Real estate for housing, parking, and commercial activities is dwindling all over the world. As a result of this, in dense metropolises, residential and commercial demand is being met through the construction of high-rise apartment buildings. Often, we see such buildings featuring stilt parking. Time and again, the safety standards in such complexes have been questioned.
The problem is even more aggravated in accident-prone areas. In areas prone to high-intensity earthquakes, a strong resilience to seismic waves is a priority. As we have learned from past calamities, buildings with unsafe structural designs are the first to collapse under the force of seismic vibrations. Though unavoidable, the harmful effects of earthquakes can be mitigated immensely by employing resistance-based structural technologies in the construction of our residential and commercial buildings.
What is stilt parking?
A parking space with partially covered walls built on the ground floor of an apartment building is known as a stilt parking space.
In more colloquial terms, it is also called a soft-story building or a building consisting of ground story parking space. Unlike an open parking space near building premises, a stilt parking occupies the ground floor of a building. The other floors are built directly above it.
What are the risk factors involved?
The sturdiness of a structure during an earthquake is determined primarily by two factors: the magnitude of the earthquake and the quality of material used in construction. Most of the risks involved during an earthquake can be mitigated if proper attention is given to structural strengthening.
In structural designs, reinforcements are used to provide strength. These are materials used in building constructions to provide ductility to other structural members like columns, beams, etc. During an earthquake, there is an increase in the lateral load of a building, i.e. the horizontal forces that act parallel to the ground. In such an event, it is the reinforcements that provide adequate ductility to a building, i.e. the ability to deform instead of collapsing.
In the case of a building with stilt parking, seismic waves can send vibrations through the building such that the vertical steel reinforcements at the top and bottom start to yield. When this happens, the building will simply ‘cave in’ and collapse, crumbling from the tremors of the natural calamity.
However, a building with stilt parking can be strengthened against a collapse by simply providing proper inputs in the structural designs.
Efficiency during an earthquake
Buildings with stilt parking can be specially designed to mitigate the effect of seismic waves. During a stilt construction, additional stress is added on to the columns in the ground story. Since the stilt parking is missing a reinforced concrete framing, it experiences a reduction in lateral stiffness. Therefore, the columns of ground story parking must be strengthened and stiffened to overcome this stress.
Apart from this, concrete shear wall reinforcements at appropriate locations can be used to avoid a sudden collapse of the building. For old building structures that are missing proper seismic-resistant features, retrofitting can be performed.
Retrofitting can be done by introducing reinforced concrete bands and embedded metal strips across the walls, running vertically and horizontally. A concrete band above the windows, doors, and roof levels will tie together all the structural components of the building. Retrofitting can help in preserving the buildings with stilt parking against a possible collapse.
Buildings with Stilt Parking: Final thoughts
There has been an exponential growth in vehicle ownership in the recent past, and with this, a rising need for adequate parking space. Many modern building structures are catering to this need through a stilt parking ground story.
It cannot be determined certainly if buildings with stilt parking spaces have due resilience in the face of an earthquake. Nevertheless, effective measures to strengthen the structural designs can greatly help in mitigating the risk.