Kategori: Uncategorized

CONCRETE PUMPING WITH SEPERATE PLACING BOOM

Pumping of concrete, conveying it with pipes and placing are carried out with three types of concrete equipment. These are stationary pumps, separate placing booms and high-pressure delivery line. The pumping process are not so easy and there are some difficulties at pumping in high and long horizontal distance. The reason would be using less powerful pump, insufficient delivery line and not benefiting from seperate placing booms.

Combination of stationary pump, delivery line and separate placing booms are inevitable in high and horizontal projects. The equipment required for a high-rise building is dependent on several factors:
-The height concrete needs to be pumped
-Whether the pump will be located indoors or outdoors.
-Whether multiple boom/pump/pipeline setups.
-How the boom will be mounted, self-supporting crane tower or self-climbing tubes, etc.

Calculating the pump pressure using nomogram:
-Concrete ‘Pressure Performance Nomogram’ was designed and developed by compiling values of several concrete pumping jobs taken from different site conditions.
-The deviation of the results on the basis of recorded values and the actual are only within the range of 5-10 %.
Nomogram consists of four quadrants showing the following values:
1.The relationship between output of concrete and pipeline diameters.
2.The resistance to flow of the entire pipeline system.
3.The workability of the concrete in terms of slump value in mm.
4.The maximum output, pressure, and power for a specific machine.

One way to place concrete quickly and economically is the use of separate placing boom in conjunction with efficient concrete pump.
The seperate placing booms are of equal design as the booms used on truck-mounted concrete pumps.

Advantages of using a seperate placing boom:
-Placing booms allow concrete to be poured into forms right where you need it!
-Placing booms lessen the need of manpower for spreading the concrete on the floor.

-Labour requirements are minimal, one person can operate the placing boom.

-Placing booms allow uniform concrete placement in wall, column and deck forms.
-Less finishing time is required because of the precise placement.
-Continuous flow results in higher quality concrete.
-Added time savings are realized by the tower crane being free to handle other lifting operations.

Related books of the autor:

-Highrise buildings – Concrete pumping (ENG)

-Concrete pump at operation (ENG)

-Betonu pompalamak (TR)

-Betonu pompalamak – Risk yönetimi (TR)

-Beton pompası performansı (TR)

-Beton pompası teknolojisi (TR)

-Pompa operatörü – El kitabı (TR)

 

www.ozsoylev.com

 

 

Do you know the cost of ‘extra mixer truck’ to your company?

Planning in ready mixed dispatch is compared to financial management! Planning, in a sense, is the budgeting of the work. Sending concrete with mixers means writing checks and subsequently converted into cash.

No commercial company want to take risks in this regard.

And the best man should be used in dispatch position like in the financial management.

Unfortunately, this is not the case in concrete shipment and the need to employ an experienced and skilled man for problem-free shipment is often overlooked or ignored.

The aim of the planning is to provide maximum service with minimum cost. This can be accomplished by planning when and where to send the mixers firstly.

The basic steps of dispatch planning are:

-Determination of the required number of mixers for the cycle

-Determining the filling time of the first mixer.

-Determining the loading time of the remaining mixers, etc.

The dispatcher should make some maths to determine the required mixer for a cycle. The formula for the calculation of this is very simple ‘cycle time / unloading time at site’.

However, it is known by everyone that the dispatchers sometimes keep some vehicles for their beloved customers. Some managers even take it with appreciation. So, why are all these calculations and plannings being made? And why there are some mixer trucks waiting for unclear request.

Does the dispatcher know the cost of an additional mixer to the company? We should ask the same question also the manager who appreciates the shipper who keep mixers his customer. How much does an extra mixer cost the company?

The calculations show that extra truck waiting idle every  day  a week and all year along cost to company around 100.000 Euro.

If the company has multiple plants, it is clear that, there may be more  trucks waiting idle which beyond the number required to haul orders for a given day.

vwww.ozsoylev.com

Is it enough just to have a heavy vehicle license to be a mixer driver?

The answer, of course, must be no! Although the mixer is generally defined as a truck-mounted equipment, it has different features from all other trucks traveling on the highways, roads and also at the construction sites.

The center of gravity of the concrete trucks is high and its location changes at any time due to the constantly moving concrete in the drum. With the effect of centrifugal force created by the rotating drum, the concrete truck seems ready to rollover at any moment!

In addition to these, there are some limitations depending on the load carried by the mixer ie the concrete. Wet concrete must be mixed during the entire transport to preserve its properties. Also it has to be poured into the forms within 60-120 minutes after it is filled in the drum at the plant.

There are some companies that see the concrete truck drivers as concrete experts

when they enter the site and expect them to take all responsibility for the product once it is loaded into the drum. Therefore the basic concrete knowledge in any case is important for concrete truck drivers.

On the other hand mixer drivers have a very important role at the dispatch starting from filling the concrete to the vehicle in the plant and pouring it into forms or pumps hopper at site. And all concrete truck drivers should be aware of this duty at all stage.

The content of this handbook consists of necessary information for the safe operation of concrete trucks. All concrete truck drivers may find some new and important information that they have not encountered so far. That’s why I recommend reading this handbook and even working on some topics together with colleques.

www.ozsoylev.com

Which is more risky pumping upward or pumping downward?

If the pump is setup closer than the safe distance, there is a danger of overturn the machine. Do you know what may happen to the outriggers if they are opened partially or none when the pump works close to a pit with fully unfold boom? They cannot withstand the additional forces and may break. And do you consider any precaution while working next to a pit with a big boom? Or do you completely trust your operator and leave the results to fate?

Setting the machine on the edges of pits, trenches and gaps away always cause a danger. This is frequently encountered in construction sites and more common in large projects during pumping down with big booms. The general rule here is defined as one-to-one or minimum 2 meters. However, while pouring the concrete down with big booms often this is impossible.

What should the operator do and do not in this case? Think that there are some additional hoses used out of rules in order to increase the total length. The boom is full of concrete up to the end of the last hose. And the operator bends the hose. Then calculate the effect of extra load in the boom.  And if he tries to move the machine a few meters with open boom and full of concrete. Unfortunately, pump operators have difficulties in such applications and the pumps are operated without static and dynamic calculations. It is obvious that this job cannot be left to the operator alone!

On the other hand, in case of an accident who will be the  responsible by law? Possible justifications and claims may be as  follows:

-The site chief says that the responsibility of the pump belongs entirely to the operator.

-The insurance company justifies that the safe distance is written on the machine. And it doesn’t make the payment.

-Does the operator automatically accept all warning signs indicated on the machine?

-Can the RMX company claim that this distance limitation clause is not specified in the policy even it is written on the machine?

www.ozsoylev.com

Do you have a performans plan for each pumping operation.

-What reduces efficiency in the boom pumps operations?

If the answer is given with a single word, changing the setup location. This is not an easy precaution to take. However, poor planning may require more displacement than anticipated. This means loss of time and production at work. When you are working at a site, it is crucial that you manage time correctly and no labour or time is used up unnecessarily. Planning and timing is the key to productivity for ready mixed concrete companies as well as contractors.

-It is essential to use the pump efficiently in operations.

The first choice in this regard should be the determination of the boom length. Ideally, the boom should be as close to the building as possible, with easy access to all formwork without machine displacement i.e. in one setup.

-Replacing the pump location during the operation.

Now the boom sizes have grown a lot but still in many projects it is not possible to carry out the entire concrete pumping operation with a single setup. Nothing kills productivity like pump displacement in the middle of pouring. Sometimes this may become mandatory but unplanned relocations are the worst. Because they take more time and this can also cause cold joints in concrete. Therefore for setup the best and also alternative different locations, if any should be determined in advance.

-Time for replacement to relocate the pump.

The operator must first fold and close the boom. With the open boom displacement of the truck are forbidden in any case even a few meters. After the boom and the legs are collected, the pump truck is moved and the legs are re-setup in the new location then unfold the boom. This process can take at least one hour even more for pumps with large booms again to reach the concrete pouring position. For smaller boom pumps, this time may be less. But, in any case the displacement and repositioning of every size boom pumps is a serious event for efficiency in concrete operations.

-Enough space for mixer trucks.

There should be areas in the field where the mixer trucks can safely wait, even for a short time and they should be able to exit back and forth after safely discharging the concrete into the pump hopper. It is better to come from one route and return from another route after unloading. But more importantly, it is experienced in terms of efficiency. The approach of concrete mixer trucks in the new positioning of the pump will be re-determined and a risk assessment will also be required for them.

-Pump setup early in the morning.

Determining the pump setup location well and completing the operation without relocation is a very important issue for both safety and efficiency. Re-searching suitable ground and assessing other risks means wasting time. Another problem in this regard is that the concrete pumps go to the construction site mostly in the early hours and the appropriate place must be selected before the sun shines. And then the machine is relocated during the operation due to this lack of visibility. For this reason, making the pump setup planning one day in advance is of great importance for safety and efficiency.

–Fast pumping to compensate lost time.

What we lose in fast pumping is more wear and more fuel. In concrete pumping operations, the pumps are operated at fast speed to compensate for the time lost due to machine displacement or other reasons. The contractor may insist on rapid pumping to make up for lost concrete volume. Maybe there’s no harm in that. However, faster pumping means more fuel consumption and also more wear on some wearing parts. On the other hand, the maintenance cost of the machine is also increased.

-Planning for cleaning.

Each pump operator should be prepared in advance by a performance program for the operation. Everything should go within the program, including moving the pump truck. The operation manager should prepare the performance program together with the other relevant parties. For pumps with a boom over 50 meter, 30-45 minutes are allocated for the cleaning process. The most practical cleaning method is by pushing the sponge ball from the hose end. Concrete is sucked along the boom and discharged into the hopper. It is not recommended to move the machine with concrete in the boom and in case of concrete hardened including the valve, the cost can reach 15-20 thousand of Euros. At least there should be enough washing area for preliminary cleaning of pumps and mixer trucks at the operation site. Apart from this, a discharge place is required for the material left in the pump hopper and the mixer drum.

This E-Book, is consisting of fwg topics; pouring concrete operation management, performans plan, risk analysis, concrete pumps and safety, problems of big boom pumps, safety precautions, , who is responsible for safety, machine factors, human factors, site factors, preparation for operation, at the operation, evaluation of the operation etc.

www.ozsoylev.com

Selecting right equipment and pumpable concrete and safety issues…

-With modern concrete pumps, building heights have reached hundreds of meters. The record for today is about 600 meter and an engine of approx. 500 kw was used in the pump. However, the powerful concrete pump alone is not enough for such performance. Increasing the speed and volume of conveying concrete and the total performance are not only depending on pump. But the other factors such as suitable pipeline system, using right placing boom, concrete receipe, safety precautions and trained as well as experienced people are also important.

-All construction projects are the areas of potential danger! However with the selection of right equipment and personnel training these hazards can be eliminated. Unsafe working causes many injuries and breakdowns and interruptions in work. Safety is the most important factor that you can complete the job in the shortest time and at the least cost. Placing line, straight sections, bends and elbows should be chosen by knowledgeable and experienced people who know in certain areas the line must not be rigid but flexible. The use of placing booms and other special equipment has made the training more important for safety.

-Increasing the cross section of the line has a direct influence on the flow rate, the wear behaviour, the pressure requirement and the period for which the concrete remains in the pipeline given the same output per hour. On the other hand under high pressure concrete pump, delivery line and special equipment are always dangerous during pouring. All components of the system must be able to handle the maximum internal pressure. In addition, cleaning operations at the end of pouring can only be done by trained personnel. Do not think that it is simple job and can be done by ordinary workers. Injuries are mostly experienced during the cleaning phase.

-The rate of wear varies greatly. Hard aggregate is of course more abrasive than a softer aggregate . In addition to physical characteristics of the concrete, wear is also affected by the concrete volume conveyed, material velocity, pumping pressure and geometry of the system. You need also an accurate concrete recipe, because you can’t just rely on chemicals. The nature of the materials both facilitates the flow of concrete and provides a permanent advantage in concrete. For highrise building projects, sometimes the pipeline cost may take priority over the pump. And many problems can arise if the pump cannot produce enough pressure. For example, the material may get stuck in the line, causing the pipe to burst and the connections to break.

-This book is prepared to provide basic information for selecting right equipment and preparing pumpable concrete and safety issues. Therefore all staff  not only operative personel like pump operators, their assistants and other workers in the field, but also for the people who make preliminary work of any highrise building project can also benefit.

www.ozsoylev.com

Why we stuck in a 4 axle truck!

-The modern buildings in the cities are all going vertical and readymix companies need to big pumps. However the use of these truck mounted big boom pumps have some problems.

-First of all the ROI of high cost of the big boom pumps are not easy as the ones used in projects which can compensate this in the total budget of the construction.

-In the readymix business each pouring operation should deserve the machine on its own. Therefore the amortization period could not be short as 40-30m boom pumps. Because it is obvious that you can not everyday find a job for these big boom pumps.

-There is also operator problem. Because another guy may be the third one should assist him, in any case, to check the pumping units and outriggers while the operator following the boom-end at a close distance. Cleaning is also another issue…

-The operator of big boom pump should be paid more than the other operators using 30-40m pumps. But when you can not find a job for this pump and send the operator with a standard pump what will happen in terms of salary and income justice for pump operators within the company?

-But the main problem for the big pumps used in readymix is another subject. The design limitations*. These machines are considered as truck-mounted equipment and the GVW cannot exceed 32 tons for 4-axle truck on the roads. In some countries highways do not allow five-axle rigid trucks.

-There is a clear need for 5 axle rigid trucks not only for concrete equipment also for municipal and some other vehicles. There are even 6 axle chassis working with special permits supplying safe, economical furthermore functional in the countries where that this truth is seen.

-It is said that this was prevented in Turkey years ago in order to stimulate the use and accordingly sales of truck tractors. It is certain that maneuverability of truck tractor + trailer combination is better. But the need for 5-axle rigid chassis is also obvious.

-To solve this weight problems, manufacturers are constantly looking for lighter but stronger steels. This causes the material to be resistant to longitudinal loads, but to be weak in transverse and breakage.

-On the other hand manufacturers competing in the cheap segment use the lowest level of steel in its class. That means the price difference** which cannot be ignored starts with the boom material from the very beginning. In this point we must say that these pumps visits the workshop more often. And it goes without saying that this shortens the life cycle of the machine.

*This limitation is for on-road and not for off-road trucks.
**Price difference is at least 30-40 pc of the total cost.

www.ozsoylev.com

 

 

Everything you need to know about concrete pumps, even more…

What is the big problem of big booms?

If you have a large-scale project, a concrete pump with big boom would be the best choice. The fact is undeniable that cutting-edge big boom pumps are highly speedy, effective and economical for high rise and horizontal conveying concrete. Therefore these pumps are frequently asked for every kind of big-sized construction projects.

In order to meet this growing demand concrete pump manufacturers have been racing for a bigger boom. Every year or at the construction fairs we hear that a company slightly surpasses its competitor in boom height. It seems that this race is not only for the function of the machine, but also just to say I am the greatest in this field!

Following questions are frequently asked:
-Where does this boom height race end?
-Are these high booms realistic or exemplary for competition?
-We heard about 101 meter, when we expect 102 meter?
-Still standing without any support over 100 meter, as if impossible!
-What is the largest boom size put into practice for daily work at a project?
-Using big boom pumps is a boon or a bane?

In fact, boom manufacturing was a separate specialization from pump producing. In the past, boom work is a different area of ​​expertise with its steel structure and welding technology.
And there were some concrete pump producers in competition
using the same booms from the same manufacturer.

When we come to today, the following questions come to mind;
-How much time and how much area are needed to install big boom pump?
-Big boom means big outriggers?
-How do you prime the big boom and get it back?
-What are the practical problems with these booms in terms of control?
-Is there any difficulties to clean the big booms?
-Whether the double-layer wear-resistant conveying pipe is suitable for big booms?
-Are these big booms for special missions and projects only?

On the other hand, should we need to classify the operators as big (over 60m for projects) and standard (less than 60m for readymix) boom pump operators? Because using huge booms is not an ordinary job and placing concrete at such height is very tough tasks.

A new generation of huge boom pump operators with keen eyes will be required who will constantly observe the concept of balance and see the tip of the boom.

Let’s finish the article with the following questions:
-Whether the pump manufacturers not find another area to compete?
-Have the mechanical, hydraulic, electrical and electronic fields related to the pump and boom been thoroughly scanned?
-As there are several operational problems in practice is it worth to race only with boom.
-The stationary pump + seperate stationary placing boom option, where applicable, cannot be evaluated enough?
-Is it difficult for companies to lay the pipes?

Timucin Ozsoylev

ozsoylev@mail.com

 

 

There will be soon a new position to be added to the norm staff in ready-mixed concrete companies!

Considering that one of the existing staff can do the business development task, the norm staff in ready-mixed concrete companies has not radically changed for a long time. But now it seems that we will have to add one more task. This is drone operator…

Drone applications, which quickly entered almost every field, are no longer fantasy and start in daily operations of ready-mixed concrete, too. No, I’ am not yet talking about the concrete delivery with drones, but their use in logistics is just around the corner.

Drones, which have already been on construction sites for a while, are now entering the machinery inventory of concrete companies.

And of course, some questions arise related the operation of drones. Who will use the drones at readymix companies.

After the plant operator, mixer operator and pump operator, drone operator position are now on the field for concrete operations. So what will their job descriptions be and more importantly, who will provide their trainings?

About thirty years ago, I made a great contribution to operator training in the ready mixed concrete association. After holding several meetings to create the system, I also personally gave the first trainings.

Now, as a mechanical engineer, but graduated from the aviation branch and also as a father of aircraft pilot, I would also like to warn the ready-mixed concrete association for this new position.

Of course for small ready-mixed concrete companies having a machine park consisting of one plant, 10-15 mixers and a few pumps, this may seem far away. But large companies should immediately put this issue on their agenda.

At the first glance;

-It can help first inspection of the site and approach roads.

-Can guide drivers on the roads.

-Can assist the dispatcher for logistics

-It can support the safety on the road and at the site

I cannot say it can deliver the lastminute missing concrete yet, but we can say that it can deliver, for example, a necessary part for the pump or a leaking hydraulic or electronic part which may stop the machine, very quickly and just on spot.

In my opinion, the ready mixed concrete association should take action to obtain training accreditation for drone operators, at their earliest convenience!

 

TIMUCIN OZSOYLEV

www.ozsoylev.com

ozsoylev@mail.com

Whatsapp : 0090-532 416 13 87