Press-in (silent) piling

How bridges get built · Driven piles · Press-in (silent) piling

Also called: jacked piles, Giken press-in, static pile pressing

How it is done

Install the first few piles with a reaction stand and counterweight, or by crane, so the press-in machine has installed piles to grip.
Mount the machine on the installed piles; it clamps them and uses their pull-out resistance as reaction to press the next pile.
Press in with repeated strokes, recording force, penetration and verticality; the machine then walks forward along the wall, or a clamp crane and pile runner work from the top of the installed piles so no ground access is needed.
In dense sand or gravel use water jetting at the toe or augering ahead of the pile; through rock, concrete or obstructions use rotary cutting press-in with a bit-fitted shoe on tubular piles.
Splice short sections where headroom is limited, under bridges or overhead lines.
Use the recorded press-in force as a check on ground conditions and, once calibrated by load tests, on capacity.
Extract temporary piles with the same machine in reverse.

Key numbers

Pile typesU, Z and hat sheet piles; tubular piles up to about 2 m diameter by rotary cutting press-in.
Low headroompiles spliced in short lengths under clearances of about 5 m.
Productivitysheet piles about 15-40 per shift; tubular piles about 3-8 per shift.
Costabout 1.5-3 times vibro-driving.

Where it fits

Urban and railway-side sites, hospitals and schools nearby, embankments next to live roads, sheet piling in confined sites.

Where it does not

Large-diameter bearing piles in hard ground where the reaction is insufficient.

Choosing it

Choose press-in over vibro or impact next to sensitive structures, live railways, hospitals or old masonry, and where headroom or access is tight.
Prefer vibro-driving on open sites in soft ground: faster and cheaper.
Prefer bored piles for large isolated bearing piles: press-in needs a line of installed piles for reaction and suits walls better than scattered groups.

Plant, pace and money

PlantPress-in machine on the pile row, service crane, power unit.

ProductivitySheet piles 15-40 per shift; tubular piles 3-8 per shift.

Cost1.5-3 times vibro-driving; the price of silence.

Risks and controls

What goes wrong

Reaction pile pull-out, machine walking off line in soft ground.

Quality assurance

Press force logs, verticality by machine sensors.

Origins

Giken in Kochi, Japan, built the first Silent Piler in 1975 to install sheet piles without noise or vibration in Japanese cities; augering and jetting assistance and rotary cutting press-in for tubular piles later extended it to hard ground and rock.

Examples

Tokyo and Osaka urban viaducts, UK railway embankment works.

Case studies

CSX railway bridge pier repair, Columbus (Ohio)USA · 2015A cofferdam of 7.5 m sheet piles was pressed in around a weakened pier under 5.1 m of headroom, spliced in short lengths at about nine pairs per 10-hour shift, without disturbing the pier or the rail girder.

Uto Bridge abutment emergency repair, KagoshimaJapan · 2016After heavy rain eroded the slope in front of the abutment, 15 steel tubular piles of 1,500 mm diameter and 15.5-24.5 m length were installed by rotary cutting press-in into sandstone, working from the installed piles beneath the girder.