Automation and Robotics in Construction XVI © 1999 by UC3M HEROIC: A CONCEPT ROBOTIC SYSTEM FOR HYDRO-EROSION IN CONCRETE REPAIR PREPARATION Denis A. Chamberlain ', Ernesto Gambao2, Stephen E.McCormac3, Miguel Angel Garcia', Thomas McCulloch `, Catarina Alexandra Alves Seibert `', Petros Souretis' and Alan Whites 'CRU, Structures Research Centre, Department of Civil Engineering,City University, London. UK; `Politecnica de Madrid, Spain;; Institute of Control Technology for Muclrine Tools and Manufacturing Units, University of Stuttgart. German.v Memlurglcas Nales S.A.Spain;'.Macken;ie Construction Ltd, Scotland.; 6.Unifi.y Alves & Irnrao, Lda. Portugal;7.Elliniki Technodonriki A.E., Athens, Greece; ".Thornbr_v Hill Engineering Consultants. Glasgow, UK. Abstract: The definition of the excavation geometry in concrete removal has a considerable effect on the longevity of the subsequent replacement repair material . Also, when removing defective material, it is important to use methods that do not cause micro-cracking and other structural damge. The hydro - erosion concept , a controlled version of hydro-demolition. represents a means of excavating material to well definded gometry without causing such damage . To achieve a robotic solution for this, it is necessary to incorporate sensing and control strategies that are roboust in the harsh environment . An experimental robot has been devised for investigations into these issues . This work is being undertaken within a European Community project named HEROIC : Hydro Erosion for Repair Of Insitu Concrete. Keywords : HEROIC, concrete , repair , hydroerosion , robot , sensing , control I INTRODUCTION There is an increasing demand for concrete repair in the developed world. This affects highways, bridges, buildings, factories, power stations, airports and coastal defences. The scale of this is indicated by the estimated 3 million kms of paved highway, 4.4 million dwellings in system buildings and 900,000 bridges in the European Community alone. In the reported research the objective is to advance the use of hydro-erosion systems for removing defective concrete prior to the placement of replacement material. Achieving timely, long lasting and low-cost repairs is therefore extremely important. Equally important factors are worker safety and protection of the natural environment. Effective use of non-destructive testing methods (NDT) that gives an accurate assessment of structural condition can take advantage of censor fusion techniques. This can give a basis for setting priorities. Longevity of concrete repair work is frequently not achieved, with repairs lasting perhaps only one or two years. A major question here is whether or not the actual repair process causes accidental damage. Also, it is known that repair design has a great influence on durability. As usual, in the field of automation and robotics for the construction industry. the potential of high cost needs to be evaluated against alternative manually operated alternatives. Regarding safety with erosion. which involves the use of high-pressure water, there are compelling advantages in remote handling of tools, which also gives the way for significantly higher capacity systems. Also, where a suitable access solution can he achieved, there is the possibility for process containment. HEROIC is a European Commission supported industrial research project No.BES2-2783. under the CRAFT BRITE-EURAM programme. It commenced in September 1998 and is due to finish in August 2000. HEROIC stands for Hydro Erosion for Repair of In-situ Concrete. The scope of this includes NDT based prediction of the repair task, control feedback for automation of the hydro-erosion process and robotic tool handling systems. The sequence of these is followed in this paper. 585