Shelle Parsons If you’ve ever stood on a post-tensioned slab during stressing operations, you know the moment of truth: the jack gauge reads one number, but does the elongation match? Getting the elongation calculation right is the bridge between design intent and field verification — and it’s one of the most nuanced calculations in structural engineering. Why … Read more
Punching shear is one of the most critical failure modes in reinforced concrete flat slabs. It occurs at columns and concentrated loads where the slab can “punch through” in a cone-shaped pattern — and when it fails, it fails suddenly. Here’s how to check it properly using ACI 318-19, step by step. What Is Punching … Read more
By FicientDesign • April 15, 2026 • 8 min read Every structural engineer learns the parallel axis theorem in school. But here’s what the textbooks gloss over: the theorem only helps you when members are actually connected. Stack three 2x4s on top of each other without fastening them, and you don’t get a deeper beam. … Read more
By FicientDesign • April 15, 2026 • 12 min read Base plate design is one of those topics that looks straightforward until you actually sit down to do it. Between bearing pressure limits, cantilever bending in two directions, and the anchor bolt capacity checks required by ACI 318-19, a routine column-to-footing connection can eat up … Read more
Wind Resistance & Coefficients of Drag Drag is the force that resists an object moving through a fluid (air, water, anything). It’s governed by one of the most important equations in fluid mechanics: Fd = ½ρv²CdA Breaking It Down ρ (rho) — fluid density (air at sea level ≈ 0.00238 slug/ft³ or 1.225 kg/m³) v² … Read more
Modulus of Elasticity — Why Stiffness ≠ Strength Here’s a fact that surprises many engineers early in their career: 36 ksi yield steel and 36 ksi yield aluminum have the same strength — but the steel is 3× stiffer. Strength and stiffness are completely independent properties, and confusing them leads to bad designs. What Is … Read more
Why You Can Drill a Big Hole in an I-Beam Web It seems counterintuitive: you can cut a large hole in the middle of a steel beam’s web and barely reduce its load-carrying capacity. But once you understand where stress lives in a beam, it makes perfect sense. Where Bending Stress Lives When a beam … Read more
Moment of Inertia — Why a 2×6 on Edge is 13× Stiffer If stress tells you whether something will break, moment of inertia tells you whether it will bend. It’s the single most important concept in structural design, and it explains why beams are shaped the way they are. The Formula That Matters For a … Read more
Stress — Compressive, Tensile, and Shear Stress is the internal force per unit area inside a material when external forces are applied. It looks like pressure (same units — psi, MPa), but it describes what’s happening inside the material, not on its surface. The Three Types σ = F / A Tensile Stress (pulling apart) … Read more
Pressure in Engineering — And Why It Gets Confusing Pressure seems simple: force per unit area. But between psi, bar, atm, Pascals, inches of mercury, feet of water head, and absolute vs gauge — it’s one of the most unit-confused concepts in engineering. The Basics P = F / A 1 psi = 1 pound … Read more