Seismic Engineering - Earthquake Engineering for Buildings
BC is the most seismically active region in Canada and our structural engineering partners are experienced in earthquake engineering to meet provincial and federal requirements. Seismic engineering is a speciality that is used in commercial and industrial buildings in urban and rural areas.
In parts of BC, from Vancouver to Prince Rupert and Kitimat, your commercial or industrial buildings may be subjected to seismic dynamics that the rest of the province are immune to.
By applying proven structural design and other innovations for multi-storey and wide-span buildings, the additional seismic load can be properly distributed to ensure the safety of your building and occupants.
Seismic loading is also important for interior equipment that requires bracing and support during an earth movement.
During an earthquake, the ground moves in 3 directions at the same time, X, Y & Z (north/south, east/west, up/down) and buildings needs to be designed with factors of safety to compensate for these additional forces.
This movement of the ground cause buildings to move, deform and oscillate. If the frequency of oscillation is close to the natural frequency of the building, resonance may occur that can cause severe damage to property and injury to people.
Since no two buildings are the same, an earthquake engineering analysis looks at the seismic hazard of ground movement in your area and ways to mitigate it within your building's structure.
The most important considerations affecting earthquake damage includes:
- The intensity of ground shaking. The estimated earthquake intensity in Vancouver is different for Prince Rupert which is different to Alberta, which by the way is experiencing an upsurge in seismic activity Earthquakes in Alberta are increasing to do fracking.
- The quality of design and construction. Wide-span buildings and multi-storey buildings have vastly different support structures and seismic engineering is different to each structure.
- The response of the building to oscillation. Resonance is a phenomenon in nature that we see in our structural, mechanical and electrical systems. Our engineering consultants in each discipline have experience and understanding of mitigation techniques to prevent the destructive forces of oscillations in each system.
Structural Resonance - Structural consultants must prevent earth movements from amplying and destroying buildings.
Mechanical Resonance - Mechanical consultants must inhibit vibrations from intensifying and destroying mountings and brackets.
Electrical Resonance - Electrical consultants must eliminate harmonic currents that can resonate and destroy electrical equipment and cause fire hazards.
Deformation in Structures
When the ground shakes, the base of the building experiences motion while the roof experiences inertial forces that causes it to stay in it's original position (Newton's First Law of Motion).
This is like when you are on a bus and it starts to go forward. Your feet will accelerate with the bus while your upper body tends to stay back, cause you to sway.
These inertial forces cause the roof to sway at one frequency while the base oscillates faster with the earthquake frequency. The walls and supporting columns connecting the two must be designed to transfer, dampen and deflect these loads to the supporting structure.
Gravitational Loads Gets Amplified
Your building is heavy but no match for an earthquake, which can move entire countries. When vertical earthquake forces are present, your entire building accelerates up and down.
The added gravity load during this change in direction puts additional forces on your support structure. The massive weight of your building is amplified and needs to be supported by the columns and foundation.
Proper earthquake engineering involves everything from soil stability around the foundation to distribution of vibrational forces from the upper floors to the solid building structure.
Earthquake Engineering - Affects of Fracking
Fracking is a modern innovation that is transforming our energy economy, transfering geo-political power and cleaning our air as we go from coal-fired to gas-fired electricity generation. As structural engineering consultants, we are just beginning to understand how this drilling technique is inducing earthquakes in the extraction zones.
In northern BC and many parts of Alberta, low intensity but shallow earthquakes are being experienced. We have received several calls for engineering analysis of industrial structures in these remote regions.
Injury is rare in these rural area but damage to remote monitoring stations, natural gas batteries, pipelines and electricity transmission lines can severely affect supply to our cities and ports.
Seismic engineering is important to our modern way of life.