New method for vertical testing and Chimney measurement

Chimney construction using slipform is among the most challenging construction exercises. Due to poor workmanship, faulty instrumentation and sometime negligence the constructed Chimneys are liable to deviate from the design dimensions of the Chimney. This leads to unpredictable forces on Chimney and needs an assessment for the structural safety. However, measuring the as-built form of a Chimney is equally difficult task as conventional methods fail or yield unreliable information.

We have developed a method based on laser scanning and total station which can yield information on all construction tolerances, e.g. deviation of centre line at different levels from vertical, internal and external shell diameter at different heights, longitudinal profiles of Chimney internal and external surfaces. In addition, we can also determine wall thickness at different levels, surface undulations of the walls, and bulging on shell surface. All these parameters are determined with high degree of reliability and can help in taking decision on retrofitting or strengthening of the Chimney which need so.

We use least squares approach to match the Chimney data and the CAD drawing of the Chimney for observing deviations.

All points as shown above are measured precisely. Millions of such points are observed on Chimney surface.

Chimney surface can be reconstructed and the undulations measured precisely.