|Location||Glasgow City Centre|
|Requirement||Restricted Access Bearing Piles|
|Techniques||Drilled , Mini Pile , Permanently Cased|
|Main Contractor||Raynesway Construction Ltd (A Balfour Beatty Company)|
Technik Ground Solutions Ltd (TGS) was awarded the contract for the design and installation of permanent bearing piles for bridge pier foundations. The works required were to connect the famous “Bridge to Nowhere” across the M8 in Glasgow City Centre.
The severely restricted 2.3m wide site was bounded by the retaining walls of Waterloo Street to the north and a multi- story car park to the south.
The works included the provision of 12 vertical bearing piles with axial loads of up to 800kN in both tension and compression. A sacrificial preliminary test pile was also carried out just outside the working area.
- Severely restricted access site with limited working space.
- Stringent axial and lateral deflection criteria at the pile head.
- Sensitivity of adjacent structures to vibration.
- Logistical issues with placing the single length steel reinforcement into the top of the pile.
TGS installed the 220/190mm diameter permanently cased, drilled piles to lengths of up to 30m below ground level. The piles were installed using a Klemm 702 minipiling rig using a remote power pack. The power pack was located 50m away from the rig and was connected to it using umbilical hydraulic hoses.
The permanent casings were installed to the top of the rock using an overburden drilling system before the down the hole hammer was used to form the rock socket. All piles were grouted using a tremme immediately on completion of the drilling and a full length central reinforcing bar was inserted. The top of the piles were further reinforced with a Universal Column to safely carry the anticipated lateral loads. This element was placed using lifting equipment on the upper floors of the existing adjacent car park.