Floor loads are often carried from slabs to beams, and from the beams to columns in the design of reinforced concrete buildings. Finally, the columns convey the superstructure weight to the structure's base. The depth of the slab determines the amount of stress that can be placed on any one beam or column. The deeper the slab, the more stress that can be carried by these elements. Beams connect floors together in buildings. They may be straight or curved, depending on the desired appearance for the building. Beams must be strong enough to carry the expected floor loads as well as the load of any additional structures that might be attached to them. The size of the beam depends on the application; typical sizes range from about 2 feet (60 cm) deep by 6 inches (152 mm) wide at the face of the slab to about 12 feet (370 mm) by 36 inches (914 mm) for large support beams in high-rise buildings. Columns are tall, slender structural members used to support heavy roofs or walls. Columns should be designed so that they can bear the anticipated load without breaking under normal conditions. The size of the column depends on the application; typical sizes range from about 3 inches (75 mm) diameter at the base of the shaft to about 18 inches (45 cm) diameter at the top of the pillar.