A fence made of profiled sheet: load calculations and the installation features

With the beginning of a new construction season, many developers are puzzled by the question of how and how to protect the site. Our portal has already said, how to build their own fence edging boardAnd profitable to do Monolithic concrete poles for the fence. Today we tell about the specifics of the construction of a fence made of profiled sheet.

1. Theoretical part

Fencing section of the trapezoidal sheet rightly bears the title of "People's fence." Most developers captivating opportunity to establish a fence alone, without recourse to the services of professional teams. In addition to cost savings, this approach increases the quality of work, as do the fence for themselves and, therefore, personally responsible for the installation.

Despite the "razzhevannost" technology, inexperienced zaborostroitel can make mistakes. Their consequences are grim: spring poles sticks, fence "walks", with a strong or gale-force winds poorly bolted sheets can break, or the fence and do the rubble.

To avoid such troubles, you should stick to proven solutions that are based on the practical experience of our users.

Pavlovich P34 (Member FORUMHOUSE):

I had to fence the perimeter of 170 meters. I decided to put a fence on their own, without assistants, "two hands." By the time it took two seasons because parallel had to do a lot of other work in the area. For the first year I was completely installed all posts and joists scalded, cooked gate and had to paint one side. In the summer managed to find time alone after work in the evening, for 2-3 hours, and on weekends. In early autumn, I was able to work only on weekends. In the second year, in the summer, strip rust metal frame, painted it in three layers and coated steel sheets.

Looking ahead, we will show that in the end it turned our user.

Fence stands like a glove. Poles are not kicked out the forces of frost heaving, the sheets are not disrupted by strong winds and pokorozhilo.

A total of 145 meters fenced capital fence trapezoidal sheet 25 and the temporary. An interesting approach Palycha P34 the construction of the fence, which he broke into a number of successive steps, which ensured a high quality result. But before you go to them, together with the user response to the three "Why".

Question 1. Why do I put the fence itself.

Pavlovich P34 (Member FORUMHOUSE):

It's simple - the budget is limited, and none of the firms in which I was treated, did not agree to do the fence in my. task, the requirements to the materials, fence installation method, the installation depth of the pillars, dyeing quality, thickness profiled sheet etc. And most importantly - control on my part - to proceed to the next phase of construction only after I take the job done.

Builders turned the unprofitable. supervision by the customer. Suitable familiar to any developer. "Professionals" from the building easier to reduce the quality of work and drive volume at a time. The calculation is simple - let's say, more profitable to put three of the fence for a week than to fiddle the same time, with one guard, making everything "on the conscience."

But this approach is not practiced by all. There are companies that make high quality and fences, unlike shabashniks which to fix the marriage, "the afternoon with fire will not find", give a guarantee on their work. Before thinking that if one firm over the fence 100 m long takes 1,000 rubles. per meter, and the other for the same work - only 800 rubles, so -. it is the best deal, it is necessary to compare, and that they offer really is. It may be that for less money and like the same perimeter of the fence you get a lower quality.

During the construction of the fence there are plenty of opportunities for unscrupulous executors warm your hands on the customer: take profiled tube of smaller cross section (80x80 not get an entry group, and 60x60) with a wall thickness of 3-4 mm and 2 mm. "Zabut", pour concrete, goal posts not on the projected depth, and only 0.5-0.7 meters, only hilt augers. Tell the customer that the way it should, and be silent that actually drill deeper (as required by the calculation!) Means to put on a drill extender, and a waste of time. Screw poorly dyed at the factory and cheap steel sheet thickness of 0.5 mm, and 0.35 mm. Reduce the number of fasteners. As a result, steel sheets in strong wind will play either at all picks.

It is no wonder that our users prefer to do many of the construction work on their own and are eager to share their experiences with novice developers.

Question 2. Why I chose the fence of solid trapezoidal sheet

Pavlovich P34 (Member FORUMHOUSE):

We had to be shielded from prying eyes. Ie the required opaque fence. Therefore, the option with the mesh-netting definitely eliminated. Making a concrete or brick wall and difficult and very expensive. No budget is not enough on the perimeter of 170 meters. Wooden did not dare, because it will have to periodically touch up. Especially, I have next to the site of a field with grass. If it lights up, the flame can spread to the fence.

Of the available materials used for the construction of the fence, was trapezoidal sheet.

Question 3. Why put a fence alone

The answer is also simple - the member of our portal are no helpers. So that Pavlovich P34 had no choice but to roll up our sleeves and do everything yourself. And, as shown by his experience as possible.

2.preparatory part

We decided - we put a fence made of profiled sheet. But it is important not to follow the path of "doing everything" or "like a neighbor," and to evaluate the operating conditions of the fence and the ground is on the site.

Pavlovich P34 (Member FORUMHOUSE):

At the outset it is necessary to assess the conditions under which will be operated by a fence. T. a. the conditions of the immense territory of our country can be radically different from each other. The fact that in one region redundant, in the sense konstruktiva fence and the compressive strength of the other may be insufficient.

About, how to install the fence postsThat they do not stick with frost heaving, we mentioned in one of our previous articles. So now we will focus on the impact of wind on a solid fence.

Calculation of wind load acting on the fence

Many people lose sight of such factors as the wind load on the fence, thinking: that can happen to a metal pipe, as it will not break in a strong wind? However, this approach can play a cruel joke. By region, place of building (open area, ie, the fence stands on a well-blown field, or put in already built-settlement) largely depends on what the load will experience a continuous web fence. Steel sheet has a large sail. If we ignore the calculation, and blows a strong wind or a storm (which lately is not uncommon in different regions), it can be seen flown away or fold fence. Therefore, under the pipe poles (its cross section and wall thickness) is not select "by eye", but on the basis of calculation.

Pavlovich P34 (Member FORUMHOUSE):

I analyzed the weather station weather reports for past periods, and saw that the wind with a force of 18-20 m / s are repeated very often. And occasionally recorded wind with a force of 24-28 m / s. Those. I actually live in a region where it is possible the passage of hurricane winds.

To verify the user loads conducted preliminary calculation flexural pillars wind load at 30m / s and a height 1.8 m sheet. Based on this calculation, stresses walked on strength (and then the min) Post embodiment of proftruby section 60h60h3mm.

Based on this, the question arises - how to calculate the wind loads on the fence stand. We plan to deliver continuous (and hence, windproof) fence made of profiled sheet. Mentally simulate a situation, when the web is a strong wind blows. Accordingly, on fence posts will be affected by a force tending to bend it, ie, bending moment. If we imagine that a post zaschemlon rigidly at one end (the one that zaglublon into the ground), the maximum force to the bending occurs at the point of exit from the soil. For simplified calculation using the online calculator, we need to find out how hard the wind pressure on an area of ​​1 square meter, and a profile of the pipe will withstand this load.

To do this, we use the following formula:

F = 0.61V2 / 9.8,

Where:

F - the force in kg;

0.61 - 1/2 air density (in normal conditions);

V - a wind speed in m / s.

We perform the calculation at a wind speed of 15 m / s:

F = 0.61 * 15 * 15 / 9.8 ≈ 14 kg per 1 sq.m.

Using this formula, you can manually calculate the force acting on 1 sq.m. area at wind speeds of 5, 10, 20 and 25 m / s. It is worth noting that the wind, the speed of which is from 20.8 to 24.4 m / s, is "strong and storm." From 24.5 to 28.4 m / s - "storm" or "storm". From 28.5 m / s to 32.6 m / s - "from the storm before the storm."

Therefore, when calculating not take the minimum value for a particular region, and, in any case, do some stock.

This will allow us to avoid a situation in which, if a sudden wind storm happens (unusual for the area, but perhaps once in 10-15 years), the fence will fall.

Go ahead. We plan to build a standard fence height of 2 m and a length of span of 2.5 m. Note: due to the increased load is not recommended 1 span of the fence over 3 meters in length. This will lead to the need to increase the cross section of each strut due to load increase. We are making the calculation:

Find the area 1 sections:

S = 2 * 5 = 2.5 m

Substitute the value into formula:

F = 5 * 14 = 70 kgs

We find the bending moment acting on the support according to the formula:

M = FLk,

Where:

F - the force in kg;

L - the point of load application. We believe that it is in the middle profiled sheet Venue 2 m, we add thereto the distance from the ground to the lower edge of the sheet: 0.3 m Total:. 1 + 0.3 = 1.3 m.

k - the safety factor = 1.5.

M = 70 * 1.3 * 1.5 = 136.5 kg · m

Now we need to pick up a pipe that can withstand this strain.

To do this, use the formula by which we define the maximum bending moment.

M = σW / 1000

Where:

σ - the yield stress of the material (kgf / mm2);

W - section modulus (mm3);

Yield stress for steel - 20-21 kgf / mm2.

Now we need to find a section modulus at bending - W.

We find it by the formulas:

W = π (D4-d4) / 32D - round tube.

W = (H4-h4) / 6H - square tube.

For example, take a round tube external diameter of 60 mm, a wall thickness of 2 mm and a square pipe 60 mm, with a wall thickness of 2 mm. In order not to be regarded as "manually" moments of bending resistance (W) to make an online calculation of the wind load of the fence in any online calculator, substituting the above values ​​pipe sections.

Total:

For a square tube W = 8682.0 mm3

For a circular pipe W = 5114.1 mm3

Substituting values ​​into the formula:

M = 20 * 8682.0 / 1000 = 173.64 kgf · m - destructive bending moment to the square tube.

M = 20 * 5114.1 / 1000 = 102.28 kgf · m - breaking point for bending round pipes.

Now look satisfy whether the selected contact tubes wind load.

As we calculated earlier, the bending moment in the place of the post out of the ground output (M) = 136.5 kg · m.

compare:

Square tube - 173.64 kg · m> 136.5 kg · m.

Round tube - 102.28 <136.5 kg · m.

A square tube is satisfied load which arises when the wind force of 15 m / s, and the round - no. Using this simplified algorithm for calculating wind loads, making, as they say in building forums "calculated column on the wind load ", you can manually choose the section and profile of the pipe depending on the operating conditions and the design of the fence, and the availability of metal in your area.

Now, defining the cross section of the pipe, proceed to the following steps: selection of ways to install counters at the ground, the selection of the right tools, the calculation of the estimate and installation of the fence. This will be discussed in the second part of the material.

In this topic, the most impatient can get acquainted with all stages fence construction in 170 meters. On FORUMHOUSE can get answers to any questions independent construction fence made of profiled sheet. Here it is photo report on the construction of the metal fence.

Beautiful fences are gallery wooden fences. And from our a movie, you'll learn how to build fence under the old Russian antiquity.

Discuss the article and read other materials devoted to country life you can on the websiteFORUMHOUSE.

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