Elevator Installation in Prefabricated Slab Buildings

There are multiple issues and potential hazards associated with installing elevators in prefabricated slab buildings, but it can be carried out under certain conditions, requiring careful evaluation and standardized operations.

Structural Issues

Prefabricated brick-concrete buildings constructed from the 1970s to the 1990s generally have poor overall integrity and are not earthquake-resistant. The prefabricated slabs are placed on the walls like puzzle pieces, lacking strong connections between them. The stairwells are weak points, and during earthquakes, the slabs are prone to falling, and the walls may collapse. Installing an elevator, especially the half-floor access plan, requires chiseling walls and removing beams, which can damage the overall structural integrity. After removing the original window sill walls and even some ring beams in the stairwells, the remaining connections are weak, raising concerns about the stability of the stairwells during earthquakes. The installed elevator shafts are tall and narrow, prone to deformation under wind and seismic forces. If rigidly connected to the main body of the old building, they can increase the load on the old building. Although regulations require the installation of seismic joints to allow the shafts to operate independently, perfect implementation is often difficult in actual construction.

Safety Hazards

Installing elevators may introduce fire safety hazards. Elevators and corridors can transform stairwells, which originally rely on exterior walls for natural ventilation and lighting, into dark spaces. In the event of a fire, these stairwells cannot vent smoke and lack natural lighting, hindering evacuation. Additionally, installing elevators involves drilling and cutting. If not done properly, such as cutting through load-bearing ring beams, the entire building may become unsafe. The foundation of old buildings may not be able to support the weight of the elevator shaft, leading to wall cracks and indoor leaks.

Installation Conditions

Before installing an elevator in a prefabricated slab building, a professional agency must inspect the cracks in the floor slabs and the rusting of the steel bars. Installation can only proceed if the inspection results are classified as AB or C. During the design phase, the elevator shaft should be constructed with steel and firmly connected to the original building. The foundation must be treated, and sometimes piles may need to be driven to distribute the weight of the elevator. In terms of policy, at least two-thirds of the unit's owners must agree. During construction, brute force should not be used to break walls; instead, static cutting should be employed. After installation, it is recommended to inspect the connection points every five years. If the building is too old and deemed unsafe, in many places, it can be demolished and rebuilt with a new elevator-equipped building. Additionally, when designing the elevator shaft, an independent type is preferable, avoiding rigid connections with the building. The construction team must be qualified, and the government must inspect the completed work. Nowadays, many cities have introduced new regulations requiring additional reinforcement of old buildings built before a certain year before elevator installation can proceed.