Floor Concrete Prefabricated Panel

Floor concrete prefabricated panels are commonly used prefabricated components in early 20th-century architecture. They are produced through standardized factory manufacturing and then installed on-site, offering advantages such as short construction periods and stable quality, but they are limited in terms of flexibility in spatial layout.

I. Types and Structures

Prefabricated panels are classified into three types based on their cross-sectional forms: flat panels, channel-shaped panels, and hollow-core panels. Hollow-core panels are the most widely used due to their light weight and cost-effectiveness, with their internal hollow structure reducing material usage; channel-shaped panels adapt to different support requirements through their positive and negative structures. During manufacturing, wooden boards are used to create hollow molds, reinforced with steel bars, and then concrete is poured. After drying, the wooden boards are knocked out to form prefabricated components.

II. Specifications and Dimensions

Standardized designs are adopted, with lengths typically being multiples of 300mm (e.g., 3.6 meters), widths multiples of 100mm (e.g., 0.6 meters), and thicknesses ranging from 120-300mm. Taking YKB3606-8a as an example, its characteristic thickness is 120 millimeters, with 8 main steel bars configured. Floor panels with a width of 60 centimeters usually have 5 holes, with a center-to-center spacing of 105 millimeters and a hole diameter of 76 millimeters, and the actual width of the panel bottom is 59 centimeters.

III. Load-Bearing Capacity

The maximum load-bearing capacity of ordinary prefabricated panels is approximately 500 kilograms per square meter (about the weight of 5 adults). National standards require that the live load of residential floor panels be at least 200 kilograms, with a total load-bearing capacity (including self-weight) of up to 760 kilograms. Load-bearing capacity is significantly affected by factors such as thickness, span, and construction: a 10-centimeter-thick panel can bear 150-250 kilograms, while a 12-centimeter-thick panel can bear up to 250 kilograms; when the span exceeds 4 meters or the supports are not secure, the load-bearing capacity decreases by 30%; construction quality defects (such as improper joint treatment) can further weaken the load-bearing performance.

IV. Installation Techniques and Requirements

1. Pre-installation Preparation: Seal the holes in the floor panels, bend up the steel bars, and set up formwork. For hard-frame formwork, calibrate the dimensions before pouring concrete.
2. Installation Process: After hoisting, cross the adjacent steel bars and add continuous reinforcement. The supports should be 8 centimeters from the wall edge (for 24-centimeter-thick walls), and additional panel strips should be added when encountering structural columns.
3. Panel Joint Treatment: The lower joint width should be 2 centimeters, and the upper joint width should be 4 centimeters, with concrete poured after the main construction is completed. Joints less than 30 millimeters wide should be filled with fine aggregate concrete, those more than 50 millimeters wide should have steel bar mesh added, 120-millimeter joints should be filled with bricks against the wall, and joints more than 120 millimeters wide should adopt reinforced concrete panel strips cast on-site.

V. Applications, Advantages, and Disadvantages

Prefabricated panels were once widely used in scenarios such as ditch covers and roof insulation layers. Although they have been largely replaced by frame structures, they are still used in prefabricated buildings (e.g., the Oodi Central Library in Helsinki, Finland). Advantages include short construction periods, stable quality, and high material utilization; disadvantages include poor flexibility in spatial layout, weaker integrity compared to cast-in-place panels, and unsuitability for hole-punching modifications.