Six-Story Prefabricated Concrete House

A six-story prefabricated concrete house is a six-story building with prefabricated slabs as its floor slabs, commonly found in brick-concrete or partial frame structures, and has specific advantages and disadvantages, service life, and safety precautions.

Structural Types

The structural types of six-story residential buildings mainly include brick-concrete and frame structures. Before 2000, most were brick-concrete structures, with load-bearing walls constructed using red bricks or sintered perforated bricks, and floor slabs mostly being prefabricated slabs or a small amount of cast-in-place concrete. After 2000, newly built structures gradually shifted towards frame structures, with reinforced concrete columns and beams as the main load-bearing structures, and walls filled with lightweight materials such as aerated concrete blocks and hollow bricks. Some may still use prefabricated slabs as floor slabs.

Characteristics of Prefabricated Slabs

• Advantages: Lightweight and soundproof, they can save materials. Compared to cast-in-place slabs, they can save about 40% of concrete, 50% of steel, and a large amount of formwork and labor, and are easy to install.
• Disadvantages: Poor overall structural integrity, assembled from prefabricated slabs with horizontal and vertical joints filled with fine aggregate concrete or cement mortar, resulting in poor connection performance and weak seismic resistance. If not properly handled during construction, building settlement can easily cause slab cracking and water leakage.

Service Life

The service life of a six-story prefabricated slab building is generally 50 years, mainly limited by the rate of concrete carbonation. Within 50 years, the concrete carbonates about 25 millimeters. Once it reaches the steel reinforcement cover, the steel begins to rust, and the structure gradually deteriorates.

Safety Precautions

• In brick-concrete residential buildings, the removal of load-bearing walls is strictly prohibited. In frame residential buildings, the removal of infill walls requires calculation by a structural engineer.
• The tilting of a prefabricated slab building is one of the core manifestations of abnormal building structure and requires timely professional inspection and handling. When the tilt reaches a certain level, immediate evacuation and reinforcement or rectification measures should be taken.

Actual Cases

In recent years, accidents involving brick-concrete prefabricated slab structures have occurred frequently. For example, a partial collapse of a six-story brick-concrete prefabricated slab dormitory building in Xinqizhou Administrative Office, Ganjiang New Area, resulted in casualties. These accidents are mostly related to factors such as poor overall structural integrity, weak seismic resistance, and unauthorized modifications.