A rectangular conerete beam 250 mm wide and 375 mm deep, is used to support a live load of 4.25 KN/m,and dead load of own weight over a span of 8 m The beam is prestressed with straight cable having eccentric of 65 mm below the centroid axis at the center of beam. Calculate the required minimum pre-stressing force at the service load stage? Take unit weight of concrete equal to 24kN/m'.

A rectangular conerete beam 250 mm wide and 375 mm deep, is used to support a live load of 4.25 KN/m,and dead load of own weight over a span of 8 m The beam is prestressed with straight cable having eccentric of 65 mm below the centroid axis at the center of beam. Calculate the required minimum pre-stressing force at the service load stage? Take unit weight of concrete equal to 24kN/m'.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Check the adequacy of a rectangular beam section with a width of 424 mm and an overall depth of 556 mm. It is subjected to a factored shear and torsion of 111 kN and 66 kN-m, respectively. The distance of the tension reinforcements from the bottom fiber of the beam is 71 mm. The specified compressive strength of concrete is 25.1 MPa. The yield strength of tension reinforcements and stirrups are 377 MPa and 284 MPa respectively. Use 12 mm stirrups. If it is adequate type-in 1, otherwise 2. Adequate = 1 Not adequate = 2
A rectangular beam 350 mm wide and effective depth of 500 mm is to be designed as subjected to an ultimate moment of 750 kN-m. The concrete strength to be used is 28 MPa and the yield strength of reinforcement of 415 MPa. If compression bars are need, it is placed 70 from the extreme compression face. Determine the depth of the stress block if the tensile strain is 0.005 when the concrete crushes at a strain of 0.003. Select the correct response: 159.3 188.4 187.5 221.7 G
Problem statement - A rectangular concrete beam has a width of 300 mm and an effective depth of 550 mm. The beam is simply supported over a span 6 m and is used to carry a uniform dead load of 25 kN/m and a uniform live load of 40 kN/m. Assume f = 21 MPa and fy = 312 MPa. Compression reinforcement if necessary shall be placed at a depth 80 mm from the outermost compression concrete. a) Determine 80 mm from the outermost compression concrete. b) Determine the required tension steel area.
A cantilever slab has a span of 2.40 m. It is 150 mm thick and has an effective depth d = 110 mm. It is reinforced with 16 mm rebars @ 150 mm o.c. If f’c = 27 MPa, fy = 276 MPa, what is the safe live load that the slab can carry? Use 2015 NSCP strength design. Unit weight of concrete for DL: 23.56 KN/cu m.
Design the Beam AB Below by using Working Stress Method: A 6.5 kN/m В 4.4 m Dead Load, D.L=17 kN/m Live Load, L.L = 6.3 kN/m The allowable compressive stress of the concrete, fc = 14 N/mm? Allowable tensile stress in steel, fs = 120 N/mm? Modulus of elasticity of steel, Es = 230000 Mpa Modulus of elasticity of Concrete, Ec 21000 Mpa Beam Width, b 270 mm
20. Determine the nominal load when the concrete strain of 0.003 and tensile steel strain is 0.002075. A. 1090 kN B. 1554 kN C. 1168 kN D. 1401 kN
Please answer with complete illustration. A cantilever slab has a span of 2.40 m. It is 150 mm thick and has an effective depth d = 110 mm. It is reinforced with 16 mm rebars @ 150 mm o.c. If f’c = 27 MPa, fy = 276 MPa, what is the safe live load that the slab can carry? Use 2015 NSCP strength design. Unit weight of concrete for DL: 23.56 KN/cu m.
What is the threshold torsion (kN-m) of a rectangular beam with a width of 402 mm and an over-all depth of 571 mm? The distance of the tension reinforcements from the bottom fiber of the beam is 72 mm. The specified compressive strength of concrete is 25.62 MPa. The yield strength of tension reinforcements and stirrups are 387 MPa and 300 MPa respectively.
A rectangular concrete beam has a width of 300 mm and an effective depth of 550 mm. The beam is simply supported over a span of 6 m and is used to carry a uniform dead load of 25 KN/m and a uniform live load of 40 kN/m. Assume fic= 21 MPa and fx = 312 MPa. Compression reinforcement if necessary shall be placed at a depth of 80 mm from the extreme compression concrete. Which of the following most nearly gives the required number of 25mm diameter tension bars? A. 6 B.7 C. 8 D. 9
The beam cross section: Service loads: Steel young's modulus Es = 29,000,000 psi A 1 kN/m distributed load. Concrete young's modulus Ec = 3,500,000 psi A 10 kN concentrated load located at midspan. 10 kN Compressive strength of Concrete f'c = 3500 psi 1 kN/m Tensile strength of concrete f 'ct = 475 psi Steel yield point fy = 60000 psi %3D A 4.0 m 10" 8.0 m y 1. Determine the stress in the steel bars and concrete 23 bottom and top fibers. 25" 2. What value of the 10 kN concentrated load will cause cracks to appear on the concrete? 3. Determine the stress in the steel bars and concrete 3 No. 12 bottom and top fibers if the value obtained in point #2 is increased by 20%.
A rectangular reinforced concrete beam has a width of 300 mm andan effective depth of 450 mm to centroid of the tension bars. Thebeam is reinforced with six 32 mm ɸ tension bars placed in twolayers with the outer layer having a depth of 478 mm, and two 28mm ɸ compression bars with centroid 65 mm from the extreme concretefiber. Use the 2010 NSCP, fc’= 34.5 MPa and fy = 345 MPa. Assumethat the concrete displaced by the compression steel shall not beneglected and that the compression steel yields. Det. the following:19. The balanced steel ratio if the beam is singly reinforced. a. 0.04607 b. 0.03555c. 0.02721 d. 0.03672 20. The maximum steel ratio for a singly-reinforced section intension control. a. 0.03555 b. 0.04607c. 0.03672 d. 0.02721 21. The maximum steel ratio for a doubly-reinforced section intension control. a. 0.02721 b. 0.03672c. 0.03555 d. 0.04607
Question 33 A rectangular beam 250 mm wide, 500 mm deep is reinforced at the bottom with 4-20-mm-diameter bars and at the top with 2-16-mm bars. Concrete cover to bar centroid at the top is 80 mm and at the bottom is 70 mm. Use concrete strength f’c = 21 MPa and steel yield strength fy = 350 MPa for 20-mm bars and fy = 275 MPa for 16-mm bars. Determine the maximum steel ratio if the beam is singly reinforced in negative bending with the given material strengths and the tensile strain is limited to 0.004 upon crushing of concrete. Write the answer in 5 decimal places only.