ABSTRACT

Cast-in-place reinforced concrete structures are typically monolithic. Casting is accomplished through a series of individual lifts, but the entire structure is one continuous element as long as the reinforcing details effect continuity. A slab cast on a beam (Figure 18.1) becomes the top ange of the beam. Such a beam is said to have a T-section.*

Chapter 18 focuses on the proportioning of beams with T-sections. We are concerned with the determinations of the moment and unit curvature capacities of the section. Before we tackle the subject, there are four issues that we should note:

1. The exural response of a T-section subjected to negative bending moment (top ange in tension) is essentially the same as that of a rectangular section except for the moment and curvature at cracking. The moments and curvatures at yield and at the limiting condition may be determined as described in Chapter 14. It is important to note that the T-beam ange can accommodate tensile reinforcement conveniently.