There are a number of challenges when connecting precast walls, namely:
1. Connections are wet, so require temporary bracing.
2. Installation time can be lengthy, so crane time is not optimised.
3. Connecting of both vertical and horizontal rebar connections is practically impossible due to the stiffness of the rebars.
At Leviat, we have a solution for all of these challenges, but here we would like to address the third one as it is arguably the most important fundamental.
So What is MOMENT Loop Box?
MOMENT Loop Box are used for connecting precast wall to wall or to a column. After casting to the formwork, the precaster will just need to remove the tape and release the loop into the operating position. A vertical rebar (sometimes called a trimmer or cottering bar) is installed into the joint through the wire loops. Lastly, cementitious grout is poured or pumped into the joint.
There are 3 types of MOMENT Loop Box – Multi, Double and Single Loop Box.
Loop boxes are installed to the formwork according to the spacing specified by the designer, before the panel is cast.
A vertical rebar is installed into a joint through the wire loops of both precast panels before grouting.
Key Advantages
Fully compliant with EN1992-1-1 (Eurocode 2), MOMENT Loop Box has been tested in accredited test labs to simulate performance in various application, transmitting forces from three directions (perpendicular, parallel and transverse load).
Below are the key advantages of loop box when compared with the traditional method of connecting precast walls:
- Flexible installation method for seamless connection between precast wall
- Reduces the total installation time by 50% with less labour
- Eliminates the clashes between U-bars from the traditional method
- Customizable length of steel box and wire loops
- Easy installation of loop box to the formwork with the option of magnet
Multi loop box acts as a shear key and simplifies the design of the formwork.
Making precast wall connection easier and faster
Key Features
Consists of high-strength, galvanized steel casing and wire loops, loop boxes connect precast walls in an efficient and time saving method. Below are the key features of loop box:
Galvanized Steel Box
A robust sheet-steel box and wire loops contain the plastic latch and wire loops
Plastic Latch
Specially designed plastic latch to secure the wire loops in position for good anchorage embedment for in concrete
Flexible wire loops
Galvanized wire loops transmit force into the concrete and connect 2 walls to each other. Loops can be bent out and straightened with a hammer claw, screwdriver or a nail.
