Section 5.12.6 refers to AISI Steel Plate Eng. Data for a guide on the design of anchor chairs. In this reference it recommends using 1.5 times the bolt load for the chair design. In section E.6.2.1.2 of API 650 it states that the anchor attachment design load is to be 3 times the bolt load...
The equation for the maximum design pressure was modified with the 2008 addendum. The variable Fy is described as the lowest minimum specified yield strength of the materials in the roof-to-shell junction. Is the value of Fy to be taken at the design temperature of the tank?
Lets say one has a bin with set dimensions and vent area. NFPA 68 can then be used to determine a value for Pred that allows the design conditions to work. Now what is the design pressure that should be used for the bin? Assume that deformation of the bin is not allowed. According to 6.3.1.2...
I am looking for opinions on what the appropriate redundancy factor would be for a tank supported by six legs with cross bracing. The seismic design category for the location is D. This would be a nonbuilding structure and in section 15.6 this factor is allowed to be taken as 1.0.
My...
Can anyone provide some background on the requirement of the bottom plate to project a minimum of 2" past the outside of the shell? I earlier editions of API 650 this distance was only required to be 1". Does anyone know the reason for increasing the distance?
Are standard F&D heads typically used for a pressure vessel of up to 25 psi? If so, what formulas should be used to calculate the required thickness? Looking at the ASME formulas and the small knuckle radius typically found on the standard heads, seems to indicate that the M factor will be...
I noticed that the coefficients on the equations for Ni and Nc have changed between Addendum 4 of the 10th edition and the 11th edition. Does anyone know the reason for the change and what effects the changes have on the calculated loads?
Also, in equation E.6.1.4-4B two new variables are...
Lets say that an analysis of a frame gives you an uplift force at the base of a column for the load combination of 0.6D + 0.7E. Now to size the footing are you required to multiply the weight of the footing and any soil above it by 0.6 to calculate the uplift resistance?
Design pressures at wall corners and roof edges calculated per ASCE 7 are to be applied over a distance a. This is listed as 0.1 x width, 0.4h, minimum of 3 feet. In the 1997 UBC this used to be limited to a maximum of 10 feet. Is ther a similar maximum now in ASCE 7?
In section V.1 of the appendix it states that it is intended to apply to tank with a normal operating external pressure exceeding 0.25 kPA, but less than 6.9 kPa. What about when the tank has an operating external pressure of 0.0 kPa and a design external pressure greater than 0.25 kPa? The...
Is it typical to dsign for an uplift, due to wind, on the roof of storage tanks? API 650 and AWWA D-100 do not seem to address the topic, they just give a formula for the lateral load. In fact the anchorage calculations in section 3 of API 650 do not include an uplift due to wind in table...
I have several references that I can use to look up the effect of elevated temperatures on the yield strength and modulus of elasticity of 304 stainless steel. Can anyone tell me what effect higher temperatures have on the tensile strength? I would assume that they would drop as well, but I...
When using Table 9.14.5.1.1 of ASCE 7-02 what would you use as a value for R when calculating the seismic loads. There are two areas of the table the could apply. The 4th line of the table is for Elevated tanks, vessels, bins, or hoppers. Here a value of 2 is suggested for Irregular braced...
I have a column with uplift and horizontal reactions in two directions at the base. I would like to size the footing to resist the uplift and keep the dimensions as small as possible. I have a copy of Principles of Foundation Engineering by Braja M. Das that I am using to calculate the...
I have received a project that calls for a flanged and reverse dished head. Can anyone point me to a reference that talks about the design of these? Are they intended to be used in a pressure/vacuum situation or are they typically only used in atmospheric applications? Thanks for any help you...
What is the highest value you have calculated and used for the gust effect factor, Gf? I am working on some tall vessels, which require me to use section 6.5.8.2 to calculate the factor. They are fixed at the base and have a guide to brace the vessel laterally at approximately half way up the...
What is the highest value you have calculated and used for the gust effect factor, Gf? I am working on some tall vessels, which require me to use section 6.5.8.2 to calculate the factor. They are fixed at the base and have a guide to brace the vessel laterally at approximately half way up the...
Appendix F gives guidelines for calculating the participating area of the roof and shell used to resist an internal pressure. The detail I am working on is similar to detail a shown in figure F-1. My question is if the vertical leg of the angle that is welded to the shell is longer than the...
I am working on reinforcing a roof to shell compression ring of a tank for an internal pressure greater than the original design pressure. This has led me into a little research of the allowable stresses for a radially loaded circular ring. Using the equation in section F.4.1, I have found...
