This paper addresses the problem of navigation of an autonomous robot when it moves in a modern concrete sewer. The robot must keep its orientation within mostly cylindrical sewer pipes. This implies a geometrical constraint on the environment in which the robot operates. We present a hybrid vision system that consists of (a) an optical camera and (b) a laser crosshair projector generating a cr...

Executive Summary This report presents detailed information on the effort to develop acoustic sensing technologies for natural gas pipe line monitoring. It starts with a historical evolution of the project and ends with the current status. The various technical accomplishments during this effort are pointed out. The latest technique involves the use of Lamb wave propagation in the wall of a pip...

To evaluate the seismic performance of pre-cast concrete shear wall with vertical reinforcements spliced by two different grout ways, quasi-static tests of two concrete shear walls holed by prefabricated corrugated pipe and one concrete shear wall holed by drawing out the pipe were tested. The test results showed that the wall holed by prefabricated corrugated pipe was basically the same as the...

1. ABSTRACT It has been about fifty years ago since the first unplasticized poly(vinyl chloride) (uPVC) pipes were installed for use in gas distribution purposes. Currently, about 22,500 km of uPVC is still in use in the Dutch gas distribution network. The pipes were originally designed for a lifetime of 50 years, but due to positive experiences the question arises if (and how long) the lifetim...