Editing Park Row Building (section)

=== Foundation ===
The foundations are sunken to a depth of {{Convert|34.33|ft|0|abbr=}}.<ref name="CB 1898" /><ref name="rer19001027">{{cite magazine|date=October 27, 1900|title=Towns Under a Single Roof|url=https://rerecord.library.columbia.edu/pdf_files/ldpd_7031148_026_21.pdf|journal=The Real Estate Record: Real Estate Record and Builders' Guide|volume=66|pages=532|via=[[Columbia University|columbia.edu]]|number=1702|access-date=April 24, 2022|archive-date=September 18, 2020|archive-url=https://web.archive.org/web/20200918134827/https://rerecord.library.columbia.edu/pdf_files/ldpd_7031148_026_21.pdf|url-status=live}}</ref><ref name="LC p. 427">{{harvnb|Landau|Condit|1996|ps=.|p=427}}</ref>{{efn|The LPC gives an alternate figure of {{Convert|36|ft||abbr=}}.<ref name="NYCL p. 8" />}} Underneath the subbasement level are 3,900 Georgia spruce [[Deep foundation|piles]], each {{Convert|20|ft||abbr=}} deep with a {{Convert|12|in||abbr=|adj=on}} diameter, driven into wet sand.<ref name="NYCL p. 3" /><ref name="CB 1898" /><ref name="NPS p. 10">{{harvnb|National Park Service|2005|ps=.|p=10}}</ref> The piles descend to below the [[water table]]. The underlying sand layer was removed to a depth of {{Convert|1|ft||abbr=}} above the top of the piles, and then concrete was poured into the space until it reached to the top of the piles. Afterward, [[granite]] blocks were placed above the poured concrete and a [[wikt:grillage|grillage]] of {{Convert|12|in||abbr=|adj=on}} [[I-beam]]s was laid atop the granite blocks. Each pile was capped by brick piers and a granite capstone, and the cellar floor was brought to the same depth as the granite capstones so that the grillage beams could be easily maintained.<ref name="SA p. 410" /><ref name="CB 1898" /><ref name="NYCL pp. 3-4">{{harvnb|Landmarks Preservation Commission|1999|ps=.|pp=3–4}}</ref>

The depth of the piles was influenced by the construction of Robertson's previous project at 150 Nassau Street, which used a similar technique to build the foundation, and is located two blocks northeast of the Park Row Building.<ref name="NYCL p. 3" /><ref name="EN p. 226" /><ref name="NYCL pp. 3-4" /> In the earlier project, pilings had been carried to a deeper level,<ref>{{cite magazine|date=December 1894|title=American Tract Society's 20-Story Office Building, New York City|url=https://babel.hathitrust.org/cgi/pt?id=njp.32101061104285&view=1up&seq=622|journal=Engineering News|volume=32|pages=526|access-date=April 24, 2022|archive-date=June 6, 2020|archive-url=https://web.archive.org/web/20200606202026/https://babel.hathitrust.org/cgi/pt?id=njp.32101061104285&view=1up&seq=622|url-status=live}}</ref> but the sand was highly compacted below a depth of 20 feet.<ref name="EN p. 226" /> The excavations were almost the same level as the adjacent, now-demolished [[St. Paul Building]].<ref name="LC p. 252" />

The centers of the piles were spaced {{Convert|16|in||abbr=}} apart beneath the vertical columns, and {{Convert|24|in||abbr=}} apart elsewhere.<ref name="EN p. 226" /><ref name="SA p. 410" /><ref name="CB 1898" /> The foundation pilings were intended to support a maximum weight of {{Convert|16|ST|LT t|abbr=|sp=us}}, or {{Convert|65200|ST|LT t|abbr=|sp=us}} in total.<ref name="CB 1898" /> Horizontal distributing girders were placed between the tops of the foundations and the footings of the above-ground vertical supports, ranging in length from {{Convert|8|to|47|ft|abbr=}} and in depth from {{Convert|4|to|8.5|ft|abbr=}}. This distributed the building's weight more easily, meaning that the vertical supports only bore loads of up to {{Convert|1450|ST|LT t|abbr=|sp=us}}.<ref name="EN p. 226" /><ref name="SA p. 410" /> There are several columns whose footings were isolated from the grillage; these columns are located atop short girders on a set of I-beams, which in turn rest on the grillage.<ref name="EN p. 227" /> Each section of the foundation was designed with a different cross section because the irregular lot shape precluded uniform loads.<ref name="EN pp. 226-227">{{harvnb|Engineering News|1896|ps=.|pp=226–227}}</ref><ref name="NYCL p. 4">{{harvnb|Landmarks Preservation Commission|1999|ps=.|p=4}}</ref><ref name="NPS p. 10" />