Basic Prestressed Concrete Design Part 3: Code Requirements and Design Example-Basic Prestressed Concrete Design

Video Transcription

Video Summary

In this video, Sherry and Sergio discuss the design process for pre-stressed concrete beams. Sergio explains the load combinations and limit states required by HCI 318.14 for design. He introduces the concept of tension-controlled and compression-controlled members and discusses development length and transfer length for pre-stressed sections. Sergio also introduces a design example involving designing pre-tensioned interior RB28 beams in a rectangular building. He explains the preliminary design process using beam load tables from the PCI 8th edition design handbook.<br /><br />The speaker in the next video focuses on the design of a pre-stressed concrete beam. They explain the terms "superimposed dead loads" and "live loads" and discuss calculating an equivalent superimposed service load. The goal is to keep the beam uncracked and limit tension stresses to 7.5 root F'c. Moments induced by different load components are calculated, and the tension stress in the bottom fiber is determined. The speaker then calculates various pre-stress losses, including elastic shortening, creep, shrinkage, and relaxation losses. They check if the assumed number of strands is sufficient to meet the required pre-stressing force after accounting for losses. Beam design details are provided, including the assumed eccentricity of strands, number of strands, spacing, and stress in each strand. The speaker concludes by mentioning the need for further checks and designs for shear strength and ultimate strength.<br /><br />No credit is given in the video transcript for either video.

Keywords

pre-stressed concrete beams

load combinations

limit states

tension-controlled members

compression-controlled members

development length

pre-tensioned interior RB28 beams

beam load tables

superimposed dead loads

live loads

equivalent superimposed service load

uncracked beam