Civil Engineering

Cracked section analysis, the k & j method, beam geometry, and design from scratch. Interactive simulations and 3 fully worked problems.

Darwin, Dolan & Nilson 15th Ed. All 17 sections with analogies, canvas simulations, sliders, and 4 quick-check quizzes.

All 6 sections — design philosophy, ACI code logic, the 4 core RC assumptions, axial load behavior, and elastic beam bending — with interactive calculators and 3 quizzes.

Whitney stress block, beam failure modes, ρ limits, M_n calculator, R_n design aids — all 7 sections with live canvas diagrams, 4 quizzes, and interactive calculators.

A complete, executable spec for the ETABS model and the AutoCAD drawing set: grid and story data, sections, load patterns and the four required combinations, BNBC 2020 seismic and wind parameters, and three hand checks worked all the way to numbers. Every value re-derives from your own A, B and C.

What concrete is, how it’s made, what governs its strength, and why steel is its ideal reinforcing partner. Includes 6 interactive calculators and 6 canvas animations.

Plane sections, strain compatibility, crack formation, and the evolution of the stress block. The theoretical bedrock of every RC calculation.

Traffic flow theory, PHF calculator, Webster’s signal timing, delay & LOS, queue analysis, gravity model, and mode split — with animated simulations and 20+ practice problems.

The transportation engineering landing page — all lessons, key formulas (Webster’s C&sub0;, SSD, flow-density), and calculator index in one place.

Industry-standard ETABS software for modelling RC buildings and bridges. Covers beam analysis, bridge portal frames with AASHTO HL-93 loads, and multi-story frames with BNBC wind and seismic loads.

The five ideas every later chapter rests on: phase relations, classification, the effective stress principle, permeability and Mohr–Coulomb strength — plus a map of where each one reappears. Start here if anything downstream stops making sense.

Why a wall's soil pressure depends entirely on which way it moves. K₀, K_a, K_p, cohesion & tension cracks, groundwater effects, and a live calculator with pressure diagrams.

The three ways a wall loses — overturning, sliding, bearing failure — and how to prove none of them happen. Wall types, preliminary sizing, the middle-third rule, and a live factor-of-safety calculator with a scaled cross-section.

Why rain collapses slopes, and how to compute it. Infinite slopes with and without seepage, failure modes, OMS vs. Bishop’s method, a live critical-circle search, and the 2017 Chattogram landslides worked through with the real measured soil data.

One exam-style problem taken completely apart: a 12.7 m two-layer slope with seepage and a slip circle cutting both soils. Geometry set-up, the full slice table, one slice worked in detail, the iteration converging, and three sanity checks on the answer.

Why differential settlement, not total, breaks buildings. The three components, the e–logσ' curve, normally vs. overconsolidated clay, and how long it all takes — with a settlement calculator that picks the right case automatically.

Where every soil parameter in the other chapters actually comes from. Boring depth and spacing, sampler disturbance and area ratio, the full SPT correction chain, and CPT vs. vane shear — with a live N → N₆₀ → (N₁)₆₀ → φ' calculator.

Failure modes, Terzaghi's theory, the general bearing capacity equation with shape and depth factors, all three water table cases, and eccentric loading — with a calculator that shows which of the three terms is carrying the load.

When shallow foundations run out. Load transfer, critical depth in sand, the α method in clay, group efficiency and negative skin friction — with a calculator showing the tip/shaft split flip as you change soil type.

Will it stand up, and can equilibrium alone give the forces? The counting formulas for beams, frames and trusses, equations of condition, and the three ways a structure passes the count and still falls down.

The diagram a moving load demands. Building ILs for reactions, shear and moment from first principles, Müller-Breslau’s shortcut, and using them for point loads, partial UDLs and wheel trains — with a draggable unit load that traces the line as you move it.

Why a hanging chain, turned upside down, becomes an arch that carries its load in pure compression. Funicular shapes, the three-hinged arch and its horizontal thrust, normal thrust and radial shear at a section, and cable sag, tension and length — with a simulator that collapses the moment diagram to zero as you switch shapes.

A wheel train can stop anywhere, so the real question is where is it worst. Why reactions and shears climb in a sawtooth and drop off a cliff, the change formulas ΔR and ΔV, loads rolling on and off the span, and the average-load criterion for maximum moment — with a locomotive you can drive across a 60 ft girder.

Influence lines find the worst case at a section you choose; this finds the worst case in the whole beam. The moment envelope, absolute maximum shear, and the resultant-bisection rule for absolute maximum moment — including the signed eccentricity everyone drops and the short spans where the rule quietly fails — with a draggable wheel train and a live candidate table.