What is an Expansion Joint of th aqueduct?
Bridge Expansion Joint as the name itself suggests is responsible for modifying the movement of the bridge. This is due to bending caused due to external loads of traffic on the bridge. In Addition, the Expansion joints serve their purpose due to contrary changes. A joint can either expand or contract by step within its allowed range of movement. Thus the expansion joint of the bridge is a connection between the joined bridge structures including attachment.
Expansion Joints are present in a wide variety. The selection criteria of Expansion joints for a bridge in Pakistan are made on several factors.
In Pakistan, respective designers for bridges have cosmic knowledge and even more experience. Which after careful observation and understanding helps them narrow down Types of Expansion joints that fulfill the requirement of the Expansion Joints. That they need to obtain from it.
Type of Traffic including heavy and light traffic along with the number of vehicles are calculated and specified. As in the case of Motorways, the traffic that is moving in terms of the heavy lanes all has to go through weight stations. For them, it is to assure that these vehicles fall under the weight specified category and do not cause any wear and tear due to overloading. In Pakistan, Motorways and roads allocate it based on the number of axles that are present in the vehicle. Being 12 tons per axle goes up to 58.5 tons for a twenty-two-wheeler with six axles. Designers are aware at most times, of the fact that un-weighted traffic maybe crosses the bridge.
At timesbuilder wins a project and is assemble years later the sourcing process is shifted further ahead. During the following case noting the current assembly in Pakistan the cost of the imported expansion joint itself (without margin for contractor and vendors) exceed the cost that the contractor initially agreed upon. Inside such a assembly scenario vendors and contractors have to face losses. Indoors is another scenario where supposedly the contractor won the project by bidder below the estimated value of the project. Now one can quite easily conclude that attaining the specified expansion joint will immensely burden the contractor leaving no other option than procuring a locally assembled expansion joint. In the following cases, the client is also kept in confidence where the client has no other option but to except a locally assembled expansion joint. This is just one example of financial constraints the contractor faces. Reasons for financial Constraints faced by the builder vary from time to time.
One can always observe the shape, type, and material of the installed expansion joint. A bridge project has an rate cost of millions to billions of rupees. An styl;ish joint that improves the aesthetic appeal of the bridge is always better when such a huge investment is involved. From personal experience, many specialists in the construction sector of Pakistan praise the aesthetic beauty signified by the Alloy Aluminum triangular teeth. As the Triangular teeth move within the gap. An expansion movement in warm due to the high temperature. And the fingers to close down in
In most cases, imported expansion joint has a working life warranty of 10 years. Therefore BOT (Build Operated Transfer) projects, contractors want durable expansion joints because in BOT projects the construction ownership is around 3 years, and the toll tax collection period is about 25 years so contractors wish to invest in expansion joints without compromising quality. Long-lasting and maintenance-free expansion joints are the first precedences of contractors and consultants because these expansions joint neither crack nor make any harm to concrete and give smooth ride quality that saves contractors time and money. Expansion joints imported and manufactured in Pakistan are installed with a working life warranty of 10 Years. Our Company has procured and Supplied Steel Mono-Block Expansion Joints SE-300. When installed by Supabizz Certified team is guaranteed a 20 Year working life warranty, making it a preferred Expansion Joint for BOT projects. Such as in the Project of Dualization of Sheikhupura-Gujranwala Road under PPP mode.
What are the Types of Movement Joints used in Pakistan?
Expansion joints are widely used in Pakistan. Selection criteria are discussed previously. We will now examine the types of expansion joints used in Pakistan. Firstly, it should be noted that there are about 50 different types of expansion joints in Pakistan. Here are some of them.
Type of Expansion Joint being used in Pakistan Bridges.
- Rubber Monoblock: Monoblock type of Expansion joints are among the most used expansion joints in Pakistan. Therefore, it is cost-effective, as these expansion joints cater to small movements. The Expansion Joint is considered noise-free as rubber when contacting with Rubber assures minimal noise after contact. In Pakistan Freysinnet N-65 Mono-Block Expansion Joints are mentioned in Drawings and BOQs. Our Company offers its Approved Equivalent Interbuna ET-75. It has been declared as an Approved Equivalent on the letter NHA issued in 2014. Installed in Mega Projects such as Lahore Sialkot Motorway, Karachi Thatta Dual Carriageway, and Hazara Expressway (E-35)
- Multiflex: Multiflex Expansion joint composed of Rubber is a noise-free Expansion Joint. This Expansion joint is ideally preferred by Supabizz for Bridge Projects in Major cities. This joint comes in two types, REJ and EJN, also from Interbuna SL Spain. In Lahore Metro Project, Kahna Kacha Flyover, and LOS Road Samanabad, Expansion joints were widely used.