CN110685217A - Seamless telescoping device of bridge - Google Patents

Abstract

The invention belongs to the technical field of auxiliary functional parts of bridges and discloses a seamless expansion device for a bridge. The invention comprises two bridge members, wherein the upper ends of the two bridge members are respectively provided with an asphalt concrete surface layer, and an elastic-plastic filling material is arranged between the two asphalt concrete surface layers; fixing pieces are embedded in the elastic-plastic filling material, and a moving piece is embedded between the two fixing pieces; a plurality of U-shaped connecting pieces are arranged between the movable piece and the fixing pieces on the two sides; the lower extreme of mounting is provided with the strengthening rib subassembly. The expansion joint has the characteristics of orthotropic, has smaller deformation rigidity and larger deformation capacity along the bridge direction so as to adapt to the deformation of the upper structure of the bridge caused by temperature change, simultaneously has larger rigidity in the vertical direction so as to bear the gravity and the impact of vehicle load, and solves the problems that the traditional expansion joint is easy to damage, difficult to maintain and unsmooth to drive.

Description

A bridge seamless expansion device

technical field

The invention belongs to the technical field of bridge accessory functional components, and in particular relates to a bridge seamless expansion and contraction device.

Background technique

The superstructure of the bridge will undergo expansion and contraction deformation along the longitudinal direction of the bridge due to temperature changes and concrete shrinkage and creep. The expansion and contraction of this deformation will lead to the destruction of the bridge structure, the cracking and arching of the bridge deck and the road surface. The traditional method is also the current A common practice is to install expansion devices with deformation joints between the beam bodies, between the beam body and the bridge abutment to adapt to this expansion and deformation.

The traditional expansion joints have the following disadvantages: the existence of the expansion joints makes the bridge deck a discontinuous structure, and the vehicle will have an impact when passing through the expansion joints, resulting in uneven driving and affecting the driving comfort; repeated impact when the vehicle passes makes the expansion joints easier Looseness, deformation and damage, and the damage of the expansion joint aggravates the impact of the vehicle, forming a vicious circle. The impact of the vehicle will also cause damage to the bridge itself, reduce the service life of the bridge, and even endanger the driving safety in severe cases; If the joints are exposed, the long-term accumulation of dust and garbage will fill the gaps of the expansion joints, resulting in the failure of the expansion joints. Therefore, bridge expansion joints "repeatedly repaired and broken" have become one of the typical difficulties in bridge maintenance, which not only requires long-term maintenance but also costs a lot.

The fundamental reason for the defects of traditional bridge expansion joints is the discontinuity of the bridge deck structure. Therefore, the development of seamless expansion devices to achieve continuous bridge decks is one of the important ways to solve the defects of traditional expansion joints. "The best expansion joints are seamless. Expansion joints", this concept promotes the development of bridge seamless technology. In the late 1970s, it began in the United Kingdom, and a filled bridge seamless expansion device using high elastic-plastic materials was developed and applied. The reserved slot is filled with a hot mix elastic-plastic body composed of a variety of high molecular polymer modified asphalt, anti-aging agent and aggregate, so as to realize the continuity of the bridge deck and improve the driving comfort. This technology was introduced into my country in the 1990s and has been developed and applied to a certain extent. However, this elasto-plastic body-filled telescopic device also has some obvious shortcomings. Since the elasto-plastic body itself is relatively soft and has low rigidity, it deforms greatly under the action of the wheel load. The interface is prone to debonding, and the bridge deck pavement is gnawed and damaged. Therefore, the durability of this expansion joint device is poor, and its application has not been popularized.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a bridge seamless expansion and contraction device.

The technical scheme adopted in the present invention is:

A seamless expansion and contraction device for bridges, comprising two bridge components arranged at intervals, the upper ends of the two bridge components are both provided with an asphalt concrete surface layer; the gap between the two bridge components is a beam joint, and the gap between the two asphalt concrete surface layers An elastic material filling space is arranged between the two sides, and the width of the elastic material filling space is greater than the width of the beam seam, and an elastic plastic filling material is arranged in the elastic material filling space; the elastic material filling material is pre-embedded with fixing parts located on both sides of the elastic material filling space. , a movable piece is pre-embedded in the elastic-plastic filling material between the two fixing pieces; a plurality of U-shaped connecting pieces are arranged between the movable piece and the fixing pieces on both sides; the lower end of the fixing piece is provided with reinforcement A stiffener assembly for connectivity between elastoplastic filler material and two bridge members.

Further preferably, the two bridge components are both beam bodies, or the two bridge components are beam bodies and bridge abutments respectively.

It is further preferred that the fixing member comprises a first perforated steel top plate, a fixing member steel bottom plate and a plurality of anchoring bars arranged in sequence from top to bottom, the fixing member steel bottom plate is arranged on the upper end of the bridge member, and the anchoring bars are embedded in the upper end of the bridge member. inside the bridge member, and the anchoring rib is connected with the reinforcing rib assembly; the first perforated steel top plate and the fixed part steel bottom plate are connected by the first perforated steel web or the first short reinforcement, and the first perforated steel The web or the first short steel bar is connected to one end of the U-shaped connector.

It is further preferred that the reinforcing rib assembly comprises bridge member pre-embedded steel bars and transverse bridge direction steel bars that are connected to each other, the bridge member pre-embedded steel bars and the transverse bridge direction steel bars are both pre-buried in the bridge member, and the bridge member pre-embedded steel bars are pre-buried. The steel bars and transverse bridge bars are connected with the corresponding anchor bars.

It is further preferred that the movable part comprises a second perforated steel top plate and a movable part steel bottom plate arranged below the second perforated steel top plate, and the second perforated steel top plate and the movable part steel bottom plate pass through the second perforated steel top plate. The webs or the second short steel bars are connected, and the second perforated steel webs or the second short steel bars are connected with the other end of the U-shaped connecting piece; the two ends of the steel bottom plate of the movable piece are respectively arranged on the two fixed piece steel plates. on the bottom plate.

More preferably, the beam gap below the steel bottom plate of the movable part is filled with foam.

It is further preferred that the first perforated steel top plate and the fixing piece steel bottom plate are connected by a first perforated steel web; the upper end surface layer of the fixing piece steel base plate is flush with the upper end surface of the bridge member. .

More preferably, the first perforated steel top plate and the fixing member steel bottom plate are connected by first short steel bars.

More preferably, the first perforated steel top plate is a steel bar, and a plurality of openings are evenly arranged on the first perforated steel top plate.

The beneficial effects of the present invention are:

The invention is a seamless expansion device of orthotropic steel frame used for highway bridges. By connecting and setting a fixed piece, a movable piece and a U-shaped connecting piece of the fixed piece and the movable piece, it has the characteristics of orthotropy, and can be used in parallel bridges. The direction has a small deformation stiffness and a large deformation capacity to adapt to the deformation of the bridge superstructure caused by temperature changes, and has a large vertical stiffness to withstand the gravity and impact of vehicle loads; the reinforcing rib assembly strengthens the asphalt The connectivity between the concrete surface layer and the bridge components effectively forms the layer structure into a whole, which further strengthens the overall deformation resistance, bearing capacity and impact resistance. Replacing the traditional expansion joint with this orthotropic steel skeleton seamless expansion device will realize the seamless continuity of the bridge pavement and solve the problems of easy damage to the traditional expansion joint, difficult maintenance and uneven driving.

Description of drawings

Fig. 1 is the sectional structure diagram of the bridge seamless expansion and contraction device of the present invention;

Fig. 2 is the top view structure diagram of the bridge seamless expansion and contraction device of the present invention;

Fig. 3 is the perspective view when the first perforated steel web is used in the fixing member of the present invention;

4 is a side view of the fixing member of the present invention when the first perforated steel web is connected to the U-shaped connecting member;

Fig. 5 is the perspective view when the second perforated steel web is used in the movable part of the present invention;

Fig. 6 is the perspective view when the first short steel bar is used in the fixing member of the invention;

Figure 7 is a side view of the fixing piece of the present invention when the first short steel bar is connected to the U-shaped connecting piece;

8 is a perspective view of the movable element of the present invention when the second short steel bar is used.

In the figure: 1- Bridge component; 2- Asphalt concrete surface layer; 3- Elastoplastic filling material; 4- Fixing piece; 41- The first steel top plate with holes; 42- Fixing piece steel bottom plate; The first perforated steel web; 45 - the first short steel bar; 5 - the movable part; 51 - the second perforated steel top plate; 52 - the movable part steel bottom plate; 53 - the second perforated steel web; 54 - the second Short steel bar; 6-U-shaped connector; 7-Reinforcing bar assembly; 71-Embedded steel bar for bridge components; 72-Transverse bridge direction steel bar; 8-Foam.

Detailed ways

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly introduced below with reference to the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following descriptions about the structures of the drawings are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

The technical solutions provided by the present invention will be described in detail below by means of embodiments with reference to the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help the understanding of the present invention, but do not constitute a limitation of the present invention.

In some instances, some embodiments are not described or described in detail because they belong to the prior art or conventional art.

Furthermore, technical features described herein, or steps in all methods or processes disclosed, except mutually exclusive features and/or steps, may be combined in any suitable manner in one or more embodiments. It will be readily understood by those skilled in the art that the steps or order of operations of the methods related to the embodiments provided herein may also be varied. Any order in the figures and examples is for illustration purposes only and does not imply that a certain order is required unless it is explicitly stated that a certain order is required.

The serial numbers themselves, such as "first", "second", etc., for the components herein are only used to distinguish the described objects, and do not have any order or technical meaning. The "connection" and "connection" mentioned in the present application include both direct and indirect connections (connections) under reasonable circumstances (if no self-contradiction is constituted).

Example 1:

As shown in Figures 1-8, this embodiment provides a bridge seamless expansion and contraction device, including two bridge members 1 arranged at intervals, and the upper ends of the two bridge members 1 are both provided with an asphalt concrete surface layer 2; The gap between 1 is a beam joint, an elastic material filling space is provided between the two asphalt concrete surface layers 2, and the width of the elastic material filling space is greater than the width of the beam joint, and an elastic-plastic filling material 3 is arranged in the elastic material filling space ; The elastic-plastic filling material 3 is embedded with fixed parts 4 on both sides thereof, and the elastic-plastic filling material 3 between the two fixed parts 4 is embedded with movable parts 5; A plurality of U-shaped connecting pieces 6 are arranged between the fixing pieces 4 ; the lower end of the fixing piece 4 is provided with a reinforcing rib assembly 7 to strengthen the connection between the elastic-plastic filling material 3 and the two bridge members 1 . The movable part 5 and the fixed part 4 are welded by the U-shaped connector 6 to form an orthotropic steel skeleton, which is suitable for a larger amount of expansion. The plastic filling material 3 can be an existing high-elastic asphalt concrete material such as epoxy asphalt mixture or rubber asphalt mixture, which is not specifically limited. It should be further noted that the two bridge members 1 are both beam bodies, or the two bridge members 1 are beam bodies and bridge abutments respectively.

The present invention is an orthotropic steel frame seamless expansion and contraction device for highway bridges. Features: It has small deformation stiffness and large deformation capacity in the direction of the bridge to adapt to the deformation of the upper structure of the bridge caused by temperature changes, and has large vertical stiffness to withstand the gravity and impact of vehicle loads; strengthen The rib assembly 7 strengthens the connection between the asphalt concrete surface layer 2 and the bridge member 1, effectively forms the layer structure as a whole, and further strengthens the overall anti-deformation capacity, load-bearing capacity and impact resistance capacity. Replacing the traditional expansion joint with this orthotropic steel skeleton seamless expansion device will realize the seamless continuity of the bridge pavement and solve the problems of easy damage to the traditional expansion joint, difficult maintenance and uneven driving. Meanwhile, the present invention also has the following characteristics:

(1) The seamless expansion device is installed with an appropriate length along the bridge to replace the conventional expansion joint, which can realize the seamlessness of the whole bridge, improve the driving stability and comfort, and avoid the conventional expansion joint caused by the impact of the vehicle. The resulting bridge diseases greatly reduce the maintenance and repair workload.

(2) The orthotropic steel skeleton formed by the present invention and the elastic-plastic filling material 3 are combined to form a composite structure, which improves the overall vertical stiffness of the expansion joint, so that it matches the vertical stiffness of the bridge deck, and is compatible with the conventional filling expansion joint. In comparison, it is possible to avoid diseases such as gnawing and cracking of the reserved groove caused by the large deformation difference when the wheel runs over the expansion joint.

(3) The concave and convex of the elastic-plastic filling material 3 can also be avoided due to the support and restraint effect of the orthotropic steel skeleton.

(4) It has good deformation ability in the direction of the bridge to adapt to the slow expansion and contraction deformation of the beam due to shrinkage, creep and temperature changes, but it also has a certain rigidity in the direction of the bridge, which can effectively resist the superstructure of the bridge. The horizontal displacement under the action of the braking force can also reduce the deflection of the bridge pier, which is beneficial to the force of the bridge pier.

(5) Since the displacement of the beam body under the action of the braking force is limited, it is not necessary to consider the increased expansion and contraction amount due to the installation error as conventional expansion joints, so for the same coupling length, the required expansion and contraction amount is small.

(6) Since the orthotropic steel skeleton of this kind of expansion device effectively improves its vertical rigidity, a larger width and height of the elastic-plastic filling material 3 can be used. Compared with the conventional filled expansion joint, it can make more expansion and contraction Large telescopic device. When the required expansion and contraction amount is large, it can be achieved by increasing the number of moving parts.

(7) This kind of seamless expansion device has good deformation ability and reasonable stiffness in the direction of the bridge, and can play a good role in buffering and limiting the displacement of the beam when it is subjected to horizontal earthquakes; The composite structure composed of the cross-isolated steel skeleton and the elastic-plastic filling material 3 has good viscoelastic properties and can play the role of seismic energy dissipation. Therefore, the use of this seamless expansion device can significantly improve the seismic performance of the bridge.

(8) The construction speed is fast. Generally, the installation and pouring of a telescopic device can be completed in a few hours, and the traffic can be opened 24 hours after completion.

(9) Convenient maintenance and small workload. This kind of seamless expansion device has good durability and can reduce the workload of maintenance and maintenance; even if there are diseases, it is very convenient to maintain. If cracks appear, they can be sealed with hot-melt elastic-plastic materials. Surface layer. In addition, this kind of telescopic device has good vertical shear deformation ability, and is also very convenient for lifting and replacing the support. Under the condition of reasonable control of the lifting amount, the telescopic device will not be damaged.

(10) The cost of this seamless expansion joint is about 50% higher than that of ordinary expansion joints, but because it can improve durability, reduce maintenance workload, improve bridge performance and driving conditions, from the perspective of performance and life cycle costs Comprehensive consideration, it has good technology and economic benefits.

Embodiment 2:

This embodiment is a further improvement made on the basis of Embodiment 1, and the specific differences between this embodiment and Embodiment 1 are:

What needs to be further explained in this embodiment is that, as shown in FIG. 3 , FIG. 4 , FIG. 6 and FIG. 7 , the fixing member 4 includes a first perforated steel top plate 41 and a fixing member steel bottom plate which are arranged in sequence from top to bottom. 42 and a plurality of anchoring ribs 43, the steel base plate 42 of the fixing part is arranged on the upper end of the bridge member 1, the anchoring ribs 43 are embedded in the bridge member 1, and the anchoring ribs 43 are connected with the reinforcing rib assembly 7; the first steel with holes The top plate 41 and the steel bottom plate 42 of the fixing member are connected by the first perforated steel web 44 or the first short steel bar 45, and the first perforated steel web or the first short steel bar is connected with one end of the U-shaped connector 6 . It should be further noted that the first perforated steel top plate 41 is a steel bar, and the first perforated steel top plate 41 is evenly provided with a plurality of openings. As shown in FIG. 3 or FIG. 6 , the fixing member 4 is combined into an I-shaped structure to provide vertical rigidity support; the first perforated steel top plate 41 is preferably a narrow steel bar, with holes at regular intervals, so as to fill the elastic The plastic materials are interconnected to form a whole. There are two fixed parts 4, which are located on both sides of the expansion joint (that is, the gap between the two beam bodies), and the movable part 5 is set between the two fixed parts 4. According to the required expansion and contraction amount, one or an odd number can be set multiple. The adjacent movable parts 5 and the fixed parts 4 are connected and erected by the horizontally arranged U-shaped connectors 4. The U-shaped connectors 4 are preferably made of steel bars, so that the expansion joints have suitable stiffness and stiffness in the direction of the bridge. deformability. The use of the first perforated steel web 44 can strengthen the restraint on the fixing member 4 and the elastic-plastic filling material 3 to avoid debonding between the elastic-plastic filling material 3 and the side surface of the asphalt concrete surface layer 2 . Using the first short steel bar 45 has the same effect as using the first perforated steel web 44, and the first short steel bar 45 has a simpler structure, is more convenient to manufacture, and has a lower cost. The first perforated steel web 44 also achieves the desired effect.

Embodiment three:

The present embodiment is a further improvement made on the basis of the second embodiment, and the specific differences between the present embodiment and the second embodiment are:

It should be further explained in this embodiment that the reinforcing rib assembly 7 includes a bridge member pre-embedded steel bar 71 and a transverse bridge direction steel bar 72 connected to each other, and the bridge member pre-embedded steel bar 71 and the transverse bridge direction steel bar 72 are both pre-buried in the bridge Inside the component 1, the bridge component pre-embedded steel bars 71 and the transverse bridge direction steel bars 72 are connected with the corresponding anchoring bars 43. The bridge member pre-embedded steel bars 71 and the transverse bridge direction steel bars 72 are both connected to the bridge member 1, and at the same time are connected to the anchoring bars 43, which can well strengthen the connection between the elastic-plastic filling material 3 and the bridge member 1, and effectively improve the layer structure. form a whole to avoid damage to the elastic-plastic filling material 3 in long-term use.

Embodiment 4:

This embodiment is a further improvement made on the basis of Embodiment 2 or Embodiment 3. The specific differences between this embodiment and Embodiment 2 or Embodiment 3 are:

It should be further explained in this embodiment that, as shown in FIG. 5 and FIG. 8 , the movable part 5 includes a second perforated steel top plate 51 and a movable part steel bottom plate 52 arranged below the second perforated steel top plate 51 , The second perforated steel top plate 51 and the movable part steel bottom plate 52 are connected by the second perforated steel web 53 or the second short steel bar 54, and the second perforated steel web 53 or the second short steel bar 54 is connected with the U-shaped connecting piece 6 is connected to the other end; the two ends of the movable piece steel base plate 52 are respectively arranged on the two fixed piece steel base plates 42 . Under normal circumstances, all the parts of the movable part 5 are connected by welding, and the stability is good. The use of the second perforated steel web 53 can strengthen the restraint on the movable member 5 and the elastic-plastic filling material 3 to avoid debonding between the elastic-plastic filling material 3 and the side surface of the asphalt concrete surface layer 2 . The use of the second short steel bar 54 has the same effect as the use of the second perforated steel web 53, and the use of the second short steel bar 54 is simpler in structure, more convenient to manufacture, and lower in cost. The second perforated steel web 53 also achieves the desired effect.

Embodiment 5:

This embodiment is a further improvement made on the basis of the fourth embodiment, and the specific difference between this embodiment and the fourth embodiment is:

What needs to be further explained in this embodiment is that the beam gap below the steel bottom plate 52 of the movable part is filled with foam 8 . The foam 8 can play a certain buffering effect, so that the protection effect is better.

Embodiment 6:

This embodiment is a further improvement made on the basis of any one of Embodiments 2 to 5. The specific differences between this embodiment and any one of Embodiments 2 to 5 are:

It should be further explained in this embodiment that the first perforated steel top plate 41 and the fixing member steel bottom plate 42 are connected by a first perforated steel web; the upper end surface layer of the fixing member steel bottom plate 42 is connected to the The upper end surface of the bridge member 1 is flush. The moderate distance in this embodiment can ensure a better stabilization effect and play a good protective role.

Embodiment 7:

This embodiment is a further improvement made on the basis of any one of Embodiments 2 to 6. The specific differences between this embodiment and any one of Embodiments 2 to 6 are:

It should be further explained in this embodiment that the first perforated steel top plate 41 and the fixing member steel bottom plate 42 are connected by first short steel bars. The moderate distance in this embodiment can ensure better stabilization effect and play a good protective role. At the same time, the distance between the two end fixing parts 4 and the side surface of the notch is small, and the distance between the fixing part 4 and the side surface of the notch is relatively small. A small part of the elastic-plastic filler has a good constraining effect, which can effectively prevent the debonding between the elastic-plastic filler and the side of the asphalt layer at the notch, and the bridge deck gnawing damage occurs.

The present invention is not limited to the above-mentioned optional embodiments, and anyone can draw other various forms of products under the inspiration of the present invention, but no matter what changes are made in its shape or structure, all fall within the definition of the claims of the present invention. The technical solutions within the scope all fall within the protection scope of the present invention.

Claims (9)

1. The utility model provides a seamless telescoping device of bridge which characterized in that: the composite structure comprises two bridge members (1) which are arranged at intervals, wherein the upper ends of the two bridge members (1) are respectively provided with an asphalt concrete surface layer (2); the gap between the two bridge members (1) is a beam seam, an elastic material filling space is arranged between the two asphalt concrete surface layers (2), the width of the elastic material filling space is greater than that of the beam seam, and an elastic-plastic filling material (3) is arranged in the elastic material filling space; the elastic-plastic filling material (3) is internally embedded with fixed pieces (4) positioned at two sides of the elastic-plastic filling material, and a movable piece (5) is embedded in the elastic-plastic filling material (3) between the two fixed pieces (4); a plurality of U-shaped connecting pieces (6) are arranged between the movable piece (5) and the fixing pieces (4) at the two sides; and the lower end of the fixing piece (4) is provided with a reinforcing rib assembly (7) for reinforcing the connectivity between the elastic-plastic filling material (3) and the two bridge members (1).

2. The seamless bridge expansion device of claim 1, wherein: the two bridge members (1) are both beam bodies, or the two bridge members (1) are respectively beam bodies and bridge abutments.

3. The seamless bridge expansion device of claim 2, wherein: the fixing piece (4) comprises a first perforated steel top plate (41), a fixing piece steel bottom plate (42) and a plurality of anchoring ribs (43), wherein the first perforated steel top plate, the fixing piece steel bottom plate (42) and the plurality of anchoring ribs (43) are sequentially arranged from top to bottom, the fixing piece steel bottom plate (42) is arranged at the upper end of the bridge member (1), the anchoring ribs (43) are embedded in the bridge member (1), and the anchoring ribs (43) are connected with the reinforcing rib assembly (7); the first top plate (41) and the fixing steel bottom plate (42) are connected through a first open-hole steel web plate (44) or a first short steel bar (45), and the first open-hole steel web plate or the first short steel bar is connected with one end of the U-shaped connecting piece (6).

4. The seamless bridge expansion device of claim 3, wherein: the reinforcing rib assembly (7) comprises bridge member embedded steel bars (71) and transverse bridge direction steel bars (72) which are connected with each other, the bridge member embedded steel bars (71) and the transverse bridge direction steel bars (72) are all embedded in the bridge member (1), and the bridge member embedded steel bars (71) and the transverse bridge direction steel bars (72) are all connected with corresponding anchoring bars (43).

5. The seamless bridge expansion device of claim 3 or 4, wherein: the movable piece (5) comprises a second perforated steel top plate (51) and a movable piece steel bottom plate (52) arranged below the second perforated steel top plate (51), the second perforated steel top plate (51) and the movable piece steel bottom plate (52) are connected through a second perforated steel web plate (53) or a second short steel bar (54), and the second perforated steel web plate (53) or the second short steel bar (54) is connected with the other end of the U-shaped connecting piece (6); and two ends of the movable part steel bottom plate (52) are respectively arranged on the two fixed part steel bottom plates (42).

6. The seamless bridge expansion device of claim 5, wherein: and foam (8) is filled in a beam gap below the movable piece steel bottom plate (52).

7. The seamless bridge expansion device of claim 3, wherein: the first top steel plate (41) with the hole and the fixing steel bottom plate (42) are connected through a first steel web plate (44) with a hole; the upper end surface layer of the fixing steel bottom plate (42) is flush with the upper end surface of the bridge member (1).

8. The seamless bridge expansion device of claim 3 or 6, wherein: the first top steel plate (41) with the hole and the fixing steel bottom plate (42) are connected through a first short steel bar (45).

9. The seamless bridge expansion device of claim 3, wherein: first band-pass steel roof (41) are the billet, and even being provided with a plurality of trompils on first band-pass steel roof (41).

Images