FOB Price
Obtenir le dernier prix60 ~ 300 / Meter
|Minimum Order
Localité:
-
Prix de commande minimale:
Commande minimale:
10 Meter
Packaging Detail:
pallet
Delivery Time:
1 week
Supplying Ability:
5000 Meter per Month
Payment Type:
T/T, L/C, Western Union
Personne àcontacter Ms. sara
NO.777 hengzao road, Hengshui, Hebei
~1.Structural features
Model MDZ expansion joints are made of domestic hot-rolled shaped steel. They consist of edge beam, middle beam, cross beam, displacement-control system and rubber seal tape. Their bearing structure and displacement-control system are separated without any interference, which ensures the safe veering and uni
Model MDZ expansion joints
form displacement and enables all the middle beams within the range of the displacement-control box to be supported by one cross beam, instead of 2 cross beams, which is the previous way of supporting a middle beam. This is very advantageous for expansion joint of a large displacement, since it will reduce quantities of the necessary cross beams, minimize the volume of displacement-control box and reduce the steel consumption. In every connection, a rotary and sliding structure is adopted; hence they are extremely suitable for slope, bent and wide bridge and meet the requirements for various bridge designs.
2.Code and its norm for Model GQF-MDZ bridge-purpose expansion joint
Example: GQF-MDZ **0(EPDM) Model MDZ bridge-purpose expansion joint recommended by the ministry standard, expansion amount **0mm, ethylene/propylene rubber seal tape.
The expansion joint with CR seal tape is suitable for the region of **5 ℃~ *0 ℃ and the one with EPDM seal tape for the region of **0 ℃ ~ *0 ℃ .
3.Schematic diagram of expansion joint
1. Side beam 2. Middle beam3. Across beam 4. Stainless steel
slide plate 5.Bearing base 6. Compressing bearing 7.Rubber seal
tame
4.Specifications and design parameters of Model MDZ bridge-purpose expansion joint
(1)Specifications
The design displacement of Model MDZ expansion joints may be freely combined according to required modules. The modules from *0mm to ***0mm in *5 grades are chosen for this series. The joint of an expansion amount above ***0mm may be separately designed.
(2)The design parameters and general layout of Model MDZ expansion joint.
1.The design parameters of Model MDZ are listed in Fig.5, 7.
2.The general layout of Model MDZ expansion joint is shown in Fig.8.
1.How to choose, install and maintain Model MDZ expansion joint
(1) How to choose expansion joint
The expansion joint, a member that is most susceptible to wearing in the bridge, is directly subject to the load of wheels, contamination of atmosphere, oil, rain and sand, and its performance will directly influence vehicles running efficiency. Therefore, it is very important for the designers to choose a good expansion joint, especially for the bend, slope and wide bridge. Thus a good structure must be selected, which can not only satisfy crosswise, longitudinal and vertical stagger, but also have a low friction and an even displacement and can freely expand in case of stagger. There were once many expansion joints limited in crosswise displacement, some of which even have no such properties. Model MDZ expansion joint has been subject to the following symmetrical tests in two test sections (test sections length: 6m, expansion amount: **0mm, consisting of 2 side beams, 3 middle beams, 3 middle beams and 4 seal tapes):
1.Test of stress and flexibility of both longitudinal and cross beam( under the max. desighed load).
2.Test of friction and evenness of displacement during elongation and compression.
3.Test of relative stagger.
a. Longitudinal stagger: *4mm max.
b.Crosswise uneven stagger ( in a fan area): *0mm in 4m range.
c.Vertical stagger: corresponding to formation of a 5% longitudinal slope along the bridge.
4.Test of max. horizontal force (simulated brake force).
5.Test of dynamic properties.
Other tests( including the convenience of replacing the
rubber seal tapes and bearings and the water-resistance of the seal
tapes).
As shown in the test report, these types of expansion joints are
superior to other ones in performance and have a good suitability.
If required by the user, the friction and even displacement may be
test through elongation and compression test. All the other items
may be tested at the expense of the user.
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(2) Calculation of expansion amount
When choosing the expansion amount the following factors shall be taken into consideration:
1. The influence by temperature variation;
2. The influence by the drying shrinkage and creep of the concrete bridge;
3. The influence by the rotary displacement at the beam end resulted from constant and active load;
4. The influence by the displacement of veering resulted from brake force;
5. The influence by the vertical displacement at the movable end of the bridge due to large longitudinal slope;
6. The influence by the displacement at the conjunctions of oblique or bent bridge; and
7. Other factors such as the installation error, manufacture error, the prestress and prestress loss.
Due to the above factors, at present it is rather difficult to accurately calculate the expansion amount, therefore sufficient allowance shall be considered in design. The expansion amount will directly influence the selection of the size of expansion joint, which will directly influence the joints effect. Meantime, the clearance between the beam and slab shall be fully considered so as to ensure the joints complete anchoring and thus ensure its optimum performances. For this reason, a sufficient allowance shall be taken into consideration to ensure this expansion joints durability and efficiency when choosing the expansion amount.
(3). Technical documents to be supplied to the plant
After Model MDZ expansion joint is chosen, the following technical documents shall be supplied to the plant:
1. Crossection drawing of the bridge: including the detailed data of the lateral slope, sidewalk, safety zone, and handrails;
2. The temperature and temperature variation during construction and installation;
3.Users special requirement.
By this way the joint may be preassembled according to users requirements to avoid unnecessary reconstrution. If no temperature variation is provided, the joint will be designed on basis of being compressed to 1/2 of its max. longitudinal sidth.
(4).How to install Model MDZ expansion joint
Even for an excellent expansion joint, different installation quality will result in different durability and efficiency, hence installation is essential to its performances. These expansion joints shall be installed as follows:
1. The grooves shall be preserved according to the drawings for the expansion joint between beam( slab) ends and between beam end and abutment, and there the anchoring bars shall be embedded. The bars shall be surely anchored with the beam end or abutment, and welding of the main bars, if necessary, shall meet the bridge construction regulations.
2. These preassembled joints shall be delivered to the site by the manufacturers vehicle. If assembly shall be made on site due to the limit in transportation or other reasons, it shall be done under the manufactures guidance. They cant be stored in open air and shall be padded at least *0cm from the floor.
3. Before jinstallation, check if the clearance between the completed main beam(slab) ends are in accordance with the designed value, and the position of embedded anchor bars or members. If the designed requirements are not met, one shall decide whether the previous model of the joint is applicable. Otherwise, one should take such corrective measures as modifying the previous chearance value or replacing and expansion joint of another model code.
4. Before Model MDZ expansion joint is installed on the bridge, the positioning value shall be regulated according to the actual temperature during installation ( in case of deviation from the one supplied by the buyer), and only after checked and signed by the person in charge of construction and installation, can the joints be fixed with special fixture.
5. Before lifting the joints, the preserved concrete grooves shall be roughened and cleaned. When delivered, these joints have had their lifting points marked with color and shall be lifted through these points on site. If necessary, proper strengthening measures shall be taken to ensure safe and reliable installation. The center line of the joint shall concise with that of the bridge with a max, deviation of *0mm. The longitudinal width(a) of the joint and the bars preserved on the beams shall be simultaneously welded together. If simultaneous welding is difficult, one side may be first welded and the another end shall be welded when the preset installation ambient temperature reaches. Finally the fixtures are released and the joint may freely expand.
6. After the above steps, the moulds shall be fixed and epoxide concrete(>C*0) shall be poured into the preserved grooves according to the drawings. During pouring, the concrete shall be well compacted and care shall be taken to avoid concretes entering the displacement-control box and splashing onto the rubber seal tape. Otherwise, correction shall be timely made, and the concrete well cured.
7.The water-proof course and pavement shall be finished together with the entire deck. Before paving the expansion joints shall be temporarily protected from impact or vehicles load. After paving no crack will occur on the deck.
Proper maintenance of the joints can ensure their normal performance and prolong their serive life and the joints shall be maintained as follows:
1.The sand and stone chip collected in the rubber seal tapes shall be timely removed to avoid the interference of free expansion and the entrance of water and sand due to breaking of the tape by stone. Otherwise, the rubber seal tape shall be immediately replaced.
2.Always check if there is any leakage resulted from damage or crack on the junction between the side beam and the pavement. Should these phenomena occur, correction shall be immediately made to avoid the impact on the anchoring strength between the joint and the beam or slab.
3.Always check if the top of the expansion joint is flat. If it is not flat, check if the slide veering base or slide compressing bearing is damaged, and the damaged one, if any, shall be immediately replaced. For Model MDZ expansion joints, convenient replacement of parts has been fully considered, which has been proved practicable through many experiments.
4.If an excessive uneven displacement is found in the clearances, the displacement-control system shall be inspected. The damaged parts, if any, shall be replaced with the standard ones. Generally, this phenomenon will not occur, since the durability and strength of this system have been fully considered in design.
5. Though Model MDZ expansion joints of the steel structure have
been well protected before delivery, they will rust after a long
period of operation under serious conditions, which is quite
normal. The expansion joints shall be regularly subject to
anti-rust treatment to prolong the service life. .
~Fig.5 Table of design parameters of Model GDF-MDZ expansion joints
Model
Expansion amount
f
Distance from supporter to beam end
R
Width a of the expansion joint
Clearance
Size of the preserved groove
a min
a max
c min
c max
h
b
MDZ**0
*0
-
*0
**0
*0
**0
**0
**0
MDZ***0
**0
*5
**0
**0
*0
**0
**0
**0
MDZ***0
**0
*5
**0
**0
**0
**0
**0
**0
MDZ***0
**0
*5
**0
**0
**0
**0
**0
**0
MDZ***0
**0
**5
**0
**0
**0
**0
**0
**0
MDZ***0
**0
**5
**0
**0
**0
**0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
**0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
***0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
***0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
***0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
***0
**0
**0
MDZ***0
**0
**5
**0
***0
**0
***0
**0
**0
MDZ****0
***0
**0
***0
***0
**0
***0
**0
***0
MDZ****0
***0
**0
***0
***0
**0
***0
**0
***0
MDZ****0
***0
**0
***0
***0
**0
***0
**0
***0
