Floor Openings in Two-Way Slabs-Practical Design-A Supplement to Academics, Floor Openings in Two-Way Slabs (PDF)

Practical Design-A Supplement to Academics, Floor Openings in Two-Way Slabs (PDF)

Pdf Summary

The article from Concrete International, July 2006, provides guidance on designing openings in two-way slabs, whether for new construction or modifications to existing structures. The focus is on effectively analyzing and accommodating structural requirements, considering the location and size of slab openings to maintain integrity.<br /><br />Two-way slabs, including flat plates, flat slabs, and beam-supported slabs, are integral to multistory buildings. Flat plates, the simplest to construct, require column spacing of around 15 to 25 feet and slab thickness of 6 to 10 inches. Drop panels and two-way beam-supported slabs offer variations to accommodate different span needs.<br /><br />New construction allows architects and engineers to plan openings early, while modifications in existing structures often entail more complexity. ACI guidelines provide criteria for opening sizes based on column and middle strips, ensuring reinforcement is uninterrupted around openings. Factors such as flexural and shear strengths are critical considerations.<br /><br />For existing slabs, cutting openings should be cautious and typically involves core-drilling or sawing. Guidelines suggest avoiding openings at column intersections due to potential shear issues; the most structurally favorable spots are often less ideal architecturally. Openings in beam-supported slabs can often be larger, provided beam integrity is maintained.<br /><br />When reinforcement becomes necessary, methods like adding steel plates or fiber-reinforced polymer strips, installing steel beams, or applying collars around columns are suggested. These methods should prioritize maintaining system strength and consider fire protection.<br /><br />The expertise and experience from seasoned engineers are invaluable when implementing these measures to ensure both safety and functionality. The article emphasizes seeking professional advice, highlighting the importance of experience in navigating the technical complexities of designing and modifying slab systems.

Keywords

two-way slabs

slab openings

structural integrity

flat plates

beam-supported slabs

ACI guidelines

reinforcement methods

flexural strength

shear strength

core-drilling