렉스틸 - Construction Process

Prepare on-site construction

Establish measurement plan for construction plan and structural deformation
Secure space for steel plate placement and roads for equipment access to the site
Check the height of foundation concrete indicated on the drawing and verify if it is cured
Check the arrangement and diagonal length of base channels to be assembled with corrugated steel plates, and remove foreign substances

Material inspection

Test tensile strength, yield stress and elongation test
Inspect coating amount (more than 900g/㎡ based on double-sided coated steel plate)
Inspect the depth of crest(top) and trough(bottom)
Inspect thickness
Check the quantity of steel plates per specification and the quantity of bolts and nuts indicated in the drawing

Joint waterproofing and back drainage

To prevent water penetration from joints or bolt holes, waterproof joint gaskets, urethane sealants, and rubber caps
If necessary, install a waterproofing screen in the fill and backfill parts

Primary gasket waterproofing

Install rubber gaskets between the steel plates and get bolted to maintain watertightness by pressure

Secondary urethane sealant and rubber cap waterproofing

Urethane sealant is applied to each corner of the overlapping part of steel plates, and the cap mixed with urethane sealant is placed on the joint bolt parts and cured for secondary waterproofing.

Schematic diagram of secondary waterproofing for overlapping parts

Sectional displacement measurement

For corrugated steel plate structures, measure the changes in the shape size of the cross-section immediately after ① assembly, ② backfilling (including soil cover) ③ after construction.
Measure the cross-section before backfilling, and if it deviates more than 5% from the desired shape, loosen the bolts to match the shape and assemble again.
During and after each stage of construction, the cross-sectional size is examined at least three locations. If the deformation exceeds the tolerance range, the construction should be paused, the cause should be identified, and reinforcement measures should be taken to reduce the deformation within the tolerance level.

Tolerance level of structural deformation during and after construction

Classification	Tolerance level of cross-sectional deformation
For standard steel plate	within 5% of structure height (Rise, R)
For deep corrugated steel plate	within 2% of structure height (Rise, R)

Sectional displacement measurement

Backfill should be evenly compacted using granular materials with low compressibility or materials with suitable particle size distribution. The foundation ground and backfill materials should be the same or less heterogeneous so that an even earth pressure can be exerted around the structure.
Backfill part of underground steel plate structure is divided into structural backfill part that directly affects the behavior of structure and general backfill part on the outside.
- Structural backfill material : Materials or mixture with low compressibility and excellent durability (subgrade or higher, subbase layer SB-1,2)
- General backfill material : Application of perimeter materials to the outside structural backfill area in accordance with the drawing.
The difference in the compaction thickness on both sides of the underground steel plate structure should be less than 20 cm. In case of structural deformation, some backfills should be removed, and the cross-sectional shape should be readjusted before backfilling is re-performed.
During compaction work in the structural backfill area, the operation of heavy equipment and transportation equipment, excluding compaction equipment, must be controlled within 60cm of the steel plate wall.

When installing an underground steel plate structure in the fill area

When installing after excavating the foundation ground