Title: Equivalent Beam Model for Flat-Slab Buildings:Part I: Interior Connections

Author(s): Y. H. Luo and A. J. Durrani

Publication: Structural Journal

Volume: 92

Issue: 1

Appears on pages(s): 115-124

Keywords: beams (supports); flat concrete slabs; frames; lateral pressure; loads (forces); reinforced concrete; stiffness; Design

DOI: 10.14359/1534

Date: 1/1/1995

Abstract:
Flat-slab buildings are commonly modeled as two-dimensional frames to calculate lateral drift, unbalanced moments, and shear at slab-column connections. For gravity loads, the slab-column frames are analyzed using equivalent-column approach, while equivalent beam approach is typical for lateral loads. The equivalent beam approach is convenient for computer analysis, but no rational procedure exists for determining the effective width of floor slabs. At present, the determination of the equivalent slab width and its stiffness is a matter of engineering judgment. To account for cracking, overly conservative assumptions are made regarding the stiffness of the slab. A rational approach is therefore needed to realistically estimate the equivalent slab width and its stiffness for unbalanced moment and lateral drift calculations. Based on the test results of 40 interior connections, an equivalent beam model is proposed in which columns are modeled conventionally, and the effective slab width is determined as a function of column and slab aspect ratios and the magnitude of the gravity load. The proposed approach is verified with selected experimental results and is found to be practical and convenient for analyzing flat-slab buildings subjected to gravity and lateral loading.