Field of the Invention:

The invention is about a new moduler product, made from high performance precast concrete to be an alternative solution to known expansion joint mechanism problems used in highway, railway bridges and marine piers.

Background:

Bridge Deck (or otherwise known as superstructure) is an independent movable structural component of a bridge, it behaves seperately and vibrates continuously relative to its substructure (abutments and bents), due to vehicle traffic passing on it. A gap between deck and abutments is a structural necessity, which is called; "bridge expansion joint". Thermal expansions along the deck and vibrations due to vehicle passes and sismic loads are all tolerated with the help of this gap.

This gap should be covered at the surface of the asphalt for a smooth vehicle pass. Also, a sealing and drainage system should be m corperated, to prevent uncontrolled water fall inside this gap. The bridge expansion joint mechanisms are used to satisfy these two requirements.

Already known and used bridge expansion joint mechanisms may be classified in three main catagories as; Rail Type, Finger Type and Trans-flex type mechanisms.

The Rail type mechanisms are the most known and widely used ones, all over the world. This mechanism is especially used for decks that are made with precast concrete beams, with a gap requirement up to 100 mm. This mechanism is constructed by placing two "F" shaped metal rail profiles at both sides of the gap and a "V" shaped rubber seal attached in between. By doing so, it forms the expansion joint mechanism.

For larger gap requirements in longer spanned bridges, in addition to the side "F" profiles, some extra inner "I" profiles are added in between, called as "modular". In fact, there is no modular behaviour along the longutidual rail direction, but it is named as modular since the rails are added side by side.

The main disadvantage of the Rail type expansion joint mechanism is that; the gap between the rails has to be perpendicular to traffic flow direction. This causes high impacts during vehicle passes, especially on the 2nd rail profile. The Profile weights are not heavy enough to resist and absorb these vehicle impacts. The rail profiles are rigidly fixed, anchored to the concrete bases. The assumption is that the profiles that are in contact with the asphalt pavement cover on top "will not move or vibrate" due to impacts.

Finger Type bridge expansion joint mechanisms have been developed as an alternative solution, to decrease these high impacts. Cantileverly supported moduler thick metal alloy plates with fingers on both sides are extended to cover the gap, with a zig-zag shaped form. Vehicle passes on finger type joints are smoother compared to Rail type mechanisms.

In both types, it is assumed in principle that, mechanisms are rigidly fixed, anchored to the concrete bridge components and will not be loossened or moved or vibrated.

A third category is the trans-flex type bridge expansion joint mechanism. It may be manufactured from fiber reinforced flexible rubber plates. It is anchored by bolts and nuts at both sides of the gap. Another aplication is to place a plate on the gap with one side sliding and cover it with asphalt pavement. Similarly filling the gap with elasto-mastic like sealing materials and similar applications can all be classified in this category.

Within the known parameters, a national patent file with Ref. No. 2012/02986 is investigated and found that the invention is about a "Rail Type" bridge expansion Joint mechanism.

Within the known parameters, a patent file with Ref. No. W02008016241 is investigated and found that the invention is about a "Finger Type" bridge expansion Joint mechanism.

Within the known parameters, vibrations due to vehicle impact, movements and thermal alongations cause micro cracks and seperations between the rail - asphalt or rail - base concrete anchores. Micro damage starts on the expansion joint area which will develop and result in larger damage, under non-stop vehicle impacts .

It is known, finger type mechanism examples have moduler alloy plates with extended fingers. They are cantileverly supported and anchored with the bolts to the concrete base on one side only, with extended free finger ends on the gap. Since there is not a link support on the other side of the gap, under vertical vehicle loads, plates strech, move and loosen the achore bolts or even break the finger extensions.

It is known, some finger-type, grill like shaped mechanism trials that are not supported cantileverly on one side but at both sides of the gap exists. However, such designs work mostly under uni axial movements only and can not resist and tolerate multi-axial deck movements and fail in practice.

It is known and understood that, trans-flex type bridge expansion joint mechanisms are not suitable for heavy and high speed traffic loads, due to strength problems of flexible materials. Bridge expansion joint mechanisms have important safety requirements, working under high speed traffic loads and vehicle impacts. Better altenative solutions for bridge expansion joints are still searched for all over the world. As a result, due to short service life caused by damage, non- repairable high replacement costs and insufficiency of existing solutions and alternatives, a new development and invention on bridge expansion joint mechanisms is required.

Objectives of the invention :

The main objective of this invention is, to create a new bridge expansion joint mechanism with longer service life and lower cost.

Sub-content aims of the invention:

To decrease the impacts on bridge expansion mechanisms.

To absorb the impact energy occured on road surface with the Rubber Pads and the loose-fit upper parts of the mechanism.

To protect the bottom base plates from vehicle impacts. These base plates are anchored and fixed rigidly to bridge components.

To increase the adherance between the mechanism and the surrounding asphalt by absorbing vibrations. This will increase asphalt service life.

To increase the longevity and maintanence periods of the sealing gasket.

To protect the sealing gasket against vehicle impacts.

To solve asphalt damage problems, especially observed on Rail type mechanisms, caused by thermal alongations and vibrations.

To incrase the compatibility between the bridge components and the expansion joint mechanism.

To reduce the manufacturing and maintenance costs of the mechanism.

The advantages, structural and design properties of the invention are all referred to and explained in detail within the attachments and drawings of this application and should be reffered to as a whole with this application.

Brief Description of the Drawings:

FIGURE-1; Drawing showing a top perspective view of the invention FIGURE-2; Drawing showing a bottom perspective view of the invention.

FIGURE-3; Drawing showing top perspective view of the invention mounted on a bridge structure.

FIGURE-4; Drawing showing section view of the invention mounted on a bridge structure.

Referance Numbers:

1. Fixed Base Supports

2. Loose-Fit Top Plates 2A. Link Bars 2B. Link-Lock Spines

3. Vibration Absorber Pads

4. Re-centering Springs

5. Re-centering Spring Holders

6. Sealing Gasket 7. Joint Sealer

8. Expansion Gap (bridge component)

9. Abutment (bridge component)

10. Deck (bridge component)

11. Asphalt Pavement (bridge component)

Description of the Invention :

The invention is called; Articulated loose-fit type bridge expansion joint mechanism. It consists of fixed base supports (1), anchored rigidly to the bridge concrete components abutment (9) and deck (10) at both sides of the expansion gap (8). And the expansion gap (8) in between is bridged with the loose-fit top plates (2) sat on vibration absorber pads (3).

Loose-fit top plates (2) are fitted on fixed base plates (1) and impacts are absorbed by vibration absorber pads (3) in between.

The articulated movable property of the loose-fit top plates (2) and vibration absorber pads (3), protects the fixed base supports (1) against vehicle impacts.

Besides the embedding and supporting functionality, the fixed base supports (1) prevent the direct contact between the Asphalt Cover (11) and the loose-fit top plates (2).

Vibration absorber pads (3) are inserted and embedded into the holes on the fixed base supports (1) with inclined angles.

The stability and the balance of the articulated loose-fit top plates (2), which are embedded on the vibration absorber pads (3), is always ensured with a tripod support configuration even under multi-axial deck displacements and vibrations.

The vibrations and displacements on the deck are tolerated by the space in between the fixed base supports (1) and the loose- fit top plates (2), without negatively impacting the vehicle passes.

With the inclined embedding and support angles of the fixed base supports (1) and re-centering springs (4) located in the expansion gap (8), the articulated loose-fit top plates (2) always stay in the correct position, re-centering and balancing itself continously under the deck vibrations and vehicle impacts.

The movements of the loose-fit top plates (2) along the expansion gap (8) line are restricted by the re-centering spring holders (5) which are linked to the loose-fit top plates (2), passing through the re-centering springs (4) and the link bars (2A).

The loose-fit top plates (2) are mounted and locked up vertically and irreversibly to the re-centering springs (4) by the help of the link-lock spines (2B). The group effect of the loose-fit top plates (2) tied together at bottom, prevents the release of a "single" unit from the embedment.

Re-centering spring holder (5) has two functions. It Works as an embedder and holder both for the re-centering spring (4) and the sealing gasket (6).

Sealing gasket (6) is located under the loose-fit plates (2), inside the expansion gap (8) and is protected against vehicle impacts. Simply by removing the loose-fit top plates (2), it is possible and easy to reach the sealing gasket (6), for cleaning or replacing.

The mounting clearence between two side by side sequentially fixed base supports (1) is filled and sealed with the joint sealer (7) to prevent water leakages. Surface water is drained to the sealing gasket (6), passing over the joint sealer (7).

On the surface, asphalt pavement (11) is adhered to the fixed base plates (1) at both sides of the mechanism. These fixed base plates (1) are also rigidly anchored to the bridge components, the Abutment (9) and the Deck (10) concrete. It is known, in Rail type mechanisms, specifically manufactured rolled profiles are used as the main material. In Finger type expansion joints, thick extruded Aluminium alloy plates are used. Both mechanisms have high material and manufacturing costs.

In the invention, high performance precast concrete sections are used as the main material of the mechanism. The compatibility and adherance resistance between precast concrete and the bridge components abutment (9), deck (10) and asphalt pavement (11), compared to metal plates and rail profiles, are far superior.

The advantanges of the mechanism, related to the invention, are;

The precast concrete parts used in the mechanism are simple, durable and low-cost, easy to manufacture and mount, with higher mass ratios compared to the known metal mechanisms. The articulated loose-fit design is able to resist and absorb more impact and vibration energy.

It is known in Rail and Finger type mechanisms, an articulated loose-fit form is not used as a design principle. Instead Rails and finger plates are rigidly fixed to the bridge components. Under continuous vehicle impacts, these fixed parts, bolts and nuts loosen, finger extensions break, weldings tears, seperation from anchored bridge components (asphalt and concrete) occur. Cracks or even breaks are the commonly observed damage types.

On the other hand, the mechanism of the related invention is based on "articulated loose-fit" design principle.

The loose-fit top plates (2), that are supported and embedded on fixed base supports (1), can move seperatly and independently. This articulated loose-fit structural property, protects the fixed base supports (1) by reducing vehicle impacts. Energy is absorbed by the vibration absorber pads (3) and transferred to limited movements.

It is known that, welding or bolt-nut connections are used in existing mechanisms.

In the mechanism of the related invention, neither welded, nor bolt-nut connections exist.

It is known that, in Rail type mechanism, sealing gasket (6) should be located on the road surface, between the two parallel rail profiles. Otherwise, it can not be reached, cleaned or replaced. If the sealing gasket (6) is not cleaned periodically, debris deposits fill the "V" shaped rubber channel. Together with the impact pressure of vehicle tires, the rubber gasket (6) rips, water leakage occures which causes damage to the substructure of the bridge.

For larger expansion requirements, side by side multi "V" shaped rubber channes are used. The rubber channel section is limited within the space between the rails. It is not possible to use larger channel section.

In Finger type mechanisms, the sealing gasket (6) is protected under the finger extended plates against vehicle impact. The rubber channel is a single "U" shape, with a larger sloped section compared to the Rail type, which is very important for self cleaning of the channel during heavy rain.

Although it is not easy or practical to clean or replace the sealing gasket (6), since bolts have to be released and rigidly fastened finger plates have to be removed, to reach the sealing gasket (6). Each maintenance attempt risks damage due to movement of the rigidly anchored plates. The sealing gasket (6), in the mechanism of the related invention is located under the loose-fit top plates (2), well protected against vehicle impacts. It is easy to reach, clean and replace, simply by removing the loose-fit top plates (2).

It is known that, in Rail type mechanisms, although the gap distance that vehicle tire has to pass over is assumed to be 10 cm maximum, in practice this gap may widen up to 15 cm due to deck movements. With the high speeds of the vehicles, the impact of the tires on rail profile is very detrimental. The rail profiles that are positioned across the traffic flow which are rigidly anchored to the bridge components, are exposed to such impacts continuously. After a while, rail profiles start to seperate from the Asphalt and then the mechanism breaks its anchore welds inside the concrete or cracks the concrete in the surronding area.

In the mechanism related to the invention, vehicles pass over the gap m two half stages, instead of the total gap m one go. That means, the gap distance that has to be passed over, is reduced to half, compared to Rail type mechanisms. With the resultant lessening of stress, damage and traffic noise.

High mass ratios and articulated modular structure of the fixed base supports (1) and the loose-fit top plates (2), help absorbing impact. Loose-fit design property and the vibration absorber pads (3), protect the fixed base supports (1) against vehicle impacts. The longevity of both the mechanism and the surrounding bridge companents, abutment (9), deck (10) and asphalt pavement (11) is greatly increased.

It is known that, in Rail type mechanisms, damage is generally observed not on mechanism itself, but at the bridge components surrounding the mechanism. Thermal alongations along the continuous rail profiles and vibrations due to vehicle impacts cause rail profiles to seperate from asphalt pavement (11).

In the mechanism related to the invention, the stuctural form of the fixed base supports (1) is a combination of short modular pieces. Small mount spaces exist between the pieces which eliminates longitudial thermal alongation effects. Incompatibility due to thermal alongations between the two materials, asphalt pavement (11) and the fixed base plates (1) does not occur. A direct contact does not exist between the asphalt pavement (11) and the loose-fit top plates (2), which means isolation of vibration. This mechanism increases the adherance resistance between the fixed base supports (1) and the surrounding bridge components; abutment (9), deck (10) and asphalt pavement (11).