The structural engineering of Stonehenge November 2009

Facts Built between 3100 – 1100 BCE Sophisticated mathematical and geometrical knowledge Bluestones and Sarsen stones - 240 miles away Thirty million hours of labor Nine hundred stone rings exist in the British Isles Stonehenge was built between 3100 – 1100 BCE. The monument began about 5,000 years ago as a large, circular ditch and bank rimmed with circular pits. Over the next 1,500 years, timber posts were erected within the circle, later to be replaced by large bluestones and even larger sarsen stones, seen here. The circle was aligned with the midsummer sunrise, the midwinter sunset, and the most southerly rising and northerly setting of the moon. There were two types of stones used in its construction: the ‘bluestones’ (weighing as much as four tons and brought from 240 miles away) and the Sarsen stones (averaging eighteen feet in height and twenty-five tons in weight). It has been estimated that the construction of Stonehenge required more than thirty million hours of labor. More than nine hundred stone rings exist in the British Isles. Of these, Stonehenge is the most well known. Facts

Design and Construction circular enclosure outlined by two banks and a ditch with an entrance to the northeast a standing stone a bit away from the entrance outer circle was made from earth was 380 ft in dia, 8 ft wide, and 2 or 3 ft high. Stonehenge was basically a circular enclosure outlined by two banks and a ditch with an entrance to the northeast and a standing stone a bit away from the entrance. The outer circle was made from earth and even though it is now mostly destroyed, it was about 380 feet in diameter, 8 feet wide, and 2 or 3 feet high. Design and Construction

Design and Construction Sarsen stone found 20 miles away heel stone leans inward toward the circle at an angle of about 30 degrees from the perpendicular believed that the stone was once standing straight. Many of the natural sandstone called sarsen which are thought to have come from Marlborough Downs, 20 miles to the north of Stonehenge. Currently the heel stone leans inward toward the circle at an angle of about 30 degrees from the perpendicular, but it is believed that the stone was once standing straight. Design and Construction

Stonehenge Builders Village Video http://video.nationalgeographic.com/vide o/player/news/culture-places- news/stonehenge-village-vin.html Stonehenge Builders Village Video