The Turkish Building Earthquake Code (TBDY 2018) came into force on 1 January 2019 and introduced special rules for tall buildings. One of them is the installation of a structural health monitoring (SHM) system in certain tall buildings: the building's response to earthquakes and wind is measured continuously with accelerometers, and the data is transmitted to AFAD, Türkiye's Disaster and Emergency Management Authority, in real time.
- Scope: buildings taller than 105 m in Earthquake Design Class (DTS) 1 or 2.
- Legal basis: TBDY 2018, special rules for tall buildings, article 13.8.1.
- Implementation rules: AFAD's Structural Health Monitoring System Implementation Directive (in force since 9 January 2020).
- Responsible party: the building owner who obtains the occupancy permit; installation and maintenance are the owner's responsibility.
Which buildings are covered?
The requirement applies to buildings that fall under the TBDY 2018 definition of tall buildings, are in Earthquake Design Class 1 or 2 and are taller than 105 metres. The Earthquake Design Class depends on the seismic hazard at the site and the building's occupancy class; buildings in high-hazard regions fall into these classes. The safest way to check is the DTS value in the project's design reports.
What does the directive require?
AFAD's directive requires accelerometer data to be transferred simultaneously to the Structural Health Monitoring Centre (YSİM) within AFAD, so that damage threatening safety can be detected quickly after an earthquake from the building's dynamic properties. Key technical requirements include:
- Accelerometers must be synchronised and connected to a digital recorder with at least 24-bit resolution and GPS time stamps.
- The system must record continuously and transmit data in real time via internet, modem, satellite or a similar channel.
- It must run autonomously for at least one week during power or communication outages; equipment must be protected against fire and impact.
- Wired connections are preferred, with cable runs preferably under 100 m; wireless systems must demonstrate that they do not lose synchronisation.
- Recorders must support continuous and triggered modes. The default trigger level is 0.005 g (5 gal); a triggered record starts 300 seconds before and ends 600 seconds after the event.
Source: AFAD, Structural Health Monitoring System Implementation Directive (09.01.2020), articles 1–6.
When should the system be planned?
The cleanest and most economical approach is to plan the sensor layout during design and structural construction, when cable routes, the recorder room and power lines can easily be built into shafts and slabs. Retrofitting a completed building can disturb finishes, lengthen cable runs and raise costs.
Beyond compliance: what is the data for?
The directive requires the data to be collected and sent to AFAD; the real value lies in interpreting it. With a well-designed system you get:
What Motusmec does
Motusmec is a structural and earthquake engineering firm at Boğaziçi University Technopark, Istanbul. For tall buildings we provide:
- Sensor layout design and a system that meets the directive,
- Installation and commissioning, including data transfer to AFAD,
- 24/7 monitoring with our in-house software, developed with TÜBİTAK-TEYDEB support: dynamic identification, post-earthquake condition assessment and fatigue life estimation,
- Long-term performance reports and automatic event-driven reports.
Our team published long-term monitoring experience from three instrumented tall buildings in Istanbul, including measurements before, during and after an Mw 5.7 earthquake, in the Bulletin of Earthquake Engineering. The AFAD-funded research project on a structural health monitoring standard for tall buildings (UDAP-G-17-01) was carried out at Boğaziçi University.
Frequently asked questions
Is monitoring mandatory for buildings under 105 m?
The TBDY 2018 requirement applies to buildings taller than 105 m in Earthquake Design Class 1 and 2. It is not mandatory for lower buildings, but it is increasingly installed voluntarily in hospitals, data centres, base-isolated buildings and critical public buildings so that decisions can be made quickly after an earthquake.
Who is responsible for installation and maintenance?
Under AFAD's directive, the building owner who obtains the occupancy permit must arrange and pay for the installation and maintenance of the accelerometers and is accountable to AFAD.
Where does the data go?
Accelerometer data is transferred in real time to the Structural Health Monitoring Centre (YSİM) within AFAD and is processed under Türkiye's Personal Data Protection Law No. 6698.
Can a system be retrofitted to an existing tall building?
Yes. In a retrofit, sensor locations, cable routes and the recorder location are planned around the existing architecture. For new projects, the best time is the structural construction phase.
What if a system is installed but nobody interprets the data?
The directive's minimum requirement is to collect and transmit the data. Deciding whether a building is safe and usable after an earthquake requires regular analysis; Motusmec can connect to existing systems and take over analysis and reporting.