Concrete Press Piles Foundation Repair: Building Code non-compliance Part 4
Here’s our Fourth installment on the series on this type of foundation repair from the building code perspective (The building code is the “Bible” of Engineers and local governments); more specifically, proving that the concrete press piles foundation repair system doesn’t work, as evidenced by not meeting the requirements of the code. For those of you who are not technically inclined, please read our simpler and summarized version, Foundation Repair.
a) What the Code Says
The International Building Code (IBC), the code required to be used in San Antonio, Austin, San Marcos, Houston, Dallas, etc and many other cities in Texas, says the following about foundations on expansive soils. Below is a portion of the code which we’ll discuss in this Part 4.
1810.1 General. Deep foundations shall be analyzed, designed, detailed and installed in accordance with Sections 1810.1 through 1810.4.
In part 3, we talked about 1810.1.4 as it relates to deep foundation methods that are not explicitly mentioned in the building code. In this part 4, we want to keep on going through the requirements outlined in 1810.1 and our next section of the building code is:
1810.2 Analysis. The analysis of deep foundations for design shall be in accordance with Sections 1810.2.1 through 1810.2.5.
From the above referenced sections of the code, we are most interested in the applicable sections 1810.2.1 and 1810.2.4, which state:
1810.2.1 Lateral support. Any soil other than fluid soil shall be deemed to afford sufficient lateral support to prevent buckling of deep foundation elements and to permit the design of the elements in accordance with accepted engineering practice and the applicable provisions of this code. Where deep foundation elements stand unbraced in air, water or fluid soils, it shall be permitted to consider them laterally supported at a point 5 feet (1524 mm) into stiff soil or 10 feet (3048 mm) into soft soil unless otherwise approved by the building official on the basis of a geotechnical investigation by a registered design professional.
1810.2.4 Lateral loads. The moments, shears and lateral deflections used for design of deep foundation elements shall be established considering the nonlinear interaction of the shaft and soil, as determined by a registered design professional. Where the ratio of the depth of embedment of the element to its least horizontal dimension is less than or equal to six, it shall be permitted to assume the element is rigid.
Before we get into why these sections of the building code are also not satisfied by the concrete press pile foundation repair method, we see these there is some terminology that needs to be explained.