DOB Findings and Recommendations for WTC, Feb 2003

NYC 9/11 Public Portal Document

per foot of clear wall height in either direction in the plane [5/c] of the partition. A partition may be considered substantial when that partition or a combination of such partitions, one above the I floor and one below the floor and substantially in the same plane, is able to resist the following distributed force transmitted by the floor in the plane of the partition and in an upwards or downwards direction: 0.18 5(2b—S) kip per foot of clear span ■5 where b is clear span and S is the clear spacing of partitions or the clear distance from a partition to an i- adjacent free edge of the floor. (2) A strengthened vertical portion of the wall (not exceeding 1/3 story height in the horizontal direction) which will not fail under a load of 3 kip per linear foot of clear wall height acting perpendicular to the plane of the wall in either direction along the interface between the strengthened wall portion and the portion of the wall that lost its load carrying capacity. (c) The term "nominal extent of floor"denotes the following: (1) For a floor spanning in one direction, the extent is the clear span. In the perpendicular direction the extent is to be taken as the smaller of the following: (i) The distance between adjacent "substantial" partitions arranged in the direction of floor span. (ii) The distance between a free edge and the nearest "substantial" partition arranged in the direction of the floor span. (Hi) In the case where partitions are not "substantial" the extent is to be taken as 2.25 times the clear span. (2) For a floor spanning in two directions the extent shall be taken as the area bounded by the clear spans in both directions. (ii) Specific local resistance methods. Any single element essential to the stability of the structure, together with its structural connections, shall not fail under the loads stipulated in this criterion after being subjected to a load equivalent to that caused by a uniform static pressure of 720 psf. This pressure shall be applied in the most critical manner to the face of the element and to the face of all space dividers supported by the element or attached to it within the particular story. In those cases where the stability of the element depends upon the lateral support provided by the attached space dividers, these space dividers, or a portion of these space dividers which can provide adequate lateral support, must also satisfy requirements of this paragraph.

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February 2003 WTC Building Code Task Force Page 29 Findings and Recommendations

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