Formwork Blog

Posts Tagged ‘Bridges’

Northern Expressway Adelaide SA

Starter steel for a 7.2 meter high concrete bridge pier which will support concrete bridge spans at Healslip Road Interchange Adelaide.

Center Pier Starter Steel

Formwork will be used to box the column just as soon as the rest of the steel is lifted into position by crane. This center pier will be 13m long, 600mm wide at the bottom and 1500mm wide at the top.

Location: Port Adelaide South Australia

This is the formwork which will be used to cast the bridge bearings into position on top of the concrete columns. Silicon sealer was used to completely seal the formwork in order to stop any grout leakage, while at the same time holding the formwork securely in position.

Bridge Bearing Grout Formwork

You’ll notice that the original holes that were voided out during the concrete pour have been filled in with grout and new holes have been core-drilled. Why? ..

This happened because either the wrong hole centers were supplied to the formworkers, or a different size Bearing Pad was supplied in the end. Every column top had to be core-drilled in this way

You’ll also notice that the surface has been scabbled. This is specified as part of the job to ensure that the grout bonds properly to the concrete.

Tip: Don’t try and get away without scabbling the concrete if instructions were not given to do this job. Treat it as part of the job and do it without being told.

Location: Port Adelaide South Australia

Here’s Joe surveying the exact locations of the bridge bearings which will be cast on top of the concrete bridge columns at Port River Expressway roadworks project.

Joe at Port River Expressway

Because the bridge spans will be sitting temporarily on timber packers, Joe also had to calculate the correct height of each packer for each corner of every column.

Not only that, each corner of each timber packer will be a different height because of the North/South and East/West bridge span angles.

Promise not to leave you up there when we go to lunch Joe

Location: Road Bridge – Port Adelaide South Australia

After each column concrete pour, the column formwork gets stripped down to be cleaned with high pressure water blasting and grinding with a wire wheel to remove all the slurry.

Cleaning Column Formwork

After cleaning, a special oil is applied to the forms which ensures they will strip off easy next time, and also helps provide a nice smooth finish on the concrete.

Location: Road Bridge – Port Adelaide South Australia

Here is the concrete bridge columns resulting from the use of this column formwork. The bridge will eventually span accross one railway track and one busy main road.

Concrete Bridge Columns

Formworkers are now almost ready to cast in the bridge bearings on top of these columns which will support the steel bridge spans. But first, surveyors must mark out the exact location of the bridge bearings.

Alternative View of Concrete Bridge Columns

Instead of scaffolding, elevated work platforms (EWP’s) will be used to gain access to the column tops. For safety, tube and coupler guard rails will be errected on top of each column before any other work begins.

Location: Turner River Rail Bridge Mining Construction Site Pilbara Region, WA

The formwork used for the first concrete pour of this concrete bridge abutment.

Formworker Getting Ready to Concrete this Abutment Formwork

The red “spreader timbers” were also used to support the template which will leave the required penetrations for the Structural Bearings (also called bearer pads, bearing pads, bridge bearings). The Bearer Pads will fit neatly into these penetrations which will then support the bridge spans.

Concretors could not be hired for this job because Turner River Camp is only a small 70 person camp and all dongers were full. For this reason, the three formwork carpenters were required to do the concreting jobs as well.

Structural Bearings – Bridge Bearings – Also known as bearer pads or bearing pads.

Structural Bearing – Bridge Bearing

Bridge Bearings go inbetween the structure and the bridge span. For example, Bearing Pads can be fixed onto abutments, bridge columns and/or headstocks then bridge spans are fixed onto them.

Location: Road Bridge – Port Adelaide South Australia

Concrete pump operator places the concrete into these bridge column forms, the concretor vibrates while the formwork carpenter stands by to secure the Bearer Pad Template.

Pumping Concrete into Bridge Column Formwork

Once the concrete is pumped almost to the top, a formwork carpenter secures the Bearer Pad Template on top of the column forms. The concrete is then topped up.

Concretor Vibrating Concrete

Due to space restrictions, the Bearer Pad Template was made strong enough to stand on so that the concretors could hand-trowel the entire surface without stepping on the concrete.

Location: Road Bridge – Port Adelaide South Australia

All the access scaffolding is now complete on this bridge column formwork. We are not quite ready for concrete yet because city council inspectors must give the okay first.

Four Bridge Column Forms Ready for Concrete

City Council inspectors will climb up the access scaffolding and make sure that the column forms and reinforcement steel inside the concrete forms are positioned according to the specifications on the plan. In most cases, the inspector will give it the go-ahead.

In my experience, the only times an inspector does not approve a concrete pour is when some formworker did not do what they knew had to be done. These formworkers hope that the inspector does not see that bit of steel too close to the concrete form, or that bar-chair that fell down to the bottom.

Or worse, sometimes a supervisor will instruct a formworker “not to worry about it”, then after the inspector picks it, they rush around like a freaking idiot trying to get it fixed

Arial view of this formwork.

Location: Road Bridge – Port Adelaide South Australia

Arial view of concrete forms for bridge columns. The concrete forms have been braced with concrete counter-weights and scaffolding has been errected in order to provide access for construction workers to complete the formwork and steelfixing and place/finish the concrete.

Bridge Column Forms with Access Scaffolding