Structural Dynamics
Cumulative tutorials
Multi-part problems that span several modules, where the hard part is deciding which idea applies.
A lesson question tests the idea just taught, with the method fresh and the context given. These are different. Each one sets a situation and expects you to decide what applies, then carry one answer into the next part — which is what practice actually looks like.
There are 20 tutorials and 80 parts between them. Every numeric answer is recomputed from the course’s calculation library by a test before publication, so a wrong answer cannot be carried silently from one part into the next.
01A plant platform that shakes
4 parts
Decide whether a dynamic problem exists at all, then quantify it.
M1M3M4M5
02Reading a free-decay test
4 parts
Turn a measured decay trace into the damping and the damper the model needs.
M3M4M5
03Isolating a machine that is already installed
4 parts
Transmissibility decides the mounts, and the answer is softer, not stiffer.
M5M6
04A pressure pulse on a wall panel
4 parts
The duration relative to the period decides everything about a short load.
M6M7
05Choosing a time step, and proving it
4 parts
Stability, accuracy and the demonstration that the step is adequate.
M4M8
06A two-storey frame from first principles
4 parts
Two masses, two stiffnesses, two frequencies — and a check that they are right.
M9M10
07Lumped or consistent mass
4 parts
Two defensible mass models that bracket the exact answer from opposite sides.
M2M10
08Three storeys: modes and mass
4 parts
Read a modal output and decide how many modes the analysis actually needs.
M10M11
09Fitting Rayleigh damping, and checking it
4 parts
Anchor the damping at two frequencies, then find out what every other mode received.
M11M12
10From modes to base shear
4 parts
Turn a modal output and a spectrum into a force, then check it is credible.
M11M13M14
11SRSS or CQC
4 parts
When modal periods are close, the independence SRSS assumes is not there.
M11M14
12What a spectrum analysis does not tell you
4 parts
The same building, the same record, two methods, and the gap between them.
M14M15
13Setting up a time-history run
4 parts
Pick the step from the right mode, count the cost, and demonstrate convergence.
M8M11M15
14A frame that is allowed to yield
4 parts
Ductility demand, the strength it buys, and the displacement it does not reduce.
M5M16
15Yield, or isolate
4 parts
Two ways to survive the same earthquake, and what each does to the building.
M16M17
16Sizing an isolation system
4 parts
From a target period to a moat width, and the factor of two in between.
M14M17
17A damper retrofit
4 parts
Size a damper, place it by modal drift, and say what it added.
M11M18
18Designing a tuned mass damper
4 parts
Choose the mass, and everything else follows — including the sensitivity.
M6M19
19Auditing an analysis you did not run
4 parts
Six checks in order, on an output that looks entirely normal.
M11M14M20
20One building, end to end
4 parts
The whole course applied to a single structure, and the decision it leads to.
M11M14M16M17M18M19