end caps. The outer protective layer is made of ultra-high performance concrete (UHPC). The inner filling concrete is made of ordinary concrete with a slump greater than 200. The connecting rods are 600mm long and 22mm diameter HRB400 hot-rolled ribbed steel bars, placed inside the joints of the outer protective layer to reinforce the connection. The support frame is welded from 10mm diameter steel bars and supports the connecting rods. Furthermore, the outer protective layer is a thin-shell structure with openings at both ends. Each segment is 4m long and 3cm thick. It is prefabricated in the factory and transported to the site for assembly. The top of the outer protective layer has square mounting holes and rectangular pouring holes. The columns are inserted into the concrete structure through the mounting holes, and the side length of the mounting holes is slightly larger than the side length of the columns. The connecting adhesive material is preferably silicone structural adhesive, which is applied to the splicing surface of the outer protective layer to seal it when the internal filling concrete is poured. The ends are installed at both ends of the spliced ​​outer protective layer to seal it.

[0008] Furthermore, the internal filling concrete is poured into the outer protective layer through the pouring hole. After the internal filling concrete sets and solidifies, it effectively connects the spliced ​​outer protective layer and the column to form an integrated protective structure.

[0009] The construction method for this semi-assembled, durable, low-deformation composite guardrail includes the following steps: Step 1. Measure and lay out the site, clear the site, and transport the prefabricated external protective layer and steel structure to the site.

[0010] Step 2. Apply the connecting adhesive evenly to the splicing surface of the external protective layer to be installed, and weld the connecting rod and the support frame into a whole.

[0011] Step 3. Splice the outer protective layer longitudinally at the installation position. During splicing, the connecting adhesive should be squeezed out at the joints of adjacent outer protective layers to ensure that the spliced ​​surfaces fit tightly. Place the connecting rod and support frame inside the connection position of the outer protective layer.

[0012] Step 4. Repeat the above steps until the entire outer protective layer is spliced ​​together, and install the end caps at both ends of the spliced ​​outer protective layer.

[0013] Step 5. After connecting the column and the Z-shaped steel with bolts, insert them into the mounting holes. After adjusting the column to be vertical, weld the column and the support block into a whole. Connect the crossbeam and the column with bolts and connectors.

[0014] Step 6. Pour the internal filling concrete into the pouring holes. When pouring, start from the lower end of the elevation and pour every other hole. After the internal filling concrete overflows from the adjacent pouring hole, move to the next hole for pouring.

[0015] Step 7. After the internal filling concrete reaches the design strength, the longitudinal beam, friction beam, column, Z-shaped steel, and connecting plate are effectively connected by welding and bolts.

[0016] This semi-assembled, durable, low-deformation composite guardrail is obtained according to the above construction method.

[0017] The present invention has the following advantages: 1. The combined guardrail makes full use of the lower concrete to increase the overall structural height, reducing the amount of steel used; the horizontal welded steel pipes and Z-shaped steel on the upper part of the guardrail posts together extend the upper impact surface, effectively reducing the maximum dynamic external intrusion equivalent value of vehicles.

[0018] 2. The concrete section of the combined guardrail has the same cross-section as the traditional separate concrete guardrail, and the overall alignment of the road section with the concrete guardrail is uniform and aesthetically pleasing.

[0019] 3. The lower concrete part of the combined guardrail adopts a semi-prefabricated construction method, which does not require steps such as formwork and steel bar binding. The upper steel structure part can be combined with the lower concrete part through simple installation. This reduces the professional requirements of construction personnel and machinery and improves construction efficiency.

[0020] 4. The outer protective layer of the composite guardrail is made of UHPC material, which has excellent durability and can effectively resist the damage of corrosive materials such as de-icing agents to the concrete guardrail, greatly improving the service life of the guardrail. Attached Figure Description

[0021] Figure 1 This is a side view of the combined guardrail. Figure 2 This is a top view of the combined guardrail. Figure 3 This is a cross-sectional view of section AA; Figure 4 This is an enlarged side view of the middle section of the combined guardrail; Figure 5 This is an enlarged top view of the middle section of the combined guardrail; Explanation of reference numerals in the attached drawings: 1-Column, 2-Longitudinal beam, 3-Friction beam, 4-Z-shaped steel, 5-Horizontal beam, 6-Type I connecting plate, 7-Type II connecting plate, 8-Type III connecting plate, 9-Type IV connecting plate, 10-External protective layer, 11-Internal filling concrete, 12-Bolt, 13-Pouring hole, 14-Mounting hole, 15-Connecting adhesive, 16-Connecting rod, 17-Support frame, 18-Support block, 19-End. Detailed Implementation

[0022] To make the present invention easier to understand, it will be further described below with reference to the accompanying drawings and embodiments. It is worth noting that the description herein is limited to explaining the present invention, and any modifications and alterations made to the present invention without departing from its principles are within the scope of protection of the present invention.

[0023] Step 1. Measure and lay out, clear the site, and transport the prefabricated external protective layer 10 and steel structure to the site.

[0024] Step 2. Apply the connecting adhesive 15 evenly to the splicing surface of the outer protective layer 10 to be installed, and weld the connecting rod 16 to the support frame 17 into a whole.

[0025] Step 3. Splice the outer protective layer 10 longitudinally at the installation position. When splicing, the connecting adhesive 15 should be squeezed out from all four seams of the adjacent outer protective layers 10 to ensure that the splicing surfaces are tightly fitted. When splicing, place the connecting rod 16 and the support frame 17 inside the connection position of the outer protective layer 10.

[0026] Step 4. Repeat the above steps until the outer protective layer 10 is fully spliced, and install end caps 19 at both ends of the spliced ​​outer protective layer 10.

[0027] Step 5. After connecting the column 1 and the Z-shaped steel 4 with bolts 12, insert them into the mounting hole 14. After adjusting the column 1 to be vertical, weld the column 1 and the support block 18 into a whole. Then, connect the crossbeam 5 to the column 1 with bolts 12, type I connecting plate 6, and type IV connecting plate 9. The type I connecting plate 6 is connected to the column 1 by welding.

[0028] Step 6. After all the columns 1 and beams 5 are installed, pour the internal filling concrete 11 through the pouring holes 13. When pouring, start from the lower end of the elevation and pour every other hole. After the internal filling concrete 11 overflows from the adjacent pouring hole 13, move to the next hole for pouring. After all the pouring holes 13 are filled, clean the surface of the guardrail and the site.

[0029] Step 7. After the internal filling concrete 13 reaches its design strength, install the longitudinal beam 2 onto the guardrail using type I connecting plate 6, type II connecting plate 7, and bolts 12. The type I connecting plate 6 and type II connecting plate 7 are connected to the longitudinal beam 2 by welding. Similarly, install the friction beam 3 onto the installed guardrail using type II connecting plate 7, type III connecting plate 8, and bolts 12. The longitudinal beam 2 and the friction beam 3 are longitudinally connected by bolts 12 and an internal sleeve. A picture of the completed installation is attached. Figure 1 Appendix Figure 2 Appendix Figure 3 Appendix Figure 4As shown.

Claims

1. A semi-prefabricated, durable, low-deformation composite guardrail and its construction method, characterized by the following construction steps: Step 1. Measure and lay out, clear the site, and transport the prefabricated external protective layer (10) and steel structure to the site; Step 2. Apply the connecting adhesive (15) evenly to the splicing surface of the outer protective layer (10) to be installed, and weld the connecting rod (16) and the support frame (17) into a whole; Step 3. Splice the outer protective layer (10) longitudinally at the installation position. When splicing, the connecting adhesive (15) should be squeezed out at the joint of the adjacent outer protective layers (10) to ensure that the splicing surfaces are tightly attached. When splicing, place the connecting rod (16) and the support frame (17) inside the connection position of the outer protective layer (10). Step 4. Repeat the above steps until the outer protective layer (10) is fully spliced, and install end caps (19) at both ends of the spliced ​​outer protective layer (10). Step 5. After connecting the column (1) and the Z-shaped steel (4) with bolts (12), insert them into the mounting hole (14). After adjusting the column (1) to be vertical, weld the column (1) and the support block (18) into a whole. Then connect the crossbeam (5) to the column (1) with bolts (12), type I connecting plate (6), and type IV connecting plate (9). The type I connecting plate (6) is connected to the column (1) by welding. Step 6. After all the columns (1) and beams (5) are installed, pour the internal filling concrete (11) through the pouring holes (13). When pouring, start from the lower end of the elevation and pour every other hole. After the internal filling concrete (11) overflows from the adjacent pouring hole (13), move to the next hole for pouring. After all the pouring holes (13) are filled, clean the surface of the guardrail and the site. Step 7. After the internal filling concrete (13) reaches the design strength, install the longitudinal beam (2) onto the guardrail using type I connecting plate (6), type II connecting plate (7), and bolts (12), wherein the type I connecting plate (6) and type II connecting plate (7) are connected to the longitudinal beam (2) by welding. Similarly, install the friction beam (3) onto the installed guardrail using type II connecting plate (7), type III connecting plate (8), and bolts (12). The longitudinal beam (2) and the friction beam (3) are longitudinally connected by bolts (12) and an internal sleeve.

2. The semi-prefabricated durable small deformation combined guardrail and its construction method according to claim 1 are characterized in that the material of the outer protective layer (10) is ultra-high performance concrete (UHPC); the material of the inner filling concrete (11) is ordinary concrete with a slump greater than 200mm; the connecting rod (16) is a 600mm long and 22mm diameter HRB400 hot-rolled ribbed steel bar, which is placed inside the splice of the outer protective layer to strengthen the connection.

3. The semi-assembled durable small deformation combined guardrail and its construction method according to claim 1 are characterized in that the outer protective layer (10) is a thin shell structure with open ends, each segment is 4m long and 3cm thick, and is prefabricated in the factory and transported to the site for assembly. The top of the outer protective layer (10) has a square mounting hole (14) and a rectangular casting hole (13).

4. The semi-assembled durable small deformation combined guardrail and its construction method according to claim 1 are characterized in that the column (1) is composed of a vertical square steel pipe welded to a horizontal square steel pipe at the top, and the horizontal square steel pipe and the Z-shaped steel (4) extend the upper impact surface of the guardrail to reduce the maximum dynamic external intrusion equivalent value of the vehicle after the vehicle hits the guardrail.

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