Accompanying this are files AA.XSF, BB.XSF, CC.XSF, DDe.XSF and DDi.XSF that are in inch-pound units. This example requires the application version 5.2.1 or later.
The Reinforced Concrete Design Handbook –SP-17(14) published by the American Concrete Institute, September 2015 Volume 1, Beam Example 1, pages 143 to 160 describes the design and detail of an interior, continuous, six-bay beam, built integrally with a 7 inch slab.
The accompanying files AA.XSF, BB.XSF, CC.XSF, DDe.XSF and DDi.XSF represent Section A-A, Section B-B, Section C-C and Section D-D respectively shown in Fig. E1.11 and Fig. E1.12 in that handbook. There are three different sections labeled D-D in Fig. E1.11. One is on the end span: DDe.XSF represents that section. The other two are on an interior span: DDi.XSF represents them.
Computations by the application using those files are equivalent to the corresponding flexural strength computations set out in the handbook and are intended to demonstrate that the application is consistent with the Handbook.
The sections shown in Fig. E1.12 include #7 bars in both the tension part and the compression part and also #5 bars. Generally however the flexure computations in the handbook ignored the steel bars in the compression part and also ignored all the #5 bars. Thus the sections represented in the files include only the #7 bars in the tension part of the section.
Each of the XSF files includes one load-case to compute the ultimate strength moment. In section A-A and section B-B the situation of interest has compression at the top. Thus in AA.XSF and BB.XSF the reference angle is set at 180 degrees. In section C-C and sections D-D the situation of interest has compression at the bottom. Thus in CC.XSF, DDe.XSF and DDi.XSF the reference angle is set at zero.
Table 1.1 on page 148 in the handbook sets out some information on each section. The first five columns on the table herein were copied from that table.
The sections represented in the files include the ‘provided’ number of #7 bars. However the area of each bar is such that the total area of steel is only the required area. The application computations assess the strength with that amount of steel. Finally the strength reduction factor ϕ = 0.9 was taken into account to give a moment comparable with the given factored moments Mu.
| Location | Mu, | As, req’d | Number of #7 bars | File | Bar | Moment as computed | By ϕ =0.9 | ||
| ft-kips | In2 | Req’d | Prov. | name | in2 | k.in | ft-kips | ft-kips | |
| ME1 | 267 | 2.23 | 3.7 | 4 | CC | 0.557 | 3559.4 | 296.6 | 267.0 |
| ME2 | 428 | 3.65 | 6.1 | 7 | DDe | 0.521 | 5704.6 | 475.4 | 427.8 |
| MI | 389 | 3.30 | 5.5 | 6 | DDi | 0.550 | 5188.8 | 432.4 | 389.2 |
| ME+ | 306 | 2.49 | 4.1 | 5 | AA | 0.498 | 4086.6 | 340.5 | 306.5 |
| MI+ | 267 | 2.17 | 3.6 | 4 | BB | 0.543 | 3567.1 | 297.3 | 267.5 |
This is intended to demonstrate that the application is consistent with the Handbook. With minor changes to the input information the application could assess the actual strength of the design presented in the Handbook.