Lecture 17 – Page 1 of 17 Lecture 17 – Concrete Analysis/Design using “RAM” Software RAM is a commercially available software package used for analysis and design of structures. It is very powerful and accurate. We will be using it to analyze and design the flexural reinforcing for a simply-supported reinforced concrete beam. EXAMPLE 1 GIVEN : A simply-supported 12” x 20” concrete beam uses f’ c = 4000 psi and Grade 60 bars. All loads shown are factored, and includes beam weight. REQUIRED : 1) Draw and label the complete shear + moment diagrams . 2) Determine the minimum required area of tensile steel , assuming “d” = 18”. 3) Using RAM software, determine the support reactions and maximum moment . 4) Using RAM software, determine the minimum required area of tensile steel . Step 1 - Draw and label the complete shear + moment diagrams . 1’-0” R2= 14.0 Kips R1 = 22.0 Kips 22 kips 17 kips 1 kips 5’-0” 15’-0” w u = 1000 PLF (incl. beam wt.) 16 Kips 0 -14 kips 0 98.0 Kip-ft 97.5 Kip-ft M max = 98.0 Kip-ft 0 0
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Concrete member analysis design using ram software
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Lecture 17 – Page 1 of 17
Lecture 17 – Concrete Analysis/Design using “RAM” Software RAM is a commercially available software package used for analysis and design of structures. It is very powerful and accurate. We will be using it to analyze and design the flexural reinforcing for a simply-supported reinforced concrete beam. EXAMPLE 1 GIVEN: A simply-supported 12” x 20” concrete beam uses f’c = 4000 psi and Grade 60 bars. All loads shown are factored, and includes beam weight. REQUIRED:
1) Draw and label the complete shear + moment diagrams. 2) Determine the minimum required area of tensile steel, assuming “d” = 18”. 3) Using RAM software, determine the support reactions and maximum moment. 4) Using RAM software, determine the minimum required area of tensile steel.
Step 1 - Draw and label the complete shear + moment diagrams.
1’-0”
R2= 14.0 Kips R1 = 22.0 Kips
22 kips 17 kips
1 kips
5’-0” 15’-0”
wu = 1000 PLF (incl. beam wt.)
16 Kips
0
-14 kips
0
98.0 Kip-ft 97.5 Kip-ft
Mmax = 98.0 Kip-ft
0 0
Lecture 17 – Page 2 of 17
Step 2 – Determine the minimum required area of tensile steel, assuming “d” = 18”.
Using Mmax = Mu, use 2bdM u
φ from Lecture 4:
where: Mu = 98 Kip-ft = 1,176,000 lb-in φ = 0.9 b = 12” d = 18”
2bdM u
φ = 2)"18)("12)(9.0(
1176000 inlb −
= 336.1 psi
Use ρ = 0.0059
12”
18” 20”
Lecture 17 – Page 3 of 17
Recalling bdAs=ρ
Solve for As = ρbd = (0.0059)(12”)(18”) Required As = 1.27 in2
Lecture 17 – Page 4 of 17
RAM Software
Step 1 – Create a model of the beam as shown below: