The provisions of Section 1810 of IBC are adopted by reference with the following modifications:
1. Revise Section 1810.1.2 to read:
"1810.1.2 Use of existing deep foundation elements.
Deep foundation elements left in place where a structure has been demolished shall not be used for the support of new construction unless satisfactory evidence is submitted to the building official, which indicates that the elements are sound and meet the requirements of this code. Such elements shall be analyzed by a registered geotechnical engineer using non-destructive testing or material testing, load tested or redriven to verify their capacities. The design load applied to such elements shall be the lowest allowable load as determined by analysis, tests or redriving data."
2. Revise Section 1810.2.1 by replacing "registered design professional" with "registered geotechnical engineer."
2.1 Revise the exceptions to Section 1810.2.2 to read:
"Exceptions:
1. Isolated cast-in-place deep foundation elements without lateral bracing shall be permitted where the least horizontal dimension is not less than 30 inches (762 mm), adequate lateral support in accordance with Section 1810.2.1 is provided for the entire height and a reinforcing cage is provided for the full depth unless an engineering analysis shows that a full depth cage is unnecessary.
2. A single row of deep foundation elements without lateral bracing is permitted for Group R-5 occupancies and light-frame construction not exceeding two stories above grade plane or 35 feet (10 668 mm) in building height, provided that the centers of the elements are located within the width of the supported wall."
3. Revise Section 1810.2.3 to read:
"1810.2.3 Settlement.
The settlement of a single deep foundation element or group thereof shall be estimated based on accepted engineering analysis. The predicted settlement shall cause neither harmful distortion of, nor instability in, the structure, nor cause any element to be loaded beyond its capacity."
4. Revise Section 1810.2.4 by replacing "registered design professional" with "registered geotechnical engineer."
5. Revise the title and first sentence of Section 1810.2.4.1 to read:
"1810.2.4.1 Seismic Design Category D.
For structures assigned to Seismic Design Category D deep foundation elements on Site Class E or F sites, as determined in Section 1613.2.2, shall be designed and constructed to withstand maximum imposed curvatures from earthquake ground motions and structure response."
6. Revise Section 1810.3.1.1 by deleting "approved."
7. Revise Section 1810.3.1.3 to read:
"1810.3.1.3 Mislocation.
The foundation or superstructure shall be designed to resist the effects of the mislocation of any deep foundation element (individual pier or centroid of a group) by not less than 3 inches (76 mm) and not less than any larger tolerance identified in the report of geotechnical investigations. To resist the effects of mislocation, compressive overload of deep foundation elements to 110 percent of the allowable design load shall be permitted."
8. Revise Section 1810.3.2.1.1 by replacing "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D."
9. Revise Section 1810.3.2.5 by replacing "approved by the building official" with "recommended by the registered geotechnical engineer."
10. Add a new Section 1810.3.2.5.1 to read:
"1810.3.2.5.1 Steel piles.
For steel piles subjected to a corrosive environment, 1/32 inch (0.8 mm) of steel shall be deducted from the exposed surface in computing allowable load. The registered geotechnical engineer shall provide testing to establish corrosivity of fill, or it will be assumed to be corrosive. Natural soils below the water table shall be assumed to be non-corrosive."
11. Revise Table 1810.3.2.6, excluding the notes, as follows:
MATERIAL TYPE AND CONDITION
| MAXIMUM ALLOWABLE STRESS a |
MATERIAL TYPE AND CONDITION
| MAXIMUM ALLOWABLE STRESS a |
1. Concrete or grout in compression b | |
Cast-in-place with a permanent casing in accordance with Section 1810.3.2.7, Section 1810.3.5.3.4 or bedrock | 0.4 f 'c |
Cast-in-place in a pipe, tube, other permanent casing | 0.33 f 'c |
Cast-in-place concrete without a permanent casing | 0.3 f 'c |
Cast-in-place grout without a permanent casing | 0.25 f 'c |
Precast nonprestressed | 0.33 f 'c |
Precast prestressed | 0.33 f 'c - 0.27 f 'pc |
2. Nonprestressed reinforcement in compression | 0.4 fy ≤ 30,000 psi |
3. Steel in compression | |
Cores within concrete-filled pipes or tubes | 0.5 Fy ≤ 32,000 psi |
Pipes, tubes, helicals or H-piles, where justified in accordance with Section 1810.3.2.8 | 0.5 Fy ≤ 32,000 psi |
Pipes or tubes for micropiles | 0.4 Fy ≤ 32,000 psi |
Other pipes, tubes, helicals or H-piles | 0.35 Fy ≤ 24,000 psi |
4. Nonprestressed reinforcement in tension | |
Within micropiles | 0.6 fy ≤ 40,000 psi |
Other conditions | 0.5 fy ≤ 40,000 psi |
5. Steel in tension | |
Pipes, tubes, helicals or H-piles, where justified in accordance with Section 1810.3.2.8 | 0.5 Fy ≤ 32,000 psi |
Other pipes, tubes, helicals or H-piles | 0.35 Fy ≤ 24,000 psi |
6. Timber | In accordance with the ANSI/AWC NDS |
12. Revise the last sentence of Section 1810.3.2.8 to read:
"The design and installation of the deep foundation elements shall be under the direct supervision of a registered geotechnical engineer knowledgeable in the field of soil mechanics and deep foundations or their qualified representative who shall submit a report to the owner stating that the elements as installed satisfy the design criteria. The report shall be made available to the building official."
13. Revise Section 1810.3.3 to read:
"1810.3.3 Determination of allowable loads.
The allowable axial and lateral loads on deep foundation elements shall be determined by an accepted engineering analysis or load tests."
14. Revise the first two sentences of Section 1810.3.3.1.1 to read:
"The allowable compressive load on any driven deep foundation element where determined by the application of a driving formula shall not exceed 60 tons (598 kN) on soil and 100 tons (996 kN) on rock. For allowable loads above those values, the wave equation method of analysis shall be used to estimate driveability for both driving stresses and net displacement per blow at the ultimate load."
15. Revise Section 1810.3.3.1.2 to read:
"1810.3.3.1.2 Load tests.
Where design compressive loads are greater than those determined using the allowable stresses specified in Section 1810.3.2.6, where the design load for any deep foundation element is in doubt or exceeds the value in Table 1810.3.3.1.2, or where cast-in-place deep foundation elements have an enlarged base formed either by compacting concrete or by driving a precast base, control test elements shall be tested in accordance with ASTM D1143, ASTM D4945 or ASTM D8169. When using ASTM D1143 or ASTM D8169, loading procedure B shall be used in soil and loading procedure A shall be allowed to be used in rock. One element or more shall be load tested in each area of uniform subsoil conditions. Where required by the building official, additional elements shall be load tested where necessary to establish the safe design capacity. The resulting allowable loads shall not be more than one-half of the ultimate axial load capacity of the test element as assessed by one of the published methods listed in Section 1810.3.3.1.3 with consideration for the test type, duration and subsoil. The ultimate axial load capacity shall be determined by a registered geotechnical engineer with consideration given to tolerable total and differential settlements at design load in accordance with Section 1810.2.3. In subsequent installation of the balance of deep foundation elements, all elements shall be deemed to have a supporting capacity equal to that of the control element where such elements are of similar type, size and relative length as the test element; are installed using the same or comparable methods and equipment as the test element; are installed in similar subsoil conditions as the test element; and, for driven elements, where the rate of penetration (for example, net displacement per blow) of such elements is equal to or less than that of the test element driven with the same hammer through a comparable driving distance."
16. Insert new Table 1810.3.3.1.2 to read:
TABLE 1810.3.3.1.2
MAXIMUM AXIAL LOADS ALLOWED WITHOUT LOAD TEST
MAXIMUM AXIAL LOADS ALLOWED WITHOUT LOAD TEST
TYPE OF PILE |
MAXIMUM ALLOWABLE AXIAL LOAD WITHOUT LOAD TEST (tons)
|
Helical piles | 10 |
Micropiles and non-driven piles | 15 a |
Timber piles | 30 |
Driven structural steel piles in soil | 60 |
Driven structural steel piles to bedrock | 100 |
For SI: 1 ton = 907 kg
a. Nondestructive tests are required for non-driven piles.
17. Revise Section 1810.3.3.1.3 to read:
"1810.3.3.1.3 Load test evaluation methods.
Load test results must be accepted by the registered geotechnical engineer who prepared the geotechnical investigation report, unless otherwise approved by the building official. It shall be permitted to evaluate load tests of deep foundation elements using any of the following methods:
1. Davisson Offset Limit.
2. Brinch-Hansen 90-percent Criterion.
3. Butler-Hoy Criterion.
4. The failure load corresponding to a settlement of 0.2 √D + PL/AE
where D = the diameter or diagonal dimension in inches, P = Load, L = Length, A = Area, E = Modulus of Elasticity.
where D = the diameter or diagonal dimension in inches, P = Load, L = Length, A = Area, E = Modulus of Elasticity.
5. Other methods approved by the building official."
18. Revise Section 1810.3.3.1.4 to read:
"1810.3.3.1.4 Allowable shaft resistance.
The assumed shaft resistance developed by any uncased cast-in-place deep foundation element shall not exceed one-sixth of the bearing value of the soil material at minimum depth as set forth in Table 1806.2, up to 500 psf (24 kPa), unless a greater value is recommended by the registered geotechnical engineer and allowed by the building official on the basis of a geotechnical investigation as specified in Section 1803 or a greater value is substantiated by a load test in accordance with Section 1810.3.3.1.2. Shaft resistance and end-bearing resistance shall not be assumed to act simultaneously unless determined by a geotechnical investigation in accordance with Section 1803."
19. Revise Section 1810.3.3.1.5 to read:
"1810.3.3.1.5 Uplift capacity of a single deep foundation element.
Where required by the design, the uplift capacity of a single deep foundation element shall be determined by accepted engineering analysis based on a minimum factor of safety of three or by load tests conducted in accordance with ASTM D3689 or ASTM D8169. The maximum allowable uplift load shall not exceed the ultimate load capacity as determined in Section 1810.3.3.1.2, using the results of load tests conducted in accordance with ASTM D3689 or ASTM D8169, divided by a factor of safety of two."
20. Revise Section 1810.3.3.1.7 to read:
"1810.3.3.1.7 Load-bearing capacity.
Ultimate load capacities shall be determined in accordance with Section 1810.3.3.1.7.1, 1810.3.3.1.7.2 or 1810.3.3.1.7.3.
1810.3.3.1.7.1 Load testing.
Deep foundation elements shall develop ultimate load capacities of not less than 2 times the design working loads in the designated load-bearing layers when load testing is used.
1810.3.3.1.7.2 Routine soil testing.
Deep foundation elements shall develop ultimate load capacities of not less than 3 times the design working loads in the designated load-bearing layers when routine soil testing is used to determine soil properties. Analysis shall show that soil layers underlying the designated load-bearing layers do not cause the load- bearing safety factor to be less than 3.
1810.3.3.1.7.3 In-situ soil testing.
Deep foundation elements shall develop ultimate load capacities of not less than 2.5 times the design working loads in the designated load-bearing layers when in-situ soil testing is used to determine soil properties. Analysis shall show that soil layers underlying the designated load-bearing layers do not cause the load-bearing safety factor to be less than 2.5."
21. Revise Section 1810.3.3.2 by replacing "an approved method of analysis" with "accepted engineering analysis."
22. Revise the exception to Section 1810.3.5.2.2 to read:
"Exception: The length of the element is permitted to exceed 30 times the specified diameter, provided that the design and installation of the deep foundations are under the direct supervision of a registered geotechnical engineer knowledgeable in the field of soil mechanics and deep foundations or their qualified representative. The registered geotechnical engineer shall submit a report to the owner stating that the elements were installed in compliance with the permitted construction documents."
23. Delete the second sentence of Section 1810.3.5.2.3.
24. Revise Section 1810.3.5.3.4 to read:
"1810.3.5.3.4 Steel pipes and tubes.
Steel pipes and tubes used as deep foundation elements shall have a nominal outside diameter of not less than 7 inches (178 mm). Where steel pipes or tubes are driven open ended, they shall have not less than 0.34 square inch (219 mm2) of steel in cross section to resist each 1,000 foot-pounds (1356 Nm) of pile hammer energy, or shall have the equivalent strength for steels having a yield strength greater than 35,000 psi (241 MPa) or the wave equation analysis shall be permitted to be used to assess compression stresses induced by driving to evaluate if the pile section is appropriate for the selected hammer. Where a pipe or tube with wall thickness less than 0.179 inch (4.6 mm) is driven open ended, a suitable cutting shoe shall be provided. Concrete-filled steel pipes or tubes in structures assigned to Seismic Design Category C or D shall have a wall thickness of not less than 3/16 inch (5 mm). The pipe or tube casing for socketed drilled shafts shall have a nominal outside diameter of not less than 18 inches (457 mm), a wall thickness of not less than 3/8 inch (9.5 mm) and a suitable steel driving shoe welded to the bottom; the diameter of the rock socket shall be approximately equal to the inside diameter of the casing.
Exceptions:
1. The minimum diameter for drilled micropiles shall be 4.5 inches (114 mm) and for jacked piles shall be 3 inches (76 mm).
2. For mandrel-driven pipes or tubes, the minimum wall thickness shall be 1/10 inch (2.5 mm)."
25. Revise Section 1810.3.5.3.5 to read:
"1810.3.5.3.5 Helical piles.
Dimensions of the central shaft and the number, size and thickness of helical bearing plates shall be sufficient to support the design loads. The minimum pipe shaft shall have a diameter of not less than 3.5 inches (89 mm) and wall thickness not less than 1/4 inch (6.4 mm)."
26. Revise the first paragraph of Section 1810.3.6 to read:
"1810.3.6 Splices.
Splices shall be constructed so as to provide and maintain true alignment and position of the component parts of the deep foundation element during installation and subsequent thereto and shall be designed to resist the axial and shear forces and moments occurring at the location of the splice during driving and for design load combinations. Where deep foundation elements of different materials or different types are being spliced, splices shall develop the full compressive strength. Where structural steel cores are to be spliced, the ends shall be milled or ground to provide full contact and shall be full-depth welded."
27. Revise the title and first sentence of Section 1810.3.6.1 to read:
"1810.3.6.1 Seismic Design Categories C and D.
For structures assigned to Seismic Design Category C or D splices of deep foundation elements shall develop the lesser of the following:"
28. Revise the title and first sentence of Section 1810.3.8.2.2 to read:
"1810.3.8.2.2 Seismic reinforcement in Seismic Design Categories C and D.
For structures assigned to Seismic Design Category C or D, precast nonprestressed piles shall be reinforced as specified in this section."
29. Revise Section 1810.3.8.2.3 to read:
"1810.3.8.2.3 Additional seismic reinforcement in Seismic Design Category D.
For structures assigned to Seismic Design Category D, transverse reinforcement shall be in accordance with Section 1810.3.9.4.2."
30. Revise the title and first sentence of Section 1810.3.8.3.3 to read:
"1810.3.8.3.3 Seismic reinforcement in Seismic Design Category D.
For structures assigned to Seismic Design Category D, precast prestressed piles shall have transverse reinforcement in accordance with the following:"
31. Revise the title and first sentence of Section 1810.3.8.3.4 to read:
"1810.3.8.3.4 Axial load limit in Seismic Design Categories C and D.
For structures assigned to Seismic Design Category C or D, the maximum factored axial load on precast prestressed piles subjected to a combination of seismic lateral force and axial load shall not exceed the following values:"
32. Revise exception 3 to Section 1810.3.9 to read:
"3. For Group R-3, R-5 and U occupancies not exceeding two stories of light-frame construction, reinforcement is permitted to be placed after concreting, while the concrete is still in a semifluid state, and the concrete cover requirement is permitted to be reduced to 2 inches (51 mm), provided that the construction method can be demonstrated to the satisfaction of the building official."
33. Revise Section 1810.3.9.4 to read:
"1810.3.9.4 Seismic reinforcement.
Where a structure is assigned to Seismic Design Category C, reinforcement shall be provided in accordance with Section 1810.3.9.4.1. Where a structure is assigned to Seismic Design Category D, reinforcement shall be provided in accordance with Section 1810.3.9.4.2.
Exceptions:
1. Isolated deep foundation elements supporting posts of Group R-3, R-4, R-5 and U occupancies not exceeding two stories of light-frame construction shall be permitted to be reinforced as required by rational analysis but with not less than one No. 4 bar, without ties or spirals, where detailed so the element is not subject to lateral loads and the soil provides adequate lateral support in accordance with Section 1810.2.1.
2. Isolated deep foundation elements supporting posts and bracing from decks and patios appurtenant to Group R-3, R-4, R-5 and U occupancies not exceeding two stories of light-frame construction shall be permitted to be reinforced as required by rational analysis but with not less than one No. 4 bar, without ties or spirals, where the lateral load, E, to the top of the element does not exceed 200 pounds (890 N) and the soil provides adequate lateral support in accordance with Section 1810.2.1.
3. Deep foundation elements supporting the concrete foundation wall of Group R-3, R-4, R-5 and U occupancies not exceeding two stories of light-frame construction shall be permitted to be reinforced as required by rational analysis but with not less than two No. 4 bars, without ties or spirals, where the design cracking moment determined in accordance with Section 1810.3.9.1 exceeds the required moment strength determined using the load combinations with overstrength factor in Section 2.3.6 or 2.4.5 of ASCE 7 and the soil provides adequate lateral support in accordance with Section 1810.2.1.
4. Closed ties or spirals where required by Section 1810.3.9.4.2 shall be permitted to be limited to the top 3 feet (914 mm) of deep foundation elements 10 feet (3048 mm) or less in depth supporting Group R-3, R-4, R-5 and U occupancies of Seismic Design Category D, not exceeding two stories of light-frame construction."
34. Revise the title and first sentence of Section 1810.3.9.4.2 to read:
"1810.3.9.4.2 Seismic reinforcement in Seismic Design Category D.
For structures assigned to Seismic Design Category D, cast-in-place deep foundation elements shall be reinforced as specified in this section. Reinforcement shall be provided where required by analysis."
35. Revise Section 1810.3.9.5 to read:
"1810.3.9.5 Belled drilled shafts.
Where drilled shafts are belled at the bottom, the edge thickness of the bell shall be not less than that required for the edge of footings. Where the sides of the bell slope at an angle less than 60 degrees (1 rad) from the horizontal, the effects of vertical shear shall be considered. The bell diameter shall not exceed three times the shaft diameter.
The design of the belled drilled shaft shall be based on the predicted settlement and on the allowable load bearing pressure on the bottom of the bell; side resistance shall be ignored.
Continuous special inspections of belled drilled shafts using an explosion proof camera, defined by Sections 1810.4.12, 1705.7 and 1705.8, shall be required to confirm the suitable bearing soil and bottom of bell cleanup to remove excess cuttings. Alternatively, where belled caissons are used, the caisson bell diameter shall be allowed to be oversized by 15 percent, for a minimum diameter increase of 6 inches (152 mm) up to a maximum diameter increase of 1 foot (305 mm)."
36. Revise Section 1810.3.9.6 to read:
"1810.3.9.6 Socketed drilled shafts.
Socketed drilled shafts shall have a permanent pipe or tube casing that extends down to bedrock and an uncased socket drilled into the bedrock, both filled with concrete. Socketed drilled shafts shall have reinforcement or a structural steel core for the length as indicated by accepted engineering analysis.
The depth of the rock socket shall be sufficient to develop the full load-bearing capacity of the element with a minimum safety factor in accordance with Section 1810.3.3.1.7, but the depth shall be not less than one foot (305 mm)."
37. Revise Section 1810.3.10.2 to read:
"1810.3.10.2 Materials.
Reinforcement shall consist of deformed reinforcing bars in accordance with ASTM A615 Grade 60, 75 or 80 or ASTM A722 Grade 150.
The steel pipe or tube shall have a minimum wall thickness of 1/4 inch (6.3 mm). Splices shall comply with Section 1810.3.6. The steel pipe or tube shall have a minimum yield strength of 45,000 psi (310 MPa) and a minimum elongation of 15 percent as shown by mill certifications or two coupon test samples per 40,000 pounds (18 160 kg) of pipe or tube."
38. Revise Section 1810.3.10.4 to replace "Seismic Design Category D, E or F" with "Seismic Design Category D."
39. Revise the title and first sentence of Section 1810.3.11.1 to read:
"1810.3.11.1 Seismic Design Categories C and D.
For structures assigned to Seismic Design Category C or D, concrete deep foundation elements shall be connected to the pile cap by embedding the element reinforcement or field-placed dowels anchored in the element into the pile cap for a distance equal to their development length in accordance with ACI 318."
40. Revise the title and first sentence of Section 1810.3.11.2 to read:
"1810.3.11.2 Seismic Design Category D.
For structures assigned to Seismic Design Category D, deep foundation element resistance to uplift forces or rotational restraint shall be provided by anchorage into the pile cap, designed considering the combined effect of axial forces due to uplift and bending moments due to fixity to the pile cap."
41. Revise Section 1810.3.12 to replace "Seismic Design Category D, E or F" with "Seismic Design Category D."
42. Revise Section 1810.3.13 to replace "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D."
43. Revise the exception to Section 1810.3.13 to read:
"Exception: In Group R-3, R-4, R-5 and U occupancies of light-frame construction, deep foundation elements supporting foundation walls, isolated interior posts detailed so the element is not subject to lateral loads or exterior decks and patios are not subject to interconnection where the soils are of adequate stiffness."
44. Revise section 1810.4 by adding the following sentence at the end:
"Where installing drilled shafts through unstable soils or soft clay, the installation procedures shall include casing or drilling slurry as recommended by the registered geotechnical engineer. The registered geotechnical engineer shall analyze the soil for shaft squeeze-in potential in soft clay."
45. Revise Section 1810.4.4 to read:
"1810.4.4 Preexcavation.
The use of jetting, augering or other methods of preexcavation shall be allowed where recommended by the registered geotechnical engineer. Where permitted, preexcavation shall be carried out in the same manner as used for deep foundation elements subject to load tests and in such a manner that will not impair the carrying capacity of the elements already in place or damage adjacent structures. Element tips shall be advanced below the preexcavated depth until the required resistance or penetration is obtained."
46. Revise Section 1810.4.5 to read:
"1810.4.5 Vibratory driving.
Vibratory drivers shall only be used to install deep foundation elements where the element load capacity is verified by load tests in accordance with Section 1810.3.3.1.2, unless the pile installation is completed by driving with an impact hammer in accordance with Section 1810.3.3.1.1, or the pile is to be used only for lateral resistance. The installation of production elements shall be controlled according to power consumption, rate of penetration or other approved means that ensure element capacities equal or exceed those of the test elements."
47. Revise Section 1810.4.8 to read:
"1810.4.8 Hollow-stem augered, and drilled displacement cast-in-place elements.
Where concrete or grout is placed by pumping through a hollow-stem auger, the auger shall be permitted to rotate in a clockwise direction during withdrawal. As the auger is withdrawn at a steady rate or in increments not to exceed 1 foot (305 mm), concreting or grouting pumping pressures shall be measured and maintained high enough at all times to offset hydrostatic and lateral earth pressures. Concrete or grout volumes shall be measured to ensure that the volume of concrete or grout placed in each element is equal to or greater than 110 percent of the theoretical volume of the hole created by the auger. Where the installation process of any element is interrupted or a loss of concreting or grouting pressure occurs, the element shall be redrilled to 5 feet (1524 mm) below the elevation of the tip of the auger when the installation was interrupted or concrete or grout pressure was lost and reformed. Augered cast-in-place elements shall not be installed within six diameters center to center of an element filled with concrete or grout less than 12 hours old, unless approved by the building official. If the concrete or grout level in any completed element drops due to installation of an adjacent element, the element shall be replaced. All piles shall have a full-length reinforcing bar with a centralizer at the tip."
48. Revise Section 1810.4.9 to read:
"1810.4.9 Socketed drilled shafts.
The rock socket and pipe or tube casing, if any, of socketed drilled shafts shall be thoroughly cleaned of foreign materials before filling with concrete. Steel cores shall be bedded in concrete or sand/cement grout at the base of the rock socket. Concrete or sand/cement grout shall be placed using a tremie method."
49. Delete item 3 to Section 1810.4.10.
50. Revise item 5 to Section 1810.4.10 to read:
"5. Micropiles shall be grouted as soon as practical after drilling is completed."
51. Revise Section 1810.4.11 by replacing "registered design professional" with "registered geotechnical engineer."
(Amend Coun. J. 2-19-20, p. 14473, Art. II, § 81; Amend Coun. J. 1-26-22, p. 43756, Art. II, § 18)