Problem 2: The section of a prestressed double-tee concrete floor joist is shown is FIGURE-1. The prestressing force in each tee is 750 kN. Unit weight of concrete is 23.5 kN/m³. Simple span L=8m. The properties of thesection are: b Effective slab width, b = Area, A Moment of Inertia, I yı y2 ys - Service loads on the floor Dead Load Live Load 2.5 m 220,000 mm² 1890x10 mm 90 mm 270 mm 75 mm 2.5 kPa 6.0 kPa У1 y2 SHIVAM a.) Determine the initial stress at the bottom fibers, due to prestressing force alone in MPa. b.) Determine the stress at the bottom fibers due to service load and prestress force. Assume that there is a loss of prestress of 20% at service loads in MPa. c.) Calculate the additional load (kPa) the floor could carry so that the stress at the bottom fibers at midspan is zero.

Problem 2: The section of a prestressed double-tee concrete floor joist is shown is FIGURE-1. The prestressing force in each tee is 750 kN. Unit weight of concrete is 23.5 kN/m³. Simple span L=8m. The properties of thesection are: b Effective slab width, b = Area, A Moment of Inertia, I yı y2 ys - Service loads on the floor Dead Load Live Load 2.5 m 220,000 mm² 1890x10 mm 90 mm 270 mm 75 mm 2.5 kPa 6.0 kPa У1 y2 SHIVAM a.) Determine the initial stress at the bottom fibers, due to prestressing force alone in MPa. b.) Determine the stress at the bottom fibers due to service load and prestress force. Assume that there is a loss of prestress of 20% at service loads in MPa. c.) Calculate the additional load (kPa) the floor could carry so that the stress at the bottom fibers at midspan is zero.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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