How to Interpolate a Contour Map the AutoCAD way.

The coordinate-method is one way of drawing a contour map. Surveyors start at a certain reference point and indicate points on locations that are of an increment distance away from the reference. In this example,

points are incremented by 10 meters from the reference. The elevations at each point are measured and tabulated. Point A1 is the reference and has a coordinate of (0, 0, 1522.82). Point A2 has a coordinate of (10, 0,

1559.25), point B1 has a coordinate of (0, -10, 1440.00), etc.

To draw the contour map using the spline-loft method of Autocad, use first the 3dmesh command.

Type 3dmesh in the command line. Then from there you will be asked what of what size will your mesh be in the M direction. This will be the number of coordinates you will have on the x-axis direction. For this

example input 6. Then for the N direction, input 7.

After that you will be asked for the locations of vertices. These are the coordinates of each point and there are 6x7 coordinates/vertices in this problem.

the first vertex is point A1. Input for the first vertex: 0,0,322.82

Why 322.82? The vertical reference elevation for this problem is considered to be 1200 since the lowest point on the map is 1290.56. Any reference elevation can be used but it will be best if it is lower than the lowest

elevation and divisible by 100 (which is the index cotour). 322.82 came from the difference between the point elevation of A1 and the reference elevation.

When asked for the second vertex, it should be B1 because the arrangement of input for a 3dmesh is [M][N]

the second vertex should be 0,-100,240

100 is used instead of 10 to increase the horizontal scale of the map by a factor of ten. It would make the appearance of the final mesh clearer.

next, input the coordinates of C1 (C1 is 0,-200,195.45), D1, E1, F1, G1, A2 (A2 is 100,0,359.25), B2...

You can continue to input these values up to G6, or just start a new file and paste this on the command line:

3dmesh

Enter size of mesh in M direction: 6

Enter size of mesh in N direction: 7

Specify location for vertex (0, 0): 0,0,322.82

Specify location for vertex (0, 1): 0,-100,240

Specify location for vertex (0, 2): 0,-200,195.45

Specify location for vertex (0, 3): 0,-300,209.56

Specify location for vertex (0, 4): 0,-400,236.73

Specify location for vertex (0, 5): 0,-500,270.35

Specify location for vertex (0, 6): 0,-600,345.35

Specify location for vertex (1, 0): 100,0,359.25

Specify location for vertex (1, 1): 100,-100,241.32

Specify location for vertex (1, 2): 100,-200,225.68

Specify location for vertex (1, 3): 100,-300,253.68

Specify location for vertex (1, 4): 100,-400,279.15

Specify location for vertex (1, 5): 100,-500,320.44

Specify location for vertex (1, 6): 100,-600,365

Specify location for vertex (2, 0): 200,0,285.1

Specify location for vertex (2, 1): 200,-100,262.38

Specify location for vertex (2, 2): 200,-200,306.44

Specify location for vertex (2, 3): 200,-300,345.15

Specify location for vertex (2, 4): 200,-400,295.65

Specify location for vertex (2, 5): 200,-500,290.68

Specify location for vertex (2, 6): 200,-600,319.5

Specify location for vertex (3, 0): 300,0,213.45

Specify location for vertex (3, 1): 300,-100,251.65

Specify location for vertex (3, 2): 300,-200,280.37

Specify location for vertex (3, 3): 300,-300,260

Specify location for vertex (3, 4): 300,-400,251.3

Specify location for vertex (3, 5): 300,-500,265.4

Specify location for vertex (3, 6): 300,-600,290.23

Specify location for vertex (4, 0): 400,0,162.12

Specify location for vertex (4, 1): 400,-100,191.05

Specify location for vertex (4, 2): 400,-200,200.72

Specify location for vertex (4, 3): 400,-300,210.28

Specify location for vertex (4, 4): 400,-400,234.05

Specify location for vertex (4, 5): 400,-500,252.98

Specify location for vertex (4, 6): 400,-600,275.1

Specify location for vertex (5, 0): 500,0,90.56

Specify location for vertex (5, 1): 500,-100,140

Specify location for vertex (5, 2): 500,-200,171.58

Specify location for vertex (5, 3): 500,-300,193.19

Specify location for vertex (5, 4): 500,-400,230

Specify location for vertex (5, 5): 500,-500,258.16

Specify location for vertex (5, 6): 500,-600,270.75

Use ZOOM EXTENDS (Type Z *Enter* E *Enter*)

You can see a mat like figure on the screen.



Use the spline command. Type spl on the command line.

Click consecutively on the points of intersection from A1 down to G1. After clicking G1, press Enter three times.

Do the same for the range of A2 - G2, A3 - G3 up to A6 - B6.

Select the splines using the left-to-right rectangular selection method and give the splines a color of red.



Use again the spline command, this time to the horizontal coordinate ranges. Ex: A1 - A6, B1 - B6, G1 - G6

Slect the new splines and color them green.



Select SW Isometric on the view toolbar.

Delete the white colored mesh. Only the colored splines will be left.



Draw a rectangle with corners at (0,0,0) and (500,-600,0). Use ZOOM EXTENDS again if the figure is out of the boundary.



On the UCS2 toolbar drag down list select Front



Use the 3d orbit (command: 3dorbit) to adjust the view to something similar to the figure below. This is done so that the endlines of all green splines are seen.



Use the polyline command (command: pl). When asked which is the first point, click the left end of the first green spline (the one nearest to you). The next point is the corner of the rectangle directly under the left end of the green spline. The next point is the other corner of the rectangle (directly below the right end of the green spline). Then the last point is the right end of the green spline.



Repeat the same process to the succeeding green splines (The same corners of the rectangle are still the 2nd and 3rd point). Then delete the rectangle at the bottom.

Use the region command (command: reg). Select all green splines and polylines. Press Enter after selecting all. This time the green splines will be combined with the polylines and will be colored white again.



Draw a line from 0,0 to 0,0,60. Array this line with a column count of 6 and a row count of 1. The column offset should be 100



Use the loft command (command: loft). Select all regions (The combined green splines and polylines) then press enter.



After pressing enter, there will be choices. Choose Guides by pressing g then enter.
The guide curves are all the red splines and lines drawn under (which are arrayed). Press Enter.



Using the left-to-right rectangular selection method (or the quick select method). Delete all red splines and lines at the bottom. You will have a final block which is the simulated figure of the contour map in 3d.




The front UCS must still be active in the UCS2 toolbar. Draw a line from (-100, 0, -100) to (600, 0, -100). Extrude (Using extrude command, shortkey: ext) this line to the direction of the positive axis by 800.



Array the extruded line, with a row count of 19, a column count of 1 and a row offset of 20.



Press Front on the view toolbar.

Use slice command (command: sl). Select the Block (The contour block). Then press Enter.



In the options choose Surface by typing s then pressing enter. Select the 2nd level extruded line (The one above the original) then press enter.

Repeat the last two steps. Use slice, select the block, choose surface, but this time use the 3rd extruded line, 4th extruded line on the succeeding repetitions, up until the last extruded line (at the very top is used as the slicing surface).



Delete all the extruded lines.

On the view toolber choose Top.



Enjoy your contour map.

script for english

MADRIDEJOS: What is the agenda of this meeting?

ALEJANDRINO: We have invited here a group of engineers to discuss about a new innovation product called precast concrete.

MADRIDEJOS: You can start your presentation gentlemen.

MALABANAN: Sir, in this presentation we are going to discuss about the use of precast concrete products on the construction of several structures. What is a Precast concrete product? Precast or 'prefabricated' concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment, transported to the construction site and lifted into place. In simple terms, precast is like a piece of your favorite building block: factory-built and ready for installation. Let’s give a little background about precast concrete. The concept of precast construction includes those buildings where the majority of structural components are standardized and produced in plants a location away from the building, and then transported to the site for assembly. These components are manufactured by industrial methods based on mass production in order to build a large number of buildings in a short time at a low cost. Precast concrete has been part of the construction business history but is only now recognized as an effective product. These innovation products makes the construction of structures such as houses, fences, warehouses and even buildings of lower than five stories, much easier, faster and cleaner. Precast concrete products resolve the issues of substandard materials being used in the lesser prioritized components of the building.

ALEJANDRINO: So that’s what a precast material is all about. But can you enumerate what types of building components are included in the scope of precast concrete?

SURBANO: Sir, there are three typical precast concrete members. These are the slabs, beams and walls. Slabs can be classified as either flat or hollow with choice thickness of 4, 6 or 8 inches. For beams, there are six shapes for beams including common sections like L shapes, T shapes and inverted T shapes. The spans of these beams, sir, can be from 50 feet to 120 feet. Wall panels have a standard width of 8 inches. They can be flat, or have architectural features such as window and door openings, ribs, reveals, textures and built-in insulation.

MADRIDEJOS: But how do you connect these members? Are there many ways to connect them or is there a standard?

SURBANO: How do we connect precast concrete members? There are two ways. The most common method is by use of steel weld plates. Typically, the precast members have embedded plates that can be used as welding surfaces for loose connecting plates or angles. Another connecting method is by Rebar and Grout. Rebar and Grout are usually used with slabs. Reinforcing bars are spliced into parts and grouted in place. That’s how we connect the precast concrete members.

MADRIDEJOS: Ok, so in your report you say that there are multiple systems in which precast concrete members can be built. What are these systems and do they differ?

DIAZ: For precast concrete systems, there are four categories. Depending on the load bearing structure, precast can be categorized as: a large-panel system, Frame system, Slab-column system or mixed system. Large panel system refers to multistory structures composed of large wall and floor concrete panels connected in the vertical and horizontal directions so that the wall panels enclose appropriate spaces for the rooms within a building. These panels form a box like structure. Both vertical and horizontal panels resist gravity load. Wall panels are usually on e story high. When properly joined together, these horizontal elements act as diaphragms that transfer the lateral loads to the walls. Depending on the layout, there are three basic configurations of large panel buildings. There’s the cross-wall system, Longitudinal-wall system and two-way system.

MADRIDEJOS: What’s the difference between the three?

DIAZ: Sir, Cross walls are placed in the short direction of the building, Longitudinal walls are placed in the longitudinal direction and Two way system walls are placed in both directions.

ALEJANDRINO: Ok thank you, can you talk about the other three systems for constructing the precast concrete members?

BANTATUA: Let me talk about precast frames. Precast frames can be constructed using either linear elements or spatial beam-column sub assemblages. Precast beam-column subassemblages can be placed away from the critical frame regions; however, linear elements are generally preferred because of the difficulties associated with forming, handling, and erecting spatial elements. The use of linear elements generally means placing the connecting faces at the beam-column junctions. The beams can be seated on corbels at the columns, for ease of construction and to aid the shear transfer from the beam to the column.

SOTO: The third category of precast construction is the Slab-column systems. These systems rely on shear walls to sustain lateral load effects, whereas the slab-column structure resists mainly gravity loads. There are two main systems in this category: One is the Lift-slab system with walls and the other is prestressed slab-column system. Lift-slab systems, as you can see gentlemen, were introduced in the last decade of the soviet union from 1980 – 1989. Also known as the “Seria KUB”, the load bearing structure consists of precast reinforced concrete columns and slabs. Precast columns are usually two stories high and all precast structural elements are assembled by means of special joints.

MADRIDEJOS: How about the prestressed slab-column system?

BATOL: Prestressed slab-column system uses horizontal prestressing in two orthogonal directions to achieve continuity. The precast concrete column elements can be ranged from 1 to 3 stories high. The reinforced concrete floor slabs fit the clear span between columns. After erecting the slabs and coluns of a story, the columns and floor slabs are prestressed by means of prestressing tendons that pass through ducts in the columns at the floor level and along the gaps left between adjacent slabs. After prestressing, the gaps between the slaps are filled with in situ concrete and the tendons then become bonded with the spans.

ALEJANDRINO: I assume that the mixed-system is a combination of the first three. Am I right?

BATOL and SOTO: Yes sir. It’s more of a frame panel with walls, slabs and columns.

ALEJANDRINO: You say that pre-cast concrete makes construction of walls and structural frames easier. Can you enumerate all the advantages of Precast concrete that is most appropriate for the marketing of these products?

JOCSON: In general, precast building systems are more economical when compared to conventional multifamily residential construction or apartment buildings in many countries. There are many advantages of precast concrete. Aside from producing a standard in the dimensional design of structures and having a rapid speed of erection for members,
Precast concrete also has high quality because of the controlled conditions in the factory.
Prestressing is easily done which can reduce the size and number of the structural members.
Entire building can be precast - walls, floors, beams, etc.

ALEJANDRINO: Then what do you think are its main disadvantages?

JOCSON: There are also some disadvantages of precast concrete
Precast members are very heavy members and cranes are required to lift panels. Another is that connections may be difficult and joints between panels are often expensive and complicated.
Also precast components need bracing during on-site erection of structure and skilled workmanship is required in the application of the panel on site.

ALEJANDRINO: How about its response to earthquake?

TABON: There is a general concern among the earthquake engineering community regarding the seismic performance of precast construction. Based on experience in past earthquakes in Eastern and Central Asian countries where these systems are used, it can be concluded that their seismic performance has been fairly satisfactory. However, when it comes to earthquake performance, the fact is that “bad news” is more widely recognized than “good news”, therefore making these systems more effective on places that earthquakes rarely occur. However, few engineers are aware of the good seismic performance of several LARGE-panel buildings under construction at the same sites. Large-panel buildings as described in the WHE report 55 from the Russian federation, such as the Seria 111 were similar to the precast concrete frame system of Sera IS which received no damage during the seismic activity of 2003.

ALEJANDRINO: So what is your conclusion about this product?

SOTO: In the expanding constructions business industry, we could say that precast concrete is a good investment for your company to produce since it is of a cheaper cost that on site construction.

BANTATUA: It also allows contractors to do a better job since their work is minimized.

MADRIDEJOS: Then I declare this proposal be approved. (Everybody claps)

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MCL CE Students

This would be the official blogspot of the Malayan Colleges Laguna CE students. Some people could author posts inside this blog as long as it does not contain vulgar/offensive words or images. Posts that disobey the latter rule and posts which make no sense will be deleted. Requests for authority of the blog should be sent to me as PM. News about CE-MCL will be discussed here. As for now, wait for updates. - LMM

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