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One crucial aspect of precast building structures is the connections. Precast concrete connections are systems that link two or more precast beam elements into a cohesive unit. These connections serve to transmit forces acting on the beams, such as shear forces, tensile forces, and compressive forces.
Types of Precast Concrete Connections:
Some commonly used types of precast concrete joints are:
1. Dry Connections
Dry connections do not use liquid bonding materials like concrete or mortar. They typically employ sliding key systems or mechanical connections.
2. Wet Connections
Wet connections involve liquid bonding materials like concrete or mortar. Connection systems with grouting or local casting commonly occur in wet connections. After welding, the precast joint gap will be filled with grouting material.
Grouting materia grouting and sealant as a construction joint, functioning as an expansion joint for precast concrete.
The surface to be filled with grouting material grouting and sealant and sealant must be thoroughly cleaned to avoid unwanted materials, such as dust, paint, and others, mixing with grouting/sealant the grouting/sealant material.
The next step is the application of a waterproofing layer to prevent leaks on walls, roofs, or ceilings. This step is known as work of waterproofing material. The application of waterproofing material is done similarly to painting work. After the work of waterproofing material is dry (24 hours after application), a 24-hour immersion test is conducted to identify any leaks or dampness in the precast concrete.
Planning Precast Beam Connections
When planning precast beam connections, several factors need to be considered, including:
1. Loading Type
The type of loading on the beam determines the type of connection used.
2. Planned Loads
Planned loads are estimated loads that will act on the beam during the structure's service life. These planned loads are used to calculate the connection's strength.
3. Connection Strength
The connection must be strong enough to withstand the planned loads acting on the beam.
4. Material Availability
The selected type of connection should be in line with the availability of materials at the project site.
