correction: sorry bret, but in response to comments by rick crockett, i did do a check of my calculations, and found an error. the natural frequency of your bare pier (14 foot 6inch schedule 40 pipe protruding 12 feet out of a concrete block) is 12.26 cycles/second, not 1.7 or so as i originally wrote. when i write these notes, i am in constant fear of being nocked off the internet by my isp for no show of activity , and i definitely pushed the submit button before checking my calcs. sorry, but it does not really change things much, except to prove that the pier is stiffer than the first calc showed. the natural frequency of a 12 foot cantalievered pipe is not something that one would intuitively know. nuff, tom