Metro Dubai ( my sections )

Material above Ground

 

There are such materials that were used to build the above ground shape. The materials are piers, pier caps and viaduct deck segment.

Pier:

It is the column that we put above the pile as a completion of the pile. That is to make it a strong and stable to the body of the project (the Viaduct form), so it will not be affected by the weather such as air storm.

Pier cap:

It is the completion part of the pier which we put above the pier. There are holes that are required in the pier caps to attach them with the piers which have the reinforcement bars. That is to make in one shape.

Viaduct deck segment:

The shape of the piers jointing with the pier caps are made to carry the viaduct deck segment.

This figure give’s the engineers an artist’s impression of the viaduct which was proposed at the conceptual design stage.

 

 

“The viaduct superstructures were typically formed from U-shaped cross sections. The post-tensioned precast segmental deck segments were cut using either long line or short line moulds” (Hendy, C et al, page: 4)

These two figures illustrate the previous idea:

                 

 

“The viaduct substructures generally comprise reinforced concrete piers, with flared pier heads to support the deck, and reinforced concrete abutments” (ibid, page: 4). The pier heads are for the single spans. The spans which were constructed by using the method of thin precast reinforced concrete shells are twin spans and station spans. “The pier heads for the single track and 3-span continuous internal piers are of in situ reinforced concrete construction. All piers and abutments are founded on large diameter bored piles” (ibid, page: 4).

Material Underground

 

There are such services for the underground like, water supply, sewage drainage, electrical cables, military services and telecommunication. Before we start the construction building we have to do piling. That is to say that piling is the foundation for the whole project. Before we put the piles in the ground we have to excavate sand from the ground because if excavation work has not been done, this will affect the pile works underground and it will damage services underground also. Pile is one part of foundations, pile is used for bridges and high buildings that contain 30 floors or more and last for long period of time. The pile is placed underground after using heavy equipment’s like rig machine. “This machine is used for drilling the ground to reach the hard level of soil of the earth” (Mohamed Ali, 2010). After drilling and reaching the hard level of soil in the earth the structural steel is inserted like rebar and concrete is poured to the ground level. Pier is a part that supports the body of the project structure which is the pier cap. “All piles and piers are casted in the construction site” (Mohamed Ali, 2010).

Tunnels

 

Two lines of the metro system are currently under construction. The red line is not totally constructed, but it will have twenty-nine stations four of them will be underground, the green line will have fourteen stations six of them will be below ground and they will have interchange between them. The work for new tow lines underground is extended due to financial problems.  Blue line and purple line are the two lines that will be constructed underground. Before beginning construction work underground there are several tests that must be done for the tunnel. These tests are bore holes and insitu-test within bore holes, lab testing, pumping trials and surveys. To make the tunnel underground first of all we have to dig with a big digging machine and every step they finish underground they put wood, concrete and steel bars to make it more safe and good for the reinforcement.