Analysis of assumptions made in design of reinforcement in Slender Reinforced Concrete (Tilt-Up) panels with openings

Abstract

This report uses and references (Analysis of Vertical Reinforcement in Slender Reinforced Concrete (Tilt-up) Panels with Openings & Subject to Varying Wind Pressures) (Bartels, 2010) to investigate the design philosophy and assumptions used in Section 14.8 of the ACI 318-08 (ACI Committee 318, 2008). The design philosophy and assumptions are analyzed to determine the applicability and accuracy of Section 14.8 of the ACI 318-08 (ACI Committee 318, 2008) to the design and analysis of slender concrete panels with openings. Special emphasis is placed on identifying and quantifying the degree of effect that each assumption has on the final design of the panel. These topics include stress distribution around openings, the effect of varying stiffness of the member on the P-delta effect, stiffness variations due to workmanship and tolerances, and the effect of axial load on the stiffness of the member. This is accomplished through the use of specially designed computer analyses that isolate an assumption or effect to determine its impact on the final design. This study shows that two-way effects are almost non-existant, the portion of the panel above the opening has very little effect on the P-delta effects, the code specified reduction in bending stiffness due to workmanship and tolerances appear to be appropriate, and the effective area of reinforcement overestimates the stiffness of the panel.