Question

Make any reasonable assumptions Q1 (50 pts): Design the T-beam shown below for bending: 4 in 24 in I + 4 ft Span=240 Use: Driveway and car parking f'c-4,500 psi fy = 60 ksi

Answer 1

Given (T-Beam) fc = 4500psi = 4.5ksi fy = 60000 psi = 60ksi = 4" hf a = ch-3) = (24-3)=21" b= 2411 Span Cl)=24 Take cover=3" centre to centre aistance = 4' By A CI Code :- Step I:- Calculation of effective flange wiath (be): - The effective flange wiath is smallest ofan (i) be= - ) - (24.X12 )= 72 in (ii) be =(164 +6w) (Assume bw=12") = (16X4+12) = 76 in (ii) be=centire to centre of adjacent slabs = (4x12) = 48 in Therefore, be = 48 in Step I:- Jocheck the depth of stress block in It the section behaves as a rectangular ones than the stres block lies within the Hange.

In this case o the wiath of beam is used equal to (4x12) = 48 ibah We know that C As fy Let As=48 =4X0.79) = 3.16952 be= 48in 0.85 fcbe 2016 X 60 0.858405848 a=1.03 in <t Hence, it is a rectangular section. Step III :- calculation of (sw) :- We know that Sw As bud > 8 min=0.00333 (31 16 ) >, smin Ĉ0.0125> 0.00333 Hence uk step :- Jo check (et): we know that where Et= = [0.003 (dt-C) a=1.03 in c =/.03 0.85 3)=1-21in de=d=21".

= 0.003 (21-1-21) 1.21 Et = 0.049 > 0.005,0 2009 Hence ok Step :- calculation of Comb) in We know that & Mn = 0 As fy (d-o 20.gx3:46*60 (21-103) = 3495.56 k-in 291.29 Kft &Mn hf=4" d=21" h=24! 4#8 y bw=12" KT fig :- T-Beam detailing