Roman Architecture
...od over sixty feet above the river. For major or busy bridges sometimes stone went in place of wood. The semicircular arch was usually used for bridges. Aqueducts were like a bridge but built over land and carried pipes of water instead of a roadbed. Rome alone needed 340 million gallons of water per day to supply its great arched baths and other needs. Surveyors made an imaginary line with measuring sticks and a chorobate, a leveling instrument like the level used today, to make a straight line for a profile map. The surveyors designed a plan to keep the water from rushing too fast. They made a system of a fall of six inches for every one hundred feet and often added long detours to avoid a too sudden descent. Due to the materials and construction methods, many of the aqueducts survived and are still used today. Sometimes a route of an aqueduct required that a short tunnel be dug through a hill. Every twenty yards vertical shafts were sunk from the surface of the hill to the level of the proposed aqueduct. The depths of the shafts were measured from the profile map. The engineers used the profile map to construct foundations up to the imaginary line, then built the piers for fifty feet, then put the stone arches in. The reason the arches were built high over the ground was to prevent people from stealing or poisoning the water. The pipes were made with the inner surfaces lined with hard cement to prevent leaks, then a rectangular pipe was built to cover the water pipes. When the aqueduct hit a hill underground pipes were built, the profile maps measured the depths of the new pipes to be placed. When the shafts were dug a pulley was put over the opening of the shaft to lower men, tools, and materials needed down the shafts. When the tunnel was dug and connected with the other shafts, masons lined it with cement and stone, closed the shaft with dirt, then moved on to the next shaft to repeat the process. The aqueduct was supported by a continuous row of arches built on tall square piers which rested on deep foundations. The laborers used bricks and granite blocks to form the foundations, piers, arches, and the rectangular pipes. The masons used hard cement and blocks to make pipes that held water and underground water ways. One special feature of Roman design was the combined use of arches. The arch is the central revolutionary concept of Roman architecture. With its development, the Romans bypass the earlier building concepts of vertical and horizontal, support and load. The arch makes possible a new idea of space. The Romans didn't need the columns, but they put the columns in for looks. There were two forms of arches, semicircular and triumphal arch. The semicircular arch was used more fluently than the triumphal arch. The semicircular arch was an arch that formed like a half circle. The Triumphal arch was a form of arch that had three arches with support beams that separated the arches. A dome was just a network of arches. The Romans were the first to complete the feat of the dome without columns and the Pantheon is one famous example standing after five thousand years. The Pantheon is one of the first domes ever built. It was a circular temple dedicated to all gods. The arches were usually built of brick, but in the later years of Rome, the arches were built of cement. To support the tremendous weight of the arches, it was necessary to provide a way of transmitting the force to massive piers and ultimately to the foundation of the arch. The Romans acheived this feat through the use of the keystone block. The force was directed down on to the top of the keystone. Because of its shape, the force was translated to the voussoir blocks of the arch which in turn translated the force through the post to the piers. During the construction, the vousoirs were supported by a temporary wooden frame until the keystone was inserted. The voussoir is bricks that form the arch and the keystone is the stone that is put in the middle of the arch. The temporary frame of the arch was wooden, the brick or cement were put on top of the frame and removed when the mortar or cement dried. The dome was a series of arches meeting at their highest point. The dome was built of concrete placed on a temporary wooden frame like the arch and it needed no columns for support. The dome was often placed on top of arches to split the weight. The dome was built from bottom to top in sections and one section was dried before moving on to the next section, so the weight would not cause the dome to collapse. The roof structure was unique compared to others because it needed no support colu...