Prefabricated Wall Structure Design

The design of prefabricated wall structures for buildings requires comprehensive consideration of various factors such as structural systems, layout principles, connection details, and technical indicators to ensure structural safety and reliability.

Design Principles for Prefabricated Assembled Shear Wall Structures

As the primary load-bearing structure in high-rise buildings, shear walls must effectively resist lateral forces and optimize spatial layout. Prefabricated assembled shear walls should adhere to the following principles:

1. Lateral Stiffness and Layout: The difference in lateral stiffness between the two principal axes should not be excessive. Shear walls should form distinct wall segments and coupling beams, with a simple and regular planar layout to avoid one-way wall arrangements. Walls should be continuously arranged from bottom to top, with door and window openings aligned vertically and in rows. The width difference between wall segments on either side of openings should not be too large. In seismic zones I to III, staggered wall openings are prohibited in the bottom reinforced sections, and overlapping staggered wall openings should be avoided throughout the height.
2. Bottom Reinforced Sections: In high-rise buildings, the walls in the bottom reinforced sections should preferably be cast-in-place concrete. If the height-to-width ratio meets the requirements of the "Technical Specification for Concrete Structures of High-Rise Buildings" (JGJ 3), prefabricated cavity walls can be used.
3. Wall Segment Thickness: The load-bearing portion of prefabricated cavity walls in high-rise buildings should have a thickness of not less than 200mm.

Connection Design and Details for SPCS Prefabricated Cavity Walls

1. Bottom Joints: Joints should be located at the floor level, with a height of not less than 50mm. The post-cast concrete must be compacted, and the upper surface should have a roughened finish with a depth of not less than 6mm.
2. Horizontal Joints Between Upper and Lower Walls:
   • For boundary elements, vertical reinforcement should be lapped individually, with a lap length of not less than 1.6laE and a center-to-center spacing of not more than 4d (where d is the reinforcement diameter).
   • For non-boundary elements, circular connecting bars should be used, with a lap length of not less than 1.2laE, a spacing of not more than the vertical distribution reinforcement spacing and not more than 200mm, and a diameter not less than that of the corresponding vertical distribution reinforcement. They must meet the requirements for shear capacity calculations. If the thickness of the upper and lower walls differs, the connecting bars should be bent at an angle of not more than 1:6 and extended into the cavity by a length of not less than 1.2laE.
3. Single-Row Reinforcement Connections: Except in specific cases (such as seismic grade I or seismic grades II to IV with an axial compression ratio > 0.3), single-row reinforcement connections can be used when the load-bearing thickness of the wall is ≤ 200mm. The connections must meet the following requirements: the connecting reinforcement should be centered, with a spacing of not more than 300mm, a total tensile capacity of not less than 1.1 times the larger value of the upper and lower reinforcement, and an embedded length of not less than (1.2laE + bw/2) (where bw is the wall thickness). Additionally, tie bars should be provided to enhance connection reliability.

Prefabricated Double-Skin Composite Shear Wall (Double-Wall) System

1. Technical Characteristics: This system consists of two prefabricated wall panels connected by lattice reinforcement, with in-situ concrete poured into the cavity to form a monolithic structure. It has the same mechanical properties as cast-in-place shear walls but requires a multiplication factor of not less than 1.1 for the bending moments and shear forces of in-situ horizontal lateral force-resisting members.
2. Scope of Application: Suitable for multi-story and high-rise buildings as well as underground projects (such as basements and utility tunnels) in seismic zones with a seismic intensity of 6 to 8. It offers excellent integrity and waterproofing performance.
3. Differences from Ordinary Shear Walls: Vertical connections are achieved by inserting reinforcement into the cavity and pouring concrete, resulting in a larger connection area and more reliable connections. The ample installation space makes construction more convenient than with ordinary prefabricated shear walls.