Which countries require structural monitoring of buildings

Two distinct functions, and where they get confused

The distinction that makes the international picture readable is between two functions that regulatory texts treat separately. In English each carries its own name in the codes themselves, and the conflation arises in commercial literature rather than in legislation.

Earthquake recording instrumentation consists of accelerometers with dataloggers and a common time reference, installed to record the seismic input and the response of the structure. It serves three declared purposes: improving technical codes, providing diagnostics after an event, and supporting occupancy decisions. The instrument records when the earthquake arrives.

Continuous structural monitoring, referred to as SHM, is a broader set that covers ambient vibration, inter-storey drift, strain and tilt measurements, with possible degradation detection and internal alerting functions. The instrument observes the structure through the years in which nothing happens.

The picture by jurisdiction

The two cases where the requirement covers continuous monitoring

Türkiye is the most advanced case. The seismic code for buildings, the Türkiye Bina Deprem Yönetmeliği of 2018, includes a section dedicated to structural health monitoring systems, requiring compliance with a guideline issued by the national disaster and emergency management authority. The requirement is circumscribed: it applies to buildings above 105 metres in height in the most severe seismic design classes, and the guideline sets a minimum number of channels that grows with height, from 16 to 32. The official communication from that authority specifies that the system must allow real-time storage and management of the records by the agency and by the building owner alike.

This architecture, with the authority and the owner both accessing the data in real time, is rare in building codes, and it is what makes the Turkish case a reference.

China has a national technical code for the monitoring of structures, GB 50982-2014, which includes tall buildings among its objectives. The case does require qualification. A single clause of the code, 3.1.8, is marked as a mandatory provision, while the remainder of the text is recommendatory: presenting China as a country with a general requirement for continuous monitoring would be inaccurate. The text also covers bridges and other typologies, so applying it to buildings requires selecting the relevant sections.

How the requirement is constructed in the United States

The United States is the territory with the most granular regulation, and it offers the most instructive variety.

Los Angeles writes the requirement directly into the city code, applying it to buildings for which permits were issued after 1 July 1965.

San Francisco pairs the code with a set of administrative procedures detailing installation, monitoring and data reporting, both for required instrumentation and for instrumentation installed voluntarily, and invokes the adoption of Appendix L. The same geometric thresholds as Los Angeles govern its application.

Seattle introduces a criterion that narrows the scope intelligently: alongside the geometric thresholds, the requirement is triggered when a site seismic hazard threshold is exceeded, avoiding installations where hazard is low. The text of Appendix L specifies that its application requires an explicit reference in the adopting ordinance.

Oregon has introduced an alternative mechanism that deserves attention: in place of installation, payment of the equivalent cost into a dedicated public fund is permitted, administered by the state, which retains the data and makes it available on request. It is a model that moves installation from individual buildings to points chosen by the agency.

The federal public client operates by a route other than the building code: the General Services Administration's P100 standard requires that defined federal buildings be equipped with accelerographs approved by the national geological survey. It is a requirement that originates in procurement specifications rather than in law, and it acts on procurement.

The thresholds and requirements that recur everywhere

The convergence across different jurisdictions is notable, and it concerns three elements.

The trigger thresholds. The pairing of more than 6 storeys with at least 60,000 square feet of aggregate floor area, or more than 10 storeys regardless of floor area, appears identically in Los Angeles, San Francisco, Seattle and Oregon. The Philippines and Pakistan use a seismic zone criterion instead.

The number and distribution of instruments. At least three measurement points, placed at the lowest level, at mid-height and near the top. Distribution along the vertical is what makes it possible to reconstruct inter-storey drift and the torsional component of the response.

Synchronisation. Common triggering and timing between instruments is a recurring requirement. Without a shared time reference, comparison between different floors loses meaning.

Where the requirement is to assess rather than to instrument

A distinct regulatory model exists, in which the law requires knowledge of the condition of a building without prescribing any instrument. Italy is the documented case.

No requirement to install measuring instruments on buildings applies in Italy. Ordinance of the President of the Council of Ministers 3274 of 2003 introduced a mandatory seismic vulnerability assessment for buildings and works of strategic and public interest, both public and private, in every seismic zone. The assessment is mandatory, and any resulting intervention remains subject to the availability of funds.

A public permanent monitoring network does exist, the Osservatorio Sismico delle Strutture run by the Civil Protection Department, which instruments 173 publicly owned structures with accelerometers, among them 160 buildings and in particular 70 schools, 46 town halls and prefectures and 29 hospitals. Its scope covers buildings selected by the Department, so it operates as a public programme rather than as a general requirement.

What this picture tells a building owner

Three conclusions follow from the comparison.

Where the requirement exists, it covers the earthquake. The provisions concern the recording of the event and the availability of the data afterwards. They cover the moment at which the structure is loaded, and leave uncovered the years in which the structure ages.

The design criteria are already written, even where the requirement is absent. The distribution of instruments along the vertical and synchronisation between measurement points recur in every jurisdiction that has legislated, with a convergence that crosses continents and different regulatory traditions. They are criteria usable as a design reference anywhere, including in the absence of a local requirement.