The tank is comprised of 5 bands with full-pen welds at the seams between the bands and also at the individual segments making up each band. The tanks are being constructed one after the other with the same welders. I calculated that we have a total of about LF of weld. We are using Section The other interpretation is that the tests should be performed as the work progresses and one test is to be taken in each LF of weld as the work progresses or progressed.
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Scott, P. Revised wind design criteria and definitions consistent with ASCE Revised erection tolerance requirements for ground-supported flat-bottom tank shells when subject to small compressive stress levels.
Revised testing requirements such that leak testing of shell-to-bottom joints is required for both Sec. Ground motion hazard analysis requirements revised to reference procedure of ASCE Revised the scaling requirements for base shear and overturning moment when the alternate procedure of Sec. Expanded requirement that piping and supports be designed to not impart significant loads to the tank shell. Previously addressed only in Sec. Clarified Sec. Added top and intermediate wind girders to the list of components that do not have to comply with width-thickness limitations of Sec.
Added requirement that Method 1 shall be used to determine allowable local buckling compressive stress for ground-supported flat-bottom tank shells.
Added requirements for self-supporting cone roofs. Limited design of self-supporting roofs in accordance with API to apply only to unstiffened carbon steel plates. Added requirement that a Site Response Analysis is mandatory for sites classified as Site Class F except for short period structures on liquefiable soils. Added requirement that the site-specific procedure must comply with ASCE when a site-specific procedure is required or specified.
Deleted requirement allowing live load to be used to reduce the overturning uplift. Deleted Sec. Leslie D. Corrected upper limit of maximum longitudinal shell compression stress in Corrected definition of a in Sec.
Revised all references to ASCE 7 to edition. Added commentary on design of piping systems and supports. Corrected API reference. Corrected period used to calculate SDS.
Updated reference for calculating response spectrum to ASCE Through his original employment and as the result of acquisitions, mergers and corporate changes he has served in significant roles for six different companies located in the San Luis Obispo, CA region. He has extensive experience in estimating, engineering, detailing, and project management of shop-built and field-erected storage tank construction projects with special emphasis in seismic design aspects and code requirements.
Projects have served the following industries: potable water, water treatment, wine, wastewater, sewer, petroleum, chemical, fertilizers, industrial gases, and aviation fuel. He was the inventor or co-inventor on two storage tank related patents and has been a speaker at several industry related seminars.
Flex connectors have some level of resistance to the deflection that is intended to provide flexibility. Some connectors have extremely high levels of resistance. Before flexibility is realized on these connectors, friction forces must be overcome, so connections to the tank require special foundation construction with thrust blocks integral to foundation so that forces are not transferred to tank.
Seismic loading can vary dramatically within a geographic region, so it is important to determine exact location before developing preliminary design information. Be sure that when your preliminary design information is developed that in includes freeboard considerations. Mar 9, o Coatings generally for shop built tanks, consult your corrosion engineer Interior submerged surfaces o Details easy to coat o All joints seal welded o All stainless steel components must be electrically isolated from the tank.
Dissimilar metals o If stainless steel components are used inside the tank below the water level, AWWA D requires that electrical isolation be provided. This would be for accessories, structural components and connected piping. If stainless steel external piping is specified, it must be electrically isolated at the connection to the tank to prevent corrosion of the tank.
Interior Roof and Structure o Match coating system features with selected details of construction o Most shop applied primers must be held back from edges to be welded to avoid compromising weld integrity o Alternate construction details Match coating system with anticipated service conditions How Roof Construction Details Affect Coating, Maintenance and Life Expectancy - Conventional - Seal welded laps and seams - umbrella roof higher profile, steeper - umbrella roof, seal welded higher profile, steeper - Seal welded laps, seams and structure - Seal welded laps and seams with external, seal welded structure Issues with additional welding The seal welding of the components simplifies the coating process, reduces long term maintenance and extends coating system and tank life.
However, all the extra welding does create shrinkage distortion in the roof. Although the roof will be stiffer, roof deflection and small areas of ponding may occur except on the umbrella roof options.
A couple of options to reduce the weld distortion effects are increase roof minimum thickness to and increasing roof pitch to or even
Download: Awwa D100-11.pdf
Download: AWWA Standard D100-11 Pdf.pdf
Significant Changes in AWWA D100-11