The first is the lofting before the installation of guardrail board. The setting out of guardrail column should be carried out according to the design of the drawing. The positioning measurement of guardrail column can take bridges, culverts and channel interchanges as control points. The adjustment interval can be adjusted by using the adjustment section, and the odd number of the interval can be handled by the allocation method.

     In order to ensure the current and accurate setting out of the guardrail, check and close the partition. After setting out the columns, investigate the surface position of each column. If the buried column depth is insufficient due to water discharge, communication pipeline or culvert, the position of the column should be adjusted appropriately to change the column fixing method suitable for the terrain.

     Next, install the guardrail. According to the requirements of the drawing design, drill the column, check the coordination with the road after drilling, and if the subgrade allows, the column installation method will be adopted. During the construction and installation, the positioning should be accurate. The column should be driven into the soil to the designed depth. If it is driven too shallow, it should reach the required depth. If it is driven too deep, it should be pulled out for correction. If it is difficult to drive the column, it should be drilled When using the foundation of reserved hole, the sundries in the hole should be cleaned before installation. If there is water in the hole, it should be sucked dry. A layer of asphalt should be coated at the bottom of the hole, and then the column should be installed according to the designed elevation. Some will install the guardrail plate at the end of the transition section, so the installation should also be controlled according to the design requirements, and it will be parabolic after installation.