Problem 1 Wh at is the calculated compressive strength of th

Problem 1: Wh at is the calculated compressive strength of the cor 3569

Solution

2) magnitude of concentrated force applied = F/2=5.52/2=2.76 kips

d=6\"

since the beam is symmetrically loaded and supported, the reaction force at each support will be equal

Reaction force at each support=F/2=2.76 kips

maximum moment in beam=M=(F/2)*d=2.76*6=16.56 kip-in=16560 lb-in

elastic section modulus of section =S= d*d²/6=6*6²/6=36 in³

maximum tensile stress in beam =M/S= 16560/36=460 psi

Per ACI, modulus of rupture is given by 7.5*sqrt(f\'c)

From part 1, f\'c = 3569 psi

Therefore, per ACI, modulus of rupture = 7.5*sqrt(3569)=448 psi

Modulus of rupture from experimnent is 460 psi whereas per code it is 448 psi

3) from part 1, compressive strength of concrete=3569 psi

modulus of elasticity = 57000*sqrt(3569)=3405243.16 psi

From part 2, modulus of rupture = 460 psi

compressive strength of concrete = (460/7.5)² = 3761.8 psi

modulus of elasticity = 57000*sqrt(3761.8)=3496010.3 psi