Mexican Rapid-Transit Rail System Expands with Help from Terex Cranes
May 20, 2015 - In Monterrey, Nuevo León, Mexico, the Monterrey Metro (aka, the Metrorrey) rapid-transit rail system accommodates more than 480,000 passengers each day. To further reduce traffic congestion, a third Metrorrey line is under construction. When completed, Line 3 will connect the Line 2 terminus at General Zaragoza northeast to Hospital Metropolitano. Its 26 trains and nine stations are expected to serve an additional 280,000 passengers daily.
Enlarge Image
Two Terex all-terrain cranes were used to build elevated Metrorrey lines.
The contract to construct the 7.5-km-long elevated metro line was awarded to a consortium of Alstom Mexicana, Constructora Garza Ponce and Constructora Moyeda, a leading construction company in northeast Mexico that specializes in the design and construction of civil works (particularly bridge) projects.
According to Arturo Moyeda Morales, CEO of Constructora Moyeda S.A. de C.V., crews needed cranes with the capacity to erect U girders, as well as lift at one end of the job in the morning and then move a couple of kilometers during the day to erect in different locations in the evening.
Each U girder weighed 230 t, the heaviest precast pieces ever erected in Monterrey, and measured 37 m in length, 1.85 m in height, and 5.2 m wide. The girders had to be placed to heights between 15-22 m.
Moyeda said two Terex all-terrain cranes—a 350-t capacity AC 350/6 and a 500-t capacity AC 500-2—were selected for the project because they had the capacity to lift the girders. The cranes are roadable, he added, and needed only six flatbeds each to transport the counterweights. In addition, a crew of 12 people were able to set up the cranes in just three hours. “Once a crane was moved,” said Moyeda, “and we had the go-ahead from the transit authorities, a lift could be done in less than 30 minutes per girder.”
Challenging city work
One of the challenges the crews faced while working in the confined spaces of the Monterrey metropolitan area was that Line 3 was to be erected above highway bridges, over pedestrian bridges, and between power lines. Existing traffic patterns, old drainage lines and main water lines were also factors the consortium had to consider as they planned for, prepped and executed the project plan.
The original project proposal required the use of a launching gantry; however in order to use this method of construction, it was imperative that the construction sequence was done consecutive from pier to pier. If one pier could not be constructed due to interference all erection would have had to be halted. To circumvent this issue, Moyeda and his crews used the Terex cranes to construct a viaduct, in different fronts at the same time, so maintaining the continuity with a launching gantry was not needed.
“Most of the lifts were done with minimal traffic interruptions and in very confined spaces, with a number of underground and aerial obstacles,” said Moyeda. “On top of those site conditions, we also had to keep our crews productive in the Monterrey weather conditions, where temperatures can reach 115° F in the summer.”
According to Metrorrey, Line 3 is due to be commissioned in August, 2015.
