Hatching concrete according to state standards
How is reinforced concrete hatching done on drawings? Are there any rules that establish a way to design cuts and types of building structures? We have to find answers to these and some related questions.
Information sources
They will serve for us:
- GOST 3455-59.
- Replaced him GOST 2.306 - 68.
Explanation: the release of a new standard regulating the same sections of production as the old one automatically cancels the effect of the old document. In our case, the first GOST is removed from the dusty cabinet to clarify some confusion with the material designation system.
- GOST R 21.1207-97.
Investigation
Как и читатель, автор статьи некогда был школьником и, среди прочего, посещал уроки черчения. Hatching разрезов и тогда была в ходу; некоторые обозначения запомнились особенно хорошо. Среди них - способ обозначения бетона, требовавший некоторых навыков художника: его следовало изображать чем-то вроде пейзажа пескогравийного карьера, выполненного рукой Остапа Бендера (см.также статью «Температура замерзания бетона – важная информация для строителей»).
As it turned out much later, the drafting teacher simply did not know about the new standard adopted after he received his higher education and taught the schoolchildren the way he was taught.
GUEST 3455 - 59
Стандарт начал действовать 1 января 1959 года и был отменен ровно через 12 лет, 1 января 71-го. Его название - «Чертежи в машиностроении. Штриховки в разрезах и сечениях».
We are, of course, interested in, first of all, the material designation system adopted in the document.
| Material | Hatching |
| Metal | Oblique lines at regular intervals |
| Non-metallic materials (except those listed separately) | Overlapping sloping lines with right and left slopes |
| Wood across the grain | Image of a slice with radial cracks and annual rings |
| Wood along the fibers | Very realistic image of larch texture |
| Concrete without reinforcement | Notorious sandy landscape |
| Reinforced concrete | Sandy gravel landscape with sloping shading |
| Building brick | Lines similar to metal but more rare |
| Special brick (chamotte, acid-resistant, and so on) | Intermittent solid and dashed sloping lines |
| Plexiglas glass | Groups of three strokes with vertical and horizontal gaps |
| Liquids | Horizontal lines with gaps and decreasing bottom-up intervals |
| Bulk soil | Landscape of a sandy gravel pit diluted with gratings of three lines horizontally and vertically |
GOST 2.306 - 68
Принятый в 71-м году документ переработал систему схематических изображений в сторону упрощения. «Художественному таланту не место на чертежной доске!» - сказали представители министерства и предоставили новый перечень штриховок. Чтобы не повторяться, перечислим лишь изменения.
| Material | Hatching |
| Wood | The image consists of arcs of the same radius filling it at a constant interval. |
| A natural stone | Oblique dotted lines |
| Ceramic and silicate bricks, blocks and building stones | Groups of two sloping lines interspersed with wide gaps |
| Concrete | Oblique dash line |
| Priming | On the upper edge of the relevant section of the drawing - a group of three short strokes, interspersed with gaps |
When making a drawing with your own hands according to GOST, you need to follow several rules:
- Sloping lines are drawn at a 45 degree angle.
However: this angle can be maintained not only relative to the frame of the drawing, but also relative to the axis or contour of the image.
- Hatching может быть левой или правой; наклон должен выдерживаться одинаковым на всех сечениях одной детали (даже если соответствующие изображения разнесены по нескольким листам).
- The distance between the lines on all sections of one part is chosen the same. The step is chosen depending on the image size in the range from 1 to 10 millimeters.
- Narrow and long cuts can not hatch completely, but only at the edges and in several arbitrary places. Especially narrow cuts (less than 2 mm thick in the drawing) are allowed to be shown completely blackened.
- For adjacent sections of two parts, multidirectional hatching is selected (left and right).
So, according to the current regulatory documents, the instruction on concrete shading in the drawing is quite understandable: it is indicated by dash-dotted lines. What happens if you use outdated designation?
Fortunately, the cost of error is not too high: according to the document we have just studied, it is allowed to use unforeseen notation when constructing drawings. It is only necessary to explain them in the drawing.
GOST R 21.1207-97
As is easy to see, we did not find the current GOST for reinforced concrete shading. In the old document the designation was present, in the new one it disappeared.
So what to do when building a drawing? Use a loophole with arbitrary material designation and a footnote below? Or are there any rules yet?
The answer will be found in a rather unexpected place - the standard governing the symbols in road construction, when constructing road drawings.
Along with asphalt, waterproofing materials and bulk soil in the document appear:
- Proper concrete. Its designation is already familiar to us - the dash-dotted line.
- Concrete с армированием. Reinforced concrete is indicated by intermittent continuous and dash-dotted lines.
- Reinforced concrete with prestressed reinforcement. Heating or mechanically stretching the reinforcement before pouring the monolith, after it cools or removing the tensile force, you can obtain a material with increased bending strength. Its section is depicted by the alternation of two solid and one dash-dotted lines.
Conclusion
We hope that our material answered all the reader's questions related to the designation of concrete in the drawings. As always, additional thematic information can be found by viewing the video in this article. Successes!