Building Construction Crane

Building Construction Crane: The world of construction cranes is very wide, and knowing what to do at all times, like a tower crane, is difficult. Find the tower crane and the amount that suits a construction project.

We are perplexed by the complexity of the theme and the different options, characteristics, classifications or types of machines used in the works, a theme in which not only tower cranes can be used.

This time we will cover all the instances of the installation and maneuvers of a tower crane.

How are tower cranes erected

How to install a tower crane?

When we plan the work economically, (one of the first tasks that we must carry out), we must already know what is the exact number of tower cranes that we are going to use, and for how long and for this reason its location is important to know.

On the contrary, if we make mistakes in these decisions, we suffer for almost all the work and will suffer all participants in it that require this means of elevation.

To do this, we must take into account a number of factors, we will start by considering that we can place the crane where we are interested, and gradually we will adopt that location.

They are detailed below in the form of Steps:

Tower crane assembly

Assembly of tower crane:

If we know our term (contractual term), we also know the execution term that we have for the realization of the structure, the experience helps us enormously, without the need to elaborate a Planning of Times, although this is always desirable (essential if you do not have a lot of experience) and in the majority of the constructors the Work Manager will be required.

Let’s say for example that I have 20,000 m² of the floor, they are calculations estimated in broad strokes, it is not necessary to be thorough at this time, it will be time to be a retailer … Let’s suppose that we have to build a building in 18 months (a usual term now). From the outset we already know that the structure (not the foundation) will take us from 4 to 6 months (this data is based on experience), we also know that we will overlap with the masonry from 2 to 3 months …

Climbing Tower crane

Equally the experience dictates the other necessary data: the m² of structure that can develop a tower crane, which is approximately 1,500 m² to 2,400 m², we should not be optimistic thinking that we will develop more, nor take the work in a relaxed way thinking that we will recover in other phases … The structure, being a long critical path, is very relevant when taking into account these data.

Construction crane

In the first calculation, I will take into account the most conservative data:

20,000 m² / (1,500 m² / Ud. Tower crane x 6 months term to execute the structure)> 2. If we are able to execute the critical path structure with the resulting number of cranes, we will be able therefore to execute the rest of the work, with this number of tower cranes.

And in any case, always in specific moments of greater accumulation of production of different units of work, I will be able to have other auxiliary means of support, which I will also have foreseen. The first data we get is greater than 2, if we do the calculations with 4 months, pressing the accelerator, we get something more than 3 units.

Therefore, since we will never give up trying to improve ourselves, we choose 3. If you’re not convinced, try comparing the cost of this extra crane (from 2 to 3 pcs) against the total indirect costs of two months of work execution (more rapid calculations), the IC of work represents 18% to 22% of the direct cost, approximately, of it) … Make the calculations. Of course, crane rental prices have dropped considerably, but even with the highest prices, the economic data speaks for itself …

Of course, in a work of smaller dimensions, such as a single-family home, does not apply … 3 is the number of tower cranes that we should consider at first in our example.

Work area protection

Location: Since the second fact, that will determine the final number of tower cranes to install, will be the shape of the building to be built.

To do this and before proceeding to its location, in all cases we will try to fulfill the following steps, we have a variable in our favor, the length of the pen, if expanding it, we can not cover the whole work, we will make other decisions, of which We will talk later. Now let’s see what are the premises that each of our cranes must meet.

Download area

Each crane must access the truck unloading area corresponding to each crane, without needing the support of another crane, or other means of lifting. We must have clear access roads to our work, circulation areas, storage areas, etc … It is necessary to make some points here:

No tower crane should maneuver over pedestrians or other buildings. This usually does not affect its location, it turns out to be very strict in the instructions for the grower and crane monitoring.

Building Construction Crane: We will not let neighboring buildings fly over our work with their cranes.

The lower the boom they have better, the cheaper the rent, the shorter the route and the sweeping of the crane (it favors the security, the follow-up of the gruísta, the rapidity of unloading), the greater the load it will be able to bear in the tip to equal conditions …

Under construction building

In a building, the installation of the crane will affect certain units of work, which can not be carried out and/or finished off by the existence of said crane and until the disassembly thereof. Therefore, we must install them by damaging areas whose units are the latest (in the beginning, and with the shortest execution time) in our Time Planning, such as, for example, urbanization areas, taking care not to intercept services, pipes, etc…

In many buildings, these urbanization areas are on garages (one, two or three floors, or even more …), in this case, the recommendation is to continue plying them there, but we will leave in the planned structure (in the perimeter of that hollow), in an easy way, the execution of that stretch of structure, when we have disassembled the crane, with armors waiting, and other systems such as metal profiles can be left waiting, etc …

That we provide above all the shoring, the formwork without affecting lower holes in the same lead, because in this way we can streamline and even run all the holes at once, without having to wait for a succession of stripping, which is what most time of execution will take us in the replacement of those sections of holes, we will devise a way of being able to form them all at once, in the event that we have affected more than one plant, yes, WITHOUT AGAINST SCAFFOLDS that are prohibited.

In the case of affecting buried garages, it is better that it be in areas of circulation that are not inside technical rooms, because of the work units that are going to be affected.

Stages of construction

The important thing is to locate the tower crane outside of buildings in height, for the aforementioned, if we do not have urbanization, we will look for the light yard, setbacks areas, etc …

Tow cranes should NOT be installed on stairs of buildings in height (although we have more than one): the term that would take its execution, to cut access roads to the work, the incidence of the crane in the roof waterproofing, and from this in the entrance of water, the damages of said filtrations on all the floors of the building, in the areas adjacent to the staircase, we can imagine them and for that reason it is necessary to avoid it.

If there are stairs from the urbanization only to the garage not coincident with building in height, things change, and it is a possible location to analyze.

I do not recommend the installation of the crane on the elevator shaft, since the execution of the masonry of the same, we would only control the wall of the interior of the building, not the hole, leaving it full of burrs; the auxiliary means that we will need to cast this hole, the finishing touches on each floor of the received door, large burrs can vary the dimensions of the shaft, the damages produced by the crane when disassembling it, the possible leaks as in the case of the staircase , we can not control the work inside the hole when disassembling the sections of the crane, nor can we observe the state of welds and other components of the crane during execution.

Isolated footing

Revision of the impact of the crane shoe on the projected foundation. It will be very difficult to avoid 100% and will depend on the characteristics of each Project. We will always try to avoid matching the tower crane shoe with another shoe of the foundation, but if it is impossible, we will try to make this incidence, on the smallest number of possible shoes.

Building Construction Crane… Of course, it will never prevent the construction of pillars and/or walls (nor their demolding) …

When we have coincidence, we will draw a shoe that absorbs one of the cranes and the one of the complete foundation, or that absorbs several if the incidence is on several. Imagine how important this point is because the crane’s shoe can end up being large, being also great singing, and being armed normally enough the cost skyrockets …

The crane’s shoe will be subjected to the structural calculation of course. Any engineering of the crane rental company will provide you with its dimensions and its assembly, but they must always be reviewed and approved by the Facultative Management beforehand.

Building Construction Crane: The shoe of the crane can be calculated for eccentric loads, that is, we can leave this step perfectly defined, and need to move the mast of the crane, not the shoe of the same, to meet the next step. This shoe will be calculated eccentric.

Structural calculations

When we have a proposal well analyzed, we will always present it, in all cases, to the Facultative Management so that they authorize:

• the location (with and without incidents)
• calculations of that crane shoe, which will have taken into account the incidence with other shoes.

Logically, Project Management should review this incidence and structural calculations for the importance they have, so … the sooner you start with all these efforts much better, if we do not want to delay the work.

Although our building construction crane shoe does not coincide with another foundation shoe, its proximity to the unloading areas of other shoes, we must also review it in terms of structural calculations, refers …

Beware of the incidence of the tower crane footing on slopes, retaining walls, piles, and other screens, it must be taken into account in the calculation of said shoe and said screen, that is, before the start of the work

We will make the necessary location corrections to meet this step.

Construction site crane

Once the location has been decided, we will check the incidence of the tower crane’s hollow with the structure, the time has come to be more detailed, we will have the data of the dimensions of the crane, including its mast; we will avoid incidents with girders, beams, and pillars that affect areas of the building …

… by this means that if we are interfering with a pillar of an urbanization pergola, it will have a minor consideration that we have explained above. (Building Construction Crane)

In no case, we can affect relevant elements of the structure.

Logically beams or some section of small slab (where your way of working is not changed) will be affected, and we will have foreseen the way to build this section, which will be quick and effective, once we remove the crane, and always from very concrete of the work, that is, urbanizations, garage …

We will also make sure that the areas adjacent to a said tower crane, or rather, the hollow produced by the tower crane, have their complete and adequate supporting structure …

Of course, and as I mentioned before, all this previously authorized by the Project Management of the work. We will make the necessary location corrections to meet this step.

Minimum tolerances

We must also take into account the separation of the crane (from its mast) to slabs and facades.

The placement of the auxiliary means that we use in their construction, on the width of continuous formwork, on the bending zone of the beams, scaffolding, façade separation, safety separation, and the movement of the crane, which suffers greater displacements the greater its height…

Reading construction plans

We will make the necessary location corrections to meet this step.

It is time to observe the sweep of the cranes superimposing them on a plane … are there dead spaces of work where none of them is accessed ?, we must play with the possible combinations that give us the different boom lengths (taking into account that the last 1, 5 meters or 2 meters from the end of the boom, the car does not arrive, therefore, the load either), knowing that they go in sections of 5 in 5 m. This is a trial job, to try different possibilities.

Building construction

It is time to take into account the horizontal and vertical distances between cranes and from these to other buildings or emerging elements.

Finally, we must analyze not the height of existing buildings, but these plus the antenna and the lightning rod of both our building and buildings under sweep of our crane, if we do not meet this height (to take into account the up to 6 meters of slings or chains hanging from our crane), then we must separate horizontally the distance dictated by the regulations.

Calculation review: if after having made a great effort and having analyzed the possible scenarios, you still do not find solutions …, the initially stipulated number may have to be revised and the whole process restarted. But before that, let’s see other possibilities that perhaps interest us more:

Coverage area

If the dead point (without crane sweep) is minimal, a corner, analyze which elevations, discharges, and work units are those that will be affected, because if it is a corner, we will have affected the concrete … (of course, in this type of works we pump, so this problem no longer exists …

Building Construction Crane: Be careful with the height of the building, if it is very high, the crane truck will not reach more than 26 m vertically, if there is also a horizontal section to be saved, the reach will be smaller,

… and the façade would be affected, in this case, and if it is only that, it would leave 3 cranes, and would make the forecast of another auxiliary means, such as truck crane, for specific cases, with short or very intermittent execution times … is a matter of analyzing costs and see what interests us more. Equal costs, we are interested in having the work as organized as possible, avoiding surprises (such as the delay in the service of a truck crane, etc …)

Building Construction Crane Cost

Cost analysis in construction.

If the area without sweeping is wider or affects many months of execution, it would be desirable to resort to another crane, or provide another means that covers this area. analyze costs.

We can raise the issue with another crane, from the first step. In our case 4, but yes, he observes that although with one more crane, if they do not all arrive to directly unload trucks, they do not develop more work than 3.

The explanation is simple, if a crane is subject to the support of another or another auxiliary means provided to cover another different area, we can mount a collapse in the area of ​​the first crane, since you will have to wait for the second time’s downtime or leave paralyzed its zone, although at first, we think that with an hour a day or two is enough and we will not cause too much disruption to the work.

If this is well carried and at full capacity, the disorder will be fat, and it will never be a good time … Bear in mind that in the phases of greatest use of the crane, each crane can get to download 2 to 4 trucks (or trailers) ), depending on the size of the work … and this takes time …

Building permit

We must bear in mind that in many cases cranes are mounted only for a specific phase of the work, with the expectation of disassembling them before normal … for example, if we arrive at an urbanization with several buildings under construction near our work, and We are the last builders, it is more than likely that we have many problems to place our cranes as they affect those of the neighboring existing builders.

To do this: o If there is a collaboration between them, it is possible to reduce the boom of the crane of the neighboring builder, or even height, provided that the second run at all costs and is outside normal production hours.

Analyze costs of the whole process, because it is clear that who arrived first … will not be running expenses.

Or, for needs it is decided to place cranes lower than normal (they will come to collide with our own building) that develop most of the work in structure, and when it is necessary to continue building up to the top they are dismantled, leaving these areas pending of others means (of higher cost) that we already have in the cost of our work. Analyze costs and also, note the importance of the development of the work, if it is a single volume building is clear …, but if it is a work with several blocks, it is essential to know the order of the work.

Surely you are thinking that you have to know many things and have them clear before starting a job if we have the experience, the lack of time we usually have is a problem, but if we also lack experience it is almost impossible …

Number of cranes

This task, to locate the cranes and decide their proper number, is a job that requires several scores, some time and creativity, so cheer up…What I assure you is that the time spent, as well as the headaches, will be rewarded throughout the work … The opposite will also be seen and will be suffered throughout the work .. All the participants in it, or most of them will also notice in their day to day this work of previous planning … The economy of the work will be directly affected … There are many reasons why these details should be taken care of, and of course, also your quality as a professional it will be splattered, both for good and for bad.

Permit to build

Needless to say, we must comply with and observe all current regulations. We must observe compliance with the regulations regarding the assembly, use, and disassembly of the tower crane.

Must be Legalized by the Ministry of Industry and the corresponding Town Hall. And of course comply with all the Health and Safety regulations in the work, special communication must be had with the operator of the tower crane, and therefore, its follow-up must also be constant.

Conclusions: And finally, at the time of rethinking, please, extreme caution, checks in accuracy and number, using a surveyor, if necessary, and even when it intervenes, my recommendation is to make the appropriate verification of stakeout.

Our efforts are useless if mistakes are made in the work, they occur, but the reviews detect and resolve them in time.

Building Construction Crane

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