A lot of activities and businesses have the potential to have negative effects to their environment because of the vibration that they produce. For example, construction (for example during piling), mining and and other vibration-generating activities. This vibration can disturb the comfort and health of people around it, and even can have destructive effects to nearby buildings.
In Indonesia, the vibration limit is regulated through Ministerial Decree of Ministry of Environment No. 49 Year 1996. This regulation was made to ensure healthy environment for human and other living creatures to live in. Consequently, the vibration generated from human activities need to be regulated.
In this regulation, businesses and activities are required to:
- Comply to the vibration limit in the decree. This is required for businesses and activities to obtain certain relevant permits to be able to operate.
- Use vibration reduction equipment
- Report vibration monitoring activities at least once in 3 (three) months to the Governor, Minister, Government agencies that are responsible to control environmental impact, other technical institutions that is responsible for the activities and other organizations that might need the vibration monitoring report.
The vibration limit is separated into few parts which are:
- Vibration limits for health and comfort
- Mechanical vibration limits based on its destructive effects
- Mechanical vibration limits based on building types
- Shock limits
The following table and graphs is the vibration limit for health and comfort:
Acceleration = (2πf)2 x displacement
Velocity = 2πf x displacement
The graphic representation of the table above is as follows:
The table below is the vibration limits based on the destructive effects:
As seen above, the peak velocity limit from the vibration is separated into 4 categories which are:
- Category A: non-destructive
- Category B: Possibly destructive for plastering (crack, or in certain cases the plaster can fell off the wall)
- Category C: Possibly destructive for structural components that bear loads
- Category D: High risk of destruction of load bearing walls
The following graph is the vibration limit based on destructive effects in a graphical form:
Mechanical vibration limit can also be categorized into the types of buildings. The buildings are categorized into 3 which are:
- Buildings for commercial, industrial, and other similar use.
- Residential and other buildings with similar design and usage
- Structures that are sensitive to vibration and cannot be categorized into category 1 and 2, for example preserved buildings with high cultural value
Below is the vibration limits for the building category above:
The table below is shock limit for buildings:
|Category||Building Type||Maximum velocity (mm/s)|
|1||Old buildings with high historical value||2|
|2||Buildings with existing defects, cracks can be seen on the walls||5|
|3||Buildings with good condition, minor cracks on plaster is acceptable||10|
|4||Buildings with high structural strength (for example industrial building which is made from concrete and steel)||10 – 40|
The ministerial decree also describe the measurement and analysis method for vibration as follows:
- Vibration transducer (Accelerometer or seismometer)
- Vibration measurement device or analysis device (Vibration meter or vibration analyzer)
- 1/3 octave or narrow band filter
- Signal recorder
- FFT Analyzer
- Measurement procedure:
- Vibration measurement related with health and comfort:
- Place transducer on the floor or other vibrating surface, and connect it to the measuring device with filtration
- Set the measuring instruments to measure displacement. If the measuring instruments do not have that on display, the conversion from acceleration or velocity can be used
- Reading and recording is conducted for frequency between 4-63 Hz or with signal recording device
- Measurement results with at least 13 data shall be plotted on graph
- Vibration measurement for structural health:
- The measurement method is similar with the vibration measurement above, however the physical measure that is assessed is the peak velocity.
- The 13 data which are plotted on graph shall be compared with the vibration limits. The vibration is considered above the limit if the vibration level exceeds the limit at any frequency.
- Vibration measurement related with health and comfort:
The definition used in the regulation of ministry of environment No 49 Year 1996 is as follows:
- Building structure is a part of building that is planned, calculated, and functioned to:
- Support any kind of load (static load, dynamic load, and temporary load)
- Functioned for building’s stability as a whole. For example: frame and bearing wall
- Structure’s component is a part of a building structure that contributes to structure’s function. For example: beams, columns, and slab.
- Bearing wall is a building structure which is a vertical plane that is functioned to support loads on top of it such as slab or roof.
- Non-structure components are parts of building that is not planned or functioned to support load. For example partition walls, door and window frames, etc.
Destructive impact on structure and non-structure:
- Destructive impact on structure: Destructive impacts that can endanger building stability (for example destruction of columns that potentially make a building collapses)
- Destructive impact on non-structure: Not dangerous to building stability, but can be a danger for building occupants (for example: when a partition wall collapses, it will not make the building collapse, but can injure occupants)
Degree of building destruction:
- Light: not dangerous for building stability and can be fixed without reducing building’s strength
- Moderate: Destruction that can reduce structural strength. To fix this, added reinforcement must be used.
- Severe: Degree of destruction that can endanger the building and potentially makes the building collapses.
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