#### Event Title

STR-855: INSTANTANEOUS DEFLECTIONS OF CONCRETE SLABS COMPUTED USING DISCRETIZED ANALYSIS

#### Location

London

#### Event Website

http://www.csce2016.ca/

#### Description

Excessive deflection of concrete floor slabs is a recurring serviceability problem (Gilbert 2012, Stivaros 2012). Current practice is to compute deflections using either a single-element idealization, where an average effective moment of inertia is assigned to the entire member, or a discretized analysis, where the member is idealized as discrete elements with unique effective moments of inertia. There are two equations available for calculating the effective moment of inertia, developed by Branson (1965) and by Bischoff (2005). Branson originally proposed two equations for effective moment of inertia, a 3rd-power equation for use in a single-element idealization and a 4th-power equation for use in a discretized-element idealization. Bischoff has proposed a single equation, based on a correct mechanical model, for use in a single-element idealization only. The research summarized in this paper investigates suitable modifications to Bischoff’s Equation for use in a discretized analysis. Simply supported members with various reinforcement ratios and live- to dead-load ratios are explored. Comparisons to experimental data are made to determine which deflection calculation procedure provides results closest to those observed.

STR-855: INSTANTANEOUS DEFLECTIONS OF CONCRETE SLABS COMPUTED USING DISCRETIZED ANALYSIS

London

Excessive deflection of concrete floor slabs is a recurring serviceability problem (Gilbert 2012, Stivaros 2012). Current practice is to compute deflections using either a single-element idealization, where an average effective moment of inertia is assigned to the entire member, or a discretized analysis, where the member is idealized as discrete elements with unique effective moments of inertia. There are two equations available for calculating the effective moment of inertia, developed by Branson (1965) and by Bischoff (2005). Branson originally proposed two equations for effective moment of inertia, a 3rd-power equation for use in a single-element idealization and a 4th-power equation for use in a discretized-element idealization. Bischoff has proposed a single equation, based on a correct mechanical model, for use in a single-element idealization only. The research summarized in this paper investigates suitable modifications to Bischoff’s Equation for use in a discretized analysis. Simply supported members with various reinforcement ratios and live- to dead-load ratios are explored. Comparisons to experimental data are made to determine which deflection calculation procedure provides results closest to those observed.

http://ir.lib.uwo.ca/csce2016/London/Structural/36