simple span. A symmetrical I section will be used with h = 1,000 mm, b = 500 mm, hf = 200 mm and bw = 200 mm. The member will be prestressed using Grade 1860 MPa low relaxation strands that are deflected from zero eccentricity at the support to 415 mm at the hold down points (located at 1/3 points of the total length of the beam). Time dependent losses are estimated to be 20% of the initial prestressing force, Pi = 1840 KN. 4. 1. Calculate the stress produced by Pi at the bottom of the beam during initial stage. 2. Determine the stress produced by Pe at top of beam during final stage
A post tensioned prestress beam is to carry a superimposed dead load of 9.3 KN/m and a service live load of 20 KN/m (considered sustained) on a 17 m simple span. A symmetrical I section will be used with h = 1,000 mm, b = 500 mm, hf = 200 mm and bw = 200 mm. The member will be prestressed using Grade 1860 MPa low relaxation strands that are deflected from zero eccentricity at the support to 415 mm at the hold down points (located at 1/3 points of the total length of the beam). Time dependent losses are estimated to be 20% of the initial prestressing force, Pi = 1840 KN. 4.
1. Calculate the stress produced by Pi at the bottom of the beam during initial stage.
2. Determine the stress produced by Pe at top of beam during final stage
3. Calculate the concrete flexural stress at critical section during final stage.
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