Leg - Base Plate/Bolt Information

Owned by Former user (Deleted)
Dec 11, 2015
6 min read

Base Plate Design Information

Base Plate Width: Enter the width of the base plate.

Base Plate Length: Enter the length of the base plate.

Base Plate Thickness: The thickness of the base plate.

Design Temperature: The maximum mean metal design temperature for the base plate. This value is also used for bolting material.

Material: A brief description of the component material. When the material selection dialog is used, the default description is based on settings on the Materials-Misc. tab under Tools > Defaults. For example, if the settings are for Spec and Type/Grade and the material is SA-516 Grade 70, this field will show SA-516 Gr. 70. If the settings are instead just for Spec, the field will show SA-516. The field may be edited by the user to say anything without breaking the relationship to the material database; while this flexibility can be very helpful, the user must take care to enter correct information.

Condition: A brief description of the component material. Similar to the "Material" field, the description will default a certain way based on settings on the Materials-Misc. tab under Tools > Defaults when the material selection is used. This field may be edited by the user without breaking the relationship to the material database. As with the “Material” field, the user must take care to enter correct information.

Density: The material density based on table PRD from Section II, Part D. For those materials that did not have a clear match in this table, every effort was made to assign conservative values. Manually editing this field will sever the connection to the material in the database as indicated by the "Unlisted Material" caption.

Stress (Hot): The material allowable stress at the base plate temperature. When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. In cases where the base plate temperature exceeds the highest temperature entry for this material’s stress line, the value will be zero. Manually editing this field will inform the software that the user is defining the material differently than what is stored in the database and the connection to the material in the database will be severed. This is indicated by the “Unlisted Material” caption.

Stress (Cold): The material allowable stress at 70 °F (20 °C). When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. Manually editing this field will sever the connection to the material in the database as indicated by the “Unlisted Material” caption.

Yield Strength: The material yield strength at the base plate temperature. This value comes from Section II, Part D, Table Y-1. In cases where the base plate temperature exceeds the highest temperature entry for this material’s yield line, the value will be zero. There are several materials that do not have clear matches in these tables. When a clear match cannot be found by the software’s assignment criteria, the software will calculate the yield strength using the external pressure chart and the method described in UG-28(c)(2) Step 3. This is more common with non-ferrous materials. If no match is found and the software cannot perform the described calculation, this value will be zero. Manually editing this field will inform the software that the user is defining the material differently than what is stored in the database and the connection to the material in the database will be severed. This is indicated by the “Unlisted Material” caption.

 

Effective Length Factor: This value can range from 0.50 to greater than 2.0, however some references recommend that values less than 1.5 be avoided. Lower values are more likely to result in a passing design and thus are considered less conservative.K=0.5 represents both ends of the leg as being fixed with no lateral or rotational movement. K=1.0 represents both ends of the leg as being pinned (rotational movement with no lateral movement). K=2.0 represents one end of the leg as being fixed and the other end as able to move laterally.

Leg-to-baseplate Attachment Factor: The rigidity of the connection between the bottom of the leg and the base plate. Lower values represent a less rigid connection and are considered more conservative. The software will use the value entered in this field to calculate a corresponding value in the "Effective Length Factor" field; to be consistent with the recommendations for that value, this value should be in the range of 0.5 to 0.75.

Bending Coefficient: The bending coefficient can be calculated per equations in various references (e.g., Manual of Steel Construction). This value should range between 0.85 and 1.0 for leg calculations; 1.0 is the more conservative value.

Bolt Design Information

Anchor Bolt Circle Diameter: The diameter of the circle that passes through the center of the bolt patterns on every base plate.

Diameter: The anchor bolt nominal diameter.

Root Area: The bolt root area based on the smallest diameter on the bolt. This field will automatically be completed if the Bolt Search is used to select the bolts.

Ultimate 28 day concrete strength: The theoretical concrete strength after at least 28 days of setup. This value will be multiplied by the concrete factor on the Wind/Seismic tab under Tools > Defaults to determine the allowable concrete strength.

No. of Bolts: The number of anchor bolts per base plate.

Bolt Size / Threads Per Inch: These fields are completed automatically when a bolt size is selected from the Bolt Search.

Material: A brief description of the component material. When the material selection dialog is used, the default description is based on settings on the Materials-Misc. tab under Tools > Defaults. For example, if the settings are for Spec and Type/Grade and the material is SA-516 Grade 70, this field will show SA-516 Gr. 70. If the settings are instead just for Spec, the field will show SA-516. The field may be edited by the user to say anything without breaking the relationship to the material database; while this flexibility can be very helpful, the user must take care to enter correct information.

Condition: A brief description of the component material. Similar to the "Material" field, the description will default a certain way based on settings on the Materials-Misc. tab under Tools > Defaults when the material selection is used. This field may be edited by the user without breaking the relationship to the material database. As with the “Material” field, the user must take care to enter correct information.

Density: The material density based on table PRD from Section II, Part D. For those materials that did not have a clear match in this table, every effort was made to assign conservative values. Manually editing this field will sever the connection to the material in the database as indicated by the "Unlisted Material" caption.

Stress (Hot): The material allowable stress at the base plate temperature. When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. In cases where the base plate temperature exceeds the highest temperature entry for this material’s stress line, the value will be zero. Manually editing this field will inform the software that the user is defining the material differently than what is stored in the database and the connection to the material in the database will be severed. This is indicated by the “Unlisted Material” caption.

Stress (Cold): The material allowable stress at 70 °F (20 °C). When a 3.5:1 safety factor is specified in the vessel screen, this value comes from Section II, Part D (Table 1A for Ferrous Materials, Table 1B for Non-Ferrous Materials, and Table 3 for Bolting). If a 4:1 safety factor is specified, this value is calculated based on the ultimate strength from Table U in Section II, Part D; furthermore, the value is limited to the values listed in the allowable stress tables for yield and creep governed cases. Manually editing this field will sever the connection to the material in the database as indicated by the “Unlisted Material” caption.