Refurbishing a nearly 350-foot pre-heater tower for a concrete manufacturing plant in Colorado's challenging winter weather was no easy task for Holcim, Inc., a global supplier of cement, concrete, and construction products. The plant location in Florence, Colo., is near several narrow, wind-channeling canyons including the Royal Gorge, home of the world's highest suspension bridge. Working in winter only added a layer of unpredictability.
U n i q u e F e a t u r e s |
» | Ensured worker safety by increasing accuracy of wind velocity predictions |
» | Created tools for short and long-term prediction of high winds |
» | Recognized with an ACEC Engineering Excellence Award - Special Projects |
These factors can create dangerous working conditions and cause construction delays. Most concrete plant pre-heater towers, which recover heat energy as raw materials pass through them through to the kiln, are dominant structures. To refurbish a tower, construction occurs far above the ground in potentially high-wind conditions. If workers were repeatedly forced off the structure during high winds, progress could slow significantly.
Holcim hired HDR to come up with a way to accurately predict high winds and provide high-wind notifications. An improved system would safeguard employees while keeping false alerts, such as those that had plagued the facility before, to a minimum.
To accurately gauge wind velocities, HDR scientists needed to understand severe weather anomalies in the area. The topography near the plant made it vulnerable to severe downslope windstorms, microbursts, and cold front passages that presented challenging atmospheric wind predictions.
HDR developed unique 24-hour wind prediction criteria by partitioning meteorological parameters to separate design wind limiting conditions (defined as 50 mph) from false alarms created from winds ranging from 40 to 45 mph. HDR produced hourly wind velocity predictions for each 24-hour period for short-term planning and a longer forecast (from 48 to 168 hours) for long-term planning.
The forecast utilized vertical wind observations from a wind profiler system near Aztec, New Mexico, to identify the approach of jet stream disturbances. These wind observations and a mountain wave forecast technique provided highly accurate forecasts. During the spring season, HDR monitored NWS WSR-88D Doppler radars to provide warning of microbursts and gust fronts.
HDR's efforts were successful in reducing the number of unnecessary work stoppages based on false high wind alerts and the tower project was completed on schedule.