In-Depth

Engineering
Spotlight

Long-form analysis of the structures, systems, and innovations defining the future of structural engineering.

DWG.REF: LB-2026-0001
Engineering Spotlight

The Çanakkale 1915 Bridge: Redefining Long-Span Engineering

Completed in 2022 but now entering its third year of structural health monitoring, the Çanakkale 1915 Bridge in Türkiye holds the record as the world's longest suspension bridge at 2,023 metres. Its engineering legacy continues to influence long-span bridge design worldwide.

  • Main Span2,023 m
  • Tower Height318 m (above sea level)
  • Cable Diameter0.80 m (each main cable)
  • Structural Monitoring824 sensors active
  • Wind Design Speed95 m/s (3-second gust)
  • Design Life100 years

The Çanakkale 1915 Bridge, named to commemorate the centenary of the Gallipoli campaign, spans the Dardanelles strait between the Gelibolu and Lapseki districts of Türkiye. At 2,023 metres, its main span exceeds the previous record holder — Japan's Akashi Kaikyō Bridge — by 32 metres.

The structural system consists of twin steel box girder decks suspended from two main cables, each 0.80 metres in diameter and composed of 19,440 individual high-strength steel wires. The towers rise 318 metres above sea level, making them the tallest bridge towers in the world.

The bridge's aerodynamic profile was refined through over 4,000 hours of wind tunnel testing at the Politecnico di Milano's boundary layer wind tunnel. The twin box girder configuration, with a central gap of 2.5 metres, provides superior flutter resistance compared to the single-box designs used on earlier long-span bridges.

Real-time structural health monitoring is provided by 824 embedded sensors measuring strain, acceleration, temperature, displacement, and cable tension. The SHM data is now being used to calibrate next-generation digital twin models for the proposed Messina Strait crossing, making the Çanakkale Bridge a living laboratory for long-span bridge engineering.

DWG.REF: LB-2026-0002
Innovation Spotlight

Ascent MKE: Proving Mass Timber at 25 Storeys

Standing 86.6 metres tall in Milwaukee, Wisconsin, Ascent MKE became the world's tallest mass timber building upon completion in 2022. Three years of post-occupancy monitoring now confirms the structural system's performance under real-world conditions.

  • Height86.6 m (284 ft)
  • Storeys25 above grade
  • Primary StructureGlulam + CLT
  • Concrete CoreCentral stability core
  • Completion2022
  • Monitoring Period3 years active

Ascent MKE demonstrates that mass timber is not merely a boutique material for low-rise architecture — it is a viable structural system for high-rise residential construction. The 25-storey building uses a hybrid structural system combining glulam columns and beams with cross-laminated timber floor plates and a central reinforced concrete core for lateral stability.

The structural engineering, led by Thornton Tomasetti, required extensive fire engineering analysis to demonstrate that the exposed timber elements could achieve the required 2-hour fire resistance rating through char formation alone, without the need for encapsulation. This approach — known as "heavy timber" fire design — has since been codified in IBC 2021 and adopted in the 2026 preview edition.

Three years of post-occupancy monitoring has yielded valuable data on long-term creep behaviour, acoustic performance, and occupant comfort. Floor vibration measurements confirm that the CLT floor system meets AISC Design Guide 11 acceptance criteria for residential occupancy, addressing one of the primary concerns raised during the design phase.