While nothing in this section requires the installation of an MH-unit to include the mechanical connection of concrete block piers, the following standards have been developed for the mechanical connection of a concrete block pier to an MH-unit and to the pier's footing.
(a) When live loads are applied to an MH-unit installed pursuant to Health and Safety Code section 18613, mechanical connection of concrete block piers shall be capable of maintaining the placement of the support system of the MH-unit to the point of the failure of either the attachment point on the MH-unit, the pier or the footing.
(1) The means of mechanical connection shall not allow the separation of the MH-unit from any pier or footing as a result of horizontal loads or vertical loads.
(2) Failure occurs when the attachment point on the MH-unit, the pier or the footing yields or fractures or is deformed to a point that threatens the health and safety of the occupants of the MH-unit.
(b) For the purposes of this section, live loads are restricted to the following:
(1) horizontal loads applied to the attachment point on the MH-unit in both directions parallel to the attachment point and in both directions perpendicular to the attachment point; and
(2) vertical loads applied to the attachment point on the MH-unit in both directions upward and downward from the point of contact between the pier footing and the ground.
(c) In order to test a device, assembly or arrangement designed to achieve mechanical connection of a concrete block pier to an MH-unit and to the pier's footing, the testing shall comply with the methods and specifications provided in this section, and the mechanical connection shall endure the testing without failure.
(d) The device, assembly or arrangement of mechanical connection of concrete block supports shall be tested in both of the following configurations:
(1) eight (8) inches by eight (8) inches by sixteen (16) inches concrete blocks shall be stacked three (3) blocks high, without wooden spacers between the blocks, upon a pressure-treated wood footing two (2) inches by twelve (12) inches by thirty (30) inches in size.
(2) eight (8) inches by eight (8) inches by sixteen (16) inches concrete blocks shall be stacked three (3) blocks high, with one (1)-inch wooden spacers between the concrete blocks, upon a pressure-treated wood footing two (2) inches by twelve (12) by thirty (30) inches in size.
(3) The concrete blocks used in the configurations shall comply with the requirements and reference standards contained in the California Building Code.
(e) A section of three (3)-inch flange by ten (10)-inch web steel “I” beam shall be used to simulate the point of attachment to the MH-unit.
(f) Two (2)-piece wooden wedges, driven together in opposition to one another and forming a thickness of not less than one (1) inch or more than two (2) inches between the topmost concrete block and the “I” beam, shall be used to simulate the typical surface bearing area between the concrete block pier support and the point of attachment to the MH-unit.
(g) The device, assembly or arrangement proposed as a means of mechanical connection for concrete block supports shall be installed in each of the configurations specified in subsection (d) and shall be subjected to the following procedures.
(1)(A) The footing shall be placed upon a level surface capable of supporting not less than one thousand five-hundred pounds (1,500) psf.
(B) The contact points between the wooden wedges and the “I” beam and between the concrete block and the footing shall be clearly marked.
(C) The “I” beam shall be raised vertically at least twelve (12) inches not less than five (5) times, without failure of the mechanical connection.
(D) Failure occurs if the points of contact of either the wooden wedges and the “I” beam or the concrete block and the footing has changed more than one (1) inch from the locations originally marked, as instructed in subsection (g)(1)(B).
(2)(A) The “I” beam shall be subjected to a constant vertical load of not less than one thousand five-hundred (1,500) psf at a point central to the concrete block pier configuration. The measurement between the level support surface and the bottom of the “I” beam shall be recorded.
(B) While maintaining the vertical load, the “I” beam shall be subjected to horizontal loads applied in both directions parallel to the “I” beam and in both directions perpendicular to the “I” beam. The mechanical connection shall withstand these forces without failure, until one or more of the concrete blocks fail to support the vertical load.
(C) Failure of one or more of the concrete blocks to support the vertical load occurs when the measurement recorded as directed in subsection (g)(2)(A) between the support surface and the bottom of the “I” beam, is decreased by one or more inches.
(D) Failure of the mechanical connection occurs if the points of contact of either the wooden wedges and the “I” beam or the concrete block and the footing have changed more than one (1) inch from the locations originally marked as instructed in subsection (g)(1)(B).
Credits
Note: Authority cited: Sections 18300, 18613 and 18613.4, Health and Safety Code. Reference: Section 18613.4, Health and Safety Code.
History
1. Renumbering of former section 1336.5 to new section 1334.2, including amendment of section and Note, filed 7-6-2004; operative 7-6-2004 pursuant to Government Code section 11343.4 (Register 2004, No. 28).
2. Amendment of subsections (d)(3). (g)(1)(A) and (g)(2)(A) filed 2-18-2011; operative 2-18-2011 pursuant to Government Code section 11343.4 (Register 2011, No. 7).
This database is current through 5/10/24 Register 2024, No. 19.
