Wall Reinforcement - Gripforce ® Soil Nails GRP Bolts - GRP Glass Reinforced Plastic

Project Title Tondu Iron Works Wall Reinforcement Client Cadw Consultant James & Nichlos Consultants Main Contractor Dimblow & Crump Ltd Featured Products Weldgrip Gripforce ® Soil Nails

The Tondu Iron Works wall stabilisation project is part of the refurbishment to one of Cadw industrial sites. The 200 year old Iron Works has many historic features including buildings, a large square chimney feature and a series of open grate furnaces. The Iron Works were built into the side of a hill, with ramps, gangways and part of the open furnace section protected by a 12 metre high retaining wall.

The first phase of the project was to dismantle and rebuild the top 3 metres of the wall and reinforce the whole area with soil nails. Weldgrip Vinylester GRP soil nails were used because of their high tensile and shear strength characteristics and also their excellent corrosion resistant properties.

The nails were 8 metres long, installed through the wall and into the made ground behind. Weldgrip Gripforce ® 25mm soil nails were installed in the wall. The nails have a tensile strength of 500 kN and a shear strength of 167 kN.

The bar has a rough profiled finish to give good grout/bar bond strength characteristics. Each nail head assembly consisted of a 125mm GRN (Glass Reinforced Nylon) end plate and a high load nut capable of withstanding forces of up to 180 kN.

The nails were installed into 80mm diameter holes, filled with OPC cementitious grout. The holes were spaced along the wall at 1.5 metre centres, with row spacing at 1 metre. All the holes were drilled using rotary drilling equipment to limit the amount of vibration on the wall.

The nails were countersunk into the wall, by overcoreing the holes, 250mm long by 150mm diameter. To improve the aesthetics of the finished work part of the cored stone was replaced to completely hide the nail head assembly.

To validate the grout/soilnail interface sacrificial on-site test nails were axially loaded to 120kN.

• The advantages of using the Weldgrip Gripforce ® soil nail system are:-
• Ease of installation.
• The light weight construction enabled longer lengths of bar to be used without couplers.
• High corrosion resistance.
• High tensile and shear strength.
• High end load nut assemblies.
• Non-metallic end plates, maintaining the corrosion resistant integrity of the whole nail system.
• Light weight bar gave savings on transport and installation costs.

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Product Brochure - Soil Nails & Rockbolts - 620k

Weldgrip are also proud to have attained BBA accreditation and ISO 9001 standards in recognition of our continuing excellence in Geotechncial products and services.