SUDAS Revision Submittal Form

Transcription

1 SUDAS Revision Submittal Form Status Date: As of 5/8/08 Topic: Traffic signal pole foundations in rock Manual: Specs & Design Manual ocation: Spec Figure 800.0; Design Sect E-, B,, d and Fig E-.04 Requested Revision: See attached Figure Section E- (Specifications Information), B (Part - Products), (Underground), d (Foundations) Foundation size and depths vary according to pole style, mast-arm length, and pole loadings. The SUDAS Specifications provide figures for both pedestal poles and for mast-arm poles (Figure E-.04). SUDAS standard Type A mast arm pole foundation in soil designs (Table E-.0 and Figure E-.04) are based on the following guidelines, parameters, and assumptions: Broms method for lateral resistance (moment/shear design) per AASHTO Standard Specifications for Structural Supports for Highway Signs, uminaries, and Traffic Signals, 6th Edition, 0 (AASHTO TS 6), with a safety factor of.86, which accounts for the possible under capacity of the soil strength (0.7) and the overload factor for the loadings (.0). Alpha method for torsion design per FHA NHI 0 06 Drilled Shafts: Construction Procedures and RFD Design Methods, May 00, with a safety factor of.0. Disturbed soil due to frost:.5 feet for moment/shear design, 5.0 feet for torsion design. Broms method as presented in AASHTO TS 6 includes an additional.5 diameters of foundation length to be added to the minimum foundation length required. The maximum value of.5 diameters or.5 feet shall be used when determining the disturbed soil for moment/shear design. Groundwater is present for moment/shear and torsion designs. Pole loadings as shown in Figure E.0, with poles designed per AASHTO TS 6 specifications. Basic wind speed equals 90 mph with a 50 year mean recurrence interval and gust effect factor of.4 for strength design. Use Category II for fatigue design. Apply only natural wind gust loads (i.e. do not apply galloping loads, vortex shedding loads, or truck induced gust loads) for fatigue design. Install vibration mitigation devices on all traffic signal pole mast arms over 60 feet in length as shown in the figures. Cohesive soils along the length of the foundation with an average blow count (N60) greater than or equal to 8, which equates to an average unconfined compressive strength (Qu) greater than or equal to.0 kips per square foot. Reinforced concrete design per AASHTO TS 6 specifications. For pole loading conditions greater than shown in Figure E-.0, granular soils, or lower strength soils, special foundation designs will be required. Soil boring testing should be performed prior to construction to verify soil types and strengths if non-typical soils are suspected. If rock is anticipated at the project site and the designer intends to utilize the Type C mast arm pole foundation in rock or a Type B foundation (see Figure E-.04), determine rock quality through a subsurface investigation completed by a geotechnical engineer licensed in Iowa. If rock is encountered unexpectedly, the contractor may undertake a subsurface evaluation conducted by a geotechnical engineer licensed in Iowa to determine the quality of the rocks encountered. Based on that investigation, the Engineer may approve the use of a Type B or Type C foundation in rock if requested by the contractor. Reason for Revision: Added option for placement in rock. Dual SUDAS/Iowa DOT figure/standard Road Plan.

2 District: District: District: District: Figure 800.0, sheet lists max; sheet just has. Note - this was corrected. District: District: Final District Action Summary: Board of Directors Action: All 6 districts approved; see comments above. Approved.

3 " Dia. Ground ire Duct Expansion Material Pavement Grade " Clearance The Type A Foundation is the normally required foundation construction. here rock is encountered, the Engineer may approve the use of the Type B or C Foundation. Prior to installing a foundation in rock, obtain a subsurface investigation certified by a geotechnical engineer licensed in the State of Iowa. " Shape top inches with forms. '-0" Min. 4'-0" Max. Ground Rod Clamp 6 Spaces at 4" O.C. Install rodent guard or non-shrink grout with weep hole. Furnish nut, nut and plate, or nut and anchor bolt Anchor Bolts Upper Tie Bar Spacing S #5 Ties Ground Rod ower Tie Bar Spacing S Max. Mast Arm ength Foundation Tie Bars Count Size Upper Spacing ower Spacing ength Count # Spaces S # Spaces S 5'-0" '-0" '-0" '- 7 9 " N/A N/A 45'-0" '-0" 4'-0" '- 9 " N/A N/A MAST ARM POE FOUNDATION IN SOI TYPE A FOUNDATION " Clearance 55'-0" '-0" 6'-0" 5'- 5 5 " 60'-0" '-0" 8'-0" 7'- 70'-0" '- 8'-0" #0 7' " 80'-0" '- '-0" 4 #0 0'- 90'-0" 4'-0" '-0" 6 #0 ' " 00'-0" 4'-0" 4'-0" 8 #0 ' FIGURE SHEET OF 4 " Clear Cover (Typ.) PAN VIE #5 Ties Stagger hooks to engage different "V" bars each row BENT BAR DETAI - ¾" Min. Typ. #5 Ties D=½" (Typ.) Note: All dimension are out to out. FIGURE STANDARD ROAD PAN TS-0 SHEET of 4 TRAFFIC SIGNA POE FOUNDATION

4 Type B Foundation is applicable for traffic signal poles with mast arm lengths up to 60 feet. '-0'' Min. If the excavation for a Type B Foundation is left open for more than calendar day, install temporary barrier rail if any part of the excavation is located within the clear zone. Temporary barrier rail layout requires the Engineer's approval. '-0" Min. Rock #4 Bars at equal spaces (typ. all sides) 5 " Typ. Pedestal '' 4 Vertical Bars 9'-0" x 9'-0" Base TYPE B FOUNDATION Ground ine '' Chamfer 4" (typ.) Anchor Bolts 7 " Clear MAST ARM POE FOUNDATION IN ROCK " Dia. Ground ire Duct #6 U-Bars at '' Centers (both ways) 5 Rock Ground Rod 6 Clamp #6 Bars at '' Centers (both ways) 6'' Min. '-0'' Min. '-0'' Min. '-0" Max. Competent rock has an average unconfined compressive strength (q u) of at least.0 ksi and rock quality designation of at least 90%. Conditions not meeting minimum requirements will require either: - A site specific design, or - Using the parameters for Mast Arm Pole Foundation in Soil. Install rodent guard or non-shrink grout with weep hole. Furnish nut, nut and plate, or nut and anchor bolt 4 Place equally spaced vertical bars. 5 Cast foundation concrete against competent rock. If foundation is formed, place backfill with concrete cast against rock. 6 hen in contact with rock, place ground rods as specified in National Electrical Code, current edition. 7 #6 bars spaced at 8 inch maximum. Ties may be welded to vertical bars. FIGURE " Clear Cover (Typ.) Stagger hooks to engage different "V" bars each row Vertical Bars 4 BENT BAR DETAI '- FIGURE STANDARD ROAD PAN TS-0 SHEET of 4 SHEET OF 4 PAN VIE 4½" Min. Typ. D=4½" (Typ.) Note: All dimension are out to out. TRAFFIC SIGNA POE FOUNDATION

5 " Dia. Ground ire Duct Expansion Material Shape top inches with forms. " Pavement Grade " Clearance Install rodent guard or non-shrink grout with weep hole. Furnish nut, nut and plate, or nut and anchor bolt '-0" Min. 4'-0" Max. Ground Rod Clamp 6 Spaces at 4" O.C. 8 hen in contact with rock, place ground rods as specified in National Electrical Code, current edition. Anchor Bolts Ground Rod 8 D Max. Mast Arm ength D R Min. Min. Foundation Tie Bars D R S Count Size ength Broken Competent Spacing Rock* Rock** 5'-0" '-0" '- '-0" 4'- '-0" Top of Rock D " " Drilled Shaft Tie Bars S 45'-0" 55'-0" 60'-0" 70'-0" 80'-0" 90'-0" 00'-0" '-0" '- 4'-0" '-0" '- 6'-0" '-0" '- 8'-0" '- '-0" 8'-0" '- '-0" '-0" 4'-0" '- '-0" 4'-0" '- 4'-0" VARIES D = ( - R ) 4'- 4'- 4'- 5'- 5'- 6'-0" 6'-0" '-0" '-0" '-0" '- '- 4'-0" 4'-0" #9 #9 #0 #0 FIGURE SHEET OF 4 MAST ARM POE FOUNDATION IN ROCK TYPE C FOUNDATION Clear Cover Drilled Shaft " Clear Cover Rock Socket (Typ.) R MAST ARM POE FOUNDATION R Rock Socket Tie Bars S " Clearance Stagger hooks to engage different "V" bars each row (See Table for Count) *Broken rock has an average unconfined compressive strength (q u) of at least.0 ksi and rock quality designation of at least 0%. **Competent rock has an average unconfined compressive strength (q u) of at least.0 ksi and rock quality designation of at least 90%. Conditions not meeting minimum requirements will require site specific designs or shall use thetype A Foundation Soil parameters. BENT BAR DETAI 4½" Min. D - '-0" R - Typ. D=4½" (Typ.) Note: All dimension are out to out. FIGURE STANDARD ROAD PAN TS-0 SHEET of 4 TRAFFIC SIGNA POE FOUNDATION

6 Shape top inches with forms. Install rodent guard or non-shrink grout with weep hole. Furnish nut, nut and plate, or nut and anchor bolt Pavement Grade Expansion Material " '- min. Top of Rock Ground Rod Clamp Ground Rod '-0" min. '-0" min. " Dia. Ground ire Duct Anchor Bolts '-0" Dia. No steel reinforcing required for pedestal foundation PEDESTA POE FOUNDATION IN SOI OR ROCK FIGURE SHEET 4 OF 4 FIGURE STANDARD ROAD PAN TS-0 SHEET 4 of 4 TRAFFIC SIGNA POE FOUNDATION