Question

In: Civil Engineering

A solid grouted 8 in masonry CMU beam is reinforced with two #4 Grade 60 bars...

A solid grouted 8 in masonry CMU beam is reinforced with two #4 Grade 60 bars andhas an effective depth of 32.5 in. Determine the allowable moment in accordance withACI 530. Use f’m = 2500 psi and assume medium weight units (140 pcf). What is theallowable load if the effective span is 10.67 ft?

Solutions

Expert Solution

Ans) As per ACI 530 , the allowable moment (M) in CMU beams is given by,

M = (Asfy + P ) ( d - a/2)

where , As = area of steel

fy = yield strength of bar ( for grade 60 rebars fy = 60000 psi)

P = medium weight unit x volume

d = effective depth

a = (P + Asfy ) / (0.8 f'm b)

Area of steel = 2 x /4 x D2

For #4 grade 60 bar, Diameter = 0.5 in

Therefore , As = 2 x 0.785 x 0.5 x0.5

= 0.3925 in2

a = [(140 / 123) x 34.5 x 10.67 x12 x 8 ) + (0.3925 x 60000)] / (0.8x 2500 x 8)

On solving, a = 1.65

Putting all values to calculate allowable moment,

M = [(0.3925 x 60000) + (140/123)] ( 32.5 - 1.650/2)

M = 745922.70 lb-in

To determine allowable load(F), we know

F = (M y /I) x bd

where, I = moment of Inertia

y = distance of neutral axis from base of beam ( y = d/2)

We know,

I = b d3 /12

= 8 x 34.53 / 12 ( 2 in added in depth for cover)

= 27375.75 in4

Hence,

F = [(745922.70 x 34.5/2) / 27375.75] x 32.5 x 8

= 122205.35 lb


Related Solutions

A solid spherical ball of radius 4 meters has a charge of 8 nC. a) Calculate...
A solid spherical ball of radius 4 meters has a charge of 8 nC. a) Calculate the electric potential at r = 2, r = 4, and r = 6 meters away from the center of the ball if it is a conducting sphere. b) Calculate the same things if it is an insulating sphere of uniform charge density. c) Calculate the same things if it is an insulating sphere of non-uniform charge density, ρ = kr2 Answers should be:...
A solid spherical ball of radius 4 meters has a charge of 8 nC. a) Calculate...
A solid spherical ball of radius 4 meters has a charge of 8 nC. a) Calculate electric flux through the sphere at r = 2, r = 4, and r = 6 meters away from the center of the ball if it is a conducting sphere b) Calculate the same things if it is an insulating sphere of uniform charge density. c) Calculate the same things if it is an insulating sphere of non-uniform charge density, ρ = kr2
Two sections of a pressure vessel are to be held together by 5/8 in-11 UNC grade...
Two sections of a pressure vessel are to be held together by 5/8 in-11 UNC grade 5 bolts. You are told that the length of the bolts is 1.5 in, the length of the threaded portion of the bolts is 0.75 in, and that their elastic modulus is E=30 Mpsi. The total load on the joint is 36 kip and the stiffness of the members is given as km=8.95 Mlbf/in. What is the minimum number of bolts that should be...
Draw the interaction diagram (P-M diagram) of the column (16”x16” with 4#8 bars plus #3 tie...
Draw the interaction diagram (P-M diagram) of the column (16”x16” with 4#8 bars plus #3 tie @12”o.c). Assume fc’ is 5 ksi and fy is 60 ksi. (10 points)
Find the mass of the solid bounded by the ??-plane, ??-plane, ??-plane, and the plane (?/2)+(?/4)+(?/8)=1,...
Find the mass of the solid bounded by the ??-plane, ??-plane, ??-plane, and the plane (?/2)+(?/4)+(?/8)=1, if the density of the solid is given by ?(?,?,?)=?+3?.
A vertically polarized laser beam (wavelength 400 nm) passes through a polarizer (60° from vertical) and two slits that are 0.1 mm apart.
A vertically polarized laser beam (wavelength 400 nm) passes through a polarizer (60° from vertical) and two slits that are 0.1 mm apart. Each slit is 800 nm wide. The light hits a screen 1 m away.a. What is the frequency of the laser light?b. What fraction of light intensity is transmitted through the polarizer?c. At what angle does the second-order maximum occur?d. One slit is blocked. What is the width of the central maximum on the screen?
What's the schematic of the 4-bit multiplier that has two 4-bit inputs and an 8-bit output...
What's the schematic of the 4-bit multiplier that has two 4-bit inputs and an 8-bit output with pure combinational logic? Can you draw the circuit?
Problem 8-70 (LO 8-4) [The following information applies to the questions displayed below.] Trey has two...
Problem 8-70 (LO 8-4) [The following information applies to the questions displayed below.] Trey has two dependents, his daughters, ages 14 and 17, at year-end. Trey files a joint return with his wife. What amount of child credit will Trey be able to claim for his daughters under each of the following alternative situations? Use Exhibit 8-8. EXHIBIT 8-8 Child Tax Credit Phase-Out Threshold Filing Status Phase-Out Threshold Married filing jointly $400,000 Married filing separately 200,000 Head of household and...
Case Study There two sets of questions for this module, 1-4 and 5-8, for a total...
Case Study There two sets of questions for this module, 1-4 and 5-8, for a total of eight questions. Using the concept of the epidemiological triangle to complete one of the following case studies: John J. is a school nurse at Jackson Elementary School, which was built in 1960. Nurse John has noticed that many students from Ms. Zee’s second grade class have come to the clinic complaining about coughing, sneezing, runny nose, and watery eyes. Nurse John has also...
X Y/1 Y/0 Years Exp Successful Unsccessful total 4 17 83 100 8 40 60 100...
X Y/1 Y/0 Years Exp Successful Unsccessful total 4 17 83 100 8 40 60 100 12 50 50 100 16 56 44 100 20 96 4 100 The data in tab #2 pertain to the years of experience of project managers and the numbers of successes and failures they have had on major projects. Use the data set given in tab #2 in the attached Excel workbook and logistic regression to find the following: The probability of success given...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT