For many centuries, wood has been and remains one of the main materials for housing construction. However, if in Russia from time immemorial houses have been built in the form of a log house, then in Canada and the USA for more than 200 years the most popular structure has been frame. Over the past 30 years, these countries have invested hundreds of millions of dollars in improvement frame technology
, which, as many years of experience shows, is the most economical, high-quality and rational.
Frame technologies have a lot of advantages. One of them is the ability to achieve ideal geometry of walls and ceilings, which ultimately reduces cost and time finishing works. However, all this is true provided that the frames are carefully marked. The topic of today's conversation is Basic structure gender.
Majority modern houses build with frame system"platform" type (Fig. 1).
In them, the floor of each floor serves as the base on which the walls are installed. Top floor completed with a ceiling and roof. This “layering” allows you to divide the marking process into simple operations.
Foundation preparation
We have already noted more than once that the basis for marking the frame of a building is upper foundation plane. Therefore, it must be carefully checked before starting any work on the installation of a load-bearing base of the floor.
First measure the diagonals and make sure that foundation- rectangular and exactly matches the dimensions in the drawing. It should be taken into account that if the dimensions differ from the specified ones by less than 25 mm, then such errors can be easily corrected by adjusting the position of the bench. To do this, install them so that they are parallel and at right angles to each other, and mark chalk lines on the upper plane of the foundation strip. For example, (Fig. 2) shows a situation in which it is possible to compensate for the non-rectangularity of the foundation if you release the bed beyond the upper right corner of the foundation by 20 mm. If the dimensions differ from the drawings by more than 25 mm, then errors will have to be corrected at the next stages - when installing joists and edging beams.
After checking the dimensional accuracy, the squareness of the foundation and making the necessary adjustments, install the level and check the height of all corners. The permissible difference in height is considered to be a difference on the long side of the foundation - 20 mm, and on the short side - 12 mm.
If the height of the corners is in permissible limits, check the top plane of the foundation for unevenness. To do this, pull the cord tightly over the “fifty” blocks cut from the board, and then take the same block in your hand and pass it along the entire foundation wall under the cord (Fig. 3).
In this case, be sure to keep in mind that the variation in thickness of the boards should not exceed 3 mm. Therefore, it is better to cut all the blocks from one board.
Correction of foundation errors
What to do with depressions and “humps” on the foundation strip? If the unevenness is within 1.5 mm, there is no need to worry. Before installing the bed, depressions up to 5 mm deep are filled with mortar or wooden wedges are placed in them. If there are “humps”, then you can trim the lower plane of the bench or do nothing at all for now, but postpone the adjustment until next steps work - installation of edging beams and joists. Finally, if upper foundation plane is too uneven or deviates significantly from the horizon, it is advisable to fill a horizontal cushion cement mortar around the entire perimeter. This problem can be solved simply - hit the level horizontal lines a few centimeters below the top of the foundation, and then, focusing on them, attach the formwork boards and fill in the mortar (Fig. 4).
Installation of beds
After carrying out the necessary modifications to those embedded in the foundation anchor bolts beds can be installed. Marking the holes for the bolts is done as follows (Fig. 5).
The bench is laid on the foundation wall and pressed against the bolts. Then, using a triangle, the position of each bolt is transferred to the board. Moreover, they do this on both sides of the bolts, as a result of which each anchor is marked with a pair of parallel lines. After this, measure the distance between the chalk line, which corresponds to the position of the bench on the foundation wall, and each bolt and transfer these dimensions to the bench. The result is squares with a side corresponding to the diameter of the anchor. The centers of the bolt holes will be at the intersection of the diagonals of these squares.
Installation of intermediate supports
Often, to support the beam, it is necessary to install an intermediate support (beam or wall), which must be flush with the beam (Fig. 6).
This often has to be done on an uneven surface of the basement base.
To get a flat surface of the main floor, pull the cord at the level across the foundation and be guided by it in further actions. If the beam is installed on brick pillars, their height can be adjusted using spacers. If the beam rests on wooden racks, they are placed where they will stand permanently, and then their height is marked along the cord. In this case, you should pay attention to the fact that during marking the racks stand strictly vertically. The racks are sawed off taking into account the height of the beam.
For construction of a load-bearing partition with a double top harness, lower a plumb line from the cord and make chalk marks on the basement floor. Having thus marked the position of the lower trim, it is sawed off from a pressure-treated board with a cross-section of 50x200 mm. After this, the lower trim is laid along the chalk line and the installation locations of the racks are marked. Since the base is uneven, each post must be measured, marked and sawed off separately. To do this, they are placed on the lower harness and the height is determined. Then the thickness of the double upper trim is subtracted from the resulting value and the racks are sawed off to size. After this you can prepare and mark top harness and assemble the wall. If everything is done correctly, the top plane of the wall will be horizontal and flush with the bench.
When working using this method, you should remember two things. Firstly, the racks need to be pressed against bottom harness with considerable effort. For example, to select the gaps between the concrete floor and the trim, you can stand on it near the post. Secondly, when marking the rack, do not forget to control its verticality with a level.
Marking and installation of the floor system
After installation central beam or a load-bearing wall, you can begin installing the load-bearing base of the floor. As we have already noted, this is another chance to correct mistakes made at previous stages of work.
Installation of the edging beam
First of all, you need mark the position of the edging beam. If the bench lies horizontally and exactly matches the dimensions in the drawing, set aside the thickness of the edging beam from its outer edge and mark its position with chalk. Now you can either install the edging beam, or mark and install the logs. Moreover, it is not very important what you decide to install first, but in any case you need to focus on the line marked on the bench.
Always save straight boards for edging, and on each “bent” board for joists, mark the convex side with an arrow. In addition, use a square to check the ends of each board, which should be sawn off strictly at right angles. Strongly “bent”, twisted and with transverse bending immediately set the boards aside. From them it will be possible to cut short parts - jumpers, spacers, etc.
What if the foundation is flawed? For example, there is a “hump” somewhere in the center of the wall. To compensate for it, select a straight board for the edging beam and use a level to install it horizontally on spacers along the marking line. Now measure the gaps with a compass and transfer them to the beam (Fig. 7). Then saw or plan the beam according to the markings and install it in place. Of course, when you fit the joists to the edging beam, their lower ribs will also have to be trimmed so that the upper ribs of the joists are flush with the edging, but this is much easier to do.
What if the foundation is horizontal, but its dimensions differ by several centimeters? In this case, there is only one solution - to cantilever the floor frame above the foundation strip.
In this case they act like this. First, nail the first and last joists, then stretch the cord between their upper outer corners, after which the intermediate joists are installed as close to the cord as possible. Finally, the edging beam is installed.
Marking the position of the lag
Logs must be installed with this step so that the plywood sheets are joined strictly along the axis of symmetry of the boards. The most common pitch is 400 mm, but other spacing may be indicated in the drawings - for example, 300 or 600 mm. To prevent errors from accumulating, it is better to work with a tape measure with a steel tape, counting the dimensions from one point. If the tape is shorter than the foundation, measurements are taken from a minimum number of points. For example, a foundation wall 14.4 m long is marked with a 7.5 m long tape in two passes.
Having made all the marks, walk along the entire length of the bench with a pencil and a square and draw straight marking lines. At the same time, mark which side of them the logs will be located on. Traditional way- put crosses on the right or left side of the lines (you will then install logs on them).
Marking with a given step
One of common mistakes- start marking not with desired point, for example, taking the edge of the bed as “0”. As a result, the first sheet of plywood has to be sawed off so that it fits onto the joist. But it’s not difficult to save time and material. For example, in order to join a sheet of plywood 2400 mm long along the axis of symmetry of a 40 mm thick log, it must be at a distance of 2380 mm from the outer contour of the trim and with a cross in front of the marking line (Fig. 8).
From the first line, mark the position of the remaining logs in increments of 400 mm.(Don't forget about the crosses in front of the marking lines.)
D. Carroll (USA). Magazine "Home" No. 8/2006
A log is a log, a beam in a horizontal, lying position in various structures and devices.
A LEVEL WILL HELP TO IDENTIFY HIGH PLACES
1. Cut down high places with a hammer drill. Separate area the foundation can be high and create a problem for marking and leveling the bed.
2. If such a section is not very long, it can be cut down quite quickly with a hammer drill.
To get the best results
1. Position the level so that you can clearly see each corner of the foundation in a relatively narrow field of view (90° or less). This will help get rid of errors associated with turning the level at large angles. To minimize error, install the level as low as possible over the foundation.
2. With an assistant holding the staff, shoot external corners abcd and write down their height. In our example, the highest angle is b.
3. From the height of the highest corner, subtract the heights of the remaining corners and write down the difference - this will be the thickness of the spacers.
4. Using shims, bring the corners to the level of a high angle with a tolerance of ±1.5 mm.
5.Stretch the lace between the corners. (For zones between them, read the section “Adjusting the level of the cord.”
LED LED lamp ceiling lamp 48 W 36 W 24…
In order to understand the design of the rafter system and correctly perceive the installation instructions, it is necessary to understand the names of the elements of the rafter system and their main functions.
Below is a diagram of the main most used elements in rafter system.
Mauerlat
Mauerlat- this is an element of the rafter system, designed to transition from a non-wooden (concrete, brick, metal, etc.) structure to a wooden one. Used as a Mauerlat wooden beam from coniferous species trees.
The most common dimensions of the Mauerlat are 150×100 mm, 150×150 mm, less commonly 100×100 mm, 200×200 mm.
Lezhny
It can be said that the main purpose of the beds, like the Mauerlat, is the transition from a non-wooden structure to a wooden one, but this is not so. The main purpose of the beams is when supporting the racks, to remove the point weight load from the floor (floor), transmitted from the roof structure through the racks. That is, so that the stand does not press on an area of, for example, 150×150 mm (presses on a point), but through the support the load is distributed over a larger area of support. It's like a person on skis, when without skis he falls into the snow; with skis - it doesn’t fail.
The size of the beds depends on the size of the racks. The main thing is that the stand completely fits on the bench.
Racks
In the rafter system, the posts are the posts that hold the purlin and rest on the beams. Their function is to keep the run.
Run
Purlin - a wooden beam, with the purpose of supporting the rafters (preventing them from bending). Purlins are used on long slopes, with heavy roofing coverings
It is not indicated in the diagram, but purlins are also used under the ridge and are called ridge purlins.
Rafter legs
The rafter (rafter leg) is the main element truss structure, roof skeleton. All calculations related to the calculation of roofs converge to the calculation of rafters. Size rafter legs accepted according to design calculations.
The traditional Ukrainian dish is lezhni, but I could only “turn it upside down” in the recipe so that the resulting dish no longer resembles lezhni. But the beds were originally planned? So, they will lie down, only with mine light hand and in my interpretation, the beds will go to the people, proudly bearing my name.
Actually, there are only a few differences: in the filling, instead of sauerkraut- mushrooms and no eggs. No eggs because now Lent, but the soul still wants variety.
So, the ingredients:
Potatoes 1 kg
Flour 8-10 tbsp. spoons for dough and 3 tbsp. spoons for deboning
Mushrooms (I used pickled mushrooms, but any will do) 400-500 g
Onion 1 medium head
Garlic 2 small cloves
Lenten mayonnaise (sour cream) 2 tbsp. spoons
1 tbsp. spoon of starch
Salt, pepper to taste
Cooking technique:
Peel the potatoes, wash them thoroughly and boil until fully cooked. Add salt, pepper and beat until pureed. Cool.
Add 1 tablespoon of starch to the cooled potatoes (preferably using potato starch) and gradually stirring, adding flour one spoon at a time. Knead well again. You should have a soft dough that sticks slightly to your hands. Cover with a napkin and let stand for 10-15 minutes.
While the dough is resting, let's make the filling.
Wash the mushrooms, strain, then fry in a greased pan vegetable oil. Salt and pepper. Peel the onion and garlic, chop finely and add to the mushrooms. When the onion turns golden, add mayonnaise (sour cream) and simmer over low heat until tender.
Take the dough with a tablespoon, level it on your palm, add the filling, pinch the edges and form a pie. When forming the lezhni, moisten your hands with water, then the dough will not stick to your hands and it is easy to sculpt the lezhni. Roll the loaves in flour and fry over high heat until golden brown on both sides. Then place it on a paper towel, you know why.
When preparing it, I miscalculated a little and didn’t have enough filling. Fantasy came into play. I found only protein red caviar in the refrigerator from lean meat. Lezhni with caviar is original in taste, but also very tasty. Although, if the caviar had been real, it would have been even tastier.
The caviar adventures are not over. Since I didn’t have enough of it either, I had to make “dummies”. The “dummies” just didn’t impress me, so I ended up with potato rings. The downside of the rings is that you have to eat them right out of the frying pan, but the upside is the crispy, delicate taste that is so alluring that the downside immediately turns into a plus.
Have a delicious one!
Lay down with a mouth full your Tatka. 
Analysis carried out bearing capacity applied crane runway structures. It has been revealed that their main drawback is the excessive labor costs in design and maintenance. A design based on a wooden “bench” with the necessary strength calculations is proposed. The calculation was carried out on the basis of the developed methodology, taking into account technical parameters elements that make up the structure as a whole, but only for uncompacted soils in the underlying layer. According to the data obtained, presented in graphical form, the possibility of using a crane track with a wooden longitudinal “bed” is shown, even for an underlying layer of uncompacted soil. Obviously, the safety margin of the structure is provided by the ratio of the bed coefficients, compacted and non-compacted soils in the underlying layer.
crane runway
bed coefficient
underlying layer.
1. GOST R 51248-99. Ground rail tracks.
2. Instructions for the design and operation, relocation of rail-mounted construction tower cranes. SN 78-79. Gosstroy USSR. M.: Stroyizdat, 1980.
3. Instructions for the design and maintenance of rail tracks for gantry cranes at TPO Sverdlesprom enterprises. Sverdlovsk, 1988. 49 p.
4. Development of a methodology for calculating rail crane tracks on a block reinforced concrete base. Report on research topic 26/83. State registration No. 01.83.0029692. Sverdlovsk, 1984.
5. Tagiltsev N.D. Calculation of hard rutted surfaces of timber roads in the Urals and Siberia // Interuniversity collection. Vol. 2. Sverdlovsk, 1979.
At enterprises operating lifting mechanisms with rail guides, crane tracks of several designs are usually used:
- wooden sleepers type: 1A, 1B according to GOST78-89;
- reinforced concrete sleepers, type: PShN1-13-325-1 and PShN4-13-325-1;
- reinforced concrete beams type: BRP-62.8.3 and BRK-6.24-04;
- reinforced concrete slab.
The design of a crane track on ULTI-6.25 beams is also known.
All design options for known crane tracks have, each individually, their own advantages and disadvantages.
An analysis of the load-bearing capacity of the crane runway of all structures shows that their main drawback is the excessive labor costs for their construction and maintenance. From which we can highlight a number of necessary studies to improve the strength characteristics and create the versatility of crane runway structures:
- research and development of more modern and robust construction crane track based on “nano bed”;
- study of the strength characteristics of guides (rails) in order to facilitate the design, or replace the guides with more modern trackless ones.
Existing crane tracks have a number of significant disadvantages. Firstly, comparatively high consumption wood, which is necessary for the manufacture of sleepers; secondly, difficulties arise when straightening the sleepers. With the design of crane tracks that is currently used, it is quite difficult to ensure that the required operating standards for crane tracks are met. One of the main disadvantages is the uneven subsidence of the crane tracks that occurs during the operation of the crane.
Currently, rail tracks with reinforced concrete supporting elements have become widely used. We also have experience in the forestry industry. In the Nizhne-Serginsky private household plot, a section was operated on ULTI-6.25 beams under an LT-62 crane for about 4 years. All this time, lifting and straightening of the track was not carried out, and the crane track, in particular its parameters, did not undergo any significant changes.
Back in 1986, for the conditions of the lower warehouse of the Tugulymsky private household plot, a new design of the upper structure of the crane track on wooden longitudinal tracks was proposed, which was tested according to the strength characteristics of the material with the definition cross section bed A log is a wooden beam with a section size of 200x200mm. The rail used in the calculation was grade R-65, as in the crane tracks in use everywhere.
The design consists of two beams connected to each other by bolts. The length of the supporting element is 6.24 m, the section of the beam is 200x200. There are widenings at the ends of the support element, which are located under the rail joints. They are made from the same timber. The supporting elements are rigidly connected to each other. This design, in our opinion, will allow reliable operation of both the crane itself and the crane tracks.
Below is the calculation sequence according to the methodology we developed.
Accepted designations, design parameters.
Mi - ordinates of the line of influence of the bending moment in the section under the i-th wheel;
Pi - ordinates of the line of influence of reaction pressure and rail subsidence in the section under the i-th wheel; b - width of the lower bed of the under-rail element, m;
l is the length of the supporting under-rail element, m;
Wp,Ip - respectively, the moment of resistance to bending, m3 and the moment of inertia of the rail section relative to the horizontal axis passing through the center of gravity of the section, m4 (accepted according to Table 24 CH 78-79);
WB,IB - moment of resistance to bending, m3 and moment of inertia of the beam section, m4;
EB, EP - respectively, the deformation moduli of wood and rail steel, MPa;
c is the bed coefficient of the supporting element, MPa, which is determined by formula 4.1:
c = (2.25...2.55) EE; (1)
A lower value of the coefficient is accepted for uncompacted granular soils, and a larger value for dense ones. EE - equivalent base deformation modulus, MPa, is determined for a two-layer base structure using formula 4.2:
Ee = Eo/(1-(2/P)(1-1/n3.5) arctan n(h/D)); (2)
where E0 is the deformation modulus of the subgrade soil, MPa, determined by stamp tests according to GOST 12374-87 with stamp diameter D=564mm n=(E1/Eo)0.4; (3)
E1 - deformation modulus of the ballast layer, MPa, taken according to the passport data quarry material; h - thickness of the ballast prism, m;
Characteristics of the path
Rail type - P65;
Distance between axles 0.97 m;
Width of the lower bed of the under-rail support element b=0.4 m;
Estimated length l=6.24 m;
Type of ballast - crushed stone E1 = 130 MPa;
Ballast thickness h=0.2 m;
Type of subgrade soil - fine-grained sand E0=15 MPa.
Characteristic wooden beams rail track
Wood deformation modulus: E=0.85.104 MPa;
Moment of inertia of the design section: IB=bh3/12=0.4.0.23/12=13.34.10-5 m4; (4)
Bending resistance moment: WБ=bh2/6=0.4.0.22 =26.67.10-4 m4; (5)
Design bending resistance: RB = 15 MPa;
Beam stiffness: WБ=bh2/6=0.4.0.22 =26.67.10-4 m4; (6)
Bearing capacity of the beam: MBpred = WБ.RB = 26.67.10-4.15.106 = 40.0 kN.m; (7)
Characteristics of Rail P65.
Bending resistance moment: WP=404 cm3;
Moment of inertia: IP=2998 cm4;
Rail stiffness: BP=6.29 MN.m2;
Load-bearing capacity: MPpred=121.2 kN.m.
Determination of stresses in rail track elements
We determine the reduced length λ of the beam, for this we determine the coefficient of relative rigidity of the beam-base system according to formula 4.8: K=(c.b/4.BC)0.25, (8)
where: c - bed coefficient of the supporting element, MPa/m;
b - width of the lower bed of the under-rail support element, m;
ВС =ВБ +ВР - total stiffness of a two-layer beam, MN.m2;
Ee - equivalent deformation modulus of the base, MPa; n=(130/15)0.4=2.37;
Equivalent deformation modulus:
Ee=15/(1-(2/3.14)(1-1/2.373.5)arctg 2.37(0.2/0.564))=26.016 MPa;
Support element bed coefficient: c=2.25.26.016=58.5 MPa/m;
Total stiffness of a two-layer beam: BC = 2.27 + 6.29 = 8.56 MN.m2;
Relative stiffness coefficient: K=(58.5.0.4/(4.8.56))0.25=0.908;
The reduced length is determined by formula 4.9: λ=K.l=0.908.6.24=5.67; Round up to λ=5.5. The beam being calculated belongs to the category of short ones, because λ<7. Из таблицы 6.1 , для соответствующей λ, выписываем табличные значения ординат линий влияния реактивных давлений РТ и изгибающих моментов МТ, по которым строим соответствующие линии влияния (см. рис. 1).
Fig.1. Lines of influence MT and RT
We determine the values of the largest bending moment in the middle section of the beam using formula 4.10: MS =P.l.∑MiT =250.6.24(0.0432-0.002)=64.27 kN.m,
where МiT are the values of the dimensionless ordinates of the lines of influence of the bending moment under the acting forces.
Bending moments in the rail and beam will be determined accordingly using formulas 4.11, 4.12:
MP=MS(EP.IP/BC)=64.27(6.29/8.56)=47.23 KN.m< MPпред=121,2 кН.м;
MB=MS(VB/VS)=64.27(2.27/8.56)=17.04 KN.m< MБпред=40,0 кН.м.
Thus, the effective bending moments are below the limit values. We determine the voltage σB in the ballast at the contact with the support element using formula 4.14:
σБ=(P/b.l)∑PTi=(0.25/0.4.6.24)(2.8273+1.7)=0.45 MPa where РiT are the values of the dimensionless ordinates of the line of influence of reactive pressures under the corresponding forces. The ballast strength condition is satisfied. To determine the stress σо, on the main site of the roadbed, we first calculate the thickness of the equivalent soil layer using formula 4.15: hE=h(E1/Eo)0.4=0.2(130/15)0.4=0.47 m; Then, using the ratio hE/b, we find the value of the coefficient of pressure change in the soil thickness: KZ=0.586; σ0=KZ.σБ=0.586.0.45=0.26 The strength condition for the main area is also satisfied. From the calculations it is clear that when the load is located in the middle of the beam, the strength conditions for both the ballast and the main platform are satisfied. Let us calculate the beam under the condition that the load will be located at the end of the beam, that is, at the hinge (see Fig. 2). In this section, the bending moment will be zero. The broadenings are present in a relatively small area of the calculated support element, so the value of the characteristics does not change until the calculation of the reduced length: λ=5.5. From tables 5 and 6 we write down the tabulated values of the ordinates of the lines of influence of reactive pressures PiT for λ=5 and λ=6. Using the interpolation method, we determine these values for λ=5.5 and construct an influence line (see Fig. 2). Rice. 2. RT influence line tabular We determine the stress σB in the ballast at the contact with the support element using formula 4.14: σB=(P/b.l)∑PTi=(0.25/0.8.6.24)(5.4247+1.6)=0.35 MPa The ballast strength condition on the extensions is met. We determine the stress σо on the main platform of the roadbed. The value hE=0.47 does not change. Using the ratio hE/b we find the value of the coefficient of change in soil thickness according to the table from: KZ=0.7675; The voltage on the main site of the roadbed is determined by formula 4.16: σ0=KZ.σБ=0.7675.0.35=0.268 On the calculated beam, all strength conditions are fully met. As a result of the calculation of the proposed version of the crane runway, the influence lines MT and PT were obtained (Fig. 1 and 2), showing the distribution of pressure of the crane runway section and the bending moment. Based on the data obtained above, the voltages σ0 and σB were determined (σ0=0.268 on the main platform of the subgrade and in the ballast in contact with the supporting elements. Their values are below the permissible values, that is, the reliability of the operational properties of such a crane runway is ensured. The most significant drawback, in our opinion, should be considered the use of heavy metal rail R-65. We have attempted to replace the P-65 rail with a lighter guide without changing the cross-sectional rigidity and reliability of the upper structure of the crane runway. Reviewers: Kovalev R.N., Doctor of Technical Sciences, Professor, Head of Department, Ural State Forestry University, Yekaterinburg. Cheremnykh N. N., Doctor of Technical Sciences, Professor, Head of Department, Ural State Forestry University, Yekaterinburg.
Bibliographic link
Salakhutdinov Sh. A., Shabardin S. V. JUSTIFICATION AND RESULTS OF CALCULATION OF A CRANE RUN ON A LONGITUDINAL LAYOUT // Modern problems of science and education. – 2013. – No. 1.;
URL: http://science-education.ru/ru/article/view?id=8323 (access date: 11/02/2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"