One-and-a-Half-Story Concrete Prefabricated House

Common practices for one-and-a-half-story concrete prefabricated houses include using five-hole prefabricated slabs for floor slabs or pitched roofs, with a construction cost of approximately 300-650 yuan per square meter, though structural safety hazards must be noted.

Structural Design and Construction Methods

1. Floor Slab Application: In some cases, the first-floor slab uses five-hole prefabricated slabs, while the second floor employs monolithic cast-in-place concrete. This combined construction method accelerates progress and reduces costs. For example, contractors can reduce on-site pouring time by using prefabricated slabs while enhancing overall structural integrity with the cast-in-place layer.
2. Pitched Roof Application: Five-hole prefabricated slabs can be directly used for pitched roofs, secured horizontally at the ends (e.g., by welding rebar or bolt connections) to prevent slippage. However, strict calculations of roof pitch and fixation methods are necessary to avoid structural instability due to concentrated loads.
3. Structural Hazards: Without ring beams or constructional columns, the connection between prefabricated slabs and walls is weak, making them prone to collapse under horizontal forces during earthquakes. For instance, a self-built house lacking ring beams experienced complete slab detachment during simulated earthquake testing.

Cost and Cost Analysis

1. Price Range: The construction cost per square meter for concrete prefabricated houses ranges from approximately 300-650 yuan, depending on brand, specifications, and region. Examples include:
   • A brand in Xuzhou, Jiangsu, quotes 368 yuan per square meter, including foundation work and standard finishing;
   • A manufacturer in Baoding, Hebei, offers 255 yuan per square meter for bare housing (excluding doors, windows, and interior finishes);
   • A popular model in rural Henan costs around 300 yuan per square meter, with a total price of approximately 70,000-80,000 yuan for a 200-square-meter house, backed by a 70-year warranty.
2. Cost Advantages: Prefabricated slabs enable mass production, reducing on-site labor and material waste, and shortening construction periods by 30%-50% compared to traditional cast-in-place methods. However, additional reinforcement (e.g., adding ring beams) may increase costs by 10%-15%.

Safety and Regulatory Recommendations

1. Mandatory Measures: According to the Code for Design of Masonry Structures (GB 50003-2011), prefabricated slab houses must include ring beams at eaves and floor slabs, with reserved tie bars at slab ends for connection to walls.
2. Seismic Design: Pure prefabricated slab structures are prohibited in seismic zones with an intensity of 8 or higher. Instead, cast-in-place floor systems or assembled monolithic concrete structures should be used.
3. Acceptance Criteria: After construction, indicators such as joint width between prefabricated slabs (≤5 mm) and anchorage resistance of fixtures (≥5 kN) must be tested to ensure compliance with the Technical Standard for Assembled Concrete Buildings (GB/T 51231-2016).