inflatable airbag for making culvert

Hebei ZaoQiang DaCheng Rubber Co., Ltd. is established in 1996, which is seated in Zaoqiang County, Hebei province and integrates with research, production and export business.Our main products include:inflatable pipe plug/bridge bearings/expansion joint/waterstop/inflatable airbag for making culvert.Our products are successively used by many famous companies, and they were exported to 18 countries, including Canada, German, USA, Russia and so on.

2013年12月11日星期三

Famous bridges in China

Shanghai Yangtze River Bridge

The Shanghai Yangtze River Bridge starts at the tunnel exit, crosses Changxing Island at ground level, then crosses to Chongming Island, ending at Chenjia Town.

It consists of two long viaducts with a higher cable-stayed section in the middle to allow the passage of ships. The total length is 16.63 kilometres (10.33 mi), of which 6.66 kilometres (4.14 mi) is road and 9.97 kilometres (6.20 mi) bridge. The overall shape of the bridge is not linear but slightly sigmoid ("S" shaped).

The central cable-stayed span is about 730 metres (2,395 ft), the longest span of any bridge in Shanghai, and the tenth longest cable-stayed span in the world.[4] The span arrangement is 92+258+730+258+72 m.[5]

The bridge has three road lanes in each direction, with a designed speed of 100 kilometres per hour (62 mph). Room on both flanks of the bridge is reserved for a future metro line, so total deck width is 35.3 m (115.8 ft).

Shanghai Yangtze River Tunnel

Tunnel starts on the south bank of the Yangtze at Wuhaogou, Pudong and ends in the south of Changxing Island. It is 8.9 kilometres (5.5 mi) in length,[1] and has two stacked levels. The upper level is for a motorway, and has three lanes in each direction, with a designed speed of 80 kilometres per hour (50 mph). The lower level is reserved for a future Shanghai Metro line.

The tunnelling was completed using two of the largest tunnel boring machines (TBMs) ever built. The TBMs were 15.43 metres (50.6 ft) in diameter, 135 metres (443 ft) long, and weighed 2,300t.

Sutong Bridge

With a span of 1,088 metres (3,570 ft), it was the cable-stayed bridge with the longest main span in the world in 2008-2012. Its two side spans are 300 metres (980 ft) each, and there are also four small cable spans. The bridge received the 2010 Outstanding Civil Engineering Achievement award (OCEA) from the American Society of Civil Engineers.

Two towers of the bridge are 306 metres (1,004 ft) high and thus the second tallest in the world. The total bridge length is 8,206 metres (26,923 ft). Construction began in June 2003, and the bridge was linked up in June 2007. The bridge was opened to traffic on 25 May 2008[3] and was officially opened on 30 June 2008. Construction has been estimated to cost about US$1.7 billion.

The completion of the bridge shortens the commute between Shanghai and Nantong, previously a four-hour ferry ride, to about an hour. It brings Nantong one step closer to becoming an important part of the Yangtze River Delta economic zone, and has further attracted foreign investors into the city. The bridge is also pivotal in the development of poorer northern Jiangsu regions.

The tower is an inverted Y-shaped reinforced concrete structure with one connecting girder between tower legs. The bridge deck is a steel box girder with internal transverse and longitudinal diaphragms and fairing noses at both sides of the bridge deck. The total width of the bridge deck is 41 metres including the fairing noses.

AECOM provided comprehensive services to the main contractor, China Harbour Engineering Co. Second Navigational Engineering Bureau in the construction phase of the bridge. The services include contractor's alternative design; development of construction methodology; construction engineering/erection analysis/geometry control; deck lifting methods and procedures; surveying and monitoring techniques and systems; stay cable installation simulations; advice on construction method statements and specifications; bridge aerodynamics and wind tunnel testing; vibration mitigation measures/devices; falsework and plant/equipment design; advice on innovation and high-technology and research and development.

Jiangyin Bridge

The Jiangyin Bridge is a suspension Bridge over the Yangtze River in Jiangsu, China. When it was completed it was the most seaward crossing of the Yangtze River however the Sutong Bridge and the Shanghai Yangtze River Tunnel and Bridge have since been built further downstream. The bridge has a main span of 1,385 metres (4,544 ft) connecting Jiangyin south of the river to Jingjiang to the north. When it was completed in 1999 it was the fourth longest suspension bridge span in the world and the longest in China. Several longer bridges have since been completed in china and abroad but it still ranks among the ten longest bridge spans in the world.

Taizhou Bridge

The Taizhou Bridge is a bridge in over the Yangtze River in Taizhou, Jiangsu, China. It is the longest double span suspension bridge in the world with two main spans of 1080m.

It won the 2013 Institution of Structural Engineers Supreme Award for structural engineering.

Second Nanjing Yangtze Bridge

The Second Nanjing Yangtze Bridge is a cable-stayed bridge over the Yangtze River in Nanjing, China. The bridge spans 628 metres (2,060 ft) carrying traffic on the G36 Nanjing–Luoyang Expressway. When it was copleted it was the third longest cable-stayed span in the world. As of 2013 it is still among the 20 longest spans. The bridge crosses from the Qixia District in south-east of the river over to Bagua Island.

Third Nanjing Yangtze Bridge

The Third Nanjing Yangtze Bridge is a cable-stayed bridge located in Nanjing, China. It is the third crossing of the Yangtze River at Nanjing. The cable-stayed portion is just a part of the 4.7 kilometers of the complete bridge. Constructed in slightly more than two years at a cost of $490 million, this bridge features dual 215 meters towers. The main span measures 648 meters. When it was completed in 2005 it was the third longest cable stayed span in the world.It still ranks among the top 20. The bridge carries the G42 Shanghai–Chengdu Expressway and the G2501 Nanjing Ring Expressway

2013年12月5日星期四

A look back and forward at Steel Bridge construction

How many do you konw about stell bridge?Let's talk about it.Look back and forward at steel bridge construction.

The original Steel Bridge opened in 1901.

For 60 years, three toots from a passing boat alerted the bridge tender to open the structure.

Using a big “watch key” crank, the tender could be seen huffing and puffing as he walked in a circle. It took 27 turns in low gear, or seven in high gear, to open the draw. But that wasn’t the toughest chore for bridge tenders. Theodore Brickhouse told The Pilot in 1961 that on winter nights, tenders hung 16 kerosene lanterns to mark the bridge.

A ship slammed into an approach in the 1930s, cutting it in half. The bridge was closed for weeks while workers rebuilt it. In 1960, Hurricane Donna sent a half-sunken barge into the bridge’s underpinnings, causing about $4,000 worth of damage.

Further complicating matters, heavily loaded trucks were not heeding the warning signs and were crossing the narrow steel structure. C.C. Battige, assistant bridge engineer for the Highway Department, told The Pilot he was worried one of those trucks might crash through the old bridge decking.

Those worries were allayed when in February 1961, the drawbridge was closed. The horse-and-buggy holdover, one of the last hand-operated structures in Virginia, was to be demolished and replaced by an electric-powered, push-button-operated bascule-type bridge.

The new Steel Bridge opened in April 1962.

And more than 50 years later, crews are hard at work to replace it yet again.

Though it’s far less work to open, those openings still prompt huffing and puffing – this time from motorists stuck in traffic.

Dominion Boulevard is one of the region’s most notorious bottlenecks because four lanes of traffic merge into two to cross the bridge. About 32,500 vehicles travel across it daily, the city said.

There are openings on the hour seven days a week from 6 a.m. to 6 p.m. and on demand from 6 p.m. to 6 a.m., with restrictions for morning and evening rush-hour traffic.

As the city’s population boomed in the 1990s, widening Dominion Boulevard became a priority.

“By 2040, the demographers are predicting that over 318,000 people will call Chesapeake home,” Mayor Alan Krasnoff said during a groundbreaking ceremony last December. “Fifty years ago, I doubt anyone could imagine that kind of transformational growth, but grow we have … and grow we will.”

The 3.8-mile project is designed to ease traffic by widening to four lanes the Steel Bridge and Dominion Boulevard, between Cedar Road and Great Bridge Boulevard. The drawbridge will be replaced with a tolled, fixed span.

While improving traffic on land, it also will free boaters from the headache of one more stop on the Intracoastal Waterway.

On its website, the city of Chesapeake also said the fixed span is more economical because there is less upkeep and operational cost than with a movable bridge. It also was designed to accommodate anticipated traffic in 2034.

The $345 million project should be completed in 2017.

20th floor,Tower B ,Taiyi Shangcheng,Zhonghua Street,Hengshui City,Hebei Province,China.
Tel: +86-318-8538202
Mob:+86-18678456530
Fax: +86-318-2210707
MSN: ztwqqq1985@hotmail.com
Skype: dachengdc678
Email:dcrubber1996@126.com
jen_dacheng@126.com
ztwqqq1985@hotmail.com
Contact:Jenny Lee

Dominion Blvd. closed near Steel Bridge into Friday

Dominion Boulevard will be closed in both directions near the Steel Bridge into Friday morning.

The closure, which began about 2 p.m., is scheduled to continue until 6 a.m., a city news release said. Drivers can use the Va. 168 Bypass or George Washington Highway as alternate routes.

The closure is not related to any incidents or injuries at the bridge. Work crews are widening Dominion Boulevard.

While placing concrete for a new bridge pier, crews noticed the concrete was not properly stabilized, the release said. Because of how close the pier is to the road, the contractor wanted to close the road as a safety precaution until a full inspection could be completed.

inflatable airbag for making bridge

2013年11月29日星期五

Bridge Construction Techniques

The final cost of a bridge is the sum of the cost of permanent materials,the proportionate cost to the project of plant and temporary works and the cost of labor .The cost of permanent materials can be estimated reasonably correctly.With experience,a bridge contractor can deal completely with cost of plant and temporary works .But the labor cost does not lend itself to exact analysis .Recent competitive designs have attempted to introduce innovations in construction methods with a view to effect economy in the cost on labor by reducing temporary works and by minimizing the duration of site work.

The suitable techniques of construction of bridge superstructure will vary from site to site,and will depend on the spans and length of the bridge, type of the bridge,materials used and site conditions. For instance, cast-in-site concrete construction could be adopted for short spans up to 40 m, if the river bed is dry for a considerate portion of the year, whereas free cantilever construction with prestressed concrete decking would be appropriate for long spans in rivers with navigational requirements. The current trend is towards the avoidance of staging as much as possible and to use precast or prefabricated components to maximum extent.Also , construction machinery such as cranes and launching girders are coming into wider use . These are greater savings to be effected by paying attention to the method of construction even from the design stage than by attacking permanent materials .

Short Span Bridges
For bridges involving spans up to 40 m , the superstructure may be built on staging supported on the ground . Alternatively , the girders may be precast for the full span length and erected using launching girders or cranes,if the bridge has many equal spans.In the latter procedure , the additional cost on erection equipment should be less than the saving in the cost of formwork and in the labour cost resulting from faster construction .

Long Span Concrete Bridges
Long span concrete bridges are usually of post-tensioned concrete and constructed either as conditions beams types or as free ver cantile structures . Many methods have been developed for continuous deck construction . If the clearance between the ground and bottom of the deck is small and the soil is firm , the superstructure can be built on staging . This method is becoming obsolete . Currently , free-cantilever and movable scaffold systems are increasingly used to save time and improve safety .
The movable scaffold system employs movable forms stiffened by steel frames . These forms extend one span length and are supported by steel girders which rest on a pier at one end and can be moved from span to span on a second set of auxiliary steel girders .
An economical construction technique known as incremental push-launching method developed by Baur-Leonhard team is shown schematically in Figure 22.1.
The total continuous deck is subdivided longitudinally into segments of 10 to 30 m length depending on the length of spans and the time available for construction . Each of these segments is constructed immediately behind the abutment of the bridge in steel framed forms , which remain in the same place for concreting all segments .The forms are so designed as to be capable of being moved transversely or rotated on hinges to facilitate easy stripping after sufficient hardening of concrete. At the head of the first segment ,a steel nose consisting of a light truss is attached to facilitate reaching of the first and subsequent piers without including a too large can yilever moment during construction . The second and the following segments are concreted directly on the face of the hardened portion and the longitudinal reinforcement can continue across the construction joint . The pushing is achieved by hydraulic jacks which act against the abutment .Since the coefficient of friction of Teflon sliding bearings is only about 2 percent, low capacity hydraulic jacks would suffice to move the bridge even over long lengths of several hundred metres . This method can be used for straight and continuously curved bridges up to a span of about 120 m .
The free-cantilever system was pioneered by Dyckerhoff and Willmann in germany .In this system , the superstructure is erected by means of cantilever truck in sections generally of 3.5 m .The cantilever truck ,whose cost is relatively small and which is attached firmly to permanent construction , ermits by repeated use the construction of large bridges . The avoidance of scaffold from below ,the speed of work and the saving in labour cost result in the construction being very economicdal . The free-cantilever system is ideally suited for launched girders with a large depth above the pier cantilever system is ideally suited for launched girders with a large depth above the pier cantilevering to the middle of the span .

Another technique is the use of the pneumatic caisson .The caisson is a huge cylinder with a bottom edge that can cut into the water bed . When compressed ar is pumped into it ,the water is forced out .Caissons must be used with extreme care .for one thing, workers can only stay in the compression chamber for short periods of time .For another , if they come up to normal atmospheric pressure too rapidly ,they are subject to the bends ,or caisson disease as it is also called , which is a crippling or even fatal condition caused by excess nitrogen in the blood .When the Eads Bridge across the Mississippi River at St.Louis was under construction between 1867and 1874 , at a time when the danger of working in compresed air was not fully understood ,fourteen deaths was caused by the bends .
When extra strength is necessary in the piers ,they sometimes keyed into the bedrock-that is ,they are extended down into the bedrock .This method was used to build the piers for the Golden Gate Bridge in San Francisco ,which is subject to strong tidies and high winds ,and is located in an earthquake zone .The drilling was carried out under water by deep-sea divers .
Where bedrock cannot be reached ,piles are driven into the water bed .Today ,the piles in construction are usually made of prestressed concrete beams .One ingenious technique ,used for the Tappan Zee Bridge across the Hudson River in New York ,is to rest a hollow concrete box on top of a layer of piles .When the box is pumped dry ,it becomes buoyantenough to support a large proportion of the weight of the bridge.

Large Span Bridge

Suspension Bridge
The suspension bridge is currently the only solution in excess of 600 m, and is regarded as competitive for down to 300. The world’s longest bridge at present is the Verrazano Narrows bridge in New York. Another modern example is the Severn Bridge in England.

The components of a suspension bridge are: (a) flexible cables, (b) towers, (c) anchorages, (d) suspenders, (e) deck and ，(f) stiffening trusses. The cable normally consists of parallel wires of high tensile steel individually spun at site and bound into one unit .Each wire is galvanized and the cable is cover with a protective coating. The wire for the cable should be cold-drawn and not of the heat-treated variety. Special attention should be paid to aesthetics in the design of the rowers. The tower is high and is flexible enough to permit their analysis as hinged at both ends. The cable is anchored securely anchored to very solid anchorage blocks at both ends. The suspenders transfer the load form the deck to the cable. They are made up of high tensile wires and are normally vertical. The deck is usually orthotropic with stiffened steel plate, ribs or troughs，floor beam, etc. Stiffening trusses, pinned at the towers, are providing. The stiffening system serves to control aerodynamic movements and to limit the local angle changes in the deck. If the stiffening system is inadequate, torsional oscillations due to wind might result in the collapse of the structure, as illustrated in the tragic failure in 1940 of the first Tacoma Narrows Bridge.

The side span to main span ratio varies from 0.17 to 0.50 .The span to depth ratio for the stiffening truss in existing bridge lies between 85 and 100 for spans up to 1,000m and rises rather steeply to 177. The ratio of span to width of deck for existing bridges ranges from 20 to 56. The aerodynamic stability will have be to be investigated thoroughly by detailed analysis as well as wind tunnel tests on models.

The cable-stayed bridge
During the past decade cable-stayed bridges have found wide application, s\especially in Western Europe, and to a lesser extent in other parts of the world.
The renewal of the cable-stayed system in modern bridge engineering was due to the tendency of bridge engineering in Europe, primarily Germany, to obtain optimum structural performance from material which was in short supply-during the post-war years.
Cable-stayed bridges are constructed along a structural system which comprises an orthotropic deck and continuous girders which are supported by stays, i.e. inclined cables passing over or attached to towers located at the main piers.
The idea of using cables to support bridge span bridge span is by no means new, and a number of examples of this type of construction were recorded a long time ago. Unfortunately the system in general met with little success, due to the fact that the statics were not fully understood and that unsuitable materials such as bars and chains were used to form the inclined supports or stays. Stays made in this manner could not be fully tensioned and in a slack condition allowed large deformations of the deck before they could participate in taking the tensile loads for which they were intended.

Wide and successful application of cable-stayed systems was realized only recently, with the introduction of high-strength steels, orthotropic decks, development of welding techniques and progress in structural analysis. The development and application of electronic computers opened up new and practically unlimited possibilities for exact solution of these highly statically indeterminate systems and for precise stoical analysis of their three-dimensional performance.
Existing cable-stayed bridges provide useful data regarding design, fabrication, erection and maintenance of the mew system. With the construction of these bridges many basic problems encountered in their engineering are shown to have been successfully solved. However, these important data have apparently never before been systematically presented.
The application of inclined cable gave a new stimulus to construction of large bridges. The importance of cable-stayed bridges increased rapidly and within only one decade they have become so successful that they have taken their rightful place among classical bridge system. It is interesting to note now how this development which has so revolutionized bridge construction, but which in fact is no new discovery, came about.
The beginning of this system, probably, may be traced back to the time when it was realized that rigid structures could be formed by joining triangles together. Although most of these earlier designs were based on sound principles and assumptions, the girder stiffened by inclined cables suffered various misfortunes which regrettably resulted in abandonment of the system. Nevertheless, the system in itself was not at all unsuitable. The solution of the problem had unfortunately been attempted in the wrong way.
The renaissance of the cable-stayed, however, was finally successfully achieved only during the last decade.

Modern cable-stayed present a three-dimensional system consisting of stiffening girders, transverse and longitudinal bracings, orthotropic-type deck and supporting parts such as towers in compression and inclined cables in tension. The important characteristics of such a three-dimensional structure is the full participation of the transverse construction in the work of the main longitudinal structure. This means a considerable increase in the moment of inertia of the construction which permits a reduction in the depth of the girders and economy in steel.

Long span concrete bridges are usually of post-tensioned concrete and constructed either as conditions beams types or as free versatile structures. Many methods have been developed for continuous deck construction. If the clearance between the ground and bottom of the deck is small and the soil is firm, the superstructure can be built on staging. This method is becoming obsolete. Currently, free-cantilever and movable scaffold systems are increasingly used to save time and improve safety.
The movable scaffold system employs movable forms stiffened by steel frames. These forms extend one span length and are supported by steel girders which rest on a pier at one end and can be moved from span to span on a second set of auxiliary steel girders.

An economical construction technique known as incremental push-launching method is developed by Baur-Leonhard team. The total continuous deck is subdivided longitudinally into segments of 10 to 30 m length depending on the length of spans and the time available for construction. Each of these segments is constructed immediately behind the abutment of the bridge in steel framed forms, which remain in the same place for concreting all segments .The forms are so designed as to be capable of being moved transversely or rotated on hinges to facilitate easy stripping after sufficient hardening of concrete. At the head of the first segment, a steel nose consisting of a light truss is attached to facilitate reaching of the first and subsequent piers without including a too large can yielder moment during construction . The second and the following segments are concreted directly on the face of the hardened portion and the longitudinal reinforcement can continue across the construction joint . The pushing is achieved by hydraulic jacks which act against the abutment .Since the coefficient of friction of Teflon sliding bearings is only about 2 percent, low capacity hydraulic jacks would suffice to move the bridge even over long lengths of several hundred metres . This method can be used for straight and continuously curved bridges up to a span of about 120 m .
The free-cantilever system was pioneered by Dyckerhoff and Willmann in Germany .In this system , the superstructure is erected by means of cantilever truck in sections generally of 3.5 m .The cantilever truck ,whose cost is relatively small and which is attached firmly to permanent construction , emits by repeated use the construction of large bridges . The avoidance of scaffold from below, the speed of work and the saving in labor cost result in the construction being very economical. The free-cantilever system is ideally suited for launched girders with a large depth above the pier cantilever system is ideally suited for launched girders with a large depth above the pier cantilevering to the middle of the span.

Another technique is the use of the pneumatic caisson .The caisson is a huge cylinder with a bottom edge that can cut into the water bed. When compressed is pumped into it ,the water is forced out .Caissons must be used with extreme care .for one thing, workers can only stay in the compression chamber for short periods of time .For another , if they come up to normal atmospheric pressure too rapidly ,they are subject to the bends ,or caisson disease as it is also called , which is a crippling or even fatal condition caused by excess nitrogen in the blood .When the Eads Bridge across the Mississippi River at St.Louis was under construction between 1867and 1874 , at a time when the danger of working in compressed air was not fully understood ,fourteen deaths was caused by the bends .

When extra strength is necessary in the piers, they sometimes keyed into the bedrock-that is ,they are extended down into the bedrock .This method was used to build the piers for the Golden Gate Bridge in San Francisco ,which is subject to strong tidies and high winds ,and is located in an earthquake zone .The drilling was carried out under water by deep-sea divers .
Where bedrock cannot be reached ,piles are driven into the water bed .Today ,the piles in construction are usually made of prestressed concrete beams .One ingenious technique ,used for the Tappan Zee Bridge across the Hudson River in New York ,is to rest a hollow concrete box on top of a layer of piles .When the box is pumped dry ,it becomes buoyant enough to support a large proportion of the weight of the bridge .

2013年11月28日星期四

PVC water stops

PVC water stops are used in concrete joints subjected to hydrostatic pressures. After being embedded in concrete, PVC water stops fill up the joints to form a continuous watertight diaphragm that prevents the passing of fluid. The water stop must be designed and installed properly to accommodate joint expansions, contraction and lateral & transverse movements. In addition to these considerations the water stop must be compatible with the concrete system and the liquids and chemicals to be contained or controlled.

Advantages
Its basic advantage is in its time of fixing. It works as a sealant and it is fixed on predetermined place while concrete slab is laid. It is easy to installing and easy to weld at site and at required angle & shape.

USES:

Dams
Ponds
Canal lining
Water cisterns
Water refining facilities
Swimming pools
Deck
Construction tunnels
Hydro electricity & thermal plants
Bridges
Refining facilities
Metro constructions
Power plants viaducts
Supporting walls
Flooring settled on ground & foundations
Industrial structures

Hydrophilic water stop

This product is made from water-swelling rubber water line to the basis of the ordinary rubber water-stop. The product will swell when contacted with the structures. As a result, the tightness is fastened between them water stop and water-proof performance is improved and the problem of circle seepage which puzzles people in a long time is solved. This series of products have been used widely in some key projects and have gotten excellent results.

Features:
Waterproof wire adopted water-swelling rubber which will be self-swelling when contacted with water. So under the function of waterproof wire ,the concrete and water can seal better, and waterproof performance can be more excellent.The sections divided into high-strength area, water-proof area and the installation area can take unequal thickness structures according to the unique function of every area. So each part of the sections can get uniform and reasonable force.Telescopic holes’ outer wall is plane; formwork folder system contact surface is large in construction and difficult to dislocation.Setting hole designed on the installation area is convenient to fix with the nearest steel bar, difficult to move , construction easily and install firmly.

Application
It can be widely applied to various type of concrete structures , such as: Dams, reservoirs, subway, culverts, tunnels, and other underground works.

2013年11月27日星期三

rubber water stop

Rubber water-stop and water stop rubber is the natural rubber and various kinds of synthetic rubber as the main raw material, adding various additives and fillers, the plastication, mixing, pressing forming.The water stop material has good elasticity, wear resistance, aging resistance and tensile properties, adapt to the deformation ability strong, waterproof properties is good, the temperature range of application for - 45 ℃ - + 60℃. When the temperature more than 70 ℃, and rubber water-stop by strong oxidation or the oil and organic solvent erosion, shall not use rubber water-stop.

Rubber water-stop method of use
Rubber water-stop must take reliable fixed measures, tie bar and a when a mold. Prevent the pouring concrete displacement occurs, guarantee the water stop in concrete in the correct position.
Only in the water stop allow part in perforated hole, for the fixed water stop. Shall not damage the local ontology.
Commonly used fixed method is: the additional reinforcement fixed; Special clamp apparatus fixed; Use galvanized iron wire and template fixed, etc. Regardless of the type of fixed method, for water-stop fixed method should be according to the design requirements of the construction standard. Must ensure that water stop location accurate, no damage to water stop effective local, convenient concrete is poured concrete.

scope
Used in underground structure, dam, reservoir, swimming pools, roofing and other building material and structure deformation joint waterproof.

2013年11月25日星期一

Laminated Neoprene Elastomeric Bridge bearings

Why Laminated Neoprene Elastomeric Bridge bearings?

Neoprene bridge bearings - plain or laminated - elastomeric bearings，Laminated bearings are much easier to install in a bridge than compared to other types of bearing used and require nil maintenance. Unlike most other elastomer, Neoprene rubber under-goes no marked stiffening at low temperature when the thermal contraction of the bridge deck is at maximum. Such stiffening could be deleterious to bearing and / or structure. Correctly-designed and suitably-compounded laminated Neoprene Rubber bridge bearings can be confidently expected to function efficiently for at least a decade.

Advantages of Neoprene Elastomeric bearings.
As efficient bearing plates for pre-cast, pre-stressed concrete or steel beams in bridges and buildings, Neoprene Pads - plain and laminated - manufactured by us permits a smooth and uniform transfer of load from the beam to the substructure and allow beam rotation at the bearing due to deflect ion of the beam under load. They further allow lateral and longitudinal movement of the beam caused by thermal forces. Neoprene Pads have no movable parts and thermal expansion and contraction are absorbed by the pad's ability to give and take in shear. There is no sliding motion between pad and beam or between pad and abutment.

Neoprene bridge bearing specifications.
The material specifications for the elastomeric bearing shall meet all the current requirements of AASHTOM M 251. Construction, of the AASHTO Standard Specifications for Highway Bridges.

Bearing pads and laminated bearings shall be of the compound known as neoprene and shall be cast in molds under pressure and heat. A plain elastomeric bearing pad and steel load distribution plate combination shall be classified as a laminated elastomeric bearing. Test specimens shall be in accordance with ASTM D 3182 or D 3183. Where test specimens are cut from the finished product, a 20 percent variation from the original physical properties is allowed.

Difference between a plain rubber block and laminated elastomeric bearings

The capability of plain rubber block to carry vertical load increases as the number of laminations..mild steel shims increases.

How a plain rubber block and laminated bearing reacts against vertical load.

Plain rubber block under vertical load compressed down where as a laminated bearing bulge out with each laminations absorbing most of the vertical load.

How a plain rubber block and laminated bearing reacts against horizontal load.

2013年11月21日星期四

non-reinforced plain pad bearings/With PTFE sheet bonded to the elastomer/Laminated bearings/Laminated bearings with outer steel plate supplier from China

Non-reinforced bearings can be used in many construction and civil engineering applications to support concrete and steel structures, and where a simple, low-cost rubber separation strip is capable of carrying compressive loads, while at the same time providing translational movement and rotational capacity. Plain pad bearings have a large and varied range of possible applications though these bearings are more typically used in prefabricated structures.
Characteristics:
Non-reinforced elastomer bearings ensure a controlled load distribution and enable stress-free horizontal movements as well as twisting in supports.
They prevent excessive load eccentricities and edge compression.
At the same time, unevenness and deviations from parallelism in bedding surfaces are compensated.

Laminated bearing with PTFE sheet bonded on the elastomer:a virgin PTFE layer is bonded to the elastomer to reduce the friction coefficient with the stainless steel welded to the top steel plate. designed as a free sliding bearing in longitudinal and transversal directions(type DF) Fitted as a fixed bearing in longitudinal or transversal directions by means of steel guides (Type DG)

Tetrafluoro plate type rubber bearing suits to bridges with large span,several spans in continuous,with simply supported beam and continuous plates structure,and large displacement.It can still used as the sliding block in pushing of continuous beam and cross sliding of T-shaped beam.The applications of rectangular and circular tetrafluoro plate type rubber bearing are the same with rectangular and circular general plate type rubber bearing,separately.

Dacheng laminated bearings with simple reinforcement are made up of multiple elastomer layers separated by reinforcing steel plates ,sulfurized and moulded together.can be manufactured in a rectangular or circular shape to meet individual engineering requirements.

General laminated bearings suits to bridges with span less than 30m and small displacement.Different flat shape suits to different bridge span structures :orthogonal bridges adopt rectangular bearing;curvilinear bridges,oblique crossing bridges and cylindrical pier bridges adopt circular bearing.

Dacheng Laminated bearing with external steel plates can be vulcanised directly onto elastomeric bearings with simple reinforcement during production, so securing the bearings to the structure with mechanical fastenings and reducing the risk of slippage. Dacheng can produce various types of bearings depending on the fastening method specified Elastomeric bearings with two external plates and holes or threaded holes for plain anchor bars, for use on in situ cast concrete structures. use on metal structures, or as an anti-lift device; in this latter case, suitable anchor bars must be fitted to the bearings for anchoring purposes.

20th floor,Tower B ,Taiyi Shangcheng,Zhonghua Street,Hengshui City,Hebei Province,China.

Tel: +86-318-8538202

Mob:+86-18678456530

Fax: +86-318-2210707

MSN: ztwqqq1985@hotmail.com

Skype: dachengdc678

Email:dcrubber1996@126.com

jen_dacheng@126.com

ztwqqq1985@hotmail.com

Contact:Jenny Lee

Pipe stoppers/Pneumatic pipe stoppers/Inflatable airbag for pipe supplier from China

Description
Trough the design of professional, this product is used in leaking hunting for drainage pipeline. It is made of high quality compounded rubber and polymer materials, and because of good gas tightness and light weight, it could be used in all kinds of non-pressure and low tension pipeline.

Features
1、Economy practical .It could be used in cast iron pipeline plug, glass fiber reinforced plastics pipeline plug, PVC, PPR pipeline plug, and double wall spiral pipeline plug and so on.
2、Service plugging ,and leak hunting.
3、Elliptic type. It easy to stuff the pipeline and it has good plugging effect.
4、Decay resistance.
5、Super strong expansibility.
6、Light weight and convenient to take, and easy to construct.
Application
Pipe plug with rubber bag is always used in pipe and culvert in order to excreting the sewage and waster water, And also used as the repairing rubber appliance. Because of its various specifications. It can be used to block the stream in various situations.

Working principle

The working principle of rubber pipe plug is made of using high quality rubber sealing gasbag by adding method so that it has expanded ,when the gas pressure of sealing gasbag reach formulary requirement, the sealing balloon will fill in the whole pipeline section, and using the friction blocked leaking ,thus achieved the goal that without ooze water in pipe, Before operation of pipeline work of flow condition, measurement the diameter of air into the sealing pipe, Hold on the side of the rubber pipe plug with air cock ,slowly put the air bag into pipes. Before inflate the airbag, insert it completely in pipe, and connect the barometer and pump, then opened slowly the valve of pressure control table .The air pressure if controlled in safety area outside of pressure marked red,. Taut drawing rope in sleepers on rope binding firm ,through pressure control list, observation data, while if reaches the formulary requirement, close the vales of pressure control, and inflating is end .After that, within 20 minutes, keep connection between pressure control tables and pipe, observe data of air pressure sealing variation ,if everything is normal, and starts the work of pipeline construction.

20th floor,Tower B ,Taiyi Shangcheng,Zhonghua Street,Hengshui City,Hebei Province,China.

Tel: +86-318-8538202

Mob:+86-18678456530

Fax: +86-318-2210707

MSN: ztwqqq1985@hotmail.com

Skype: dachengdc678

Email:dcrubber1996@126.com

jen_dacheng@126.com

ztwqqq1985@hotmail.com

Contact:Jenny Lee

订阅：博文 (Atom)