Storage Tank Foundation Analysis and Design GuideStorage Tank Foundation Analysis and Design Guide PURPOSE This practice establishes guidelines and recommended procedures for the design of Tank foundations using AFES (Automatic Foundation Engineering System). AFES can design Tank foundations as either soil- or pilesupported footings. CONTENTS This practice comprises the following: Create or Open New Project Setting Soil and Pile Parameters Creating New Structure Exporting Load Combination Assign Foundation Grouping Editing footing sizes and other parameters Pier and Footing Reinforcement Set Pile Layout for Pile Foundations Import Load Combination for various foundation groups Assigning Equipment Data Performing Design and Analysis functions Quantity BOM (Bill of Material) function Construction Drawing Export 3D Modeling Data (PDMS, PDS Frame Work Plus) FOUNDATION TYPES Types of foundations normally considered as are the following: Gravel ring walls supporting the tank shell. Concrete ring walls supporting the tank shell. Concrete mat on grade supporting the entire tank. Concrete mat on piles supporting the entire tank. Concrete rib beams and mat foundation for cold storage tanks. Concrete mat and heating coils for cold storage tanks. Foundation type to be utilized depends on the design requirements, type of tank, tank dimensions, soil and site conditions, environmental conditions, material availability, local codes, and Client requirements. 1 Storage Tank Foundation Analysis and Design Guide Design data sample for equipment is shown below based from actual projects. This equipment is a Exchanger supported by rectangular shape foundation. DESIGN CONSIDERATIONS Assumptions: The center to center diameter of ring wall is equal to the nominal tank diameter. If not applicable, an alternate foundation type shall be used. W= Empty Load − Bottom Plate Weight π x Tank Diameter Bottom Plate Weight = γ steel x Bottom Plate Thickness x Bottom Plate Area t.cal = 2 xW q x H − 2 x h x (γ c − γ s ) t.min = 300 mm γs = γ s 1 x h1 + γ s 2 x h2 h1 + h2 Where: q = unit weight of Tank fluid γ c = unitweight of concrete h1, h2 : Filling material height of ring wall γ s 1, γ s 2 : unitweight of soil under Tank W = weight of Tank shell plus the tributary weight of a cone perimeter of circumference N = thickness of Tank shell plate H = height of Tank h = height of Ring wall D = tan k diameter 2 Storage Tank Foundation Analysis and Design Guide 3 Storage Tank Foundation Analysis and Design Guide Create or Open New Project The first step is to enter project specific items. These items include general data, client data and Job data about a project. General data includes project No. Project Name, Client Name, Site Name, any more. The client data includes your client manager name, e-mail, number of telephone and fax, address. Job data includes assigned engineer, supervisor, duration of project, project rate that values the program needs to use for the specific project. The Project Number and Structure Name entered in Project Information will display as a menu header Note: General Data should be input. This data needs to use for the specific project. To open the existing project, or create a new project, Click on the “New/Open Project” from Top toolbar menu 4 Storage Tank Foundation Analysis and Design Guide Create New Project From File menu. A window dialogue will display as shown. 5 . A window dialogue will display as shown. Select New Project option then click OK button. select New/Open Project. Storage Tank Foundation Analysis and Design Guide Enter information then click OK button. 6 . Or Open Existing Project From File menu. Select Open Existing Project. A window will display as shown. select New/Open Project. Select a project then click OK button. Enter name in the Soil Bearing Capacity Name text box. Enter Soil Bearing Capacity (Qa) value. In case of New project.Storage Tank Foundation Analysis and Design Guide Setting Soil and Pile Parameters Setting of constants options include design information that AFES needs in order to design a foundation. 7 . strength reduction factors. safety factor. capacity of pile. Click Save button. Select Bearing Capacity of Soil tab. clear cover. supports and anchor bolt options. allowable increase of soil. Set Bearing Capacity of Soil from the Setting of Constant command Click Setting of Constant button. allowable increase of pile. bearing capacity of soil. This includes a number of parameters such as design code. material and unit weight. set all design parameters from the “Setting of Constant” form. Enter values for Elastic Modulus (Ep) and Pile Area. Select Pile Type. Click Save button. 8 . Enter name in the Pile Name text box. Select Capacity of Pile tab. Enter values for Allowable Capacities. Select Pile Shape.Storage Tank Foundation Analysis and Design Guide Set Capacity of Pile from the Setting of Constant button. Enter values for Pile dimensions. Storage Tank Foundation Analysis and Design Guide Creating New Structure Every input and output data can be saved in AFES Data Base according to projects. reuse data from projects conducted previously. An engineer is able to create a file for a new project. which provide work efficiency in control over project information. 9 . Choose Create New Structure button. or eliminate old and useless data for the user’s own sake. Input structure name. and then click on the “New” button. “Add: New Structure Name” dialog window will appear. it will be available for import in this program. Export Load Combination before assigning group otherwise they will be deleted. A warning message will appear as shown.Storage Tank Foundation Analysis and Design Guide Exporting Load Combination This function enables us to export load combination data that was saved in text file in AFES program. Click OK button. Click Load Combination button. Click Load Case/Combination button. 10 . The Load Combination form will appear as shown. After exporting the file. The available foundation types are as follows. we will create the structure as shown below.Storage Tank Foundation Analysis and Design Guide Click Export button. The foundation modules in red box shown in above figure are normally used for Storage Tanks. 11 . assign file name then click Save button. This is very important because it eliminates repetitions of commands. Assign Foundation Grouping. Foundations with the same load combinations are recommended to join in one group. At the end of this step. The Assign Foundation Grouping command is used for assigning group for models with multifoundations. Choose directory to save file. Enter coordinates as shown in figure above. Create 3 nodes by clicking Add button 3 times.Storage Tank Foundation Analysis and Design Guide Click Geometric Data button. 12 . Select Pile fdn. Select Tank_1 from the Group type. 13 . Click New button. Click arrow pointing to the right. Select node 1 from the Using node list form. Select Same size. option.Storage Tank Foundation Analysis and Design Guide Click Assign Foundation Grouping button. Assign name from the Group name text box. Click Save button. Assign group for node 1. Click Save button. Click arrow pointing to the right.Storage Tank Foundation Analysis and Design Guide Assign group for node 2. Select Different size. Select Tank_1 from the Group type. option. Click New button. Select node 2 from the Using node list form. Assign name from the Group name text box. 14 . Select Block Foundation. Select Non Pile fdn. Storage Tank Foundation Analysis and Design Guide Assign group for node 3. Assign name from the Group name text box. Click arrow pointing to the right. Select node 3 from the Using node list form. 15 . Select Different Size. option. Click Save button. Select Non Pile fdn. Select Tank_1 from the Group type. Click New button. Storage Tank Foundation Analysis and Design Guide The preliminary structure configuration is shown below. 16 . Size for both footings should normally be the same. Select TANK1 from the Group selection in top menu. The footing thickness shall be 12 inches (300 mm) minimum and thickened in 4 inch(=100 mm) increments. Plan footing dimensions should be in even 2 inch (50 mm) increments. Engineering judgment should be used in deciding when this might be applicable. the footing thickness shall be checked in accordance with Building Code. the possibility of the moment increasing the punching shear should be considered similar to the way it would be for slabs (refer to Building Code). 17 . The footing thickness adequate for embedment of pier or column reinforcement should be checked in accordance with Building Code. Click Feature Data/Dimension button. Edit footing size of group TANK1. If top tension exists. Choose SUPT-01 in the Soil Name selection.Storage Tank Foundation Analysis and Design Guide Editing footing size and other parameters The Feature Data (Dimension) command is used to define the dimensions and other parameters necessary for the foundation and piers. For thin footings with a large concentrated pier moment. Storage Tank Foundation Analysis and Design Guide <Footing tab> <Pier tab> 18 . Choose SUPT-01 in the Soil Name selection. Select TANK1RING from the Group selection in top menu. <Footing tab> 19 . Click Save button. Edit footing size of group TANK1RING. Click Feature Data/Dimension button.Storage Tank Foundation Analysis and Design Guide Enter values as shown in the Feature form for Footing and Pier. 20 . Click Feature Data/Dimension button. Click Save button. Edit footing size of group TANK1BLOCK. Choose SUPT-01 in the Soil Name selection. Select TANK1BLOCK from the Group selection in top menu.Storage Tank Foundation Analysis and Design Guide <Pier tab> Enter values as shown in the Feature form for Footing and Pier. Storage Tank Foundation Analysis and Design Guide <Footing tab> 21 . Storage Tank Foundation Analysis and Design Guide <Pier tab> Enter values as shown in the Feature form for Footing and Pier. Click Save button. Note that only Grout Thickness is activated. 22 . Minimum reinforcing for piers is #5 at 12 inches on each face with #4 ties at 12 inches. Reinforcement data form will 23 . Minimum dowel projection should be that required for a tension splice in accordance with Building Code. Use dowels to transfer the column loads to the footings. Pier ties are not normally detailed as column ties. The arrangement of footing bars are parallel to the X and Y axis except for Tank1 and Tank2 Ring type modules which are in radial and longitudinal directions. Size and reinforcement for both columns should normally be the same. When the required reinforcing approaches ρmax. Dowel splices are not required if the vertical pier reinforcing projection is less than 6 feet in height. investigate the pier as a column. All ties should encircle the vertical reinforcement. Size and reinforcement for each pier should normally be the same. If top reinforcing is required. as is normally the case. Minimum Pier Reinforcement Piers should be designed as cantilever beams with two layers of reinforcement.Storage Tank Foundation Analysis and Design Guide Pier and Footing Reinforcement The Reinforcement Data command is used to assign bar sizes and spacing for piers and footings. If longitudinal reinforcing is not required to resist vertical loads. Place double ties at top of piers to protect anchor bolts. click the “Reinforcement data” appear as shown in below figure. use dowels with minimum projections required for tension splices in accordance with Building Code. Below are based from our company standards. or the rebar size in feet above the top of the footing. For cases that exceed this limit. button. Set of bar array options are available in the Footing option. minimum reinforcing is #4 at 12 inches c/c. From the main tool bar. Minimum Footing Reinforcement The minimum amount of bottom reinforcing is #5 at 12 inches c/c. through ties are not required. Reinforcement bar sizes depend on the design code designated in the Setting of Constant command. Different forms for single and double layer arrangement are presented. Set Footing reinforcement arrangement. 24 .Storage Tank Foundation Analysis and Design Guide Tank1 Foundation with Ring Wall Pier Set Array Type Select from the array types of footing reinforcement layout. Select Save then Close button.Storage Tank Foundation Analysis and Design Guide Select Save then Close button. Select Pier tab. Tank1 Block Foundation 25 . Enter the values of footing re-bar as shown. Select Save then Close button. Different forms for single and double layer arrangement are presented.Storage Tank Foundation Analysis and Design Guide Set Pier reinforcement arrangement using the Pier tab. 26 . Set Footing reinforcement arrangement. Tank1 Ring Foundation with Ring Wall Pier Set Array Type Select from the array types of footing reinforcement layout. Fore further discussions. Enter the values of footing re-bar as shown. 27 . Select Save then Close button. Select Pier tab. refer to Help documents.Storage Tank Foundation Analysis and Design Guide Select Save then Close button. (PCD). Enter Star Angle.Storage Tank Foundation Analysis and Design Guide Set Pile Layout for Pile Foundations The Pile Data command is used to layout and assign piles in the foundation. Select PHC-12 from the Pile Name selection. Define pile features first before proceeding to this function in the Setting of Constant command. Select Origin Point. 28 . and Pile Circle Dia. This function is activated only when the selected type is Pile fdn. Click Regenerate button. Set Pile Arrangement for foundation group TANK1 (Circular Array) Select TANK1 from the Group selection in top menu. No. Regular pile arrangements are available for circular or rectangular arrays. Click Pile Data command. in the Assign Foundation Grouping command. Select Array Wizard tab. Click OK button. Set Circular option. The purpose of the combinations is to take into account soil bearing capacity. and pile capacity check for a pile supported foundation. 29 . add. and taking different factors for various cases. pier design.Storage Tank Foundation Analysis and Design Guide Repeat above steps in creating new circular pile array arrangement then click “Add Draw” to include to defined pile arrangement. edit or delete load cases and combinations. The Load Case/Combination command is used to define. Mainly applied load combinations are Allowable Strength Load Combination and Ultimate Load Combination. Combinations by Allowable Strength Design are normally applied with 1. Combinations referring to Ultimate Strength Design are used for footing reinforcement. uplift check. Assigned load cases can be combined with factors in accordance with a few design methods and specifications. one way shear check. Import Load Combination for various foundation groups. overturning.0 factored value. sliding. Operating Weight (Do) The operating weight (also called "wet weight") is defined as the empty weight of the exchanger/vessel (De2) plus the weight of operating fluids or products. No allowance shall be made for shielding of wind loads by nearby equipment. and ladders and platforms. including internals and attachments that are installed integrally with the vessel. Test Weight (Dt) The test weight is defined as the empty weight of the exchanger/vessel (De2) plus the weight of test fluid (usually water) and any attached piping and equipment required for the hydrostatic test. DESIGN LOADS The following design loads shall be considered for design of the foundations. In case of major discrepancies between calculated 30 . This information is taken from the vessel/exchanger drawings/data sheets and planning study drawings. This information is taken from the vessel/exchanger drawings/data sheets. Empty Weight (De2) The empty weight is defined as the in-place weight of the completed exchanger/vessel (De1) plus the weight of internals. The calculated design moments and shears due to wind load should be compared to those shown on the exchanger/vessel drawings. This information is taken from the vessel/exchanger drawings/data sheets. Verify that all items which are to be erected with the vessel are included in the erection weight. These are also based from our actual projects. Note that this load condition is considered only when the exchanger/vessel is to be field-hydrotested.Storage Tank Foundation Analysis and Design Guide Below are load cases and load combinations usually used for Horizontal Vessel and Exchanger footing based from Building code. Wind Loads (W) Transverse and longitudinal wind loads shall be determined in accordance with Design Guide 3DG-C0100001 unless project criteria dictates otherwise. Load cases definitions are also discussed for further information. Verify with the Mechanical Discipline for this condition. but excluding the weights of fluids or products which will be placed in the exchanger/vessel during operation. This information is taken from the vessel drawings. insulation. Verification of the operating conditions may be required from the Process Engineering Discipline. piping. Erection Weight (De1) The erection weight is defined as the fabricated weight of the vessel. The load combinations 0.0 EH2).Storage Tank Foundation Analysis and Design Guide wind loads and the loads shown on the equipment drawings.2 De2 ± 1.7 Lb (for exchanger foundations only) (g) 1. the factor of 1.4 Dp) ± 1. do not need to be considered since they are covered by load combinations (b) and (c).4 T + 1.3 EH1 ± 1.4) due to the transient nature of hydrotesting conditions.6 W (e) 1.2 Dt The load factors shown above are based on ACI 318.6 W (c) 1. Also. E = ±(1.75 (1.2 (Do + T + Dp) ± 1.4 (Do + T + Dp) (b) 0.6W or 1.0E). Transverse seismic forces shall be resisted by both piers using saddle or base plate reactions as the basis for computing base shear.9D ± (1.3 EH2) and E = ±(0.e. The longitudinal seismic force shall be resisted by the fixed end pier only unless the piers are tied together by tie beams below the base plates.4 Do + 1.0 E (f) 1. i. LOAD COMBINATIONS Concrete Foundation Design The following factored load combinations should be used for design of the foundations (a) 1.0 E (d) 0.75 [1. except for load combinations (c) and (e). 31 .4 De2 (or 1.4 De1)] ± 1.0 EH1 ± 0. in load combination (g). coordinate with the Mechanical Discipline for resolution.2 is used (instead of 1. as listed in ACI 318.. Seismic Loads (E) Seismic loads shall be determined in accordance with procedures presented in Company Design Guide unless project criteria dictates otherwise. which are based on the slightly more conservative requirements of IBC 2000. The horizontal seismic loads shall be applied 100% in one direction and 30% in the orthogonal direction.4 De2 + 1. (See Section R9.Storage Tank Foundation Analysis and Design Guide Wind load is calculated in accordance with ASCE 7-98 (including the directionality factor) and seismic load is calculated in accordance with IBC 2000 (based on strength-level methods. Click Import button.) The weight of the foundation and of the soil on top of the foundation shall be included as dead load in all of these load combinations. You can actually create new load combinations through the Load Combination button but in this example. rather than servicelevel). Access the load combination file then click Open button. The Load Combination form will display as shown. 32 .2 of ACI 318 for guidance. for service-level seismic loads based on another code. the seismic load factors should be increased as appropriate. the load factors for wind in the various load combinations should be reduced appropriately. we will use Import command. If wind load is calculated using another code which does not include the wind directionality factor. Click Load Combination button. Similarly. Select appropriate button as explained in the warning message form. 33 . Click Save button. Repeat same procedure for the other foundation groups.Storage Tank Foundation Analysis and Design Guide A warning message will appear as shown. Figure 2: Tank foundation modules showing equipments. 34 .Storage Tank Foundation Analysis and Design Guide Assigning Equipment Data Equipment data is essential for Storage Tank Foundations. the input load values for the Empty. Figure 1: Sample equipment input data for a certain equipment type normally used for Storage Tanks. Empty load is used to determine required ring wall thickness to be compared to the minimum allowed. Nevertheless. Tank dimensions and soil parameters including of the backfill materials are also necessary. Operation and testing weights may need to be entered again in the load case tables as they have no direct links. Storage Tank Foundation Analysis and Design Guide Performing Design and Analysis functions AFES executes Foundation Analysis and Design according to design standards widely accepted. pier. BS 8110. It is assumed that all external forces are loaded at the center of the piers and the connection between the pier and the footing is considered to be rigid enough to carry those forces. stability and sectional design of components of footing. Strength. The design codes of AFES support ACI318-99. 02. Korean. Select Analysis button. AIJ-WSD99. CP-65 and IS456 (2000). 35 . Click on the Foundation Analysis/Design button to be able to start analysis and design. corbels and tie girders are properly examined. Click Report button to view calculation report. you may refer to help menu. 36 .Storage Tank Foundation Analysis and Design Guide For through discussion on setting other functions such as General. Click Analysis button. The calculation report will display as shown below. Detail Report Option and Contents. Temperature and Shrinkage/Stability. Tank Design. backfill. Set parameters from the Afes – Bill of Material form. crushed stone. select Quantity (BOM) then Take off BOM 3D. For Active Foundation structure From Design menu. grout.Storage Tank Foundation Analysis and Design Guide Quantity BOM (Bill of Materials) function BOM functions are used for estimate of earthworks including other related items such as excavation. disposal. 37 . Click OK button. lean concrete. anchor bolts and steel reinforcements. concrete. protection materials. Options for BOM take off for active structure and all structures in a project is supported. formworks. From Design menu. 38 .Storage Tank Foundation Analysis and Design Guide The Bill of Material form will display as shown below. select Quantity (BOM) then Take off BOM 3D (All Structure). Click OK button. 39 . Check structures to include BOM Take off calculation from the form below. Click OK button.Storage Tank Foundation Analysis and Design Guide Set parameters from the Afes – Bill of Material form. Storage Tank Foundation Analysis and Design Guide The Bill of Material form will display as shown below. 40 . You can set from this command the drawing preferences to be utilized before exporting to AutoCAD. Click OK button. Click Export DXF File button.Storage Tank Foundation Analysis and Design Guide Construction Drawing AFES is a completely integrated software package for automatically producing drawings of reinforcing details for foundations that have been analyzed and designed using AFES. A form will display as shown below. The Export DXF File command is used to export the drawing files made from AFES to other programs such as AutoCAD and MicroStation. Layout and Drawing detail including plan and sections of foundation with reinforcement schedules. Set options from this form. The drawing report consists of the Standards. Standard drawings are already set up for various design codes. The program will create the DWG or DXF file format and display a construction drawing through a viewer. 41 . AFES interfaces with AutoCAD and MicroStation to create a construction drawing with bar-schedule. <Foundation Layout Plan> <Tank1> 42 .Storage Tank Foundation Analysis and Design Guide Drawing details will display as below. Storage Tank Foundation Analysis and Design Guide <Tank1Block> <Tank1 Ring> 43 . Set various parameters accordingly and click OK button. PDS Frame Work Plus) Today. modeling objects from each part allows other parts to assess those object on their work process helping streamlining the work process through project completion.Storage Tank Foundation Analysis and Design Guide Export 3D Modeling Data (PDMS. A dialogue form will display as shown. you will experience significant productivity. Export to PDS Click Export PDS Data button. you may refer to Help PDF manuals. Set Output unit and coordinate mapping options. Export to PDMS Click Export PDMS Data button. For further discussions. A 3D foundation model of the objects designed by various design parts effectively communicates the geometric design data. Check Send Model Data to PDS option then click OK button. plant design works involve many design parts. With our design to modeling interface from AFES to Frameworks Plus. Therefore automating the work process from design to 3D modeling forms an integral component of reducing overall project cost. 44 . A dialogue form will display as shown.