Evening RC-I Summer

ARBA MINCH UNIVERSITYINSTITUTE OF TECHNOLOGY

CIVIL and URBAN ENGINEERING DEPARTMENT

ASSIGHNMENT-I FOR RC-IMax. Mark (30%)

PART-ONE Use Working stress Design Method (WSD) for the following problems

1. A rectangular beam made using concrete with C-30MPa and steel with S-400MPa has width b=600mm, total depth D=460mm, and effective depth d=395mm. The tensile

steel area As=4810.5mm2. Find the maximum service load moment that can be resisted by the beam section. Which allowable stress governs moment capacity of the beam section?

Use material strengths of:C-30MPa ( )

S-400MPa ( )

n=7

2. A singly reinforced rectangular beam is to be designed, with effective depth approximately 1.5 times the width, to carry a service live load of 21.9kN/m in addition to its own weight, on a 7.3m simple span with S-400MPa and C-30MPa, determine the required dimension of beam, and area of tension reinforcement by proportioning beam section as balanced section.Use material strengths of:

C-30MPa ( )

S-400MPa ( )



BY: SILENAT D. Page 1

3. A rectangular reinforced-concrete beam of width b=600mm is limited by architectural considerations to a maximum total depth D=400mm. The beam must carry a total service design load moment of Mw=110kN-m. Design the flexural reinforcement for this member, using compression steel if necessary. Allow effective cover of d |=50mm up to center of the bars from the compression or tension face of beam.Use material strengths of:

C-30MPa ( )

S-400MPa ( )

n=7 &

4. A reinforced-concrete floor system consists of parallel T-beams spaced 3m c/c and spanning 9.6m between supports. The 150mm thick slab is cast monolithically with T-beams webs having width bw=350mm and total depth, measured from the top of the slab, of D=700mm. The effective depth will be taken 75mm less than the total depth. In addition to its own weight, each T-beam must carry a super imposed dead load of 2.4kN/m2 and service live load of 10.8kN/m2. Assume weight of floor finish about 1kN/m2. Determine the required tensile steel area of interior T-beam. Assume T-beams are simply supported. Use material strengths of:

C-30MPa ( )

S-400MPa ( )

n=7 &



PART-TWO Use Limit State Design Method (LSD) for the following problems


1. A rectangular, tension-reinforced beam is to be designed for dead load of 7.3kN/m plus self weight and service live load of 17.5kN/m, with a 6.7m simple span. Material strengths will be S-400MPa and C-25MPa for steel and concrete, respectively. The total beam depth must not exceed 400mm. Calculate the required beam-width and tensile steel area by proportioning beam section using maximum reinforcement ratio

of under-reinforced section ( for 0% redistribution of elastic

moments). The effective depth may be assumed to be 63.5mm less than the total depth of beam.

Use: C-25MPa ( )

S-400MPa ( )

Maximum design constants for single reinforcement

2. A rectangular reinforced-concrete beam of width b=600mm is limited by architectural considerations to a maximum total depth D=400mm. The beam must carry a total factored design load moment of . Design the flexural reinforcement for this member, using compression steel if necessary.

Use: C-30MPa ( )

S-400MPa ( )

Maximum design constants for single reinforcement



3. A reinforced-concrete floor system consists of parallel T-beams spaced 3m c/c and spanning 9.6m between supports. The 150mm thick slab is cast monolithically with T-beams webs having width bw=350mm and total depth, measured from the top of the


slab, of D=700mm. The effective depth will be taken 75mm less than the total depth. In addition to its own weight, each T-beam must carry a super imposed dead load of 2.4kN/m2 and service live load of 10.8kN/m2. Determine the required tensile steel area of interior T-beam. Assume T-beams are simply supported. Use EBCS-2/95 code provision to determine effective width of flange.Assume weight of floor-finish about 1kN/m2. Use 30 bars for longitudinal reinforcement.

Use: C-30MPa ( )

S-400MPa ( )

4. A rectangular beam has a width 300mm and total depth of 480mm. It is reinforced with 4-35 bars (As=3848.45mm2) in one layer placed in tension zone. Determine the ultimate moment capacity of this beam section.

Use: C-25MPa ( )

S-300MPa ( )

Maximum design constants of under reinforced section for 0% redistribution of elastic moments are , &


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Evening RC-I Summer