"They know that the north portion of the pool deck slab collapsed into the basement prior to the global collapse of the eastern part of the tower."
"Corbels can'tilever, meaning move laterally when they have too much overhang for the loads imposed upon them."
"Whilst the carpet may seem to be standing up on its own, this is an illusion. A sturdy 0.2-inch steel reinforcement provides a hidden support for an authentic handmade Persian rug."
"The foundation is kind of screwed, and that's why it leans four degrees."
"As we have seen, the biggest buildings can be strikingly beautiful and they have to be structurally brilliant."
"The first ever skyscraper... the Home Insurance Building."
"This minimalist design stems from the tower's single concrete column, which is supported by a huge net of steel cables to keep it secured in place."
"Trusses allow us to create strong structures while using materials in a very efficient and cost-effective way."
"This must be some major support for a drawbridge or a bridge."
"Triangles are always the structurally strongest shapes to work with."
"There's nothing more mind blowing than a good optical illusion."
"Science equations for how webs could be built and fully functional."
"Nobody's going to get their foot or any load on that cantilevering portion of the decking to cause the opposite side to lift up."
"As hangs the flexible line so but inverted will stand a rigid arch."
"Unreinforced masonry needs a good structural form."
"The endurance limit is a big deal to us because the most common way to do design with steel is to just decide that you are going to try to make your part last forever."
"It's quite hard as a structural engineer to work out how that works as a structural form."
"The depth or past height of the wall is also an impressive legacy."
"Bearing walls built around the building and a floor that's built of metal deck with concrete on top of it."
"Once the bridge bins were finally rested into place, erecting the rest of the structure was less stressful."
"The structural design series is similar to the aerodynamic terminology series I did."
"The Twin Towers were designed that if something was to happen to them that they would collapse like this, they would go straight down rather than just tipping over and killing everyone."
"Beams are used to carry loads in a whole range of different structures, and it’s important for engineers to be able to predict how much a beam will deflect when loads are applied to it."
"The moment-curvature equation is the first step towards being able to calculate the deflection of a beam, since it gives us information about how the beam will deform for an applied bending moment."
"It's going to give us a better representation of the final stress state in our structure."
"Understanding structural behavior is the key to understanding the structural codes."
"If I mold the whole thing into a shape and suck the air out, it maintains its shape, making a solid mass."
"The concrete surrounding these pipes would have been subjected to higher stress concentrations."
"The immediate aftermath of the collapse of the Twin Towers... the hours after, the days, and then the months, and the response by structural engineers... emotional and very personal as well as professional and intellectual."
"Other than axial forces, a member can be subjected to other external loads that can cause it to twist, bend, and shear."
"The erection of main tower large blocks is a critical stage in bridge construction demanding precision and expertise."
"Python is really a game changer for structural engineers."
"I wanted a really open-concept home, I wanted a really high ceiling in one part of my house and I could span the full 48 feet with my truss with no load-bearing walls."
"The relationship between load, shear, and moment is the graphical approach that we can use to construct shear and moment diagrams."
"Remember, you draw the beam, get your reactions, and then to draw the shear diagram you just follow the load pattern to go from zero to zero."
"You can model just about any structural vibration as the summation of the individual contributions of each natural mode."
"When we talk about structures and structural behavior, we're not just talking about code, but about physics and why things are the way they are."
"We really need to start thinking in a completely new way about how we should design structures."
"If the force demand at the factored load is smaller than the force capacity for all of the components of the structure, then your performance is satisfactory."
"The deeper the beam is, the lower those forces are going to be."
"As we allow the structure to yield and soften, we move down that period-dependent region and reduce the acceleration accordingly."
"Buckling is a sudden change in shape of a structured component under load."
"His experience includes the design of new structures, retrofit of existing buildings, nonlinear seismic analysis, and the development of new structural systems."
"The seismic load resisting system includes the vertical frames."
"The backstay effect is very important for taller buildings."
"We need to consider the amplified seismic load, Omega sub o times E."
"The behavior factor defines the baseline strength, the strength of the flexural element we are using as a fuse in the capacity design."
"Short columns usually fail by compression or shear failure, whereas long columns fail mainly by buckling under the compression force."
"If the footing is flexible, then we have anticipated the settlement will not be uniform."
"The intersection of demand curves and capacity curves near the elastic limits represent that the structure has good resistance and capacity against earthquake loading."
"It's important we accurately model the structural system in order to accurately capture the true behavior."
"Shear and moment relationships are easy; displacements or deflections are where things get a bit more complex."
"Natural frequency is a system property which depends on mass of the structure and stiffness of the structure."
"These test procedures have been found to provide a structural product that is adequate for normal structural design criteria."
"Dead loads are anything that is attached to the structures permanently; they are structural members like columns, beams, roofing, trusses, and so on."
"Live loads are not permanent in that structure. For example, office workers – most of the time of the day they are in the office, at night they are not."
"Environmental loads are the loadings from our environment, like wind load, rain, and earthquakes, which are obviously unpredictable."
"The weight of the concrete slab plus the weight of the steel beam plus the weight of the special wall – all you have to do is summation of gamma times area."
"If you are designing a structure, more if you have a symmetrical structure, it is easier for you to compute for the loadings, reactions, etc."
"The ultimate loading you need to consider is the load combination because there are cases where a structure is carrying those loadings at the same time."
"Negative moment because it's a frowning face; positive moment because it's a happy face."
"The steel can still sustain the tensile stress brought about by the applied moment."
"A section with a higher shape factor gives a longer warning before collapse."
"The force at any level in mode n is going to be equal to the spectral acceleration at that mode multiplied by the mass at that level."
"If the ultimate applied moment on the section is greater than this maximum, it means in this case the section will require compression steel."
"Dead loads are those loads that will be on this building permanently."
"After yield point, our structure has capacity to resist the earthquake, making our structure earthquake resistant."
"So before assigning the loads, let's look at some theory of the loads and classifications."
"A structure indeterminate does not mean that we cannot find out support reactions or internal forces in any member."
"Wherever the shear force diagram crosses zero is where we should see our peak moments in our structure."
"The bending moment is maximum where the shear force is zero."
"For just rigid plane truss, m equals twice j minus 3, where m equals number of members and j equals number of joints."
"Let's continue calculating the wind load on our structure."
"The larger beta is, the safer our structure is."
"If we add up all the loads and compare that to the resistances, as long as the resistance is bigger than the loads, then our structure is safe."
"Lateral load design typically gets harder as the building gets taller."
"The equivalent slenderness ratio lambda E is given as lambda E is equal to square root of k1 plus k2 into lambda vv square plus k3 into lambda phi square."
"It's great to see that the strut and tie method has been elevated to its own chapter; it's in the code now instead of in an appendix."
"When we're dealing with beams, one of the big things we need to worry about is its unbraced length."
"For a structure to be internally stable, it must have no releases and no closed loops."
"The sum of all moments relative to a point must be equal to zero for a structure to be stable."