Control of Deflection in Concrete Structures
|Publication Date:||1 January 1995|
Design for serviceabiiity is central to the work of structural engineers and code-writing bodies. It is also essential to users of the structures designed. Increased use of high-strength concrete with reinforcing bars and prestressed reinforcement, coupled with more precise computer-aided limit-state serviceability designs, has resulted in lighter and more material-efficient structural elements and systems: This in turn has necessitated better control of short-term and long-term behavior of concrete structures at service loads.
This report presents consolidated treatment of initial and time-dependent deflection of reinforced and prestressed concrete elements such as simple and continuous beam and one-way and two-way slab systems. It presents current engineering practice in design for control of deformation and deflection of concrete elements and includes methods presented in Building Code Requirements for Reinforced Concrete (AC1 318) plus selected other published approaches suitable for computer use in deflection computation. Design examples are given at the end of each chapter showing how to evaluate deflection (mainly under static loading) and thus control it through adequate design for serviceability. These step-by-step examples as well as the general thrust of the report are intended for the non-seasoned practitioner who can, in a single document, be familiarized with the major state of practice approachs in buildings as well as additional condensed coverage of analytical methods suitable for computer use in deflection evaluation. The examples apply AC1 318 requirements in conjunction with PCI methods where applicable.
The report replaces several reports of this committee in order to reflect more recent state of the art in design. These reports include AC1 435.2R, Deflection of Reinforced Concrete Flexural Members, AC1 435.1R, Deflection of Prestressed Concrete Members, AC1 435.3R, Allowable Deflections, AC1 435.6R, Deflection of Two-way Reinforced Concrete Floor Systems, and AC1 435.5R, Deflection of Continuous Concrete Beams.