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LIFTING ESCALATOR FACTORY

Category
Industrial
Focus
Floor
Location
Foshan, China
Duration / Year
12 weeks / 2010
Technology
GI

SUMMARY

In the 4 years since construction, the factory floors had subsided up to 365 mm, making some areas unproductive. The subsidence appeared to be on going, with 100 mm fall in last 12 months. URETEK successfully stabilized and releveled these subsided floors to normal tolerances without closing the factory. 

OBJECTIVES

155 x 105 meter factory was constructed in a new industrial estate that was established on land once used for aquaculture. The estate land had been by reclaimed by placing 2-5 meters of non-engineered fill over the old ponds and lagoons.

Factory’s construction was conventional, with the factory being divided into 5 lanes, 21 meters wide x 155 meters long. Ground beams ran lengthways dividing the lanes and around the factory perimeter. Piles are at 9 meter centers along the ground beams. Floor slabs, cast as slab on ground, spanned 20 meters between the ground beams.

Geotechnical tests revealed from top down –

1. Placed fill was not engineered, and is described as loose in places, and in itself is subject to settlement.

2. Highly compressible black organic clays in a 3-7 meter band below the fill.

3. Soft silty weathered clays with a Cu of 20kPa (+ or – 10kPa) in another variable 5-10 meter band above the limestone rock head

4. Caves, voids and fissures 22 – 28 meters below ground level encountered at the rock head levels.

Main objectives were fixing:

                Sunken factory floors

                2 sunken columns

                Collapsed logistics office

                Factory toilet block un-useable

                Failed kitchen floors & drains

                Subsided and broken entry thresholds

                Uncertainty of future use 

TECHNOLOGY APPLIED

Combination of URETEK techniques used. URETEK Geopolymer injections in upper 6 - 8 meters to compact soft soils & provide point lift. BENEFIL slab lifting utilizing injected resins directly under slabs to fill voids and raise the sunken floor slabs.

1. Cement grout at low pressure was used to fill the caves and voids found at the rockhead levels

2. Pagani Penetrometer testing was carried out systematically to all of the factory areas displaying settlement to map the extent and gravity of the soft clays

3. Soil Stabilisation and compaction was carried out using the URETEK GEOPOLYMER INJECTIONS technology of expanding resins at extremely high pressures at the weak locations and levels as detected by the penetrometer testing.

4. Floor slabs were lifted and voids beneath the slabs filled by using URETEK Benefil Floor Lift light weight foam injected directly below the slab. Lifts were monitored by laser levels. 

OUTCOME

URETEK completed this factory floor lifting and stabilization in stages over 12 weeks at times convenient to customer. Factory was 100 % productive throughout whole proses.

Results:

1. Floors stabilized and releveled to normal tolerances.

2. Remediation was carried out without closing factory.

3. Factory production was not halted or seriously affected by the remediation works.

4. No mess was made by the stabilization and lifting processes.

5. Client (Factory occupier) was delighted, as the only other alternative was to shift production to another location whilst floors were demolished and re-laid.