SOILS AND FOUNDATIONS

Municipal Code of Chicago tit. 14B, ch. 14B-18

in effect

Municipal Code of Chicago § 14B-18-1800 Defined terms.

14B-18-1800 Defined terms. Where provisions of Chapter 18 of IBC are adopted by reference, the following terms shall be reset in italic type: "deep foundation"; "drilled shaft"; "helical pile"; "light-frame construction"; "micropile"; "plain masonry"; "shallow foundation"; "site" and "socketed drilled shaft."

Municipal Code of Chicago § 14B-18-1801 General.

14B-18-1801 General. The provisions of Section 1801 of IBC are adopted by reference without modification.

Municipal Code of Chicago § 14B-18-1802 Design basis.

14B-18-1802 Design basis. The provisions of Section 1802 of IBC are adopted by reference without modification.

Municipal Code of Chicago § 14B-18-1803 Geotechnical investigations.

14B-18-1803 Geotechnical investigations. The provisions of Section 1803 of IBC are adopted by reference with the following modifications: 1. Revise Section 1803.1 by replacing "registered design professional" with "registered geotechnical engineer." 2. Add new exceptions following Section 1803.1 to read: "Exceptions: 1. Geotechnical investigations are not required for single-story storage structures without basements and detached private garages not exceeding 2,000 square feet (185.8 m2). 2. Geotechnical investigations are not required for alterations and additions that do not require new foundations and do not result in an increase in loads exceeding 5 percent of the existing foundation design capacity. 3. Full geotechnical investigations by a registered geotechnical engineer are not required where excavation more than 8 feet (2438 mm) below existing grade is not required, a test pit is used for soil classification and to locate the ground-water table, and the values used as the basis for design do not exceed the presumptive values in Table 1806.2(1)." 3. Revise Section 1803.3.1 by replacing "registered design professional" with "registered geotechnical engineer." 4. Revise Section 1803.4 by replacing "registered design professional" with "registered geotechnical engineer." 5. Revise Section 1803.5.2 to read: "1803.5.2 Questionable soil or fill. Where the classification, strength or compressibility of the soil or fill is in doubt or where a load-bearing value superior to that specified in this code is claimed, the building official shall require that a geotechnical investigation be conducted." 6. Revise Section 1803.5.3 to read: "1803.5.3 Expansive soil or fill. In areas likely to have expansive soil or fill, the registered geotechnical engineer shall perform soil tests to determine where such soils or fills do exist. Soils or fills meeting all four of the following provisions shall be considered to be expansive, except that tests to show compliance with Items 1, 2 and 3 shall not be required if the test prescribed in Item 4 is conducted: 1. Plasticity index (PI) of 15 or greater, determined in accordance with ASTM D4318. 2. More than 10 percent of the soil particles pass a No. 200 sieve (75 µm), determined in accordance with ASTM D422. 3. More than 10 percent of the soil particles are less than 5 micrometers in size, determined in accordance with ASTM D422. 4. Expansion index greater than 20, determined in accordance with ASTM D4829. Steel slag shall be tested for expansive properties in accordance with ASTM D4792 prior to use as a fill material." 7. Delete the exception to Section 1803.5.4. 8. Revise Section 1803.5.5 to read: "1803.5.5 Deep foundations. Where deep foundations will be used, a geotechnical investigation shall be conducted and shall include all of the following, as applicable: 1. Recommended deep foundation types and installed capacities. 2. Recommended center-to-center spacing of deep foundation elements. 3. Recommended driving installation acceptance criteria. 4. Recommended installation procedures. 5. Field inspection and reporting procedures (to include procedures for verification of the installed bearing capacity where required). 6. Load test requirements. 7. Suitability of deep foundation materials for the intended environment. 8. Designation of bearing stratum or strata. 9. Reductions for group action, where necessary." 9. Revise items 1 and 2 in Section 1803.5.8 to read: "1. Recommended specifications for the preparation of the site prior to placement of compacted fill material. 2. Recommended specifications for material to be used as compacted fill." 10. Revise items 1 and 2 in Section 1803.5.9 to read: "1. Recommended specifications for the preparation of the site prior to placement of the CLSM. 2. Recommended specifications for the CLSM." 11. Delete Section 1803.5.10. 12. Revise the title and first sentence of Section 1803.5.11 to read: "1803.5.11 Seismic Design Category C or D. For structures assigned to Seismic Design Category C or D a geotechnical investigation shall be conducted, and shall include an evaluation of all of the following potential geologic and seismic hazards:" 13. Revise the title and first sentence of Section 1803.5.12 to read: "1803.5.12 Seismic Design Category D. For structures assigned to Seismic Design Category D, the geotechnical investigation required by Section 1803.5.11 shall include all of the following as applicable:" 14. Revise item 5 in Section 1803.6 to replace "expansive" with "questionable." 15. Revise Section 1803.6 to add new items to read: "11. Construction considerations: earth retention systems, underpinning, excavation slopes, effects on adjacent structures, utilities and improvements, corrosivity, drainage systems and dewatering, as necessary. 12. Site class in accordance with Chapter 20 of ASCE 7 and the horizontal seismic forces to be considered in slope stability analysis." 16. Add a new exception following Section 1803.6 to read: "Exception: For construction not exceeding four stories above grade plane, not requiring excavation more than 8 feet (2438 mm) below existing grade, and not covering more than 16,000 square feet (1486.4 m2) of ground area, a written report of geotechnical investigations shall not be required at the time of permit application but shall be completed prior to the actual start of construction to confirm presumed conditions used as the basis for design. The report shall be made available to the building official upon request. Where the written report of geotechnical investigations, completed after permit application, does not confirm presumed conditions used as the basis for design, a revised permit application and revised construction documents shall be submitted to the building official and construction shall not commence until the revised permit has been issued."

Municipal Code of Chicago § 14B-18-1804 Excavation, grading and fill.

14B-18-1804 Excavation, grading and fill. The provisions of Section 1804 of IBC are adopted by reference with the following modifications: 1. Revise Section 1804.2.1 by replacing "approved" with "permitted." 2. Delete Section 1804.4. 3. Delete Section 1804.5. 4. Revise Section 1804.6 to read: "1804.6 Compacted controlled fill material. Where shallow foundations will bear on compacted controlled fill material, the compacted controlled fill shall comply with the provisions of a geotechnical report acceptable to the building official, as set forth in Section 1803. Exception: Compacted controlled fill material 12 inches (305 mm) in depth or less need not comply with a geotechnical report, provided that the in-place dry density is not less than 90 percent of the maximum dry density at optimum moisture content determined in accordance with ASTM D1557. The compaction shall be verified by special inspection in accordance with Section 1705.6." 5. Revise Section 1804.7 by replacing "an approved" with "a."

Municipal Code of Chicago § 14B-18-1805 Dampproofing and waterproofing.

14B-18-1805 Dampproofing and waterproofing. The provisions of Section 1805 of IBC are adopted by reference with the following modifications: 1. Revise Section 1805.1 to read: "1805.1 General. Walls or portions thereof that retain earth and enclose interior spaces and floors below grade shall be waterproofed and dampproofed in accordance with this section. Exception: Spaces containing occupancies other than Group A, E, I or R where such omission is not detrimental to the building or occupancy." 2. Delete Section 1805.1.1. 3. Revise Section 1805.1.2 by replacing "an approved" with "a". 4. Delete Section 1805.1.2.1. 5. Revise Section 1805.2 to read: "1805.2 Dampproofing. Where hydrostatic pressure will not occur as determined by Section 1803.5.4, floors and walls shall be dampproofed in accordance with this section." 6. Revise Section 1805.2.1 by replacing "approved" with "equivalent." 7. Revise Section 1805.2.2 by replacing "approved" with "equivalent." 8. Revise Section 1805.2.2.1 to read: "1805.2.2.1 Surface preparation of walls. Prior to application of dampproofing materials on concrete walls, holes and recesses resulting from the removal of form ties shall be sealed with a bituminous material or other equivalent methods or materials. Unit masonry walls shall be parged on the exterior surface below ground level with not less than 3/8 inch (9.5 mm) of Portland cement mortar. The parging shall be coved at the footing. Exception: Parging of unit masonry walls is not required where a material is intended for direct application to the masonry." 9. Revise Section 1805.3.1 by replacing "approved" with "equivalent." 10. Revise Section 1805.3.2 by replacing "approved" with "equivalent." 11. Revise Section 1805.3.3 by replacing "approved" with "equivalent." 12. Revise Section 1805.4 to read: "1805.4 Subsoil drainage system. Where a permanent hydrostatic pressure condition does not exist, dampproofing shall be provided and a granular base course shall be installed under the floor and a drain installed around the foundation perimeter. A subsoil drainage system designed and constructed in accordance with Section 1805.1.3 shall be deemed adequate for lowering the ground-water table." 13. Revise Section 1805.4.2 to read: "1805.4.2 Foundation drain. A drain shall be placed at the perimeter of the foundation." 14. Revise Section 1805.4.3, excluding the exception, to read: "1805.4.3 Drainage discharge. The floor base course and foundation perimeter drain shall discharge by gravity or mechanical means into a drainage system that complies with the Chicago Plumbing Code."

Municipal Code of Chicago § 14B-18-1806 Presumptive load-bearing values of soils.

14B-18-1806 Presumptive load-bearing values of soils. The provisions of Section 1806 of IBC are adopted by reference with the following modifications: 1. Revise Section 1806.1 by replacing "Table 1806.2" with "Table 1806.2(1) or 1806.2(2), as applicable" and deleting the second sentence. 2. Revise Section 1806.2 to read: "1806.2 Presumptive load-bearing values. Where only a limited geotechnical investigation in accordance with Section 1803.1, exception 3, is performed, the load-bearing values used in design for supporting soils near the surface shall not exceed the values specified in Table 1806.2(1). Where the building official has reason to doubt the classification, strength or compressibility of the soil, the requirements of Section 1803.5.2 shall be satisfied. Where a full geotechnical investigation is performed in accordance with Section 1803, the load-bearing values used in design for supporting soils near the surface shall not exceed the values specified in Table 1806.2(2), unless the use of higher values is recommended by the registered geotechnical engineer. Presumptive load-bearing values shall apply to materials with similar physical characteristics and dispositions. Mud, organic silt, organic clays, peat or unprepared fill shall not be assumed to have a presumptive load-bearing capacity unless data to substantiate the use of such a value are submitted." 3. Delete Table 1806.2. 4. Insert Tables 1806.2(1), 1806.2(2) and 1806.2(3) to read: TABLE 1806.2(1) PRESUMPTIVE LOAD-BEARING VALUES WITHOUT FULL GEOTECHNICAL INVESTIGATION CLASS OF MATERIALS | VERTICAL FOUNDATION PRESSURE (psf) | LATERAL BEARING PRESSURE (psf/ft below natural grade) | LATERAL SLIDING RESISTANCE Coefficient of friction a | Cohesion (psf) b Sandy gravel and gravel (GW and GP) | 3,000 | 200 | 0.35 | – Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC) | 2,000 | 150 | 0.25 | – Clay, sandy clay, silty clay, clayey silt, silt and sandy silt (CL, ML, MH and CH) | 1,500 | 100 | – | 130 Non-engineered fill | 500 | 50 | 0.1 | – For SI: 1 pound per square foot = 0.0479 kPa, 1 pound per square foot per foot = 0.157 kPa/m. a. Coefficient to be multiplied by the dead load. b. Cohesion value to be multiplied by the contact area, as limited by Section 1806.3.2. TABLE 1806.2(2) PRESUMPTIVE VERTICAL FOUNDATION PRESSURE VALUES WITH GEOTECHNICAL INVESTIGATION CLASS | DESCRIPTION | NOTES | CONSISTENCY OR RELATIVE DENSITY a | ALLOWABLE NET BEARING PRESSURE (psf) CLASS | DESCRIPTION | NOTES | CONSISTENCY OR RELATIVE DENSITY a | ALLOWABLE NET BEARING PRESSURE (psf) 1 | DOLOMITE bedrock | c | Hard, sound rock, minor jointing | 200,000 2a | Fractured DOLOMITE surface | d, h | Blocky limestone with soil filled seams and fractures | 60,000 2b | Fractured DOLOMITE surface | e, h | Blocky limestone with soil filled seams and fractures | 100,000 2c | DOLOMITE surface | f, h | Rock with minor fractures and jointing | 120,000 2d | DOLOMITE surface | g, h | Rock with minor fractures and jointing | 150,000 3 | HARDPAN, hard silty clay, or very dense clayey silt, (CL, CL-ML) | i | Very hard or very dense | 20,000 j | Hard or dense | 12,000 4 | SAND, GRAVEL or SILT, silty sand, clayey sand, silty gravel or clayey gravel (SW, SP, GW, GP, SC, SM, GC, GM, ML) | k | Dense | 3,000 Medium dense | 2,000 Loose | 1,000 Very loose | Note b 5 | Silty CLAY, Clayey SILT (CH, CL, ML-CL, MH) | – | Hard | 4,000 Very stiff | 3,000 Stiff | 2,000 Medium | 1,500 Soft | Note b Very soft | Note b 6 | Organic SILT, CLAY or PEAT | m | – | Note b 7 | Non-Engineered FILL | n | – | 500 8 | CONTROLLED FILL | o | 95% Modified Proctor | 3,000 9 | Improved In-Situ Soil or Fill | p | – | Note b For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa. a. Classified in accordance with Table 1806.2(3). b. Requires engineering analysis and testing by a registered geotechnical engineer. c. 1 foot into sound rock (recovery greater than 95% and RQD greater than 70%) with 20% increase per foot of additional penetration up to a maximum of 400,000 pounds per square foot. d. Surface of refusal to standard caisson rig rock auger, correlated to borings with recovery greater than 90% and RQD greater 40%, rock unconfined compressive strength greater than 2,000 pounds per square inch. e. Surface of refusal to standard caisson rig rock auger, correlated to borings with recovery greater than 90% and RQD greater than 50%, rock unconfined compressive strength greater than 2,500 pounds per square inch. f. Surface of refusal to standard caisson rig rock auger, correlated to borings with recovery greater than 95% and RQD greater than 60%, rock unconfined compressive strength greater than 3,000 pounds per square inch. g. Surface of refusal to standard caisson rig rock auger, correlated to borings with recovery greater than 95% and RQD greater than 70%, rock unconfined compressive strength greater than 3,500 pounds per square inch. h. No load tests are required up to presumptive bearing pressures. If higher bearing pressures are required than shown in table or RQD or rock compressive strength does not meet values shown, load tests are required to confirm allowable bearing pressure. i. Where qu is greater than 14,000 pounds per square foot, or N is greater than or equal to 50. j. Where qu is greater than or equal to 8,000 pounds per square foot, or N is greater than or equal to 30. k. Allowable net bearing value assumes minimum depth of embedment is 2.5 feet and a minimum width of 1.5 feet. Allowable bearing values shall be reduced proportionally for less depth of embedment, or the effect of reduced confinement from a rise in the water table above the foundation level. l. [Reserved.] m. Organic means more than 10% organic matter as determined in accordance with ASTM D2974. n. Presumptive value for light or temporary structure. Otherwise engineering analysis required. o. Controlled fill shall be placed in specified lifts with moisture control, under full time observation of a registered geotechnical engineer or their qualified representative in accordance with ASTM D1557. p. Improved fill or soil in-situ by dynamic compaction, compaction grouting, or other methods. TABLE 1806.2(3) STANDARDS FOR CLASSIFYING SOIL CONSISTENCY AND RELATIVE DENSITY Clay | Sand and Gravel DESCRIPTIVE TERM | UNCONFINED STRENGTH (psf) | DESCRIPTIVE TERM | SPT N VALUE Clay | Sand and Gravel DESCRIPTIVE TERM | UNCONFINED STRENGTH (psf) | DESCRIPTIVE TERM | SPT N VALUE Very soft | < 500 | Very loose | 0 - 3 Soft | 500 - 1,000 | Loose | 4 - 9 Medium | 1,000 - 2,000 | Medium | 10 - 29 Stiff | 2,000 - 4,000 | Dense | 30 - 49 Very stiff | 4,000 - 8,000 | Very Dense | ≥ 50 Hard | > 8,000 | For SI: 1 pound per square foot = 0.0479 kPa. 5. Revise Section 1806.3 to read: "1806.3 Lateral load resistance. Where the presumptive values of Table 1806.2(1) are used to determine resistance to lateral loads, the calculations shall be in accordance with Sections 1806.3.1 through 1806.3.4. Where the presumptive values of Table 1806.2(2) are used, resistance to lateral loads shall be as provided in the geotechnical report." 6. Revise Section 1806.3.1 by replacing "Table 1806.2" with "Table 1806.2(1)." 7. Revise Section 1806.3.3 by replacing "Table 1806.2" with "Table 1806.2(1)." (Amend Coun. J. 10-7-20, p. 21791, Art. II, § 29)

Municipal Code of Chicago § 14B-18-1807 Foundation walls, retaining walls and embedded posts and poles.

14B-18-1807 Foundation walls, retaining walls and embedded posts and poles. The provisions of Section 1807 of IBC are adopted by reference with the following modifications: 1. Revise Section 1807.1.3 by replacing "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D." 2. Delete Section 1807.1.4. 3. Revise Table 1807.1.6.2 by: a. Deleting all columns for 30 and 45 psf per foot; b. Deleting note d. 4. Revise Section 1807.1.6.2.1 by replacing "Seismic Design Categories C, D, E and F" with "Seismic Design Categories C and D." 5. Revise Table 1807.1.6.3(1) by: a. Deleting the columns for 30 and 45 psf per foot; b. Deleting all rows for maximum unbalanced backfill height of 7 feet or greater. c. Deleting note f. 6. Revise Table 1807.1.6.3(2) by: a. Deleting the columns for 30 and 45 psf per foot; b. Deleting note e. 7. Revise Table 1807.1.6.3(3) by: a. Deleting the columns for 30 and 45 psf per foot; b. Deleting note e. 8. Revise Table 1807.1.6.3(4) by: a. Deleting the columns for 30 and 45 psf per foot; b. Deleting note e. 9. Delete item 4 in Section 1807.1.6.3.2. 10. Revise Section 1807.2.2 by replacing "Seismic Design Category D, E or F" with "Seismic Design Category D." 11. Revise Section 1807.2.3 by replacing "1.5 in each case" with "1.5 and 2.0 respectively." 12. Revise the exception to Section 1807.2.3 by adding a sentence at the end to read: "Earthquake loads shall not be required to be considered for the design of temporary earth retention systems during construction." (Amend Coun. J. 2-19-20, p. 14473, Art. II, § 79)

Municipal Code of Chicago § 14B-18-1808 Foundations.

14B-18-1808 Foundations. The provisions of Section 1808 of IBC are adopted by reference with the following modifications: 1. Revise Section 1808.1 to read: "1808.1 General. Foundations shall be designed and constructed in accordance with Sections 1808.2 through 1808.9. Shallow foundations shall also satisfy the requirements of Section 1809. Deep foundations shall also satisfy the requirements of Section 1810." 2. Revise Section 1808.2 to read: "1808.2 Design for capacity and settlement. Foundations shall be so designed that the allowable bearing capacity of the soil is not exceeded, and that differential settlement is minimized. Foundations in areas with expansive soils or fills shall be designed in accordance with the provisions of Section 1808.6. Analysis shall consider soil layers underlying the designated load-bearing layer." 3. Add a new Section 1808.2.1 to read: "1808.2.1 Factor of safety. Foundation elements shall develop a minimum factor of safety against bearing capacity of 3.0 when routine testing is used to determine soil properties. Foundation elements shall develop a minimum factor of safety of 2.5 against bearing capacity failure when in-situ testing is used to determine soil properties." 4. Revise Section 1808.6 to read: "1808.6 Design for expansive soils or fills. Expansive soils or fills shall be removed in accordance with Section 1808.6.3." 5. Delete Section 1808.6.1. 6. Delete Section 1808.6.2. 7. Revise Section 1808.6.3 to read: "1808.6.3 Removal of expansive soil or fill. Where expansive soil or fill is removed, the soil shall be removed to a depth sufficient to ensure a constant moisture content in the remaining soil or fill. Newly placed fill material shall not contain expansive soils or fill and shall comply with Section 1804.5 or 1804.6. Exception: Expansive soil or fill need not be removed to the depth of constant moisture, provided that the confining pressure in the expansive soil or fill created by the newly placed fill material and supported structure exceeds the swell pressure." 8. Revise Section 1808.6.4 to read: "1808.6.4 Stabilization. Where the active zone of expansive soils or fill is stabilized in lieu of designing foundations in accordance with Section 1808.6.1 or 1808.6.2, the soil or fill shall be stabilized by chemical, dewatering, presaturation or equivalent techniques." 9. Delete Section 1808.7 and its subsections. 10. Delete Figure 1808.7.1. 11. Revise Table 1808.8.1 by replacing "Seismic Design Category D, E or F" with "Seismic Design Category D." 12. Revise row 4 of Table 1808.8.1 to read "4. Drilled shafts and auger cast piles." 13. Revise the second and third sentences of Section 1808.8.3 to read: "1808.8.3 Placement of concrete. Concrete shall not be placed through water unless a tremie or other approved method is used. Where placed under or in the presence of water, the concrete shall be deposited by means to ensure minimum segregation of the mix and negligible turbulence of the water." 14. Revise Section 1808.8.6 by replacing "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D"; Seismic Design Category D, E or F" with "Seismic Design Category D" and "Detached one- and two- family dwellings" with "Group R-5 occupancies." (Amend Coun. J. 2-19-20, p. 14473, Art. II, § 80)

Municipal Code of Chicago § 14B-18-1809 Shallow foundations.

14B-18-1809 Shallow foundations. The provisions of Section 1809 of IBC are adopted by reference with the following modifications: 1. Revise item 1 of Section 1809.5 to read: "1. Extending at least 42 inches (1067 mm) below final grade." 2. Revise Section 1809.6 by deleting "in an approved manner." 3. Revise the notes to Table 1809.7 by replacing "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D" and "Group R-3" with "Group R-3, R-4 and R-5." Revise the exception to Section 1809.8 by replacing "Group R-3" with "Group R-3, R-4 or R-5." 4. Revise Section 1809.10 by replacing "Seismic Design Categories D, E and F" with "Seismic Design Category D." 5. Revise Section 1809.11 by deleting "approved." 6. Delete Section 1809.12. 7. Revise Section 1809.13 by replacing "Seismic Design Category D, E or F" with "Seismic Design Category D."

Municipal Code of Chicago § 14B-18-1810 Deep foundations.

14B-18-1810 Deep foundations. 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 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. 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)

Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2666805Fetched: 10/24/2026