I am fascinated by construction. My university is building a new facility, and they are using 2 tower cranes in the construction.

Why would a contractor choose to use 2 cranes on one construction project? Is it simply a matter of saving time by having the two cranes work simultaneously? What are some other considerations that might be taken into account?

EDIT: after checking your answers, I agree that it is most likely that using two cranes in this situation was mostly done to increase productivity/throughput, and the positioning of the cranes depends on the building design and ease of loading materials to be transported by the crane. enter image description hereenter image description here


2 Answers 2


Tower cranes are a very significant cost on any construction site, and so builders will usually only use as many cranes as is necessary.

I work for a construction scheduling company, and the one of the biggest factors for deciding on the number of cranes and their location is access. Obviously the crane needs to be able to access all parts of the building during construction, but the placement of the crane is also often determined by access to roads and materials on the ground. Other big restrictions such as site boundaries and roads also often come into play in urban areas. If the access limitations mean you need two cranes, then two cranes will be used.

Secondly, as you noted, is time. Time is money on a site, and if having a second crane can save you a couple of months off your finish date, then it is usually a cost effective idea. Other times, there may be a hard deadline for a project finish, in these cases more than one crane may be used to accelerate the program at the request of the client despite it being more expensive.


I'd say it's most likely a time saving operation.

I'm sure a project manager looked at the situation and decided it was beneficial to the schedule and productivity to have a second crane operating as well.

Depending on the area and height of the building there's only so much you can do with 1 crane; everything takes time. If you can run two cranes at once and keep them both busy it's bound to benefit you from time savings.

  • 1
    $\begingroup$ It's also quite common that one crane can't reach all of the construction site due to structural limitations on boom length, so a second crane may cover the 'blind spots.' $\endgroup$
    – Ethan48
    Commented Feb 8, 2017 at 1:49
  • $\begingroup$ If you need to lift some long horizontal beams in a confined space, it may be easiest to control the motion of both ends independently with two cranes, instead of a single crane and a person pulling on a rope to rotate the beam as required. $\endgroup$
    – alephzero
    Commented Feb 8, 2017 at 2:51

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