InfraStructures - May 2011 - Chilean Bridge Earthquake-Damaged Beams Replaced with Hydrodemolition Techniques

Chilean Bridge Earthquake-Damaged Beams Replaced with Hydrodemolition Techniques

Following earthquake damage to two bridges over the Santiago’s Southern Approach (Acceso Sur Santiago) highway in Chile, hydrodemolition specialist contractor ISOTEC Ltda relied on an Aquajet HVD 6000 Robot to assist in removing damaged concrete beams and retain the rebar.

Badly damaged concrete beams on two bridges above Chile’s new Santiago’s Southern Approach (Acceso Sur Santiago) highway – caused by a recent earthquake – were removed by using hydrodemolition techniques with an Aquajet Aqua Cutter HVD 6000 robot, by Santiago-based, specialist contractorISOTEC.

The recently opened 46 km highway has been designed to relieve traffic flow in to the Chilean Capital, Santiago’s southern approaches to handle up to 25 million vehicles per year.

According to ISOTEC’s Jose Alday, the role of the Aqua Cutter was to remove the concrete above the beam’s allowing them to be lifted clear and replaced, whilst saving the rebar for reuse in installing the replacement beams.
“The hydrodemolition techniques proved ideal with no collateral damage to the remaining structure whilst removing the damaged concrete,” he said adding, “we also had to guarantee minimal impact for the highway users, allowing the highway to remain open throughout the removal process.”

Operating to a depth of up to 20 cm, the Aqua Cutter was able to expose the rebar with no damage.
ISOTEC’s hydrodemolition contract on both bridges was completed within 20 days with the damaged beams lifted clear and replaced in two night time operations by main contractor ICAFAL.

Hydrodemolition is a relatively new concept in South America, but widely used throughout Europe, with ISOTEC leading the way in Chile.

The company had initially specialized in high pressure water cleaning. “Taking advantage of this experience it was logical to expand our business into hydromolition, taking delivery of the new Aqua Cutter HVD-6000 from Swedish manufacturer, Aquajet Systems.

Hydrodemolition techniques
Concrete rehabilitation using hydrodemolition or water jetting techniques is becoming an increasingly important aspect of civil engineering and building renovation projects. Applications can involve cleaning, roughening, removal of deteriorated concrete and even cutting.

Water jetting is actively used for the removal of chloride damaged concrete layers down to the reinforcement bars or to a depth where the chloride content is at or below the permissible level.

It causes no damage or vibration to the existing rebar and prevents damage or loosening of adjacent concrete and parts.
Using a high-pressure jet of water, supplied at a pressure of 1,200 bar and a flow rate of 200 l/min by the company’s Woma pump coupled to the HVD-6000, the Aqua Cutter robot was able to blast the concrete without causing any damage to the reinforcement bars or adjoining concrete.

The Aqua Cutter robot from Aquajet is considered the most advanced offering a wide variety of features, ensuring top quality results are achieved safely at a high production rate with low operating and ongoing costs.

The robot is small and compact but at the same time big enough to handle the toughest applications.

Issued on behalf of Aquajet Systems AB by Joem Promotions