360R-06 Design of Slabs-on-Ground
R-64 ACI COMMITTEE REPORT
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- Điều hướng trang này:
- A2.3—WRI thickness selection for aisle moment due to uniform loading
- APPENDIX 3—DESIGN EXAMPLES USING COE CHARTS A3.1—Introduction
| 360R-64 ACI COMMITTEE REPORT
(Note that in.-lb/in. = ft-lb/ft) Axle load = 14.6 kips Wheel load = 7.3 kips Design moment = 281 × 7.3 = 2051 ft-lb/ft Then, from Fig. A2.3 : Allowable tensile stress = 190 psi Solution: slab thickness H = 7-7/8 in. If the design thickness differs substantially from the assumed thickness, the procedure is repeated with a new assumption of thickness. A2.3—WRI thickness selection for aisle moment due to uniform loading The procedure for the check of tensile stress in the top of the concrete slab due to this loading uses Fig. A2.1 and A2.4 . Figure A2.3 is a part of Fig. A2.4 , separated herein for clarity of procedure. The procedure starts as before with determination of the term D/k = 3.4 × 10 5 in. 4 It then goes to Fig. A2.4 as follows: Aisle width = 10 ft = 120 in. Uniform load = 2500 lb/ft 2 = 2.5 kips/ft 2 Allowable tension = MOR/SF = 190 psi The solution is found by plotting up from the aisle width to D/k, then to the right-hand plot edge, then down through the uniform load value to the left-hand edge of the next plot, then horizontally to the allowable stress and down to the design thickness. Solution: thickness = 8.0 in. Again, if the design thickness differs substantially from the assumed value, the process should be repeated until reasonable agreement is obtained. APPENDIX 3—DESIGN EXAMPLES USING COE CHARTS A3.1—Introduction The following examples show the determination of thick- ness for a slab-on-ground using the procedures published by the COE. The procedure appears in publications issued by the Departments of Defense (1977), the Army (1984) and the Air Force (1987). The following examples are presented in inch-pound units. A table for converting the examples to SI units, along with an example of the process, is provided at the end of the Appendixes. The procedure is based on limiting the tension on the bottom of the concrete at an interior joint of the slab. The loading is generalized in design index categories ( Table A3.1 ). The procedure uses an impact factor of 25%, a concrete modulus of elasticity of 4000 ksi, and a safety factor of approximately 2. The joint transfer coefficient has been taken as 0.75 for this design chart ( Fig. A3.1 ). The six categories shown in Table A3.1 are those most commonly used. Figure A3.1 shows a total of 10 categories. tải về 2.35 Mb. Chia sẻ với bạn bè của bạn:
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