London Bridge Construction – Foundations, Steel & Granite

Bottom line: The bridge is a hybrid of steel machinery wrapped in masonry. Foundations were sunk with cofferdams, the superstructure rose in riveted steel, then granite and Portland stone delivered the iconic Gothic Revival skin.

Construction Phases at a Glance

Cofferdams created dry work boxes in the Thames, enabling pier construction without halting river life.

Materials & Methods

• Riveted Steel frames carry true loads; masonry expresses style and protects.
• Granite & Portland Stone resist spray and pollution; dressed with Gothic detailing.
• Timber & Temporary Works staged lifts and scaffolded access.

Logistics

• Barges ferried stone, steel, and equipment along the Thames.
• On-site yards prefit steel elements to minimize river-blocking time.

Practical Timeline (Indicative)

Image Highlights

Geotechnics & Foundations

The riverbed comprised alluvium over gravels, transitioning to stiff London Clay. Engineers sank cofferdams and used caissons to reach strata with adequate bearing. Continuous pumping maintained a dry work face.

Foundation Snapshot

• Target stratum: compact gravels / London Clay cap where practical.
• Bearing capacity: sized for tower and bascule reaction envelopes.
• Settlement control: staged concrete pours and monitoring benchmarks.

Riveting & Erection Methods

Steel plates and angles were shop-fabricated, trial-fitted, then floated by barge for on-site riveting. Crews used pneumatic hammers; hot rivets were inserted and bucked to form permanent ductile joints.

Tip: Riveting distributes stress and resists loosening from vibration better than many early bolted connections.

Stone Sourcing & Cladding Logic

• Granite plinths resist splash, abrasion, and impact.
• Portland stone gives the Gothic Revival language and weathering character.
• Anchors tie the cladding to a steel backup, keeping loads honest to the frame.

People, Safety, and Logistics

• Multi-trade workforce: divers, riggers, fitters, masons, riveters, carpenters.
• Safety practices evolved: staging, lifelines, banksmen on barges.
• Logistics cadence: tidal windows dictated delivery and lift sequences.

Numbers at a Glance

FAQ

Why not build fully in stone? The moving roadway demands a steel machine; stone forms the civic skin, not the mechanism.

Were tides a major challenge? Yes—planning respected tide tables for cofferdam work and barge movement.

Bottom Line

London Bridge (Tower Bridge) is engineering wrapped in architecture: steel for movement, stone for memory.