Title:
Deflection Estimation of Reinforced Concrete Flat Plates Using ACI Method
Author(s):
Tahsin Reza Hossain, Robert Vollum, and Salah Uddin Ahmed
Publication:
Structural Journal
Volume:
108
Issue:
4
Appears on pages(s):
405-413
Keywords:
construction loading; deflection; flat plate; serviceability
DOI:
10.14359/51682980
Date:
7/1/2011
Abstract:
Building codes provide minimum thickness guidelines for two-way slabs to ensure that deflections are not excessive. Thinner slabs are allowed if calculated deflections are found to be acceptable, but there are relatively few reliable deflection measurements in buildings that can be used to assess the accuracy of deflection prediction methods. The construction of the seven-story in-place reinforced concrete frame building in the Building Research Establishment Large Building Test Facility in Cardington, UK, presented a unique opportunity to assess deflection prediction methods for flat plates because deflections, material properties, and loadings were measured. The first two authors have previously shown that long-term deflections were governed by short-term construction loading at Cardington. This paper proposes a refinement to the ACI 318 deflection multiplier approach, which accounts for the effect of short-term construction loading on deflections. The method is validated with deflection data from Cardington and six slabs tested by the second author.