Spring-lok Compact | Britannia Engineering Consultancy

Introduction

The Spring-lok Compact utilises vertical compression springs that are either formed from or attached to the pile or the pile sleeve. The springs provide a direct axial load path and offers a substantial increase in load capacity over the original Spring-lok. The spring load is maintained in compression and delivers the optimum fatigue performance. The individual spring load distribution is controlled via bearing rails that guarantees the springs are concentrically loaded and load share to provide a huge combined load capacity that is a multiple of that required.

Spring-lok Compact is offered in three formats:
Type I – The springs are formed from sections of the pile sleeve itself. The springs are protected locally via a sleeve mounted structural profile.

Type II – The springs form part of a sleeve that is welded to the pile sleeve. The spring sleeve is protected within the annulus gap between the pile and the pile sleeve.

Type III – The springs form part of a sleeve that is attached to the pile. The spring sleeve is protected within the annulus gap between the pile and the pile sleeve.

Each of the three types have advantages in function, layout, schedule and fabrication cost depending on the application. BECL are happy to advise on type selection.

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Common features of Spring-lok Compact and Spring-lok Original

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Application

As with the original Spring-lok the units are suitable for all structural diverless connections – See Spring-lok original.

Spring Bend Testing

The spring bend is formed at the proximal end of the cantilever using an approved temperature controlled fabrication procedure. An independent detailed metallurgical survey of the spring bend area was undertaken to verify the spring bending procedure. The complete bend area of the springs were removed from the test rig following the Qualification load test.

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The tests carried out included:

• Vickers HV10 hardness survey of the bend area covering both the bend material that plus the adjacent unaffected area.
• A micro-examination using microphotography at x 500 magnification to determine if there were any meaningful changes in the microstructure across the bend area.

The tests demonstrated:
• No reduction in material properties in the bend area.
• No deleterious effects to the microstructure of the steel in the bend area.

Above test data is available on request.

Compact Spring-lok Load Test

A detailed load test was carried out as part of the LRS approved Qualification Test program. The results showed excellent correlation with predicted values.

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