User:Fsteiger
It is generally accepted that the larger Egyptian pyramids were constructed using mud rubble ramps to move the stone blocks to the placement level. This theory lacks credibility. The single ramp illustrated in many references would have to be about a mile long and a hundred yards wide at the base in order to reach the top of the largest pyramid. Placing and removing this enormous amount of material by hand labor is clearly impractical, if not impossible. In addition, the ramp would have to be maintained as a smooth surface to allow the movement of the stone blocks. A mud surface is too soft to allow this to happen.
Another variation on the mud ramp theory postulates that the ramp spiraled around the pyramid as it was constructed. This type of construction is simply impossible because the sides of the pyramid are too steep. The ramps would slide off due to their own weight, and certainly would not support heavy stone blocks.
If one assumes that the angular facing stones were placed from the top down after all the rectangular blocks were placed, the fact still remains that the spiraling mud ramps would not support the stone blocks, especially since in this case the ramp base would have to be very narrow.
It is clear that the only practical means of moving the stone blocks is the use of movable wooden ramps. Each ramp consisted of a sloped portion and a horizontal section the same height as the vertical dimension of the stone blocks. Each block was pushed and pulled up the sloped ramp to the level of the next course, then pushed and pulled into place.
Wooden rollers were used to expedite moving over longer distances.
Before starting to place the blocks, it was necessary to orient the pyramid in a true north-south, east-west direction. On a night with no moon, two technicians with plumb bobs and oil lamps established the true north-south line. Worker A at a marked spot sighted through his plumb line to the plumb line of worker B. Worker A directed worker B to line his plumb line to coincide with the nearest polar star and mark the spot. Fortunately at that latitude the pole star was not too high in the sky. However, it may have been necessary for worker B to be elevated on a support of some kind. As the polar star made its apparent small circle in the sky, worker B shifted his plumb line to coincide with the star, as observed by worker A. After a complete shift from side to side had been observed, the midpoint of the marked spots was then marked, and the line from A to B was then true north-south. The space between A and B was as great as possible to be accurately observed. This procedure was repeated at the opposite side of the building site, and a number of intermediate locations. The east-west lines were constructed by striking right angles using the procedure of two intersecting arcs. This whole process was repeated a number of times during construction to maintain accurate alignment.
To start the initial layer of rectangular blocks, a single block was placed at the exact center. The center was determined by the intersection of two sight lines from opposite corners. A marked grid of north-south and east-west lines insured that the blocks were correctly oriented and also established the location of the corners. Then four blocks were placed alongside the initial block to form a cross. Then four more blocks were placed to form a nine block square. Four more blocks were placed at each corner in such a manner that each side of the square had only one block placed against it. Then four more blocks were moved along each side of the square simultaneously to each of the four corner blocks. This formed a sixteen block square with an extra block at each corner. The process was repeated to form a 25 block square with a block at each corner.
In this manner each layer was constructed from all four sides simultaneously. As each level was completed, the topmost ramp was moved up (and necessarily in) one level, followed in succession by each following ramp, with a new ramp placed on the lowest level to complete the sequence.
As stated, wooden ramps were used to move the blocks to the next higher level. Because the ramps were too wide for the ultimate setback at each level, the outside perimeter of each level was temporarily omitted, to be filled in later. The ramps were arranged so that the sloped end of each ramp faced the sloped ends of the ramps above and below. Sufficient space was left between ramps to allow movement of the stone blocks, and later, the angular facing stones. After the first level of blocks were placed, a ramp was placed at ground level to place the second level of blocks. After the second level was placed, the ramp was moved up to the first level and a new ground level ramp installed. This permitted the placement of the third level, and so on. Near the top of the pyramid the blocks had to be muscled in by manpower because there was no room for the ramps.
In order to maintain the proper slope, a triangular template was used with the slope angle extended downward as far as possible, probably about three courses of stone levels.
Both the rectangular and angular facing blocks were placed from all four sides at the same time, reducing the time to one-fourth of what it would be otherwise.
After all the rectangular blocks were placed to the top of the pyramid, the angular facing blocks were placed from the top down. Each angular facing block in the queue was alternated with one or more rectangular block or blocks in order to fill in the stepped back sections temporarily left empty in order to provide room for the wooden ramps. Placement started simultaneously at the top on each of the four sides. Each row started at the corner end with a double angled corner block and continued to meet the previously placed corner block of the adjacent side.
The ramps were shifted laterally as the facing blocks were placed in order to avoid having to move each block laterally over the existing rectangular blocks to its final location. Thus the assemblage of ramps in a time lapse sequence would appear to swing back and forth in slow motion as each row of facing blocks was placed. As the row of facing blocks neared the end of its course, it was necessary to move the blocks laterally over the remaining existing rectangular blocks because at this point there was no room for the placing ramp. After each row of angled facing blocks was completed, the ramps were moved down one level in a stepwise progression, beginning with the lowest ramp. The block moving crew assigned to each level moved the ramps in sequence in a sort of chain reaction. In this manner the ramps were moved in less than a day.
Successful completion required sophisticated engineering and careful planning.
The pyramids by necessity were constructed on bed rock. A sand foundation would not support the weight of the pyramid, and it would not be possible to move and place heavy stone blocks on unstable sand. After the limestone outcrop was approximately leveled and the surplus material used to manufacture blocks, it was necessary to level the site. In order to do this, a rectangular box was used to support a level similar to a surveyor's level, but without the glass lenses. The Egyptians knew how to construct 90 degree right angles by two intersecting arcs, so the box was perfectly rectangular. From the center of the top surface a plumb bob was suspended. When the plumb was directly over the center of the bottom surface, the top surface was perfectly level and provided a base for the sighting "surveyor's" level. A second surveyor carried a vertical rod marked at a point equal to the height of the "surveyor's" level. Working from the lowest point and sighting at the vertical rod, the Egyptians determined the amount of material to be removed to achieve a level surface. In addition to this procedure, the Egyptians constructed large wooden isosceles triangles with the midpoint of the base marked. A plumb bob was suspended from the top corner. The surface on which the triangle was placed was level when the bob was directly over the marked mid point. These instruments continued to be used during construction in order to maintain a level surface as the work progressed.