Shown below is a larger-scale elevation view of the left end of the continuous concrete beam shown in Figure 13.30 of the text. The structural plans call for a 10 -wide by 18 -deep (254 by 460 mm) beam with two #9 top bars and two #8 bottom bars. Fifteen #3 U-stirrups are required at a spacing of 7 (178 mm). Name: Inment #12 Column Beam 1. Make an accurately scaled drawing of the reinforcing bars In the beam, including top bars, bottom bars, and stirrups, drawing them as if the concrete were transparent. Give critical dimensions of any hooks. Do not show column reinforcing or bar deformations. 11/2 =1 (1:8) Scale: 1 square= 2 (50 mm) 107 552 Chapter 13 Concrete Construction A concrete slab supported by a number of beams bends in the same pattern as a concrete beam supported by a number of columns The apandrel beam twists alightly from the bending forces in the slab at the face of the building The thickness of the slab in these drawings is exaggerated in order to show the reinforcing better Concrete girder The country...near Taliesin, my home and workshop, is the bed of an ancient glacier drift. Vast busy gravel pits abound there, exposing heaps of yellow aggregate once and still everywhere near, sleeping beneath the green fields. Great heaps, clean and golden, are always waiting there in the sun. And I never pass... without an -Top steel for beam -The entire thickness of the concrete acts as a part of the beams emotion, a vision of the long dust-whitened stretches of the cement mills grinding to impalpable fineness the magic powder that would set my vision all to shape; I wish both mill and gravel endlessly subject to my will.... Materials! What a resource. Concrete beams FIGURE 15-30 Reinforcing for a one-way concrete slab. The reinforcing is similar to that for a continuous beam, except that stirrups are not usually required in the slab, and shrinkage-temperature hars must be added in the perpendicular direction. The slab does not sit on the beams; rather, the concrete around the top of a beam is part of both the beam and the slab. A concrete beam in this situation is considered to be a Tshaped member, with a portion of the slab acting together with the stem of the beam, resulting in greater structural efficiency and reduced beam depth. -Frank Lloyd Wright, in Architectural Record, October 1928 -Shrinkage temperature bars reinforce against cracks parallel to the main reinforcing bars The stirrups have been omitted from the beams in this drawing for the sake of clarity Reinforcing Concrete Columns Columns contain two types of rein forcing: Vertical bars (also called a umn bars) are large-diameter bars that share the compressive loads with the concrete, resist tensile stresses that may occur in columns, and impart ductility to the column (important for resistance to earthquake forces). Ties of small-diameter steel bars wrapped around the vertical bars help to prevent them from buckling under load: Inward buckling is pre vented by the concrete core of the