Monitoring structural movements in parking garages, cellars and basements
In these enclosed or semi-enclosed spaces, site access is often constrained by the daily use of the premises, which makes monitoring more difficult. How can the evolution of these movements be tracked in such an environment?
Parking garages, cellars and basements: indoor areas with restricted access
Underground parking garages, cellars and basements are spaces located below ground level and integrated into the building structure.
Underground parking garages
Underground parking garages are mainly used for vehicle parking. They are characterised by large open volumes. Circulation is organised around ramps and dedicated lanes for vehicles and users.
The daily operation of parking garages, linked to their use, dictates the periods during which observations can be carried out.
Cellars and storage rooms
Cellars and storage rooms are premises generally dedicated to storage. They often consist of compartmented spaces, located below ground level, accessed through the building’s internal circulation.
Technical basements
Technical basements house the networks and equipment required for the building’s operation. The presence of ducts, pipes and technical installations can restrict access to certain areas, particularly around load-bearing elements.
Confined spaces and restricted spaces: specific access conditions in buildings
In the building industry, underground parking garages, cellars and basements are frequently referred to as confined spaces or restricted spaces due to their access and circulation conditions.
These indoor areas generally have few, sometimes narrow, access points and limited internal pathways. The presence of vehicles, networks, equipment or partitions reduces movement possibilities and complicates site operations.
In this type of configuration, interventions must be compatible with the use of the premises, which limits the number of on-site observations that can be carried out.
Structural movements observed in parking garages and basements
Structural movements can affect load-bearing concrete elements in the underground parts of the structure, such as walls, columns, beams and floor slabs. They concern parts of the structure subject to deferred stresses and to environmental conditions specific to underground areas.
What forms do structural movements take in parking garages and basements?
These evolutions generally take the form of slow deformations, dimensional variations or changes in inclination. They develop over time and occur gradually, without any sudden failure or clearly identifiable triggering event. They are assessed by comparing observations carried out on different dates.
Which parts of the structure may be affected by these movements?
In the underground parts of the structure, movements may affect:
- The verticality of certain load-bearing elements;
- The flatness of floor slabs or decks;
- The relative position between two parts of the same structure.
These evolutions often remain difficult to detect with the naked eye, particularly in environments with limited lighting or with degraded surface finishes.
Positioning crackmeters in indoor areas
Crackmeters are positioned in parking garages, cellars and basements on load-bearing elements showing movements that need to be monitored.
How are crackmeters installed in these confined spaces?
Measurement points are chosen in areas where movements are observable and where the instrumentation can remain in place over the long term.
In high-traffic areas such as parking garages, protective covers are available to secure the equipment against accidental or malicious damage.
How can wireless crackmeters operate in confined spaces?
Saugnac wireless crackmeters rely on LTE-M and NB-IoT technologies, specifically designed for data transmission in challenging environments — cellars, enclosed premises or structures with strong signal attenuation.
These protocols offer better penetration than conventional mobile networks and can overcome additional obstacles such as thick walls. However, signal quality remains dependent on the specific characteristics of each site, and this solution is obviously not infallible.
The most reliable way to assess feasibility on specific sites with weak network coverage is to carry out an on-site test — please contact us to arrange a trial.
For challenging environments, the R2 gauge is a possible solution. It offers two specific advantages:
- a remote sensor connected by a 1 m cable (extendable up to 5 m on request), allowing the communication unit to be placed in an area with better network coverage; sometimes the connectivity limit is just a few tens of centimetres away;
- an optimised antenna providing better reception sensitivity.
Monitoring structural movements: how to use measurement instruments?
The measurement instruments used for monitoring structural movements allow progressive phenomena to be tracked through readings taken on different dates, under identical measurement conditions.
The interpretation of measurements takes into account the chosen frequency and the conditions under which the readings were carried out. In indoor areas with restricted access, this approach makes it possible to understand how movements evolve without multiplying on-site interventions.
Measurement instruments provide objective data on the evolution of observed movements. The data collected forms part of a structural monitoring approach and is intended to be interpreted by qualified professionals, with regard to the context of the structure and its operating conditions.